<![CDATA[Zero Retries]]>https://www.zeroretries.orghttps://substackcdn.com/image/fetch/$s_!TJwk!,w_256,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F732127e1-2ce3-4ebe-8fb6-b7965f95aafd_468x468.pngZero Retrieshttps://www.zeroretries.orgSubstackTue, 13 Oct 2026 18:56:55 GMT<![CDATA[Zero Retries 0265]]>https://www.zeroretries.org/p/zero-retries-0265https://www.zeroretries.org/p/zero-retries-0265Sat, 10 Oct 2026 06:00:14 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its sixth year of publication, with 3600+ subscribers.

Zero Retries Digital Conference 2026 is October 16th in San Ramon, CA
www.zeroretries.org/p/conference

Steve Stroh N8GNJ, Editor

steve@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

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In This Issue:

I-Frame

ZRDC 2026 Update 10/09/2026
By Tina Stroh KD7WSF

What’s New at Digital Library of Amateur Radio & Communications — October 2026
By Kay Savetz K6KJN

ZR > BEACON

Request To Send

Closing Thanks

Founding Members Who Generously Support Zero Retries

The Usual Administrivia

Comments on This Issue (Redirects to Comments Page)

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

Optional Paid Subscriptions, and especially Founding Member subscriptions to Zero Retries not only help offset various expenses incurred in publishing Zero Retries, but also are a large portion of the “seed capital” that is needed to host Zero Retries Digital Conference (ZRDC) 2026, and future ZRDCs. Thank You!

My thanks to Prefers To Remain Anonymous 49 for renewing (3 years!) as an Annual Paid Subscriber to Zero Retries this past week!

My thanks to Prefers To Remain Anonymous 99 for renewing as an Annual Paid Subscriber to Zero Retries this past week!

My thanks to Prefers To Remain Anonymous 138 for upgrading from a free subscriber to Zero Retries to an Annual Paid Subscriber in the past two weeks!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Zero Retries 0266 Won’t Have Much ZRDC 2026 Content

Next Friday (usual publication day) will be ZRDC 2026, and that evening will be devoted to interesting conversations post-ZRDC. I could attempt to push that issue off until Saturday, but by now I know better that booth duty at the Zero Retries table at Pacificon, and the usual unknown-in-advance, but-they-always-happen fascinating conversations and discoveries that will consume the entire day on Saturday.

I plan to push out Zero Retries 0266 next week, but it’ll probably be completed by Wednesday and queued up for auto-publish on Friday, and probably a bit lighter than issues have been of late. At least you’ll probably receive it at my stated (but often missed, lately) publication time of 15:30 Pacific on Fridays.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0265. Paid subscribers can comment directly on the web version of this issue.

ZRDC 2026 Update 10/09/2026

By Tina Stroh KD7WSF

This is the seventh in a series of updates leading up to Zero Retries Digital Conference 2026. ZRDC 2026 starts in ONE WEEK!

This is my last column in the series prior to ZRDC 2026. Next Friday, 10/16/2026 it’s show time and I think we are ready! As I am writing this, I am currently at Les Schwab getting the car fine-tuned for the trip South. Our hallway outside the garage door is filled with boxes to bring both for the conference and Pacificon. My dining room table is covered with all the items to go into the goody bags for the in-person attendees. I think we are all set, except for one thing, more attendees!

The venue, The Roundhouse, and our event coordinator Shelby have been gracious and allowed me additional time to call in the final numbers. Because of this, I have been able to extend the general admission ticket price for another week, instead of having to charge the late fee the venue imposes.

The absolute deadline with the general admission ticket will be 10/12/2026.

After that, the late fee must apply. Unfortunately, also after that date, I cannot guarantee breakfast either. However, since Steve and I are hosting the breakfast, I have padded the numbers so that everyone can have a good start to the day. Coffee, tea, infused water and sodas will be available all day for attendees. After the last speaker and we have closed the conference, I will try to locate a place where everyone can continue talking. I think that was one of the highlights of last year’s conference. Steve and I hosted a pizza party across the street from the venue at a great pizzeria. Everyone continued to talk, eat and drink but best of all, have a good time. The downside was that we all had to leave by 9 PM and some had to travel home. It seems rare to find opportunities for hams to get together and just talk about their passions and Amateur Radio with friends and colleagues. Steve received a very nice note from Cale Mooth, K4HCK who notes that he always enjoys the opportunity to speak, whether it’s a local meet-up or the radio club, and is looking forward to speaking at ZRDC. It will be interesting to hear Cale’s perspective of the Techie Ham. Cale will also participate in the panel discussion regarding encryption. My hope, as the conference manager, is to create this opportunity for like minds to come together what I have determined is needed.

Along the same line, Steve and I received a shout out from Peter Marks, VK3TPM who posted in FreeDV News on 10/3/2026, “the excellent Zero Retries Newsletter often covers FreeDV and this week is no exception” and ended his post with “thanks Steve and Tina for your excellent ongoing coverage of Amateur Radio”. So guess what? One of the co-experts regarding FreeDV, Mooneer Salem, K6AQ is one of the featured speakers at ZRDC 2026. Not interested in FreeDV, what about digital voice systems or operating digital modes using a smartphone instead of the traditional keyboard? Jeff Scoville, AE5ME and Craig Lamparter, KM6LYW have presentations geared up for you. Our goal of the ZRDC is to bring to life what you read about in Zero Retries by the people who are actually doing the work. Hear first hand from the experts and ask your questions. There are not many opportunities like this. We sincerely thank Peter for his comments because its comments like this that keep us going.

In closing, if you have not registered for ZRDC 2026, I would urge you to do as soon as possible. I have placed the links below for your convenience. The website has been updated with the list of speakers and their bios plus the schedule of the conference. Please remember, if you are unable to attend in-person, there is the option of attending via Zoom and for you to receive the proceedings in advance of the release date. If you have a logistical matters or concerns, please don’t hesitate to contact me. I am here to help!

See you all next Friday in San Ramon! Safe travels everyone.

Zero Retries Digital Conference 2026 Registration - Click Here

Zero Retries Digital Conference 2026 page

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0265. Paid subscribers can comment directly on the web version of this issue.

What’s New at Digital Library of Amateur Radio & Communications — October 2026

By Kay Savetz K6KJN

It’s fall, the season for pumpkin lattes and stocking up on candy that’s allegedly for the kids on Halloween, but I might have to “quality test” some of it in the weeks leading up to the holiday. I bet you didn’t know that it’s also the season for finding amazing forgotten ham radio newsletters and adding them to DLARC. This work is fueled by candy and pumpkin lattes.

But first off, DLARC has a new Automatic Packet Reporting System collection, with hundreds of items supplied by the APRS Foundation (which, I might add, has the generous policy of “web materials are freely available to the public unless specifically marked otherwise.”) A big part of the APRS material is the Bob Bruninga APRS documents sub-collection. Bob WB4APR created APRS: this collection includes 15 of Bob’s PowerPoint decks from 2007–2019, APRSdos documentation and technical notes, protocol-development notes, network design and operating material, and more.

So excited for this: We added 171 episodes of Glenn Hauser’s World of Radio show, bringing the number of episodes in DLARC to 1,534. Glenn has been covering shortwave news in World of Radio since 1980 (I still hope to find those earliest recordings) and amazingly, he’s still at it every week. These newly found episodes are some of the oldest episodes in the collection: the earliest is show number 115, which aired April 11, 1982. Some of the topics: Free Voice of Iran was transmitting coded messages, and in the US, the FCC conducted a crackdown on illegal shortwave broadcasts aimed at Cuba. Every one of these shows is an exciting time capsule of radio history: I pick them at random to listen in the background and end up 100% engaged with Glenn’s news every single time. The newly added recordings come from Shortwave Radio Archive, cut from much longer shortwave recordings on Internet Archive, and dark corners of dusty web sites.

Equally excited for this: DLARC has recovered more lost scripts of Amateur Radio Newsline: 103 scripts in all covering 1993 through 2009. Newsline is a weekly audio news bulletin of interest to radio amateurs. They’ve been at it since 1977. (The top story for the May 15, 1993 episode: the FCC proposes more restrictive rules for RF exposure. “Very important to most hams is that hand-held devices such as portable cellular phone, handie-talkies and the like are for the first time covered.”)

We’ve digitized two dozen more old videos from Bob Cooper’s estate: these are from PAL-format VHS tapes. Bob was an expert in satellite television who gave seminars, wrote books, and published magazines about all sorts of communications topics. These new additions (bringing the count of videos from Bob’s estate to more than 275) include talks from the 1997 Satellite and Cable Show, a 1981 panel on satellite antenna technology, and a circa 1979 discussion about RF amplifiers. Bob’s Satellite Magazine episodes are a fever dream that switches between informative technical content and a late-night community access television vibe. Very entertaining. Oh, and 23 minutes of raw footage of Arthur C. Clarke at his home in Sri Lanka. He discusses his 1945 communications-satellite proposal, the growth of satellite TV and the internet, 2001: A Space Odyssey, and the possibility of life on Mars.

New Newsletter Collections

So there’s a new service called Usenet Rewind: it’s a research archive dedicated to Usenet newsgroup posts from 1981 to the present. The folks at the service generously gave DLARC access, and I’ve been doing deep searches to find even more early e-newsletters about amateur radio, shortwave, and related topics. And boy, has it delivered, finding plenty of great material in addition to what Internet Archive’s own Usenet archive has brought us in the past few months. New newsletter collections added to DLARC, in part thanks to Usenet Rewind:

  • The Four Winds On Line: this was an e-mail-based shortwave DX newsletter edited by Giovanni Serra in Rome, Italy. Each issue includes shortwave logs, QSL reports, listener-submitted station news, and other DX bulletins from around the world. The collection includes 54 complete issues from December 1996 to October 1999. Issue 42 dated November 10, 1997 reports on pirate station RFL and its four-hour “Day of the Dead” Halloween special: music by artists “who are no longer with us” and records about death.

  • Hailing from about the same time period but from Melbourne, Australia, Electronic DX Press was an e-mail-based shortwave broadcasting newsletter compiled by Bob Padula OAM. It focused on broadcasting to and from Australia, Asia, the Pacific and the Indian subcontinent. DLARC has 64 editions from October 1997 to October 1999 plus a special 11 MHz Spectrum Study publication.

  • 166 issues of DX Hotline, which was the shortwave broadcasting news and schedules section of the Benelux DX-Club bulletin, edited by Jan Nieuwenhuis on the island of Texel in the Netherlands. The earliest editions — we have them back to 1993 — were text-only (DLARC made easy-to-read PDFs as usual). By 2001 Hotline was distributed natively as PDFs, so we have 2001-2006 in that format.

  • We added more than 1,000(!) issues of the DARC DX Newsletter (DXNL), the English-language edition of the weekly bulletin of the Deutscher Amateur-Radio-Club’s DX Committee. It reports planned and current amateur-radio DX activity, DXpeditions, IOTA operations, contest dates, and QSL information. We’ve found issues from 1996 through the present. From the December 16, 1996 issue: two Japanese hams introduced North Koreans to amateur radio during a friendship mission, and North Koreans seemed interested in organizing their own on-air activity.

  • 850 issues of California OES RACES and EMCOMM Bulletins. RACES Bulletin was published by the California Governor’s Office of Emergency Services to provide training, policy, and operational information for Radio Amateur Civil Emergency Service volunteers and government emergency communications personnel. In 1996 it was succeeded by the EMCOMM Bulletin, which continued through March 2003. This collection includes the closely related RACES and EMCOMM bulletin series, from 1985 through 2003.

Filling in the Gaps

In addition to adding those new newsletter collections, we’ve managed to fill in gaps in existing collections, making the library a little more complete.

  • We grew our collection of Gateway, the ARRL’s defunct packet-radio newsletter. DLARC already had 112 scanned issues of their paper publication. This Usenet hunt revealed that they also published an electronic version, so we’ve added 13 issues, filling in gaps from 1985. The November 11, 1985 issue reports that AMSAT and the ARRL had just proposed a packet-radio experiment, SAREX II, to include a modified TAPR TNC-2, a 2-meter HT and a laptop. (That shuttle mission would be cancelled after the Challenger disaster a few months later.)

  • 36 newly found issues of Radio H.F. Internet Newsletter, bringing that collection to 261 issues. It was a monthly electronic publication edited by Sheldon Harvey VE2SHW of Radio H.F. in Quebec, Canada, with annotated resources regarding shortwave listening, amateur radio, and scanning.

  • We also filled in gaps in AMSAT Satellite Report, with more than two dozen issues of the satellite operational status updates. We now have 460 issues spanning 2002 to 2013.

  • If you’re hungry for obsolete RTTY and teleprinter news (who isn’t, amiright?), we added about a dozen more issues of the Australian National Amateur Radio Teleprinter Society RTTY Bulletin, covering 1983-1985.

  • And as usual, a smattering of other newsletters landed in the Miscellaneous Amateur Radio Newsletters collection, including Youthnet News, UKW/TV-Nachrichten (in German), AM/FM (News from the UK Radio Industry), and 7415 Internet Pirate Radio Listeners.

More Tidbits

50 scripts of broadcasts of Radio World, from Radio Vlaanderen Internationaal. Radio World was the English-language shortwave and international-broadcasting program of Radio Vlaanderen Internationaal, a service of Belgium’s Flemish public broadcaster BRTN. The program reported on international broadcasting, shortwave reception, station schedules, radio technology, and media developments. This (incomplete) collection preserves surviving program scripts and official web transcripts from 1993 through 2005.

229 scripts/reports from Sweden Calling DXers (later called MediaScan), Radio Sweden’s bulletin covering international broadcasting, shortwave listening, DXing, satellites, and developments in global electronic media.

We’ve also added 328 issues of Ham Radio Online, an early web magazine devoted to amateur radio. Published from 1995-2000 by Ed Mitchell KF7VY and Kim Anderson-Mitchell N7VPL, the digital magazine covered packet radio, APRS, satellites, amateur television, emcomm, shortwave listening, and the growing connection between radio and the Internet. This was originally a web site, long gone but recovered from the Wayback Machine, which DLARC converted to PDFs for easier reading.

We’ve also added 35 episodes of Jerry Taylor KD0BIK’s Practical Amateur Radio Podcast spanning 2010-2016: some full audio, some transcripts only, and others lost.

In the Collegiate Amateur Radio collection, we’ve added a nice little collection of amateur radio activities at Milwaukee School of Engineering, which includes items from their amateur radio club W9HHX and its predecessors: QSL cards, bulletins, news clippings, and a 1963 RTTY image of John F. Kennedy, prepared by members of the club shortly after the assassination of JFK.

Newsbytes News Network

One more thing, if you’ll permit me a paragraph to talk about a personal project: I built an unofficial fan archive of Newsbytes News Network articles. Newsbytes was a sort of “Associated Press for tech-information junkies” documenting the formative years of personal computing, online services, telecommunications, and the Internet from 1983 to 2002. The archive has pretty much every article they published, well over 150,000 stories. There’s a good amount of radio and communications content there: look up Wayne Green, amateur radio, Morse code, packet radio, or FCC for copious amounts of news written as it happened.

Maybe I’ll see you at the Internet Archive’s annual celebration on October 21? The theme will be “Democracy’s Library: Tools for Participation”. If you find me we can share a pumpkin latte. But I’m not sharing any of my Halloween candy stash.

Digital Library of Amateur Radio & Communications is funded by a generous grant from Amateur Radio Digital Communications (ARDC) to create a free digital library for the radio community, researchers, educators, and students. If you have questions about the project or material to contribute, contact me at kay@archive.org.

Editor’s Postscript

If you enjoy “drinking from a firehose” and you have a good RSS reader app, you can follow along as new stuff is added to DLARC - http://archive.org/services/collection-rss.php?collection=dlarc. If you’re a Mac user, I highly recommend NetNewWire which has vastly improved my usage of RSS.

I’m also personally delighted to see Ham Radio Online by Ed Mitchell KF7VY appear on DLARC. KF7VY is an old friend and packet radio collaborator when we both lived in the Seattle area, and it’s really cool to see these items re-emerge into public on DLARC.

KF7VY’s HRO blog inspired me to get into blogging. KF7VH “strongly encouraged me” to do so when I began commenting a little too often about “things he left out” on HRO posts.

I’m also delighted to learn about K6KJN’s passion for Newsbytes News Network - I remember that very well and I’m delighted it’s now part of DLARC. I also stumbled into Usenet Rewind, typed in my callsign… and immediately turned away for fear of losing an entire day to nostalgia for when Usenet was the new hotness.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0265. Paid subscribers can comment directly on the web version of this issue.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

Breaking - RadioMail 2.0 is Here

Georges Auberger WH6AZ via email:

After many months of development, testing, and feedback from the TestFlight community, RadioMail 2.0 is available on the App Store.

This isn’t RadioMail 1.x with a fresh coat of paint. RadioMail 2.0 is a completely new application, built from the ground up around everything I’ve learned over the past few years.

The goal remains the same: build the best Winlink app for portable operating on iPhone and iPad (and even Mac).

What’s new

  • Automatic send and receive over Wi-Fi or cellular, with messages queued for your next radio session if you prefer

  • Built-in Packet and ARDOP modems

  • Native IC-705 radio support

  • Simplified device management and switching

  • Best Path propagation prediction to help select a station

  • Incoming peer-to-peer connections over Packet and ARDOP

  • Three-column interface for iPad

  • Message sync across iPhone, iPad, and Mac

  • Better mailbox management with search, smart mailboxes, and flags

  • Improved Winlink Forms, including experimental form reflow for easier use on an iPhone in portrait orientation

RadioMail 2.0 is free to download and includes a 30-day trial, so you have time to explore the app, confirm that it works with your equipment, and decide if it’s right for you.

After the trial, a subscription or one-time purchase is required to continue sending and receiving messages. You’ll always retain access to the messages already stored in the app.

A note about the Mac

RadioMail 2.0 also runs on Apple Silicon Macs. It works well, but it’s still an iPad app, so expect a few Mac quirks. RadioMail is built for portable operation, and now that MacWinlink exists, I don’t plan to expand it to support shack equipment like USB devices or local modem software. If that’s what you need, MacWinlink is likely the better fit. If you operate portable from an iPhone or iPad and want your full mailbox on the Mac back in the shack, RadioMail fits that workflow.

This was notable - talk about a real stress test of your app for emergency communications:

PS: This release took longer than I planned. Right before launch, Hurricane Lowell hit Kauaʻi and left me without power, water, or internet for 12 days. Then App Store review took much longer than usual, likely from the iOS 27 launch rush. You can read my field notes on what I learned from the hurricane.

I think it’s incredibly gracious… but normal for WH6AZ, to acknowledge the existence of MacWinlink, which isn’t his app.

If the rumored touchscreen Mac laptop emerges later this month, it will be an interesting tossup between RadioMail 2.0 and MacWinlink on a Mac laptop. RadioMail 2.0 running on a Mac is already “native touchscreen”.

Modern apps for Amateur Radio with well-thought-out user interfaces like what WH6AZ has become known for are breathing new life into Amateur Radio data communications. Such modern apps make Amateur Radio systems like Winlink much more approachable and usable than with older apps that are a bit clunky in comparison (but fully functional).

Breaking - One Radio Modem to Rule Them All!

Craig Lamparter KM6LYW:

Let’s run Modem73 on two Pi’s and communicate over Ham radio using TCP/IP, AX.25 and Web. Modem73 is among the new open-source modems implementing “OFDM” encodings getting us (relatively) high-speed networking with packet radio. Modem73 supports OFDM/Robust/MFSK, which, in this case was transmitting QAM16 at 3.6Kb/s using off-the-shelf radios - TIDRadio H9 and Yaesu FTM400. Modem73 supports both HF and VHF, so we could possibly see this as an alternative VARAHF for Winlink Email on HF and local AX25/IP networks on VHF.

Modem73 is supported on MacOS, Windows, Linux and Android.

https://modem73.app/

https://modem73.app/quickstart.html

https://github.com/RFnexus/modem73

https://digipi.org/

I first mentioned Modem73 in Zero Retries 0258 back in July - Modem731. Since then I’ve seen a number of mentions, and now that KM6LYW has integrated it into DigiPi, it’s going to be mainstream. I also saw a mention that’s its experimentally being added to JNOS.

I can’t wait to hear KM6LYW’s presentation at ZRDC 2026. I’m sure he’ll work in mention of Modem73 as well as Mercury now being additional modes available in DigiPi.

As I also said in Zero Retries 0258, 2026 really is turning out to be the year of widespread OFDM implementation in Amateur Radio.

Livestream - 2026 AMSAT Space Symposium & Annual General Meeting

AMSAT is apparently livestreaming its annual conference on Friday 2026-09-09 (publication day) and Saturday 2026-09-10. I had to pass on watching on Friday, but I’m going to try to catch some of it on Saturday.

G7JJF APRS Client

Bob Stephens AF9W on several email lists:

There is a new Android APRS app available that I really like. The cool part is that it works with Android Auto and you can see stations on your truck or car screen. It works great with my new Kenwood D750A and with my old Kenwood D710 except that the D750A connects using Bluetooth SPP.

If interested, check out https://www.g7jjf.com/aprs-client.html. This site describes features, has a link to the user manual, and a form to sign up as a beta tester. We need some additional beta testers to get Google to allow the app on the Play Store.

Unfortunately, there is no Apple version yet.

PS I have no connection with this app except as a happy user.

APRS Connect is Now on iPhone

Amateur Radio Daily for October 4, 2026:

The following is a message from APRS Connect:

APRS Connect, the messaging-first APRS client that launched on Android in August, is now on the App Store for iPhone (iOS 16.4 or later). It is free to install and use over APRS-IS. Connecting a radio and several advanced features are part of APRS Connect Pro, a subscription with a 7-day free trial.

APRS OTA, the on-the-air activity that runs entirely over APRS, has its own screens in the app, so you tap buttons instead of typing bot commands. Hosts go on the air in one tap. Each chaser’s call arrives with their message, where they are and a Confirm button. A bar across the top shows QSOs, points and time left, with buttons to stay longer or message every chaser at once. A live map shows you and your chasers and adds up how far your contacts have reached. Chasers get the list of hosts on the air, tap one to call, and watch each step through to the host’s QSL. Every op is saved with its map and scores and can be shared as a picture. Chasing works over APRS-IS, free. Hosting needs a radio, as APRS OTA’s rules require.

The other services on APRS get the same treatment, a guided screen instead of a command to memorize: weather, the repeater finder, WHO-IS, the SMS, email and Winlink gateways, and APSPOT and APRS2SOTA self-spotting. #APRSThursday and other ANSRVR groups open as a single net room.

On iPhone the app connects to KISS TNCs over Bluetooth LE or TCP. It can also work through a radio’s speaker and mic, using the built-in AFSK 1200 audio modem with VOX keying. Radios with a Bluetooth LE KISS TNC built in, such as the BTECH UV-Pro, connect directly.

Several things have been added since the app was first covered here:

  • The phone can be an IGate. It passes what your radio hears to APRS-IS and, if you choose, sends messages from the internet back out on the air for stations nearby. It can also be a digipeater that stays quiet when another digipeater has already repeated the packet.

  • A coverage map shows the places your beacons were picked up by a digipeater.

  • Pinned stations, a grid square screen, and the ISS on the map.

  • A setting chooses how messages go out: radio first, APRS-IS first, one link only, or every channel at once.

  • An optional account keeps messages, pinned stations and settings the same on every device. When two devices share a callsign and SSID, only one of them beacons, acks, and digipeats at a time.

  • A “Rest of the world” map layer shows stations heard anywhere on APRS-IS, not only the ones your device heard.

  • The app is more accessible for operators who use VoiceOver and TalkBack. Every button has a spoken name, and an open conversation reads new messages aloud.

The newest of these are on iPhone now and reach Android with its next Play release.

More at https://aprsconnect.com, and on APRS OTA in the app at https://aprsconnect.com/ota. Download the App: https://aprsconnect.com/get/89x5bv.

See the earlier Amateur Radio Daily story on the launch of the Android version.

Speaking of APRS apps on mobile devices, equal time for iDevices!

Simple JTTY App for MacOS

Peter Marks VK3TPM on his blog marxy’s musing on technology:

The JTTY application I made for Linux uses the QT6 framework. I could have built this for macOS but thought it would hurt my eyes so I’ve made a native macOS version.

There’s a page for it here and the source code is available here.

It does depend on hamlib for rig control. I install it with homebrew. At the moment this is left as an exercise for the reader - as they say.

Macs, thanks to developers like VK3TPM are rapidly becoming “first-class citizens” in Amateur Radio!

Utah Digital Communications Conference Call For Proposals

Email from Utah DCC:

Presenter proposals are now open for the 10th Annual Utah Digital Communications Conference, happening on Saturday, February 27, 2027, in Sandy, Utah.

We’re looking for a variety of presentations for this year’s conference, from technical topics to general amateur radio interests. If you’d like to present, please submit your proposal using the link below. Every year, we plan for a good mix of topics, including new technology for our advanced members and introductory sessions for those new to the hobby. Here are a few topic ideas, but we’re open to any amateur radio-related subject.

  • Digital Communications (D-STAR, DMR, System Fusion, hotspot), etc.

  • Software-Defined Radio’s

  • Emergency Communications/Preparedness

  • Repeater systems technology

  • POTA/SOTA and other Field Operations

  • Networking and Home Automation

  • Meshcore/Meshtastic

  • Computer Security and Amateur Radio Software

  • Satellite Communications

  • Field Day (setup, strategy, logging)

  • Interconnected/linked systems

  • Emerging technology and research

Please help us spread the word by sharing this email with your friends and club members throughout the Intermountain West. Since our email list and social media reach are limited, sharing within your local networks is the best way to spread the word. The Utah DCC conference is Utah’s longest-running educational event, and with your support, it can keep growing. We invite you to get involved by presenting, volunteering, attending, or simply sharing this information. We’re excited for great presentations and hope to see you in 2027.

Call For Proposals Form

In my opinion, Amateur Radio cannot have enough Digital Communications Conferences! Kudos for UDCC for doing their DCC for a decade!

Utah DCC 2027 might be doable for Tina and me to attend. More info at their website.

Glissando - Chirp-based Weak-signal Text Chat Mode

Jeff Baitis AG7EW on the Mount Baker Amateur Radio Club’s Digital email list:

I’ve been working on a chirp-based weak-signal text chat mode called Glissando, and the first beta is out. I’m looking for a few stations willing to try it on the air.

I wanted a mode that’s pleasant to hear, even when stations double, without giving up weak-signal performance. Every symbol is a glide (a chirp) from one note to the next, then a short held note. The data *is* the melody, rendered in pentatonic (or tritone!) scales.

Planned QSO party Monday, October 5 at 2200 UTC.

The app consists of a Linux desktop console with a waterfall that captions decoded text right on the trace, a chat window, Hamlib rig control (I run an IC-7100), and a 180 s transmit timeout that releases the radio between frames on the slow gears. It’s styled after a 1950s sci-fi serial control room, because why not.

It’s open source (modem MIT, app LGPL since it started life as a fork of freedv-gui). Windows and Mac aren’t packaged yet, and it’s a beta, so expect rough edges. Bug reports, on-air signal reports, and comments are all welcome.

It’s cool that AG7EW is in my corner of the world - Lynden (Bellingham area) Washington, USA. AG7EW’s QRZ page is worth a look.

A Media Guide to Amateur Radio

Dan Romanchik KB6NU on his blog:

I don’t know about you, but I always get a little upset when I read an article about amateur radio in a newspaper or general-interest magazine. For one thing, they almost always get the terminology wrong. For example, they often say that radio amateurs “broadcast” instead of “transmit.” Broadcasts, as you all know, are transmissions meant for the general public, and radio amateurs are specifically prohibited from making those kinds of transmissions. These aren’t egregious errors, but as a former writer and editor, they annoy me.

Whenever I would come across something like this, I would try to contact the reporter and explain how they misused a term or didn’t quite get things right. I came to realize that what we needed, however, was something more comprehensive. What we needed was a guide that explained to the media a little bit about our hobby and some of the terminology that we use. A Field Day article in our local online newspaper was the final straw. After reading this article, I knew that I had to do something. The result you see below.

I’ve sent this guide to all of the ARRL directors, section managers, and PIOs that I can find. I’m also going to send this to news outlets and reporters that write about amateur radio. If you know of any other people/organizations I should send this to, please let me know. Or, you can do it. Download the PDF and send it to whoever you think should get it.

This is a genius idea! I have no quibbles about what KB6NU included and the great deal that he left out. The goal of this is to be read, so shorter and “higher level” is better.

But beyond the KB6NU version of Media Guide to Amateur Radio, I think every organization should create their own Media Guide to Amateur Radio that reflects their perspective of Amateur Radio. For example, AMSAT, FlexRadio, HamSCI, TAPR, Winlink, Winter Field Day, and Zero Retries all have their own “perspective” on Amateur Radio with points they want to emphasize to media for better understanding of what their organization does within (the bigger picture) of Amateur Radio.

MeshTransfer and MeshTransfer Mailbox for Meshtastic

From Steffen Heuel DO5DSH via email:

I’ve created a file transfer app for Meshtastic, that I call MeshTransfer. I thought it might be of interest to your awesome Zero Retries channel.

URL:
https://localino.net/meshtransfer/

It’s working with LoRa and the Meshtastic stack.

MeshTransfer Mailbox is an optional addition to MeshTransfer. Mailbox is firmware on a small ESP32 with its own web interface. With Mailbox, the apps connect to it instead of to the radio. It is optional: without it, your phone connects to the radio as usual.

The Mailbox for ESP32 and low-speed app are free to use.

Only when people really want to transmit bigger data I am asking for a license (this small step will hopefully keep spam out of the network).

I have some testers around and appreciate any feedback on this!

I mentioned to DO5DSH that in the US, MeshCore seems to be becoming more popular, at least in Amateur Radio, because MeshCore is more “structured” than Meshtastic because repeaters in MeshCore are “deliberate” instead of “every node is a repeater”. DO5DSH agreed that it’s likely he will port MeshTransfer and Mailbox to MeshCore:

I have been playing around with MeshCore as well. The payload is about half the size of Meshtastic, but it’s straightforward to create a version also for MeshCore as the protocol was designed very modular. To my mind also MeshCore would benefit from a Mailbox to let the mobile app do the processing of coding, that lets the ESP32 space for reception and storage. Also, as data / voice transfer is transmitted in any way relatively slow to keep the network stable.

I clarified with DO5DSH that on the MeshTransfer page, for running the Mailbox, the specified unit is an ESP32-CAM, but the -CAM variant isn’t necessary. It’s intended to be used on any ESP32 unit that has BLE / Wi-Fi connectivity and a MicroSD card slot.

It’s cool that file transfers are now available with Meshtastic (and potentially, MeshCore) thanks to DO5DSH.

Update on NPR Next Generation (NPR-NG)

From Steffen Heuel DO5DSH via email:

Things are moving forward on New Packet Radio - Next Generation. We’re continuing our investigation on cheaper commercial power amps and measuring their EVMs when transmitting our OFDM signals. Therefore we implemented and 802.11ah stack that can process IQ data measured with an R&S spectrum analyser. A known frame is transmitted and demodulated to measure EVM. Some 70cm amps show good results even though efficiency is low. Unfortunately we cannot pre-distort IQ.

If there is someone in the network willing to contribute, we are happy to receive input.

I put DO5DSH in touch with Martin Alcock VE6VH of the IP400 Project.

For more context on the NPR-NG project see Zero Retries 0258 - What’s New with New Packet Radio, Next Generation (NPR-NG)?

GOGUFW Messenger: Turn a $25 Quansheng UV-K1 Into a Radio-to-Radio Text Messenger

Piju 9M2PJU on hamradio.my:

GOGUFW Messenger display on a Quansheng UV-K1 portable radio
Image courtesy of Piju 9M2PJU / hamradio.my

GOGUFW Messenger is a free custom firmware for the Quansheng UV-K1 and UV-K5 V3 handheld transceivers that adds direct radio-to-radio short text messaging over FSK alongside full analog voice operation.

The project lives at Gogu-Qs/GOGUFW-UV-K1-Messenger on GitHub. Current stable is GOGUFW 2.3.0, released 25 September 2026, built on the F4HWN 6.0.0 Fusion base with multiboot support. At the time of writing the repository holds around 42 stars, 5 forks, and close to 1,938 commits inherited through its fork history from the wider Quansheng custom firmware family.

What makes it different from every other Quansheng mod is the sidecar Messenger. Two compatible handhelds can exchange 36-character text messages directly over RF with delivery acknowledgements, retries, reply and resend controls, duplicate protection, and callsign addressing. No phone, no Bluetooth, no digipeater, no internet, and no infrastructure of any kind is required. Normal analog FM voice keeps working in parallel. So the radio remains a usable handheld first and a text terminal second.

…

That… is pretty Zero Retries Interesting! The user documentation on the referenced GitHub page seems quite complete.

My thanks to Amateur Radio Weekly Issue 441 October 3, 2026 for bringing this development to my attention for inclusion in Zero Retries.

FernSDR: An Open-Source WebSDR Server

RTL-SDR.com:

Thank you to ‘magicint1337’ for writing in and sharing with us a new program he’s created called FernSDR. The author writes that FernSDR is an open-source WebSDR server rebuilt from scratch, based on feedback from WebSDR operators. It replaces his two previous programs, NovaSDR and PhantomSDR, the latter of which we covered in 2024.

A WebSDR program like FernSDR allows users to set up an SDR receiver on a remote device, such as a Raspberry Pi or PC, and access that SDR’s data from anywhere in the world via a network connection. The author explains why FernSDR stands out:

What’s different: a single binary with no dependencies and a one-line install on any Linux, an admin panel for everything (bands, updates with rollback, modules), day/night band switching by sunrise at the station, and modules for RTL-SDR (incl. Blog V4), RX-888 MkII and SDRplay, plus an FT8 decoder with PSK Reporter spots. In my lab tests against ten other WebSDR servers it had the lowest delay and memory use; the method and raw data are public.

A live demo of FernSDR is available at demo.fernsdr.org. The code is open-source and available on GitHub.

FernSDR: A New WebSDR Server
FernSDR: A New WebSDR Server

These are additional time sink rabbit holes interesting articles mentioned at the bottom of this article:

Related Posts:

  1. No-SDR: A New Open Source Multi-User WebSDR for RTL-SDR

  2. SDR-Server: An Advanced Open Source RTL-SDR Streaming Server

  3. Ground Station: An Open Source SDR Orchestration Platform for Satellite Tracking and Decoding

  4. DSD (Open Source) with dPMR Decoding and Windows Binaries Released

  5. NyanSat: A Low Cost Open Source Satellite Ground Station

I’m still getting my RSS feeds under control, so I’m behind on RTL-SDR.com. Thus, My thanks to Tom Salzer KJ7T in EtherHam - Weekly Report: October 8, 2026 for mentioning this development for inclusion in Zero Retries.

Geekworm UPS Scap 5V5A – A Supercapacitor UPS HAT for Raspberry Pi 5

Debashis Das on CNX Software - Embedded Systems News:

Geekworm, in collaboration with Mcuzone, has launched the UPS Scap 5V5A, a new supercapacitor UPS HAT for the Raspberry Pi 5 designed to keep the Raspberry Pi running long enough (a few seconds to a few minutes) to save data and shut down safely, rather than provide hours of backup power.

Available in 100F, 60F, and 22F versions, the HAT has a built-in PD chip that negotiates a true 5V/5A output. This gives the Raspberry Pi 5 enough power to run properly without triggering the low-voltage warnings that can happen with some power supplies. The module connects to the Raspberry Pi 5 through pogo pins to detect power loss and supports I2C for checking voltage and current in real time. It also features dual independent power inputs, so you can power it with either a wide-voltage DC barrel jack or a standard USB-C PD charger.

Geekworm’s Raspberry Pi 5 supercapacitor UPS HAT

…

Using a supercapacitor(s) Uninterruptible Power Supply (bridge) for dealing with brief power bumps before “bigger” (and usually slower) UPS units to kick in, for Raspberry Pi (5) systems, makes a huge amount of sense to me.

One huge “win” with a supercapacitor is that it’s not lithium-anything.

This was yet another thing I otherwise wouldn’t have seen (in the near term) if it weren’t for a mention by KJ7T this week.

ARRL 2025 Annual Report - a Few Zero Retries Interesting Excerpts

I commend ARRL for highlighting the role of Jeffrey Goldman K3DUA and his (apparently significant) donation (pages 6 and 7):

His major gift to ARRL has made possible something truly special: an entire week of the ARRL Teachers Institute on Wireless Technology named in his honor—the Jeffrey B. Goldman, K3DUA, Teachers Institute Week. Held in August 2025 at ARRL Headquarters in Newington, Connecticut, this session brought together 13 dedicated educators from across the United States.

The Teachers Institute is one of the most commendable, and forward-looking programs that the ARRL has developed in the past decade. It’s one of my touchstones that the ARRL is working for the future of Amateur Radio.

Also highlighted in this section (pages 8 and 9) was one of my personal heroes in Amateur Radio (and a Founding Member supporting Zero Retries), Phil Karn KA9Q:

Phil Karn, KA9Q: A Visionary Engineer and Generous Steward of Amateur Radio’s Future

Phil’s technical contributions to amateur radio are legendary. He co-founded AMPRnet and developed the KA9Q NOS (Network Operating System), an early open-source TCP/IP implementation for packet radio that enabled robust networking over radio links. This pioneering work helped bridge amateur radio with modern digital communications. He also advanced protocols like MACA for collision avoidance, error correcting codes for satellites, and more.

This was powerful:

Phil’s own words echo a powerful call to action: “The world is easier to change than you might think, but it takes time and persistence…

Even if you don’t have much time for ham radio when you are busy with your career, try to stay connected with other hams. Encourage your friends and family to become hams. Attend club meetings and dinners. It will pay dividends.”

There is this nod to (potential) NewTechHams:

Phil envisions a stronger role for education and formal programs in amateur radio, inspiring technical tinkerers from outside our ranks to join us. Projects like HamSCI and university satellite groups show the potential; Phil’s work through ARDC amplifies it.

It’s kind of astonishing (and gratifying) to see ARRL acknowledge the formative role of KA9Q’s NOS in Amateur Radio - it doesn’t get much more data-centric than that. Minor demerits for ARRL to not mention KA9Q’s current project, and just as formative for Amateur Radio - ka9q-radio.

One very minor note about ARRL in 2025 - Tina and I are grateful to ARRL Northwestern Division Director Mark Tharp KB7HDX for rapid approval of our application for ZRDC 2025 in Everett, WA to be an official ARRL event.

Pi-Packet-BBS

Victor Hunter in the Facebook Ham Radio Operator group dated 2026-06-30. Found during a web search for a link to ROSE.

Pi-Packet-BBS

Working on a new raspberian and debian package that brings Radio packet mailbox/node to the modern age.

A number of features,

-Application installs and preconfigures EVERYTHING

-User setup on 1st boot, with changes possible in configuration

-duel mailbox and completely customizable node able to run semitaniously.

-Use with hardware TNC or Direwolf

- Handshake between same application unlocks new features to packet radio. Otherwise traditional plain ACSII is used.

-Telnet and rose connections available for worldwide communication with Internet and ability to share connections on peer control for all.

-BBS + Node terminal simulator for the old-school and test what others see when they connect.

- Self run FCC audit page to confirm everything is legit.

-winlink support

-news feed support

-weather and band updates

-AND yes to games ya nerds.

😉

If interested, stay tuned, hoping for full release in about a month post testing.

Looking at the comments, there’s no repository listed to date. From the passing mention of Alaska on the post, I’ll guess that he’s KL5SM.

OscarWatch – New Satellite Tracking Software

Lars Thunberg SM0TGU on the AMSAT-SE website:

OscarWatch by Peter @mm9sql is a new desktop satellite tracking multi-platform software. It takes all the best parts from all other tracking softwares and bundles it into one package.

Peter have done a lot of work with the radio doppler control part and – as I see it – it is a huge improvement from what you have seen before in older software.

OscarWatch is still under development (summer 2026) and can be downloaded from:
https://github.com/magicbug/OscarWatch-Tracker

This is the current features list 30 Juno 2026, copied from GitHub:

  • World map: equirectangular Earth texture with satellite subpoint, ground track, footprint overlays (optional motion arrows), your QTH, and an optional remote DX station grid marker; map time scrubbing from the status bar (hardware tracking stays live)

  • Sky plot: polar view of satellite azimuth/elevation relative to your station; click to focus; expand/collapse state is remembered

  • TLE catalog: fetched from https://tle.oscarwatch.org/, cached under %AppData%/OscarWatch/

  • TLE auto-update: manual refresh, on startup (if stale), or every 6 hours while running (Settings → Tracking)

  • Satellite picker: choose which spacecraft to track

  • Pass predictions: upcoming passes with TCA (time of closest approach / max elevation), min-elevation and min-duration filters; sidebar View pass plot for a single-station polar chart

  • Pass planner: multi-station profiles (home / portable), pass quality filters, satellite filter, pass radar gallery (polar plots for all upcoming passes of one satellite), and .ics calendar export for contest or field-day planning

  • Mutual pass finder: find passes visible from two stations at once (Passes → Mutual pass finder)

  • DX station monitor: enter a remote Maidenhead grid on the map; see where that station is and live azimuth/elevation for the focused satellite from their QTH (compact draggable overlay)

  • Live telemetry: azimuth, elevation, range, and altitude updated every second (UTC)

  • Voice announcements: optional spoken “rising” alerts when a satellite crosses a configurable elevation while ascending (e.g. “Alpha Oscar Zero Seven is rising”); Settings → Voice

  • Pass recording: optional automatic WAV capture from a line-in or USB audio device while the focused satellite is above configurable elevation thresholds; Settings → Recording. Files save to %AppData%/OscarWatch/recordings/ by default as {sat-name}-{yy}-{MM}-{dd}-{HH}-{mm}.wav (UTC). A red REC badge appears on the pass row while recording.

  • Doppler frequencies: draggable overlay on the world map with transponder modes from the satellite database, live radio/sat uplink & downlink, RX offsets (separate stored values for Voice and CW on linear SSB), CTCSS (access/arm), and Voice/CW toggle for linear SSB (header buttons + Ctrl+W; CAT/Cloudlog follow Settings → Radio → Linear CW: keep receive in USB/LSB)

  • Transponder database editor: Satellites → Manage transponder database… (add satellites from your TLE catalog or a custom name, Import/Export JSON, edit modes); Satellites → Update transponder database… merges published modes from tle.oscarwatch.org/satellite_database.json (new entries added with your consent; local edits kept on conflicts unless you accept remote). See documents/satellite-database.md

  • Radio CAT: doppler tracking, satellite/split setup, Main/Sub VFOs, uplink CTCSS where supported; Settings → Radio (see Supported hardware)

  • Rotator control: serial pass tracking, manual park, and manual rotator (az/el dialog in Standby for quick contacts between passes); Settings → Rotator (see Supported hardware)

  • Cloudlog: optional Radio API v2 uplink/downlink when tracking (Settings → Cloudlog)

  • Appearance: light, dark, or system theme (sky plot adapts; world map image stays light); 12- or 24-hour clock; optional greyline and footprint motion arrows on the map

I can’t quantify it, but this app looks really nice and something that I’d like to have on a dedicated computer and a dedicated screen in the shack, monitoring some of my favorite Amateur Radio (digital, of course) satellites. It would also be cool if it would display QO-100 in its geostationary orbit above the Eastern hemisphere.

This was another cool discovery from my slowly (but, constructively) declining backlog of Zero Retries Interesting RSS feeds thanks to NetNewsWire.

Packet History - The Beginnings of Packet Radio in the UK by Jonathan G4KLX

This document is based on my memories of the time. I do not keep a diary so some of the dates may be a little off, although some of them stay with me and I can date them based on other events occurring at the same time. Although this document is split into sections, and will be read linearly, the reality was that a lot of these things happened in parallel, and there will be a lot of cross referencing between different topics. It is a pity that all of this happened pre smart phone or digital cameras, as it would have been lovely to be able to show you pictures of it all.

Technically the first packet radio in the UK was in the mid-1980s following on from an article in March 1985 RadCom about a simple packet system called BBC Packet, using a BBC Micro. It was a remarkable program which included a simple terminal, and allowed simple point-to-point connections and chats. For a brief time this mode was quite busy, but was ultimately a technical dead end. However a number of us found it an interesting idea, and a latent interest in packet radio was created.

Another interesting find when searching for mentions of ROSE. This article is pretty comprehensive, from my knowledge of the developments of that era, but sketchy knowledge of packet radio development in Europe.

You'll find no mention of TheNet in this section. This seemingly came out of nowhere in (I think) later 1988 and was a complete functional clone of NET/ROM but was open source and had no encryption or callsign locking like the original. It didn't take too long for Software 2000 to take legal proceedings against the people behind TheNet. An independent software source code analyst verified that TheNet appeared to be an almost perfect copy of the Software 2000 code, but with the arguments to the functions reversed compared to the original. Ultimately the court ruled against the creators of TheNet, but the damage was done, and sales of true NET/ROMs fell through the floor. DANPAC had very little to do with TheNet, not for legal reasons, but because BPQCode was considerably more powerful and flexible. Later versions of TheNet also included IP over AX.25 routing which made it unique, but that wasn't enough of a selling point for us to use it.

From memory, TheNet came out of Europe and had much more usage there. I remember hearing about it from my reading in the US largely from the lawsuit by Software 2000 against TheNet. We were avid users of NET/ROM in the Seattle area. In my opinion, NET/ROM was a genius creation and the first real implementation of auto-discovery, auto-configuration mesh networking in Amateur Radio Packet Radio. Unfortunately it was hobbled (at the time) by its implementation in the 1 or 2 MHz clock speed and 32 kB ROM / 32 kB RAM of a TNC-2 type TNC.

Radio Autoencoder (RADE) - Good Story in QST

David Rowe VK5DGR in the November, 2026 issue of QST (pages 30-33):

The Radio Autoencoder (RADE) is a new way to send speech over HF radio (see the lead image). It employs modern machine-learning (ML) techniques to obtain impressive speech quality compared to SSB and traditional digital voice-over-radio systems. RADE is available as an open-source C library, and it has been integrated into Windows/macOS/Linux PC applications, the latest FlexRadio radios, and web-based software-defined radios (SDRs).

RADE transmits 8000 Hz audio bandwidth using just 1500 Hz of RF bandwidth. It has none of the usual background noise of HF radio and works well at both high and low signal-to-noise ratios (SNRs).

At the time of writing, the amateur radio community is at the forefront of this technology, with nothing comparable available in the commercial world. The work was partially supported by a grant from Amateur Radio Digital Communications (ARDC).

The October issue of QST was similarly notable for three Zero Retries Interesting articles:

  • The BrandMeister DMR Network

  • Getting Started with DMR

  • Long-Range Mesh Networking with Meshtastic (mentioned on the cover!)

This “burst” of Zero Retries Interesting content wasn’t accidental or coincidental. They were a result of ARRL having a Technical Editor on staff to seek out, curate, and encourage more technical topics, articles, and authors. The result of that work behind the scenes is notable in the improved (and relevant) technical content of QST.

But, unfortunately, the position of Technical Editor at ARRL is now vacant - the former Technical Editor, Conrad Trautmann N2YCH was on the QST masthead in the November 2026 issue of QST, but that position (and a number of other positions) is vacant.

This could be one reason:

We value in-person collaboration - this role is 100% on-site with no remote options.

Emphasis mine. I hope that the role of Technical Editor will be filled and there will be more Zero Retries Interesting content in future issues of QST.

It’s also been notable that there have been some Zero Retries Interesting advertisements thanks to some thinking-outside-the box outreach to new advertisers to the Amateur Radio market by now-former Advertising Sales Manager Steve Bossert K2GOG.

As always, almost all2 of the content of QST and its other magazines is behind a paywall, accessible only to paid-up ARRL members.

Post-ARRL, N2YCH is staying busy writing more great articles such as Building An Off-Grid Meshcore Network, One Node At A Time in QRPer.com.

My thanks to Ren Roderick K7JB and Wes Plouff AC8JF for bringing this development to my attention for inclusion in Zero Retries.

eBay To Require FCC IDs For (Most?) Sales of Electronic Devices

Which products require an FCC ID?

Products that intentionally transmit radio signals like Wi-Fi, Bluetooth, cellular, or other wireless technologies, commonly require FCC certification and an FCC ID. Examples include:

  • Mobile phones

  • Laptops

  • Tablets

  • Routers

  • Drones

  • Bluetooth devices

  • Wireless cameras

  • Smartwatches

  • Two-way radios

  • Remote controlled toys

A product’s category isn’t the only factor that determines if an FCC ID is required. If you’re not sure whether your product needs an FCC ID, check with the product’s manufacturer or supplier. You can also use the FCC ID Search Tool.

How to add FCC IDs to your listings

To help you provide this information, we’ve added a structured FCC ID field for applicable listings. When creating or revising a listing, add the item’s FCC ID in this field.

Here are a few things to keep in mind when listing:

  • Make sure the FCC ID you provide applies to the exact product and model you’re listing.

  • Don’t use an FCC ID from a similar product or model.

Depending on the product and listing, you may be unable to create, revise, relist, or publish the listing until you add the required information. Listings missing this information may be hidden from buyers in the US.

I can’t imagine this is a recent development, but I only saw a couple of mentions of this (non-authoritative so I won’t post links) this week. One stated that this requirement becomes effective 2026-10-13, but that date isn’t mentioned on the eBay page above.

I also saw another mention that this requirement also applies to items listed on Amazon - that will be an even more interesting effect than on eBay.

This… will get interesting, especially for Amateur Radio items, many of which predate the FCC ID requirement. How will sellers deal with this requirement for selling a unit that wasn’t manufactured in the US? Ditto something really vintage - I’ll venture that there’s no FCC ID for Hallicrafters radios. I’ve bought some vintage TNCs on eBay from Europe and Japan that wouldn’t have had an FCC ID. Ditto radios or computer components such as computer motherboards or expansion boards (or even vintage minicomputers) that predate the FCC ID requirement.

Tailcat: Tailscale without Tailscale, by Tailscale

Today we’re releasing tailcat, a remix of pieces of Tailscale that gives you a way to use the open-source Tailscale data plane (WireGuard® + NAT traversal + DERP) without the Tailscale control plane, written by the people who made Tailscale. It’s Tailscale without Tailscale, by Tailscale.

Specifically, tailcat is both an open-source Go package and a CLI tool using that package. It lets you run a server-side listener and a client to connect to that server, moving bidirectional bytes back and forth.

That is, it’s like netcat but flowing over Tailscale’s magicsock (WireGuard encryption + NAT traversal + DERP rendezvous/fallback relay).

Notably, tailcat has:

  • no IP addresses

  • no accounts (no logins, no passwords, no SSO)

  • no control plane

  • no users

  • no admins

  • no administrative controls

  • no root or admin OS access requirement

  • no relationship with or dependence on Tailscale as a company (if you run your own cmd/derper DERP server, at least)

I tagged this a month ago and I’ve missed mentioning it several times.

As marvelous as Tailscale is, and it being rabidly endorsed by people I respect like Tom Salzer KJ7T, I’m a bit uneasy to create yet another dependency on a service out on the Internet like Tailscale. But, then again, we’re probably a bit past that point given that so much of my life online is dominated by the hyper-centralized systems like Starlink, Google, and Cloudflare.

Thus, Tailcat seems like a good solution for the problems that Tailscale fixes, without relying on a centralized service for systems like Amateur Radio that are supposed to keep going when the (commercial) infrastructure is down. Yet another thing to try to grok in the months ahead… post ZRDC 2026.

XCL.is - Cellular Technology on Amateur Radio Spectrum

XCL.IS is amateur cellular — real ham radio LTE on ham bands. A project building practical ham-radio cellular (amateur LTE) and IMS on the amateur spectrum and licensing I can get my hands on.

This… is flipping the usual script of Amateur Radio over cellular, like pairing a digital voice radio hotspot to your cellular phone when you travel on road trips, but miss the gang on your local repeater.

Click the link in the title.

I’ve been casually tracking this project for some time now and yes, it is real and functional, not merely a concept. Cellular technology seems intimidating and horribly complex (because, it is), but it’s approachable and yes, we have enough spectrum within Amateur Radio to run real cellular technology.

Given that our mobile phones are now Software Defined “DC to Daylight” (mostly) Radios, they can tune into Amateur Radio cellular.

There are a number of explanatory articles on this website that explain the concept.

Tagged for possible inclusion at ZRDC 2027.

Raspberry Pi Desktop Now Available for PC and Mac

Simon Long on the Raspberry Pi website News:

We’re really sorry you had to wait so long…

Here, at last, is the fully updated Debian Trixie with Raspberry Pi Desktop for PC and Mac. Download it from our website now to give your other computers a Raspberry Pi makeover. We’ve even included a Raspberry Pi Connect client.

Raspberry Pi Desktop installed on a 2020 Dell XPS laptop

…

Earlier this year, we (or rather Serge) finally got the latest version of the Desktop running on top of a Debian Trixie image. It’s now based on 64-bit Debian (the amd64 architecture) rather than the older 32-bit version, as Debian itself has stopped supporting 32-bit for PC architectures. This shouldn’t be a major problem – most PCs made in the last 15 years or so will quite happily run the 64-bit version of Debian, as will most Intel-based Macs. (Debian support for Apple Silicon is still experimental, so unfortunately those of you with the latest and greatest shiny fruit products will not be able to run this.)

Raspberry Pi Connect compatible

The new Raspberry Pi Desktop is fully up to date with all the latest desktop changes, such as the Control Centre and the new dock. In addition, we have added the Raspberry Pi Connect client, so you can control a PC or Mac running the Desktop along with your Raspberry Pis running Raspberry Pi Connect. It works in exactly the same way as on a Raspberry Pi; the only difference is that when you set up a PC for Connect, you will be asked to enter a name with which to identify that device – this isn’t required on a Raspberry Pi, where a unique hardware ID is used instead. The name you choose will then appear in the list of devices you see when you log into the Connect website, and you will be able to use screen sharing or a remote terminal on the device.

This is really cool, interesting news. I think the biggest takeaways are that this distribution is now 64-bit, incorporates Raspberry Pi Connect, and is now up to date and looks and works like Raspberry Pi OS.

There’s a lot of folks like me who have a tenuous, at times, relationship with Linux, and many Linux distributions ind feel like “if you don’t really know what you’re doing, you shouldn’t be using this”.

Raspberry Pi Desktop is a lot friendlier - at least that’s the way it feels (to me).

So this is very cool that there is now this option for many “orphaned” PCs and even Macs. I’ll be installing it on some of my computers in N8GNJ / Zero Retries Labs.

Video - APRS over Modem73 OFDM!

Craig Lamparter KM6LYW has been busy getting familiar with Modem73!

Nowhere in the APRS spec does it say the bell AFSK tones are to be used for modulation. Let's have direwolf use the modem73 modulator for all its aprs traffic. We set modem73 to use ROBUST RDM-1200 short packets and send some beacons and do some aprs messaging. The APRS Digipeater is on the left, the APRS client/tnc/WebChat is on the right.

This is quite possibly the first APRS conversation over modern OFDM modulation?

Digipeater (left) x86 pc, direwolf/modem73, tidradio H9
TNC/Webchat(right) Raspberry Pi Zero2W direwolf/modem73, YaesuFTM400

Post production note:

I was experimenting with modes - the video shows ROBUST packet, which is an OFDM mode, but mostly for HF/SSB. I also tested OFDM, QAM16, 1/4, Short mode which seems best for APRS with these rigs and conditions. Payload is 126B at 1KB/s with forward error correction - the packet is exactly one second (plus preamble, which I'd like to lose).

I noted in the comments of this video that this isn’t the first transmission of APRS using OFDM. I can’t cite a name or callsign of the person, but APRS has been used with VARA HF which also makes use of OFDM.

XKCD’s Modern Spectrum Allocation Chart

Post-publication Update: This wasn’t in the emailed version, and I meant it to be as I saw it this week and I thought it was hilarious. Cool that both Amateur Radio and Ham Radio have their own allocations of spectrum!

My thanks to Amateur Radio Weekly Issue 442 for October 10, 2024 for bringing this development to my attention for inclusion in Zero Retries. That issue yet another excellent Zero Retries Interesting issue.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0265. Paid subscribers can comment directly on the web version of this issue.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

ZRDC 2026 Ho!

Zero Retries Digital Conference (ZRDC) 2026 will be here before we (I) know it.

1 week until Zero Retries Digital Conference 2026

on Friday, October 16, 2026,

in San Ramon, California, USA.

I felt like before I finished editing this issue of Zero Retries, on the cusp of ZRDC 2026 and Pacificon, like I should take a look at the vendors that will be at Pacificon to highlight a few that are particularly Zero Retries Interesting. And there was a mention - Did you get the app? Of course there would be an app for Pacificon 2026 🤣

Between ZRDC 2026 on Friday, the many speakers and exhibitors, and some long-deferred in-depth conversations with Zero Retries Interesting folks like Cale Mooth K4HCK, it will be an exhausting, but delightful long weekend next weekend.

I keep neglecting to mention that K4HCK will be sharing the Zero Retries booth with us, so you can find him there on Saturday and thank him for his valiant and valuable work publishing Amateur Radio Daily and Amateur Radio Weekly.

Zero Retries Media Guide to Amateur Radio

I was intending to make this yet another Zero Retries To Do, but I was inspired by KB6NU’s version and decided that it was too good an idea to not spend a few (tens of) minutes creating a basic page - click the title link.

I started with these points:

  • One of the fastest-growing aspects of Amateur Radio is Software Defined Radio where the characteristics of a radio (type of transmission, choice of spectrum, etc.) can be altered in software rather than changing the hardware of a radio.

  • There are many data networks in operation on Amateur Radio spectrum, all over the world, with little or no dependence on other telecom infrastructure.

  • Amateur Radio has its own satellites for use by Amateur Radio Operators. The most prominent organizations for Amateur Radio satellites are AMSAT (US) and AMSAT-DL(Germany). There are two Amateur Radio stations on the International Space Station, supported by ARISS.

  • Unlike other radio services, Amateur Radio Operators can create their own unique radio systems and use them on Amateur Radio spectrum. Other radio services require an onerous approval process for creating new radio systems.

  • Winlink is an email system used within Amateur Radio which (optionally) interoperates with Internet email.

This was important enough to link it from the links bar on the Zero Retries website.

I’m Agog at EtherHam’s (and KJ7T’s) Bandwidth

In this section of this week’s EtherHam Weekly Report (see a couple of sentences above), this section blew me away:

Short Stack From the Interwebs

There were many Zero Retries Interesting links mentioned - too many to reference here. I know that KJ7T has automated this with his increasing familiarity / utility of AI tools, but wow…

But then, scroll down a bit to…

Groups.io Digest

That’s when I started feeling really old and tired for trying to keep up “manually”.

After we’ve decompressed from ZRDC 2026, I’m going to have a serious talk with KJ7T about porting some of his tools (or his services) for use with make publishing Zero Retries a bit saner and less (human) labor intensive.

The Joy of Internet Archive, and DLARC

When I was young… my primary technical references were magazines. I paid for a subscription to Popular Electronics with my income from a paper route. (Yep… I’m that old.) Thus there were at least several magazines that arrived each week and I would digest them as well as I could (with my limited knowledge of electronics, and microcomputers). The limiting factors then were storage space for all the old magazines, and disposable income to afford the subscriptions. There was also the serial nature of magazines. I’d get excited reading about an interesting project or development, and then you’d hit the dreaded “Continued next month”. Argh!

But now in the mid-2020s, every issue of Byte, every issue of Popular Electronics, every issue of The Rainbow3, every issue of 73, and thousands of other periodicals is all available for reading sequentially. And soon enough, there will be an endlessly patient AI to digest all of that great content, and tutor you through nearly any idea that’s contained in those gazillions of pages of content. My mind boggles at the potential. When I reach my dotage, I cannot imagine anything more pleasurable than sitting and reading all of that stuff I never had time, or background, to digest back in my youth.

We’re Living in the Future (with Artificial Intelligence)

I had an interesting conversation today that I was asked to keep confidential, and so I will. But the very broad context of the conversation was about using AI to tackle a very large tranche of unstructured data. You know, the kind of thing where you would never imagine having enough time to tackle (unless you’re rich enough to employ “staff” that you trust to assign menial chores like grinding through near-endless unstructured data and make some sense of it. But now with AI… such things like that are possible. After that conversation, my fantasy about grinding through four decades of great ideas about Amateur Radio data communications systems doesn’t seem so… fantastic.

Future (Way Future) “Hobby” Project - Create DreamNet Out of Past Packet Radio Work

RATS ROSE X.25 Packet Switch Historical Software and Source Code (1988–1995) is a recent addition to DLARC that I happened to see in the DLARC RSS feed. ROSE (link is for context), TEXNET, FlexNet, and NET/ROM / TheNet were all great ideas and networking technologies created for the unique conditions of Amateur Radio. But their real strengths could only be partially realized given the radio and computer technology of their eras. For radios, we can go faster over the air than 1200 bps (example - Modem73), and we finally have reliable linking with the addition of Forward Error Correction (FEC) technology, and Dire Wolf’s “bit flip” technique to fix small numbers of bit errors without retransmissions.

Not to mention that we can throw ridiculous amounts of computer power at Amateur Radio links, multi-port / multiple radios on different bands are ridiculously easy, for ridiculously low prices. And to tie it all together, we have the ridiculously capable Linux OS, we have TCP/IP stacks in $5 microcontrollers, and if we want unique IPv4 addresses, there’s 44Net.

What we don’t have at the moment, other than with AREDN microwave networks, is a well-developed auto-discovery, auto-configuration mesh networking protocol for VHF / UHF operation. So… a fantasy project in the (again, way future, for me) is to throw all that historical packet radio networking info being surfaced by DLARC (Thank You Kay Savetz K6KJN!) at a “gets better by the day” Artificial Intelligence system and begin guiding it gently into the “ultimate mesh networking system” for VHF / UHF. Or, maybe, AREDN has it as right as it needs to be by implementing Babel.

There is So Much Going On in Amateur Radio!

Please believe me when I say that the varied and voluminous content in this issue is a fraction of all the things I have tagged that I received via email and found via RSS feeds, and various other inputs like YouTube (which I haven’t taken the time to delve into).

Thus it’s jarring to read some other sources of information / media in Amateur Radio that aren’t paying attention to Zero Retries Interesting developments like what I touched on in this issue. Sometimes it seems like we’ve barely advanced out of the 1970s - we’re still talking on analog SSB, we’re still arguing about contesting, or DX, or griping about band conditions. There’s an sad old phrase, applied to Amateur Radio:

Instead of trying to sell Sushi…
most of Amateur Radio media is trying to sell cold, dead fish.

It feels like this era is ripe with opportunity for the modern equivalent of 73 Magazine to make an impact on NewTechHams of this era and beyond. In saying that, I’m trying to posit the impact that 73 made in Amateur Radio, in comparison with the other “media competition” of that era - QST, CQ, and Ham Radio. If you were a reader of 73, you had your finger on the leading edge, cool stuff in Amateur Radio. There were other specialized publications like newsletters like Gateway, and television publications, and AMSAT publications, but 73 was one place where you could get a sense of the Zero Retries Interesting kind of stuff happening in Amateur Radio - like FM repeaters (yeah, there was a time when they weren’t everywhere), microprocessors (ditto), microcomputers… you get the idea.

I don’t know what it would take to really make this work - probably lots of money. But I could easily imagine something like a daily ten minute YouTube video / podcast with an accompanying website with the full text of the video / podcast, summaries, and perhaps an emailed high level summary with links.

Amateur Radio is just a fantastic resource for techies… and we in Amateur Radio that know how fantastic it is… aren’t exactly getting the word out at scale, at this moment.

But, trying not to restrict my vision… perhaps with more-powerful-by-the-day AI, perhaps we’ll be able to create such a thing as what I’m imagining with the help (or only because of) AI.

Weekends Are For Amateur Radio!

Saturday starts the last frantic 72 hours before departure for San Ramon and ZRDC 2026. This week I spent two sessions in N8GNJ / Zero Retries Labs clearing out the backlog of accumulated schtuff on my workbench to be able to have some workspace to get some things prepped.

I won’t sleep much in these next 72 hours until we’re underway in the car on Tuesday (Tina drives, I’m the primary cat comforter).

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0265. Paid subscribers can comment directly on the web version of this issue.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:

Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

Founding Members Who Generously Support Zero Retries:

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You thousands of readers of Zero Retries without which there would be little point in publishing this newsletter.

The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries | Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0265 was published on 2026-10-09. This issue was 13,359 13464 words4.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

Originally titled, incorrectly, as Modem 73, now fixed in the archives.

2

If you know where to look, one article of each issue made available for free.

3

My formative microcomputer from which I learned the most, the earliest, the fastest, was the Radio Shack Color Computer (CoCo). The Rainbow was the “Byte” of the CoCo world.

4

I think this is a new record for word count in a single issue!

]]><![CDATA[Zero Retries 0264]]>https://www.zeroretries.org/p/zero-retries-0264https://www.zeroretries.org/p/zero-retries-0264Sat, 03 Oct 2026 06:01:54 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its sixth year of publication, with 3600+ subscribers.

Zero Retries Digital Conference 2026 is October 16th in San Ramon, CA
www.zeroretries.org/p/conference

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is likely to be truncated by some email clients. Thus, it might be easier to read in a web browser:

www.zeroretries.org/p/zero-retries-0264

It’s easy and free to subscribe for your own copy of Zero Retries every week:

Subscribe now

In This Issue:

I-Frame

ZRDC 2026 Update 10/02/2026
Tina Stroh KD7WSF

Good Ideas That Look Obvious in Retrospect
Steve Stroh N8GNJ

ZR > BEACON

Request To Send

Closing Thanks

Founding Members Who Generously Support Zero Retries

The Usual Administrivia

Comments on This Issue (Redirects to Comments Page)

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

Optional Paid Subscriptions, and especially Founding Member subscriptions to Zero Retries not only help offset various expenses incurred in publishing Zero Retries, but also are a large portion of the “seed capital” that is needed to host Zero Retries Digital Conference (ZRDC) 2026, and future ZRDCs. Thank You!

My thanks to Randy Smith WU2S for renewing for a 4th year as Founding Member 0001 to Zero Retries in the past two weeks!

My thanks to Mitch Hamm N8XS for upgrading from a free subscriber to Zero Retries to a Founding Member 0027 in the past two weeks in the past two weeks!

Founding members are listed in every issue of Zero Retries!

My thanks to Sid Siegel for renewing as an Annual Paid Subscriber (4th year!) to Zero Retries this past week! Sid is an old friend from my former career who hasn’t yet been persuaded to join us in all the techie fun in Amateur Radio… but I keep hoping.

My thanks to Bill Sefton N6OWF for renewing as an Annual Paid Subscriber (3rd year!) to Zero Retries this past week!

My thanks to Craig Cherry N7RWB for renewing as an Annual Paid Subscriber (3rd year!) to Zero Retries this past week!

My thanks to David Billstrom N4SZ for renewing as an Annual Paid Subscriber to Zero Retries this past week!

My thanks to Justin Overfelt AB3E for renewing as an Annual Paid Subscriber to Zero Retries this past week!

My thanks to Prefers To Remain Anonymous 97 for renewing as an Annual Paid Subscriber to Zero Retries this past week!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0264. Paid subscribers can comment directly on the web version of this issue.

ZRDC 2026 Update 10/02/2026

By Tina Stroh KD7WSF
Zero Retries Digital Conference Manager

This is the sixth in a series of updates leading up to Zero Retries Digital Conference 2026. ZRDC 2026 starts in two weeks!

As we are getting closer to conference time, plans have been finalized, contents for the registration packet have been received (goodie bags) and we are finalizing the proceedings.

In-Person Registration

October 5th is technically the deadline to register for the in-person attendance (which includes breakfast) ticket. Although you can register at the door, your ticket WILL NOT include breakfast as the venue has imposed a 10/5 deadline to be notified of the number of attendees. I always plan for a few extra, but I just don’t want to turn people away from the catered breakfast and snacks as it just makes me feel awkward and awful. I also want to make sure I have enough supplies for the goody bags. So if you have not done so already and are planning to attend in-person, please click the link below to register.

Zero Retries Digital Conference 2026 Registration - Click Here

Virtual Attendance

If you have registered for a virtual attendance ticket, an email will be sent to you at the email address you provided on the registration form. That email will be sent on Thursday October 15th. The email will contain the address for the Zoom Webinar AND the link to download the conference materials. Should you have any problems, please contact Tina Stroh, ZRDC Manager at tina@zeroretries.net.

Club Attendance

Like last year, I created an additional platform specifically for clubs to purchase. There are two versions of the club ticket; one for virtual attendance on the day of the conference and the other for the early release of the video. It is one ticket price, regardless of how many people are participating.

ZRDC 2026 Schedule

For the past few days, I have been working on the schedule for the conference. As you are reading this issue of Zero Retries, I have updated the conference page with the schedule. I would like to thank Jim WU0I and Lawrence for their input as both will also be attending the Antenna Workshop at Pacificon the same day. Your input provided the means that I could create a flexible schedule so that both conferences could be enjoyed to some extent. As always, I have to note the order and timing may change slightly as I usually have to incorporate unforeseen conflicts and requests.

The schedule for ZRDC 2026 is as follows:

Editor’s Note - Substack’s formatting is limited, thus in Zero Retries, I can’t display the table format that Tina prefers.

0730 - 0745
Registration opens

0745 - 0800
Continental breakfast opens

0800 - 0815
Call to start 15 min to start of conference

0815 - 0820
Welcome - Tina Stroh KD7WSF
Introduce Keynote Speaker

0820 - 0910
Speaker #1: Steve Stroh N8GNJ - Keynote Address

0910 - 0920
Keynote Q&A

0920 - 0935
Break. Breakfast bar will be closed after this break.

0935 - 1010
Speaker #2: Cale Mooth K4HCK - New Tech Hams

1010 - 1020
Speaker # 2 Q&A

1020 - 1100
Speaker # 3: Craig Lamparter KM6LYW - DigiPi

1100 - 1110
Speaker # 3 Q&A

1115 - 1205
Speaker # 4: Panel Discussion - Encryption in Amateur Radio

1205 - 1245
Announce and direct to lunch

1240 - 1245
Call to resume

1245 - 1330
Speaker # 5: Jeff Scoville AE5ME - M17

1330 - 1340
Speaker # 5 Q&A

1345 - 1430
Speaker # 6: Martin Alcock VE6VH - IP 400

1430 - 1440
Speaker # 6 Q&A

1445 - 1530
Speaker # 7: Glen Popiel KW5GP - Microcontroller Communication Technologies and Protocols for Ham Radio

1530 - 1540
Speaker #7 Q&A

1545 - 1630
Speaker #8: Mooneer Salem K6AQ - Free DV

1630 - 1640
Speaker # 8 Q&A

1645 - 1730
Speaker # 9: Dave Platt AE6EO - Open TNC

1730 - 1740
Speaker #9 Q&A

745 - 1800
Closing Comments

Speakers

In addition to the schedule, I have also posted the list of speakers and their bios on the ZRDC 2026 website. Our list of speakers include Martin Alcock VE6VH, Craig Lamparter KM6LYW, Cale Mooth K4HCK, Dave Platt AE6EO, Glen Popiel KW5GP, Mooneer Salem K6AQ, and Jeff Scoville AE5ME.

I would like to mention again that some of the speakers will also be speaking at Pacificon. This does not mean their presentations will be the same. Although the topic may be the same, we have asked that their presentations be geared towards the Zero Retries audience. These speakers share our goal of dissemination of knowledge regarding Amateur Radio and to learn and develop more applicable technologies.

Sponsors

This week, we received another sponsor. Many thanks to TAPR for stepping up and being so gracious to become a sponsor and making a contribution to the door prizes. TAPR joins our other sponsors AllScan.info, ARDC, CentyLab, GigaParts, and NA6D who we continue to thank with our sincere appreciation for their support. In addition, a special thanks to Alan Johnston from AMSAT for the loan of the AMSAT CubeSatSim that will be demoed at the conference

Door Prizes

The ZRDC 2026 website has the latest list of door prizes that have been graciously donated by our sponsors. Each in-person admission ticket will have a door prize ticket that will be placed in their name badge holder for safekeeping. At various times during the day, we will draw corresponding tickets from the pool. Steve and Tina Stroh are the only people excluded from the drawing as well as the virtual attendees. We greatly appreciate the support of our sponsors and offer our sincere thanks.

Proceedings

The Proceedings of the Zero Retries Digital Conference 2026 are once again being managed by Don Rotolo N2IRZ who has done an excellent job and tries so hard to keep us on track. It is an enormous task and we can’t thank him enough for his generosity. The proceedings are available for purchase on the registration page until it is released to the general public in January.

In addition to some of the presentation slide decks, we had six original technical papers submitted for ZRDC 2026:

  • An OFDM Data Mode for Amateur Radio by Martin C. Alcock VE6VH and Nino Carillo KK4HEJ

  • AX.25 Version 2.2 by John Langner WB2OSZ

  • unambilify: a real-time neural post-filter for AMBE and Codec 2 Digital Voice by Rob Ludwick AJ7HR

  • A Unique Perspective of the New Tech Ham by Cale Mooth K4HCK

  • OpenTNC - its development, issues, and solutions by David Platt AE6EO

  • Predicting short radio paths on VHF and UHF using Radio Mobile by Don Rotolo N2IRZ

Conference Links

ZRDC 2026 Registration:

Zero Retries Digital Conference 2026 Registration - Click Here

Zero Retries Digital Conference 2026:

www.zeroretries.org/p/conference

We look forward to seeing some of you in two weeks!

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0264. Paid subscribers can comment directly on the web version of this issue.

Good Ideas That Look Obvious in Retrospect

By Steve Stroh N8GNJ

Earlier this week I saw a photo of a re-creation of the garage workshop where the first batch of Apple 1 boards were assembled. From those humble beginnings a half century ago to the one of the most influential companies in human history… my mind reels.

It can be argued older folks like me are either blessed or cursed with a longer perspective than the current generation. In my case, I grew up with the bleeding edge of microcomputers, and I watched many, many, many microcomputer companies try to perpetuate their particular vision of a microcomputer, and most of them eventually capitulated to the better idea of a IBM PC workalike running MS-DOS. That’s not to say that many of those companies didn’t have better ideas or better technology than the IBM PC with MS-DOS. Thus a company or technology that looks “dominant” in this moment “ain’t necessarily so”. A more compelling idea can easily “come from behind” to become dominant.

Things have changed rapidly in Amateur Radio in 2026. Thus the “Zero Retries Interesting” technological landscape in Amateur Radio, in five years will inevitably look vastly different than in 2026.

LinHT in Five Years Will be a GITLOiR

I’m convinced that one of those Good Ideas That Look Obvious in Retrospect (GITLOiR) 😊is the LinHT (Linux Handheld Transceiver) as a user-changeable Software Defined Transceiver. One of the reasons I say that is looking at the ads on websites and a very popular Amateur Radio magazine for the many, many, many radios that are single-mode digital voice (plus FM analog, of course). When comparing those to the capabilities of the LinHT - any of those radios that are hardware defined for a single digital voice mode will look silly (in my eyes) in comparison.

The trick with any GITLOiR technology is to actually see it in action and become convinced that it’s the right approach for the future.

To be clear, the LinHT isn't merely a potential user-changeable Software Defined Transceiver… it already works. It’s been demonstrated. What’s happening in 2026 and early in 2027 that the “finishing touches” are being applied (Rev C boards) to bring the transmit power up to a usable ~ 5 watts, and correcting some “oopses”.

To make it very explicit:

The LinHT isn’t a concept.
It’s a working, usable radio.
We just can’t buy one - yet.

So, absent a working example of a user-changeable Software Defined Transceiver that you can pick up in your own hands, most Amateur Radio Operators aren’t quite convinced, or oblivious, that such a radio is feasible. They’re used to buying a radio that’s designed by a manufacturer (or a group) for a particular use case. At most, such radios can be “lightly” modified such as firmware tweaks, or configuration modifications, or even minor hardware modifications.

But with the LinHT on the cusp of becoming widely available, I think it that will be the case in about five years that most Amateur Radio Operators won’t consider a radio that isn’t a user-changeable Software Defined Transceiver.

Amateur Radio Operators Can Create (and Use) Unique Radio Technologies

One of the most powerful… and under-appreciated aspects of being a licensed Amateur Radio Operator is that we have the ability to create and operate our own radio transmitting equipment. Most of us don’t have the capability to create our own unique radio transmitting equipment, but almost all of us have the capability to create our own unique radio transmitting equipment if we start with a user-changeable Software Defined Transceiver.

Thus, imagine the combination of a LinHT (with open source code for the firmware) and the help of an AI to modify the firmware. You don’t like something in the stock configuration of the LinHT you buy… maybe you want the “drop squelch” to sound like a Star Trek communicator chirp. So you feed that open source firmware into your favorite AI of the moment and instruct it to make the changes you want. As long as the resulting radio (code) doesn’t run afoul of the minimal Amateur Radio regulations (such as bandwidth limitations, sigh…), you get to go have fun with your unique Amateur Radio.

Yeah, right, you say.

We’ve seen promising technology come… only to fade out into obscurity. I tell such a story from my perspective / Amateur Radio career in Story 3: The Radios That Weren’t; Part 1 and Story 4: The Radios That Weren’t; Part 2.

So… what’s different now (and in the coming five years) that will make a user-changeable Software Defined Transceiver into a GITLOiR?

Four Powerful Trends Converging

I’m observing four powerful trends converging:

  1. The widely recognized need for such radios. We’re all getting tired of the Tower of Babel of incompatible digital voice modes and wanting to do different things with our radios that they weren’t necessarily designed for, like data or a new digital voice mode.

  2. The technology of this moment is enabling such a radio, and such technology can only get better, and less expensive in the coming five years. The technology of the LinHT seems to be the minimum viable implementation of a user-changeable Software Defined Transceiver. Once most of the technology of the radio you own is based in software, and we now have our ever-patient, ever-capable AI assistants, nearly anything is possible. For example, an experiment I want to try out is implementing Frequency Hopping in Amateur Radio VHF / UHF spectrum.

  3. NewTechHams are coming into Amateur Radio with new ideas and an entirely new perspective of radio technology, such as a background with GNU Radio. I predict that will accelerate in the next five years. NewTechHams will begin flooding into Amateur Radio en masse when it becomes widely understood that getting and using your Amateur Radio license is easy and enables entirely new classes of ideas in radio technology given that you can start with a radio like the LinHT that’s “mostly software”. Unlike a “lab instrument” like the popular ADALM-PLUTO that’s capable… but not exactly practical for Amateur Radio given its low transmit power… the LinHT is designed for Amateur Radio use with a five watt transmitter on the first or second most widely used Amateur Radio band - 70 cm / 420-450 MHz1.

  4. The primary proviso for Amateur Radio to have this kind of fun, creating new modes, entirely new radio technologies, in our Amateur Radio spectrum, is this obscure mention in the FCC Amateur Radio regulations (and this is applicable only to the US, of course):

    § 97.309 RTTY and data emission codes.

    …

    (4) An amateur station transmitting a RTTY or data emission using a digital code specified in this paragraph may use any technique whose technical characteristics have been documented publicly, such as CLOVER, G-TOR, or PacTOR, for the purpose of facilitating communications.

    Documented… Publicly…     is the (sole) requirement for using “any technique”2 in Amateur Radio spectrum. Thus if you create a new mode, in software, with the help of an AI, just drop your software onto a website, or a GitHub page, or a blog, etc. and you’re compliant with § 97.309 (4). For the majority of NewTechHams, “public” (sharing, open source), this is the norm because they want to demonstrate their technical chops and share their fun with their co-conspirators for the benefit of everyone.

Legacy Modes Won’t Go Away

In the above, I’m not trying to posit that various modes that are popular in 2026 will go away. Heck, we’re still using a signaling technique from more than a century ago (Morse Code) to automatically identify many radio transmitters. Various modes will persist as long as there are users that want to (continue to) use such modes.

One reason is that repeaters in Amateur Radio are expensive and fussy infrastructure that’s pretty long-lived. I’d guess that there are repeaters on the air that are more than fifty years old, still working fine.

Enabling New, Better Modes

The new technologies possible with LinHT and its successors will make new technologies possible, feasible, and soon enough, routine. I can easily imagine a “new” digital voice mode for VHF / UHF - FreeDV RADE using SSB.

The voice quality of FreeDV RADE is arguably superior to the voice quality of some of the digital voice modes intended for VHF / UHF. Even the Amateur Radio digital voice mode with the narrowest bandwidth - D-Star using a 6.25 kHz channel seems inefficient when you consider that FreeDV RADE over SSB uses a 1.5 kHz channel. FreeDV over SSB is 4x more bandwidth-efficient, and 4x better power spectral density, and probably better battery life compared to FM or digital voice.

SSB on a reasonably priced VHF / UHF portable radio? Yep. LinHT and other Software Defined Radios means any mode, including SSB.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0264. Paid subscribers can comment directly on the web version of this issue.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

M17 Next: A $60 Radio, a Linux HT, and Data on the Way

Tom Salzer KJ7T on EtherHam:

…

What’s changing is that it’s about to get easier. Two developments on the horizon are, to me, the real story:

  • A stock, inexpensive handheld, the Retevis C62, will be able to run M17 with nothing more than a firmware update. No soldering, no fiddling with surface-mount chips, no opening the case at all.

  • The same radio body can hold a full Linux computer with a software-defined radio inside (LinHT), a handheld that can learn new modes after you buy it.

Add a firmware release that brings text messaging and APRS to M17 radios already in the field, and M17 starts to look less like an experiment and more like a modern, viable platform.

The clearest summary of all this came from the weekly M17 net last Saturday on the Kansas City Wide system, which I listened to live. Net control Jeff Scoville, AE5ME, of Broken Arrow, Oklahoma, spent most of the hour on these developments. My transcription node, 588416, captured the net as well, so what follows draws on that transcript, checked against the M17 Project’s own announcements and Steve Stroh’s Zero Retries newsletter where I could.

…

Despite KJ7T’s references to Zero Retries, KJ7T was able to extract more information from the M17 references I included in Zero Retries than I was. As in, I learned more about the state of M17 reading this article than I did writing about it in Zero Retries.

KJ7T is doing a fantastic job with the Random Wire newsletter and the companion EtherHam website. He’s demonstrating a really good “division of labor” with his longer, detailed articles appearing (full length) on EtherHam and more timely, ephemeral articles (including previews of EtherHam articles) on Random Wire.

Both Random Wire and EtherHam are strongly recommended!

WSJT-X 3.2.0

Jeff Davis KE9V on ke9v.net - Weeknotes 2026-39:

WSJT-X 3.2.0 introduces a new mode, JTTY, along with new capabilities in Q65, MAP65, and QMAP and a large number of improvements and bug fixes. JTTY, a new digital mode for fast RTTY-style contest exchanges and other keyboard-to-keyboard communication. JTTY has an operational feel similar to RTTY but far better weak-signal performance and a very low error rate. It can transmit at any time rather than in fixed T/R periods. Its 4-tone GFSK waveform uses 1.888-second frames and about 127 Hz of bandwidth. Function keys F1-F8 provide contest-style exchanges, and messages can be queued while transmitting. Signal subtraction and adaptive decoding help recover overlapping or fading signals. Received and transmitted text is recorded in ALL.TXT, and an MMTTY-compatible interface connects to N1MM Logger+ version 1.0.11449 or later.

Related, in the same article:

WSJT-X Improved is becoming the “WS - Digital Mode Suite”, commonly referred to as “WS” or “WS Suite”. This rebranding was done so that there’s no longer any risk of confusion with the original version of WSJT-X.

I wasn’t aware of that fork of WSJT-X. From the link:

The WS Suite consists of three programs: WS (the main program), WS-MAP (wideband Q65 monitor) and EME65 (wideband JT65/Q65 for EME). The WS main program supports FT8, FT4, FT2, JT4, JT9, JT65, Q65, FST4, MSK144, WSPR, FST4W, and Echo.

The original WSJT wasn’t magic… but it was able to do things that we thought shouldn’t be possible with radio. But Joe Taylor K1JT put his considerable talents and experience to work on the problem of communicating below the noise threshold, and radio communications hasn’t been the same since.

Amateur Radio Microwave Organizations

KE9V also mentioned these Amateur Radio microwave organizations and documents:

Fair warning, all three of these organizations provide access to their back issues of newsletters, and also provide many informative articles. All three of these are now in queue to be added to my Zero Retries Guide - Zero Retries Directory of Independent Open Amateur Radio Technical Media.

Alas, none of the three websites seem to support RSS for easy following of their activities. Thus these websites seem like a good place to try a new Apple Safari (on Mac) feature - Notify Me.

AI Is Designing Radio Chips That Humans Couldn’t Even Imagine

Kaushik Sengupta in IEEE Spectrum:

SUMMARY

  • RFIC design is a complex “dark art” that limits progress in wireless technologies like 5G, autonomous vehicles, and satellite communications.

  • Princeton researchers use reinforcement learning and inverse design to rapidly create RFICs from scratch.

  • Diffusion models rapidly generate novel or human-interpretable RF layouts, achieving record performance and drastically reducing design time.

  • Future progress needs large, shared chip design datasets and open ecosystems so AI can learn universal electromagnetic and circuit behaviors.

I had this bookmarked from back in June, but it’s a victim of the ongoing overflow effect of there only being so much room in Zero Retries.

I second that first bullet point - Radio Frequency Integrated Circuit is, in my understanding, the most complex technology to try to encapsulate into an integrated circuit because it’s not “just digital”. Modern high-speed digital ICs are complex enough given the multi-GHz clock speeds causing “just digital” signals to behave like radio frequencies (because… they are…). But when you want an IC to act like an intentional radio frequency device… well, there be dragons.

Thus this seems like one of those perfect tasks for an AI. Some of the design decisions of an RFIC designed by an AI in the article remind me of some of the surprising 3D shapes created by AI when it’s given only basic design parameters such as minimum strength, maximum weight, mounting points, and turn it loose to create a design from absolute scratch.

The Newest ESP32 Can Actually Run Linux, and It’s Getting Uncomfortably Close to a Raspberry Pi

Adam Conway on XDA-developers:

Espressif has a new ESP32, the ESP32-S31, and that ESP32 comes with a gigabit Ethernet MAC, a USB 2.0 High-Speed host controller, an SD card interface with two slots, and a camera input. It’s a pretty standard set of features for a Linux single-board computer, but a rather strange list of things to find on a microcontroller.

My frame of reference for ESP32 class devices (microcontrollers) is managing something very low level, like a light bulb, with just barely some connectivity, basically a variant of an Arduino. But now… running Linux? Couple that with another variant of ESP32 that I recently wrote about that incorporates 5 GHz Wi-Fi, and yes, this is yet another example of “grow from behind” into greater and greater capabilities.

The World Is Full of GPS Dead Zones. Here’s What Comes Next.

Christopher Mims in The Wall Street Journal:

The proliferation of cheap, powerful GPS jammers has airline operators, shipping firms and militaries alike scrambling for navigation alternatives.

Nations and individuals alike are deploying cheap but increasingly sophisticated electronic-warfare systems, mostly to thwart attacks by drones and smart munitions. Some jammers, which drown out the relatively weak GPS signals from satellites 12,000 miles up in orbit, are as small as a cellphone and cost less than $100.

Jamming had become commonplace along the Russia-Ukraine border, but now the Strait of Hormuz, through which 20% of the world’s oil is transported, is besieged by such electronic attacks.

“GPS denial” is one of many factors making that waterway treacherous to navigate on account of America’s new war with Iran, says Ami Daniel, chief executive of maritime intelligence company Windward.

The article explains some of the (kind-of) alternatives such as increasingly capable, compact, and cost-effective Inertial Navigation Systems, magnetometers, and terrain vision systems. (I’m surprised that LIDAR and Terrain Following RADAR weren’t mentioned.) The article also didn’t mention the more capable Global Navigation Satellite Systems (GNSS) such as the most advanced GPS and the Galileo system.

This article kind of tickles me as I’ve seen a system such as what is being proposed to combine “whatever inputs are available” - forty years ago now. The core of that system was a ring laser gyro inertial sensor, Transit satellite passes (2/day) (Yes, this system predated GPS), magnetometer, a very expensive LORAN-C receiver, vessel gyrocompass, some kind of sonar for absolute vessel speed (when we were in shallow-enough water), and other inputs I’ve forgotten. Oh, and when absolute precision was required and we were close enough to shore, a Syledis shore-based radio triangulation system.

Defeating Satellite Spoofing With Galileo’s Encryption

Aaron Beckendorf on Hackaday:

Considering how important it is for everything from navigation to keeping clocks in sync, satellite navigation systems are surprisingly vulnerable to a variety of attacks, ranging from simple jamming to more sophisticated spoofing attacks. This may be changing, though, as Galileo, Europe’s GNSS, recently demonstrated its first cryptographically-secured position fix under spoofing conditions.

Most GNSS systems, including GPS, have no verification measures to keep an adversary from transmitting a false signal at a higher power and hijacking a receiver; since GNSS signals are extremely weak by the time they reach the ground, this presents no great difficulty to a moderately well-equipped attacker.

Galileo’s Signal Authentication System (SAS) aims to fix this. The Galileo ground station pre-selects signal spreading codes, which it then encrypts with a regularly-changing secret key and publishes. A receiver which anticipates needing a verified signal can then download these encrypted codes ahead of time and store them. Galileo satellites then transmit on the E6-C pilot signal, and the receiver records the signal. After transmitting a message block, it then transmits the decryption key on a separate signal, which the receiver uses to recover the spreading codes. The receiver then correlates these spreading codes with the recorded signal to find the satellite’s pseudorange.

…

This article’s use of “Encryption” in the title is inaccurate, in my opinion. As I understand it, Galileo is transmitting a cryptographically signed authentication signal. Authentication and encryption are often conflated, but they’re two very different things.

Of the two GNSS threats, spoofing is worse than jamming, in my opinion. At least with jamming, you know there’s a problem. With spoofing, you may not. I’m glad this is now, or soon, an option.

The Great Amateur Radio Digital Scavenger Hunt: AX.25 Packet Radio

Chris Lance WW2BSA on several email lists:

DATES: Saturday, October 3, 2026 to Sunday, October 4, 2026.
CONTEST PERIOD: Begins 1800 UTC Saturday, ends 1800 UTC Sunday.
CONCEPT: Compete in a digital scavenger hunt game against other amateur radio operators. Test your AX.25 amateur packet radio skills by racing against the clock to be one of the first Digital Amateur Radio Scavenger Hunters to complete the most tasks in a 24 hour period using RF, the internet or both!

Details at: https://www.qsl.net/ww2bsa/ww2bsa_digital_hunt.htm

Sounds like fun!

My thanks to Joe Hamelin W7COM for bringing this development to my attention for inclusion in Zero Retries.

More Teasing About “Big Project” by Bruce Perens K6BP

Bruce Perens K6BP on the digitalvoice email list:

Hams.com will be providing this feature [realtime language translation] in its operating console, none of which has been announced yet but it’s coming out in time for Pacificon. The software loads on your browser via the web, and then works offline. It supports 210 languages via an ML model running in the browser using WebGPU.

Other features, which will blow your mind, I’ll save for Pacificon, but my US Ham License and Incident Command System training system is announced: see https://hams.com/teachers_guide for a non-interactive version, the real thing is interactive.

Because of AI killing copyright, there are 43 patents pending. The translation part is not patented due to the pre-existing Android application.

I look forward to seeing this, and lots of other surprises, at Pacificon 2026 in two weeks.

70 cm High Speed LoRa Incredibly Great Performance

Jon Adams N7UV on the Ham-Radio-LoRa-APRS email list:

For too long, hams have run 70 cm LoRa APRS at 293 bps (BW125, SF12, CR5:8) either because “it is good enough” or just because that’s what everyone else was doing. 293 bps isn’t even legacy HF 300 baud APRS speeds. A single packet at 293 bps takes between 1.5 and 3 seconds to send, tying up the channel for an unreasonable amount of time, Fortunately, LoRa’s got knobs!

Here in Arizona, we have a high-performance network running at 15x faster speeds, providing wide coverage that spans almost 90% of the state’s population. We far out-perform legacy 2 m APRS.

The below table is a glimpse into the reason. LoRa delivers!

…

How to we achieve this performance? Good RF engineering and better sites. Every digi is solar only with the ability to stay running even during extended poor weather. We demonstrate that high speed LoRa APRS is not only viable but something the interested ham should aim for. And you know what? LoRa’s capable of even more.

How are we doing? Southern California has followed our example, growing out their own same-settings 70 cm LoRa APRS network. We’re close to closing the link between the two states!

Please consider joining us.

I didn’t attempt to reprint the formatted table - see the link for that info.

“15x faster speeds” - 15 x 293 bps = 4395 bps. Not bad, but it should be noted that 4800 bps is reasonably achievable with packet radio. The Nino TNC has a 4800 bps mode and the IL2P Forward Error Correction built into the NinoTNC corrects for single bit errors that plague packet radio at speeds faster than 1200 bps.

What’s notable with this announcement is that they’re apparently using off-the-shelf LoRa units (for 433 MHz), with resulting minimal transmit power (for the Europe ISM band). They’re integrated plug and play - no separate radio and modem, etc.

So… yes, a notable achievement!

Bruce Perens K6BP on Encryption on Amateur Radio

K6BP on his LinkedIn page:

If anyone tells you we need encryption on ham radio, they are not technically competent. Sorry, that’s just the way it is.

If you have a problem accessing an https site from your ham gateway, translate https to http at your gateway. If your browser rejects certain content as http, use an Open Source browser like Chromium, with a very slight modification for over-the-air use.

If you want to securely control a satellite or repeater over the air, use digital signature instead of encryption. It works within today’s Part 97 rules.

If you put an Amateur Radio WiFi device on the air and keep non-licensed folks off of it, there are easy ways like using published keys (to stay within Part 97), and MAC address lists. There are harder ways like modifying the already-Open-Source firmware used for your relay to use digital signature instead of encryption, but those definitely lock out the riff-raff. Use local-only Part 15 WiFi for your phone, etc. with its normal encryption.

The problem with encryption on the air is that it breaks amateur self-policing and allows all manner of abuse of Amateur frequencies, starting with commercial use. As if we didn’t have enough slims with Baofengs. You will probably have to treat every encrypted communication as if it was an emergency one, because you can’t tell that it isn’t. So, it takes priority over other communications. If one organization retains the over-the-air keys for a communication, you still probably can’t tell if the communication in _your_ neighborhood is legitimate, nor can the organization possibly have enough bandwidth to handle routine monitoring. You also cannot decrypt the communication without perfect reception of all packets.

If you are a legitimate public service communicator and can’t avoid transmitting HIPAA PII by anonymizing it, you probably already have access to public service bands, and it’s the operator they want, not the frequency. In general the reasons hospitals, etc. find it hard to accept our operators are more connected with the need to have vetted personnel for insurance and safety reasons than anything to do with ham radio.

We’ve been through this before, folks. ARRL wisely objected to encryption last time.

This is apparently a reaction to the idea of having a panel discussion about encryption in Amateur Radio at ZRDC 2026. The pointed reference to “they are not technically competent” is probably directed at me for having floated the idea. That’s OK, I take no real offense. I’ve been accused of worse.

K6BP offers some valid points of discussion, but…

Things… change… One of my major talking points about this is that the official source of truth for the status of an Amateur Radio license is the FCC’s website… which cannot be accessed without using HTTPS end to end encryption.

Some of the things that have changed recently about the possibility of increasing3 the use of encryption in US Amateur Radio are that the ARRL Board actually announced that encryption would be a subject of discussion / study. Radio Amateurs of Canada now has a key escrow program. Perhaps repeaters should also be able to use encryption, especially in a “grid down” scenario where the Internet back-channel isn’t available?

Anyway… all that, and much more will be discussed at the Encryption panel discussion at ZRDC 2026.

Help Finance For the LinHT Rev C Board

Bruce Perens K6BP on Facebook:

The M17 project is building LinHT, the most important project in Amateur Radio today. They get no more than $175/month from their repeat donors, and a board turn costs them about $1300. They do not receive funding from ARDC. They really need your help. Please use the link, and please re-post this.

I verified this with M17 Foundation. The cost is for the complex boards (RF running around) and components. It wasn’t clear if that cost included assembly, but that $1300 is mostly being borne by the developers with some help from the ongoing donations to M17 Foundation. I’ll be chipping in.

Pi Pico Recreates The Heathkit Pocket Packet

Zoe Skyforest on Hackaday:

Packet radio is a particularly fun part of the ham radio hobby. Once upon a time, you might have squirted data about the airwaves using something like the Heathkit HK-21 Pocket Packet. Heathkit stopped being a going concern some time ago, but [btech] has now recreated the device with modern hardware.

[btech] has called the project the Pocket Pico, and like the hardware that inspired it, it acts as a terminal node controller for amateur packet radio. It literally runs the same firmware as the real HK-21. It achieves this by using the Raspberry Pi Pico to run a Z80 processor emulator that can run the same code, while also using the microcontroller to do the work of modulating and demodulating Bell 202 audio tones at 1200 baud to avoid the need for a dedicated modem chip.

Thanks to running the same firmware as the HK-21, you can use the Pocket Pico with lots of old packet radio software. It’s fully capable of doing APRS as well as AX.25 Level 2, and has a built-in Personal Bulletin Board System for other stations to leave messages.

Three things I love about this article and project. This microcontroller has the compute power to emulate another microprocessor (Z80), and demodulate the audio tones, and run a (personal, minimal) Bulletin Board System.

The original article by Gene Heiter N7WDZ has much more detail on the project. N7WDZ’s About page is also pretty informative. I admire his compact antenna farm.

Introducing the AIOC Toolkit

AIOC is All In One Cable, a combined programming interface and audio interface in a single device for use with portable radios (that follow the same connector spacing and electrical functions of a Kenwood portable radio).

Mark Herbert G1LRO on his website:

Configure and Flash Your AIOC From One Browser Tab

If you’ve got an AIOC adapter for your handheld radio, you’ve probably used a couple of different tools to look after it: one to set PTT sources, audio gain, and GPIO behaviour, and — separately — dfu-util on the command line whenever new firmware comes out. I’ve combined both jobs into a single page: the AIOC Toolkit.

This seems like a godsend for maintaining AIOC devices easily with “just” a browser.

Easily Turn an AIOC into a CM108 Sound Card

Mark Herbert G1LRO on his website:

TL;DR: You can make an AIOC (or URC, or Model 50) appear to your computer as a standard CM108 sound card, so it works plug and play with AllStarLink and other software with no patches or Python required. Use TF3HR’s browser-based utility at https://g1lro.github.io/aioc-toolkit/to change the Vendor ID to 0x0D8C and Product ID to 0x000C, click Store to Flash, then unplug and reconnect.

The AIOC, and associated devices like the URC and Model 50 USB transceiver, are based on the same AIOC sound processor. This is a software-defined sound card with a serial port function and several GPIO control lines for PTT, COS and similar functions.

The AIOC is becoming well supported by applications such as AllStarLink (ASL) and DigiPi, but there are still gaps compared with the popular CM108 sound card standard. The CM108 is a sound chip that has been used in PCs and other audio applications for well over a decade, so support for it is effectively universal.

Where an application doesn’t recognise the AIOC, there are two ways forward:

  • Modify the application to support the AIOC, either by editing the core software or applying a patch script, or

  • Modify the personality of the AIOC so it reports itself to the software as a CM108 and just works, plug and play, with no further tweaking.

G1LRO is on a roll with improving the utility of AIOCs with this helpful update, also browser-based.

I’m Starting HomelabFest (in St. Louis, Sep 2027)

Jeff Geerling (who is also KF0MYB):

…

Over the past few years, I realized the homelab community (which isn’t really a defined thing—that’s okay) hasn’t had its own gathering, the way makers, software engineers, embedded developers, and HPC professionals do.

There are many events that have crossover into the homelab realm, but nothing focused on energy-efficient servers, privacy-respecting self-hosted software, keeping old hardware useful, or cable management and rack mounting on a budget.

The space has grown tremendously since 2020, and I think the time is ripe for an in-person event focused on this hobby I enjoy.

HomelabFest

So I’m starting HomelabFest. It will run from September 12-14 2027, in my home town, St. Louis1.

I’m inviting all the homelab content creators I know.

…

A subset of Homelabs is the Mini Rack concept which seems a perfect fit for Zero Retries Interesting radio systems that combine computers, modems, routers, power supplies, etc. all in a neat form factor for desktop use. What makes the Mini Rack concept even more fun is if you have a piece of equipment that isn’t designed for a Mini Rack, just make a bracket for it with your 3D printer (or order one).

Geerling is also an influencer about all things Raspberry Pi (he’s often seeded with new Raspberry Pi products under embargo), thus he’s my go-to source of information when something new emerges from Raspberry Pi.

This sounds like a really interesting event and I wouldn’t be surprised if there isn’t something that comes out at this event from Raspberry Pi - a RPi 6 (?) in Mini Rack format would be pretty cool.

A New IEEE STEM Book Series for Tweens from TryEngineering

Danielle Cann in IEEE Spectrum:

…

Six topics in the collection

Here are the books in the new collection:

Artificial Intelligence: The Future of Smart Technology explores the systems behind streaming services, search engines, and health care. Readers learn how AI works while exploring ethical concerns such as bias, deepfakes, hallucinations, and privacy. Pupils can better understand one of the most influential technologies of our time as it evolves.

Communication Technology: From Morse Code to Smartphones teaches readers about smoke signals, semaphore towers, telephones, and wireless networks. The pupils can gain an understanding of how engineers are changing communications technology through innovations such as 6G and space-based networks. The book highlights career opportunities in the aerospace and telecommunications fields.

Electric Vehicles: Powering the Future of Transportation covers how e-cars, e-bikes, e-scooters, and electrified trains are transforming the way people travel. Readers can discover how hybrid and fully electric vehicles operate and how the batteries that power them work. They also can learn about the roles engineers play in developing smarter transit systems.

Ocean Engineering: Protecting Our Ocean Environments highlights the vital ecosystem role played by the world’s oceans, which require careful stewardship. play in our ecosystem. Readers can learn how engineers study the underwater world using submersibles and floats, how they address pollution, and how they protect marine environments.

Semiconductors: The Building Blocks of Modern Electronics focuses on the technology behind nearly every electronic tool we use. Microchips power smartphones, computers, and countless other products, all thanks to semiconductors. Readers can learn about insulators and conductors, how microchips are manufactured, and why semiconductor engineering is a fertile field for innovation.

Signal Power: The Hidden Waves Behind Modern Tech explores how engineers analyze and manipulate signals to make technologies work more effectively. Whether it is a phone call reaching the correct person despite background noise or a medical device monitoring a patient, signal processing plays crucial roles in modern life. The book introduces different wave types, the signal processing workflow, and careers in the field.

…

Interesting approach and a great idea to mention “careers in the field”.

But, I fear that IEEE has the same bias from their membership of engineers (that have advanced reading skills) that I have with Zero Retries - the relative popularity of longform text versus video in this era. These topics would make for great 10-15 minute YouTube videos and thus more likely to engage an audience 10x or more than what they’re likely to experience from these topics presented in books that must be purchased.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0264. Paid subscribers can comment directly on the web version of this issue.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

ZRDC 2026 Ho!

Zero Retries Digital Conference (ZRDC) 2026 will be here before we (I) know it.

2 weeks until Zero Retries Digital Conference 2026

on Friday, October 16, 2026,

in San Ramon, California, USA.

Sometimes it Takes Me a While to Engage

I’m still grinding away in spare moments / idle time (like watching entertainment television) at creating indexes for each issue / month / year of Zero Retries. Thus I’m rediscovering things that I’d forgotten I wrote.

Case in point - this Request To Send from Zero Retries 0072 on 2022-11-11:

We’re Doing a Mediocre Job at Promoting Technological Innovation In Amateur Radio.

In that article, I said:

Whither TAPR?

While it’s far from a perfect “fit” for the above, perhaps TAPR could be a vehicle for the above.

  • TAPR was founded on technological innovation in Amateur Radio - it’s literally in the DNA of the organization. In fact, Amateur Radio (and communications technology in general) has caught up with TAPR’s focus on digital communications technology as all communications are now digital communications (or if using legacy modes, enabled by digital techniques).

  • TAPR embraces open access, not only in its content, but also in its products and projects.

  • TAPR embraces international participation.

  • TAPR not only has a newsletter but also is the primary sponsor of the well-regarded and influential annual Digital Communications Conference.

  • TAPR has even waded into regulatory issues in Amateur Radio with the US Federal Communications Commission (which is sorely needed, again, in this era).

Sometimes, instead of creating something from scratch, you have to use the tools you have available to you and adapt them to accomplish a new task. TAPR is here, now.

I recently received my renewal notice for TAPR membership, and not only will I renew my TAPR membership, but I think it’s time that I became involved in TAPR’s activities again. I recommend to Zero Retries readers to, at a minimum, join, renew, or restart TAPR membership, and consider joining me in getting more actively involved with TAPR.

(Emphasis in the above paragraph added for this article.)

Looking back since that article, I did get lightly more involved with TAPR, including participating in the online TAPR annual meetings, submitting papers to the final couple of TAPR DCCs, some intensive (long, pointed) emails to each TAPR Board member, and submitting articles for the PSR. In retrospect, those efforts were at best “tinkering at the margins”, and none seem to have materially affected TAPR’s direction.

Thus, we’ll see how my candidacy (again) for TAPR Board goes, and if elected, whether I can affect TAPR’s direction “from the inside”. Amateur Radio really needs TAPR or an organization like it to represent “NewTechHams” and Data Communications Networking that’s becoming a larger and increasingly important aspect of Amateur Radio.

Per TAPR PSR #162 October 2026, I’m the fourth candidate for one of the three TAPR Board positions that are expiring in 2026. Thus there will be an election.

If you’re a Zero Retries reader that’s also a member of TAPR, I’d appreciate your vote for TAPR Board of Directors.

Weekends Are For Amateur Radio!

As an organizer, I got an early look at the ZRDC 2026 Proceedings and wow… there is some really good stuff in there, all queued up for ZRDC 2026.

Some of the behind-the-scenes email correspondence Tina and I have been getting from ZRDC in-person attendees is great. No matter what the numeric turnout will be, we’re all going to have a fantastic time cross-fertilizing with each other.

Basically, as of tomorrow (Saturday), I’ll be in panic mode to get some demo systems set up for ZRDC 2026. Departure for San Ramon is one week from Monday.

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0264. Paid subscribers can comment directly on the web version of this issue.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:

Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

Founding Members Who Generously Support Zero Retries:

Founding Member 0000 - Steven Davidson K3FZT (Renewed 2026, 4th year!)
Founding Member 0001 - Randy Smith WU2S (Renewed 2026, 4th year!)
Founding Member 0002 - Chris Osburn KD7DVD (Renewed 2026, 4th year!)
Founding Member 0003 - Don Rotolo N2IRZ (Renewed 2026, 4th year!)
Founding Member 0004 - Bill Arcand W1WRA (Renewed 2026, 4th year!)
Founding Member 0005 - Ben Kuhn KU0HN (Renewed 2026, 4th year!)
Founding Member 0006 - Todd Willey KQ4FID (Renewed 2025, 3rd year!)
Founding Member 0007 - Merik Karman VK1DF / VK2MKZ (Renewed 2026, 4th year!)
Founding Member 0008 - Prefers To Remain Anonymous 08 (Renewed 2025, 3rd year!)
Founding Member 0009 - Prefers To Remain Anonymous 19 (Renewed 2025, 2nd year!)
Founding Member 0010 - Merik Karman VK1DF / VK2MKZ (Renewed 2025, 3rd year!)
Founding Member 0011 - Rick Prelinger W6XBE (Renewed 2026, 3rd year!)
Founding Member 0012 - Ryan Tolboom N2BP (Renewed 2025, 2nd year!)
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Zero Retries 0264 was published on 2026-10-02. This issue was 9078 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

That’s the frequency allocation for the 70 cm band in most of the US. In the rest of the world, it’s more restricted such as 430-440 MHz in Europe, and 430-450 MHz in Canada.

2

I think we’re comfortably out of the era of new analog radio modes, and any new radio mode will be implemented in digital, thus this section is applicable.

3

Many Amateur Radio Operators aren’t aware that encryption is allowed in Amateur Radio - for commanding satellites and remote control vehicles.

]]><![CDATA[Zero Retries 0263]]>https://www.zeroretries.org/p/zero-retries-0263https://www.zeroretries.org/p/zero-retries-0263Sat, 26 Sep 2026 06:02:06 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its sixth year of publication, with 3600+ subscribers.

Zero Retries Digital Conference 2026 is October 16th in San Ramon, CA
www.zeroretries.org/p/conference

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

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In This Issue:

I-Frame

ZRDC 2026 Update 09/25/2026
Tina Stroh KD7WSF

The Tao of Zero Retries Digital Conference
By Steve Stroh N8GNJ

APRS Foundation Comprehensive Strategic Plan
Steve Stroh N8GNJ

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Comments on This Issue (Redirects to Comments Page)

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

Optional Paid Subscriptions, and especially Founding Member subscriptions to Zero Retries not only help offset various expenses incurred in publishing Zero Retries, but also are a large portion of the “seed capital” that is needed to host Zero Retries Digital Conference (ZRDC) 2026, and future ZRDCs. Thank You!

My thanks to Ben Kuhn KU0HN for renewing as Founding Member 0005 to Zero Retries in the past two weeks (4th year)!

My thanks to Prefers To Remain Anonymous 47 for renewing as Founding Member 0018 to Zero Retries this past week (xx year)!

Founding members are listed in every issue of Zero Retries!

My thanks to Harris Butler NN0Y for renewing as an Annual Paid Subscriber to Zero Retries this past week!

My thanks to Prefers To Remain Anonymous 95 for renewing as an Annual Paid Subscriber to Zero Retries this past week!

My thanks to Prefers To Remain Anonymous 137 for becoming a new Annual Paid Subscriber to Zero Retries in the past two weeks!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0263. Paid subscribers can comment directly on the web version of this issue.

ZRDC 2026 Update 09/25/2026

By Tina Stroh KD7WSF
Zero Retries Digital Conference Manager

This is the sixth in a series of updates leading up to Zero Retries Digital Conference 2026.

We are counting down to ZRDC 2026 with just three weeks until conference day! This week, I have confirmed all of our speakers, the menu has been set for a welcome breakfast, we have received an additional door prize, media releases sent to various amateur radio blogs, invitations sent to Oregon and California Ham Radio Clubs, and invites sent to California and Oregon colleges and universities with active amateur radio clubs. In total, over 400 emails have gone out.

There are two items I would like to review regarding registration. First, if at all possible, please register by 10/9/2026. Like last year, I will need to give the venue a head count for breakfast. It will be possible to register at the door but unfortunately, it would not include breakfast. So, please register ASAP.

The second item is the types of registrations. I have created various ways to attend the conference. For instance, if you prefer not to attend in person, you can purchase a virtual ticket. With an added expense to us, we have asked our AV vendor to set up a live feed so that anyone purchasing this ticket can see AND participate just as if you were in the conference center. Another option for those who may not be available on 10/16/2026 is to purchase the conference video prior to its release date to the public. With these options, I continue to encourage people to attend in-person as nothing can take the place of face to face conversations with fellow Hams or joining in a panel discussion, however we do respect and honor travel and time constraints.

Roster of Speakers

Steve Stroh, N8GNJ
Topic: Review of ZRDC 2025, Update on LinHT Project, AMSAT CubeSatSim

Glen Popiel, KW5GP
Topic: Microcontroller Communication Technologies and Protocols for Ham Radio

Mooneer Salem, K6AQ
Topic: Free DV

Craig Lamparter, KM6LYW
Topic: Digi Pi

Jeff Scoville, AE5ME
Topic: M17

Cale Mooth, K4HCK
Topic: NewTechHams

Dave Platt, AE6EO
Topic: Open TNC

Martin Alcock, VE6VH
Topic: IP 400

Panel Discussion regarding encryption:
Steve Stroh, N8GNJ
Bruce Perens, K6BP
Craig Lamparter, KM6LYW
Others TBD

Hospitality

Because the conference will be starting early and many local people may be traveling, there will be morning refreshments/Continental Breakfast to get your day started. Donated by your hosts Tina and Steve Stroh.

Lunch will be on your own at any of the five restaurants and food stations directly in the conference center. Unfortunately, no outside food can be brought into the Conference Center per their rules. However, there is outside seating for those who wish to bring their own food. Coffee, tea and infused waters will be available all day.

Door Prizes

Unlike other events, you will not need to purchase additional tickets to win a door prize.

Each in-person registered attendee will have a door prize ticket in their registration packet / goody bag that will be given to the attendee upon arrival.

Donors and Door Prizes include:

  • GigaParts: five (5) QRZ-1 radios. The Explorer QRZ-1 VHF/UHF 5W handheld transceiver that can be personalized with your name and callsign.

  • AllScan.info: five (5) UR150 USB Radio Interface - AKA AIOCC++

  • CentyLab: three (3) Pocket PD HW 1.3 - Anderson Powerpole version and six (6) PPS Trigger V2.2

  • NA6D: five (5) AIOC assembled with enclosure and two (2) OpenTNC with both cables.

Sponsors:

We we would like to thank our sponsors for their gracious donations:

  • Allscan.info

  • ARDC

  • Centy Labs

  • GigaParts

  • NA6D

Conference Links:

ZRDC 2026 Registration - Zero Retries Digital Conference 2026 Registration - Click Here

Zero Retries Digital Conference - www.zeroretries.org/p/conference

About Zero Retries - www.zeroretries.org/about

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0263. Paid subscribers can comment directly on the web version of this issue.

The Tao of Zero Retries Digital Conference

By Steve Stroh N8GNJ

A Zero Retries reader recently took me mildly to task for “blathering on constantly about Zero Retries Digital Conference (ZRDC)”. They asked “What… is the big deal about this conference of yours?”

I think that ZR reader raises a fair point that deserves an answer.

Many of the most profound experiences of my Amateur Radio career, that has been the basis of a lot of info that I impart here in Zero Retries, has been from attending a number… perhaps as many as fifteen or so, (Amateur Radio) Digital Communications Conferences (DCCs) in various cities in North America.

I also helped Tina host DCC 1996 and DCC 2013 in the Seattle, Washington area, which were the first and second best-attended DCCs. Tina and I assisted TAPR with a number of DCCs after DCC 1996. Tina and I also negotiated with TAPR to host DCC 2017 in the Seattle area, but those negotiations just didn’t quite work out.

Attending the DCCs has been intense experiences for me. You can be around and listen in on conversations by some of the smartest people in Amateur Radio about some of the most interesting projects and technology in Amateur Radio. You can also ask questions and learn from those smart people. An Amateur Radio DCC is qualitatively different than professional conferences because we’re all “just Hams” and everyone at a DCC is universally helpful, informative, and pleasant. I just couldn’t help but get excited about the incredible possibilities inherent in Amateur Radio from those exposures to smart people doing interesting things in Amateur Radio. Not only did those experiences influence my Amateur Radio career, but they also meaningfully contributed to my “work” career path from being an electronic technician into being a technology writer.

Disclaimer - Most of what follows about the history of the DCCs is from personal memory, which is incomplete and may be faulty.

Terse History of the DCCs

The first “DCC” (actually, the ARRL Computer Networking Conference)1 was held in 1981 and there has been an annual DCC through 2023 - more than four decades! From 1993 through 2023, the DCC has been hosted by TAPR with some assistance from ARRL. In the final decade of (what I call) the TAPR DCCs, they were organized by a small pool of volunteers at TAPR, primarily Steve Bible N7HPR.

One of the complexities of the TAPR DCCs was an early decision to “rotate them around North America”. That meant that every year, much of the work of planning a DCC had to start from scratch - a new city, a new venue, etc.

Tina and I both witnessed the “power” of the DCCs. Just one small vignette was a trial at DCC 1996 (I think) to host two students to present an academic paper at a DCC. There was a “Call for Student Papers” and the submissions were professionally vetted by several academics associated with TAPR.

I think that ARRL contributed financially to a small stipend for the expenses of the two finalist students to travel to the DCC, along with a small cash award. My impression was that traveling to and presenting at DCC was formative for those two students

But, over the past decade, putting on the DCC had become increasingly expensive and complex.

In TAPR PSR #156 Summer 2023, there was this terse mention of TAPR DCC 2023:

2023 ARRL and TAPR Digital Communications Conference (DCC)

The officers and directors of TAPR are weighing the options for holding a Digital Communications Conference this year. Most likely it will be an online virtual conference rather than a live in-person conference. An announcement concerning the DCC will be forthcoming soon.

Ultimately, TAPR decided to hold an (online only) Mini DCC and Membership Meeting on 2023-12-09.

In TAPR PSR #157 Spring 2024, there was this terse mention of TAPR DCC 2024:

2024 DCC Plans

The 2024 ARRL/TAPR Digital Communications Conference is scheduled tentatively for September 20-21, 2024, in Knoxville, Tennessee. Phil Erickson, W1PJE, Director of the MIT Haystack Observatory, has agreed to be the DCC banquet speaker.

More details will be forthcoming.

On 2024-07-19, this article was posted on the TAPR website:

2024 DCC Canceled

After careful consideration and weighing all available options, we regret to inform you that the 2024 ARRL/TAPR Digital Communications Conference (DCC), scheduled for September 20-21, 2024, has been cancelled. This decision was not made lightly, but due to logistical challenges, we believe it is in the best interest of all involved.

We understand the inconvenience this may cause and sincerely apologize for any disruption to your plans. We appreciate your understanding and support during this time. Should you have any questions, please do not hesitate to contact us.

That was the last mention of a TAPR DCC (that I’ve seen, to date).

At Hamvention 2025, at the TAPR booth, I talked to one of the TAPR officers, and that person told me (paraphrased):

TAPR is out of the DCC business. We just don’t have the resources anymore.

Genesis of the Zero Retries Digital Conference

Having seen all the cool things that happen at DCCs, and the beneficial effect of the DCCs on Amateur Radio, Tina and I felt that it was a real loss for Amateur Radio to not have an in-person, three day DCC.

After the announcement of the cancellation of TAPR DCC 2024, Tina and I began casually brainstorming how / when to put on a conference as an outgrowth of Zero Retries. We felt we had a few advantages that we could leverage for a new version of a DCC2:

  • Publishing Zero Retries for more than three years has provided a wide perspective of various technological innovations that were occurring in Amateur Radio.

  • Tina and I have a tight “coordination loop”. We’re both retired, live in the same household, and Tina is fantastically organized.

  • We had some “seed capital” to work with from the (optional) paid subscribers, especially the Founding Members, of Zero Retries.

  • We don’t feel constrained that we have to follow the same format, etc. as the TAPR DCCs.

  • Since the TAPR DCCs were no longer being held, in creating our own conference, we weren’t going to be competing with the TAPR DCC.

In early 2025, we learned that the GNU Radio Conference (GRCon) 2025 would be held that September in (nearby to us) Everett, Washington. GNU Radio is, of course, Zero Retries Interesting and Tina and I decided to offer our services to GNU Radio since we were local, and none of the GNU Radio staff were local to Everett. We quickly learned that none of the GNU Radio staff had seen the venue in person.

Not only did we have a great time working with the GNU Radio staff for GRCon 2025, I was able to attend GRCon 2025 for the entire week and I learned a lot.

GRCon 2025 was Monday through Friday, and Tina and I quickly realized that “tagging on” to GRCon 2025 and its venue was an ideal opportunity to realize our ideas for our Zero Retries Digital Conference. We scrambled a bit, and (the first) Zero Retries Digital Conference 2025 was held on Saturday, September 13, 2025 at the same venue as GRCon 2025.

We consider ZRDC 2025 a great success, especially for a very small team and only a few months of preparation. Everyone who attended ZRDC 2025 seemed to have a great time and learned a lot. Most importantly, we were strongly encouraged to do a ZRDC in 2026.

ZRDC Content Mix

One of the things I observed at the TAPR DCCs, particularly the last decade or so is that the content mix of the speakers was pretty ad hoc, at least compared to the content mix of prior decades of the DCCs. TAPR would post a notice that the DCC was accepting proposals for speaking and technical papers for the upcoming DCC… and whoever responded, on whatever topic, became the agenda. Other than a preference for “digital” related to Amateur Radio, there was little curation of topics.

When considering the content mix for Zero Retries Digital Conferences, we had a strong advantage of a high-level view of the technological innovation that was occurring in Amateur Radio. Thus we had a good overview of “who was doing what” that would make for an interesting presentation at ZRDC. At ZRDC 2025, Tina and I were particularly proud that we presented some new, unique technological innovations in Amateur Radio such as The KK7NQN Transcriber Service Node by Hunter Inman KK7NQN and Earth Moon Earth With Software Defined Radio by Dennis Rosenauer AC7FT.

Fast forwarding to ZRDC 2026, we’ve applied the same “filter” of technological innovation occurring in Amateur Radio in 2026, with a (mostly) new mix of Zero Retries Interesting topics.

At ZRDC 2026, there will be demonstrations including the AMSAT CubeSatSim and an M17 repeater, hopefully M17 data communications, and a demonstration of the new NA6D OpenTNC (especially the use of FX.25 and AX.25 Version 2.2). We had hoped to demonstrate the new IP400 Advanced Mesh Network Controller (AMNC) board, but unfortunately the timing of “production” AMNC boards wasn’t compatible with the ZRDC 2026 schedule.

See Speakers and Topics on the ZRDC 2026 page.

As for replicating the three-day experience of the TAPR DCCs, that is a long-term goal for future Zero Retries Digital Conferences. But, we’re still learning how to do marketing that’s effective enough to attract enough attendees to financially justify a three-day standalone conference. Or, alternatively, finding the right mix of attendees and fiscal sponsors.

Lastly, it’s worth mentioning that there have been other “DCC” events such as the Utah Digital Communications Conference.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0263. Paid subscribers can comment directly on the web version of this issue.

APRS Foundation Comprehensive Strategic Plan

By Steve Stroh N8GNJ

I very, very nearly missed this development. I’ve been checking the APRS Foundation website for “signs of life” for some time (I’ve had high hopes for the organization). I did so again today in preparation for a couple of articles in this issue. At a glance… no signs of life - the last article on the main page was APRS updates - July 2025.

But, because I’ve visited this website a number of times, I noticed “something” at the last moment (I had actually clicked away from the website). I returned to the website and noticed a new item on the top bar:

Strategic Plan

OK, maybe that’s worth a quick check. I’m glad I did.

The following is merely some bare bones intro of the 34 or so pages of this document. There’s a lot of substance to this document and it’s going to take time to digest, but I think it will be worth doing so.

Letter from John Tarbox (WA1KLI), the Foundation President

May 20, 2026

Dear APRS Enthusiast,

Thank you for taking the time to read and consider our project, the APRS Foundation’s

Comprehensive Strategic Plan. I personally knew the inventor of APRS back in the day, Bob Bruninga, WB4APR (SK), and I like to think that he would be proud of his creation and of what we, the APRS Foundation, are working on to keep it alive.

My team has labored for over a year on this plan. It took long hours of deliberation, research, and late nights to come up with a strategy that would carry Bob’s vision forward as he intended: to have APRS owned and developed by the ham radio community. We believe this plan embodies this very idea: APRS is so large now that it does need some organization, but that organization must come from the APRS hams themselves.

This plan represents our best effort to help the APRS community today and for many, many more tomorrows. It will change and adapt, like everything in Amateur Radio, but this is where we begin, and that beginning represents a lot of effort yet to come.

If, after reading this plan, you are interested in helping make any of this happen, please use the Contact Us form to reach out! We can use all the help we can get!

Thanks for being part of this amazing hobby!

John Tarbox, WA1KLI
President
APRS Foundation

…

Introduction

Welcome to the APRS Foundation’s Comprehensive Strategic Plan. This document details the Foundation’s long-term (more than 10 years) perspectives and goals on how it can best serve the APRS community today and tomorrow. Strategic plans are living documents and can change as the Foundation and APRS changes over time. What is presented here are our best ideas as to what the Foundation can provide to help keep APRS working and relevant. Over time the goals in this document will become more refined and true. We welcome you to be a part of that process by engaging with the Foundation on any of its strategic goal teams.

Until the passing of Bob Bruninga, WB4APR (SK), APRS’s direction and vision was held by one man, the inventor of APRS, Bob. The Foundation recognizes that since Bob first published APRS in 1992, APRS has grown to become a world-spanning ecosystem. This size and complexity go well beyond Bob and his initial vision: it is people from all parts of the globe coming together with different solutions and technologies to form a whole ecosystem of what APRS is today. Because of the sheer size and complexity of APRS the Foundation believes cooperative teams are needed to maintain a unified strategic heading with APRS while managing the adoption of new technologies into the ecosystem.

This document does not linger on the detailed definition of APRS. That is left to the technical aspects of the APRS Standard and APRS Reference Implementation. What this document does do is establish the core principals the APRS Foundation believes must be present in APRS to be successful long-term. Those strategic principals are then extended to activities and outcomes that support those principals. You’ll find those later in this document.

If you’re interested in helping the APRS Foundation, please use the Contact Us form to reach out!

The APRS Foundation is always looking for people who are invested in APRS and want to see the best for it and the amateur radio community.

Strategic Plan Components

The APRS Foundation’s Strategic Plan encompasses the following:

  • A definition of what APRS is and is not.

    • This definition is critical to understand what the Foundation will focus on in a world that widely uses the term “APRS”. While we believe APRS is specific, the term “APRS” has come to mean a wide variety of similar things that may often change. While some “APRS” things will naturally fall outside of our definition, we don’t assert that they aren’t APRS. The definition we use focuses the Foundation’s efforts solely on specific, achievable deliverables.

  • A statement of purpose.

    • Following the passing of Bob Bruninga, WB4APR (SK), the Foundation believes there is a need for a more formal effort to maintain the APRS community.

  • Specific strategic goals.

    • We have identified a series of must-have strategic goals that we believe make APRS a success for Amateur Radio. These are the goals that all our actions live up to.

  • A set of “within-the-next-few-years” deliverables to the community.

    • The Foundation has identified a set of tasks and an organizational infrastructure that will best serve the entire APRS community. The Foundation will assist in building these deliverables in accordance with our must-have strategic goals.

Again, roughly 34 pages (per my printer setup). As for me, I’m going to print this out (yes, guilty as charged for being old school) and mark it up and then follow up.

Kudos to the authors of this document:

  • John Tarbox WA1KLI

  • John Langner WB2OSZ

  • Pete Loveall AE5PL

  • Jason Rausch K4APR

  • Ron Startzel KB5LNC

  • Don Rolph AB1PH

  • Lion Templin K1LEO

because it’s a thorough deep dive of a vision of long term evolution and success for APRS and by extension, Amateur Radio in the 21st century.

Lastly, ’ll permit myself one “snipe” at APRS Foundation leadership:

Why didn’t you publicize this significant document far and wide and loudly?

It’s a very significant document and worth a serious study and consideration by anyone who cares about the evolution of APRS and its keystone role in Amateur Radio.

Well, maybe a second “snipe”…

Why didn’t APRS Foundation reach out to the techies / techie publications within Amateur Radio, including Amateur Radio Newsline, ARRL News, Zero Retries, and every “media” in Amateur Radio?

I’m well connected, well read on the subject of technological innovation in Amateur Radio… and I only accidentally found out about this - four months after it was released.

In my opinion, APRS Foundation could use some “marketing / promotion” help in getting the word out in the future.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0263. Paid subscribers can comment directly on the web version of this issue.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

Followup on Amateur Radio ATSC 3.0 from Ron Economos W6RZ

In Zero Retries 0262 - Amateur Radio ATSC 3.0 and Narrow Band TV, I mentioned:

ATSC 3.0 --- Ron [Economos], W6RZ, of Mountain View, California, also reports doing experimentation on ATSC 3.0. (w6rz@comcast.net).

…

This is a Zero Retries Interesting development! I had no idea that ATSC 3.0 equipment / systems had been driven downscale to the point where it might be feasible to use for Amateur Radio… though with all things SDR, ATSC 3.0 is probably mostly software. Maybe with the datacasting capability of ATSC 3.0, if it becomes adopted within US Amateur Radio, we could “bridge the divide” between realtime television folks and data communications folks on the same system / spectrum. This potential is actually kind of a SuperPeater.

I’ve emailed W6RZ for more details.

W6RZ replied with a lot of detail!

As you know, I have a GNU Radio OOT that implements an ATSC 3.0 transmitter.

https://github.com/drmpeg/gr-atsc3

It should run on any transmit capable SDR, but I’ve only tested it on the Ettus B210 and Nuand bladeRF 2.0. It only implements the PHY layer and the legacy Transport Stream interface, so it doesn’t work with regular ATSC 3.0 TVs or STBs. These devices expect the ROUTE/DASH packet layer that delivers video/audio.

However, it does work with the popular HDHomeRun FLEX 4K receiver from SiliconDust (which supports the legacy Transport Stream mode).

https://shop.silicondust.com/shop/product-category/atsc/

I have a couple of demo clips on YouTube. The first one is running on a BeagleBoard X15 to show that it doesn’t need a big CPU to run on.

The second clip is running at a negative (-2 dB) SNR. The SNR meter on the HDHomeRun doesn’t go below 0 dB, so you have to watch how I decrease the B210 power level to see how I arrived at my -2 dB estimate.

I haven’t made any real contacts. It’s all just between two rooms in my house. You’ll notice that the HDHomeRun is tuned to cable channel 65, which is 468 to 474 MHz (471 MHz center frequency). But I’m really transmitting on 2304 MHz (2301 to 2307 MHz) and using a Kuhne 2 GHz downconverter with a 1833 MHz LO. So 2304 -1833 = 471 MHz. This is so I can use small antennas with plenty of gain inside the house.

I’ve implemented almost the entire PHY specification including multiple stream modes (known as Physical Layer Pipes or PLPs). The only thing missing is MIMO (which there are no commercial receivers for). Here’s a pic of a flowgraph with a block that has a huge amount of parameters.

ATSC 3.0 flowgraph

I did join the ATSC as an observing member. This was so I could get my hands on the verification and validation test vectors. These files test each block with a binary input file and an expected binary output file. I would not have been able to finish the project without them.

As for amateur radio use, I was happy to see KD6ILO getting some mileage out of gr-atsc3. However, most hams don’t like the complexity of GNU Radio and prefer packaged solutions like the HiDes DVB-T equipment.

D’Oh! Of course GNU Radio would have a version of ATSC 3.0 because GNU Radio does everything related to radio technology.

One of my takeaways from attending GRCon 2025 is that if you are able to develop a GNU Radio flowgraph, you don’t have to treat it like a perpetual prototype. It’s possible to “package” a flowgraph to “just run it” for the benefit of those, like me, who aren’t intimately familiar with GNU Radio. I don’t remember the details3, but that’s one of the many things (I think) I picked up at GRCon 2025.

VA7EET’s AETV Project - Video in 2.25 kHz

Email from Patrick Laing VA7EET in response to Zero Retries 0262 - Amateur Radio ATSC 3.0 and Narrow Band TV:

After seeing in Zero Retries this week about ZL1WTT’s [full motion video in] 100 kHz project, I felt I should share with you my AETV project that can fit video into bandwidths as small as 2.25 kHz using an autoencoder based approach, similar to RADE.
For more info, I have a blog post with video samples over both emulated and real paths at https://plaing.ca/posts/aetv/

It’s low resolution, and a bit... impressionistic at times, but it is moving pictures in some VERY small channels :)

Repo - with windows/linux portable packages : https://github.com/plaingca/AETV

It is still pretty early in development, and you might run into a few bugs here and there, but the core modes have all been tested over the air, primarily with FlexRadio hardware to KiwiSDRs for HF and PlutoSDR / RTL SDR for receive for the AC16 - 16 kHz wide mode, and seem to work pretty well given the extreme compression occurring here.

Feel free to send over any questions or comments!

VA7EET instantly intrigued me with this Zero Retries Interesting description of his experiments in the referenced blog post:

AETV - Teaching a machine to squish video where it shouldn’t fit

September 17, 2026 · 7 min read

What if we squeezed video through a radio channel barely wide enough for a conversation? AETV uses neural compression, questionable amounts of GPU time, and amateur radio to turn pictures into strange numbers, fire them through the ether, and politely ask another neural network to put them back.

The journey

Back in the middle of August, while farting around with new frontier LLM drops from Google, Anthropic, and OpenAI, an old idea I’d had for a couple of years resurfaced:

SSTV with convolutional autoencoders should result in higher-quality images under a similar power and bandwidth bottleneck.

That was the hypothesis, anyway. The fun part was finding out it actually works.

The appeal is pretty straightforward. I want to move pictures through a radio channel with very little room to spare, without losing the graceful degradation that analog SSTV provides.

He had me at questionable amounts of GPU time 🤣

Long-time Zero Retries readers are probably tired of me repeating this chestnut from my career writing about Broadband Wireless Internet Access. I was told in the early days of implementing OFDM in Broadband Wireless Internet Access systems, before it was widely used in mobile telephones and Wi-Fi, OFDM had been developed decades earlier. But… then it required the compute power of a (very expensive and very large) DEC VAX. For OFDM to be practical and widely used, technology had to catch up.

The “moral” of this story is to not make the mistake that a particular idea isn’t practical or doable because of current technology constraints or cost-effectiveness. If something can be implemented, however rude, crude, unattractive, not quite practical, or not yet cost-effective… eventually technology will catch up to make it practical and cost-effective.

There are gazillions of examples just in Amateur Radio. One of my favorite examples is the background single bit error passive correction technique in Dire Wolf, practical because why wouldn’t you put the idle CPU power to work doing something useful in an otherwise underutilized quad core 1.2 GHz 64bit CPU in a $35’ish Raspberry Pi 3B+ (or similar units).

I wonder if “questionable amounts of GPU time” falls within the capabilities of the newest consumer Macs?

The current “low end” MacBook Air ($1299) processor complement is:

Apple M5 chip

  • 10-core CPU with 4 super cores and 6 efficiency cores

  • 8‑core GPU

  • Neural Accelerators

  • Hardware-accelerated ray tracing

  • 16-core Neural Engine

  • 153GB/s memory bandwidth

Macs are now being bought solely because they are good enough platforms for doing offline (non-hosted) AI work. So, I bet they could handle the workload outlined by VA7EET for his low-bandwidth video experiments.

So apparently we’ll soon (enough) have full(ish) motion video in a narrow bandwidth! My thanks to VA7EET for imagining this possibility…

It just didn’t occur to me to imagine the possibility
of video using the equivalent of an FM voice radio.

I really love the brain trust like W6RZ and VA7EET that has self-selected around Zero Retries.

GNU Radio World - GNU Radio in a Browser

Welcome to GNU Radio World!

GNU Radio, entirely in your browser — explore the open-source SDR ecosystem with zero install! GNU Radio World is a browser-based GNU Radio Companion flowgraph editor and WebAssembly runtime. It includes most actively maintained OOTs, dozens of example flowgraphs, and signal recordings to play with.

…

New to GNU Radio? Start with the beginner-level GNU Radio tutorials. New to RF signal processing and SDR? Check out PySDR.org. Then try the built-in Challenges under Example Flowgraphs.

GNU Radio World includes a collection of RF recordings that are streamed to your browser when you use them within a flowgraph. Visit the Signal Recordings tab and try clicking the “View” button on one of the recordings to inspect it in the built-in recording view, adapted from IQEngine. Many of the included example flowgraphs use these recordings, so OOTs can be demonstrated with real recordings of their corresponding signals. You can also contribute your own SigMF recording.

This is another development that wouldn’t previously have occurred to me, but seeing it, it makes complete sense. This is a low-barrier way to experiment with existing GNU Radio flowgraphs that you’re curious about.

Hackaday also had a good overview of GNU Radio World - It’s GNU Radio Companion, But In The Browser.

Free Electrical Engineering Books from the University of Michigan

Dan Romanchik KB6NU:

…

Michigan Publishing Services is the publishing arm of the University of Michigan, and you can freely download the PDF versions of a wide variety of their books.

This month’s edition of their newsletter, The Voracious Reader, features several electrical engineering books. If you really want to dig deep into the theory behind amateur radio and electronics, here’s your chance.

Book cover for the book Digital Communications showing a satellite above the Earth.
Digital Communications is one of the electrical engineering books featured in this month’s newsletter from Michigan Publishing.

You can find the entire selection of EE books offered by Michigan Publishing by going here. But, the first title to catch my eye was Digital Communications: Modulation, Coding, and Information Theory. Digital modes are a big deal in amateur radio today, and if you really want to understand the theory behind packet radio and FT8, I suggest you give this book a go.

Wow - what a great resource! I’ve read that universities and especially professors are increasingly creating their own textbooks so that can incorporate the elements they consider critical instead of assigning “additional reading beyond the textbook” and be able to make it available at no cost, via PDF, to their students, some of whom just would try to limp through the course without buying the (expen$ive) textbook.

My thanks to Zero Retries Pseudostaffer Dan Romanchik KB6NU for bringing this development to my attention for inclusion in Zero Retries.

Press Release from Alberta Digital Radio Communications Society (ADRCS)

Press release provided by ADRCS:

Calgary, September 25th, 2026. We are pleased to announce that the development effort to verify the pre-production prototypes of the Advanced Mesh Network Controller has been completed, and it is now ready for production. The society has engaged Digital Hamstore Inc. to facilitate this effort, an agency that specializes in manufacturing and distribution through partner networks. The distribution channels and availability will be announced at the upcoming Zero Retries Digital Conference.

The Digital Hamstore site is currently “under construction” but it sounds interesting.

Post-publication Update - The Digital Hamstore site is live, and the first item listed under Projects is the Advanced Mesh Network Controller… but no details on availability or price.

Unfortunately the timing of the AMNC going to production means that there won’t be any units available to demonstrate in person at ZRDC 2026 in three weeks. But, Martin Alcock VE6VH promises a demonstration of his (development version) AMNCs as part of his (remote) presentation.

The RP2040 Minimalist HF Transceiver: A Low-Cost, High-Fun Sandbox for the Radio Tinkerer

Learn on the fly blog:

After taking a break from homebrewing, seeing the incredible creativity and dedication in the ham radio community completely inspired me to dive back in. I’m taking things slow this time around, focusing on a rough prototype that is incredibly easy to build upon, swap parts, and experiment with. My latest project moves away from legacy design complexities, opting instead for a modern, digital-first approach.

It’s a work in progress, but it’s a fantastic canvas for tinkering. I’m excited to see where this experimentation leads—stay tuned for updates as I continue to tweak

By pairing the dual-core processing power of the Raspberry Pi RP2040 with highly integrated, inexpensive breakout boards (the Si5351 and Si4732), this setup bypasses legacy design complexities to get you on the air quickly and cheaply. Plug a single USB cable into your PC or phone, fire up WSJT-X or FT8CN, and you are ready to transmit!

Project Philosophy: The Joy of “Good Enough” Radio

Let’s be clear: this project is not trying to compete with factory-built, precision instruments like the QMX or QDX. Those are highly optimized rigs with tightly engineered multi-stage filters and custom transformers. I could feel the amount of heavy work needed just by struggling with my FSK routines to send the FT8 audio to ether. Not to mention the other hurdles in putting everything into an orchestra!

Instead, this rig is all about complete hardware ownership and experimentation. It is an open sandbox proving that getting on the air with digital modes doesn’t require a $$$ commercial setup. It is pure, old-school amateur radio tinkering updated for the 21st century! If you want an out-of-the-box and inexpensive solution, I strongly recommend a QMX or QDX or G90.

Features

  • Single-Cable Digital Station (UAC2 + CAT): No external sound cards or tangled interface boxes. A single USB connection handles both bidirectional digital audio (24-bit/48kHz) and Kenwood TS-480 CAT control commands concurrently.Works with WSJT-X, qFT8, FT8CN, and FT8TW etc

  • Stand-Alone Beacon Mode: Test your antennas or propagation completely headless. Set up the radio as an independent, fully autonomous FT8 or WSPR beacon—no computer required.

  • “Type-to-Talk” CW Terminal: Plug into any standard serial terminal (like PuTTY, minicom, or screen). You can use a physical automatic keyer, or simply type text into the terminal to send beautifully timed Morse code over the air.

  • QMX-Style Interactive Serial UI: Includes a comprehensive terminal command suite. Type ? to explore, change bands, tune frequencies, calibrate the internal reference clock down to parts-per-billion (ppb), or check real-time system diagnostics.

  • Massive RX Coverage, Focused TX Power: Enjoy wide-open listening across the Si4732’s entire multi-mode spectrum (AM, FM, and shortwave SSB bands). For transmission, the firmware controls a simple Power Amplifier (PA) and Low-Pass Filter (LPF) switched across two targeted bands (easily expandable by mapping more GPIOs).

  • Rock-Solid Dual-Core Architecture: Core 1 dedicates its entire focus to flawless, low-latency DMA analog audio capturing. Core 0 manages the smooth graphics on the OLED, processes your encoder inputs, runs the beacon sequencing, and handles USB traffic without missing a beat.

Recently I’m seeing a lot of Amateur Radio projects making use of the Raspberry Pi RP2040 microcontroller.

This was spotted via Hackaday - A Thoroughly Modern Minimalist Transceiver.

MacWinlink

J.C. Wilson KC8JC:

This is one of those times where I feel like I’ve been living under a rock.

The main UI of the MacWinlink application. It looks like, well, a modern mail client.
The main UI of the MacWinlink application. It looks like, well, a modern mail client.

Where Did This Come From?

I’m not sure when this project fired up, but it’s the kind of thing that I feel like I should have picked up on sooner. Oh well! At least I got to the party. And it is a party.

I’ve gone on at length about Winlink and the many and varied ways to send email over RF. My current GoTo system has been pat with a side helping of VARAHF most days running under a CrossOver (WINE) setup with rigctld as the backbone. Running this on my Mac Just Works™ and it makes me happy. pat on the command line is a dream. Easy to use, quick to configure, and available on any platform in my shack (mobile or otherwise).

For me, a person who is comfortable with the command line and rigctld and all of the other little bits and pieces that go into this process of getting an email sent, this isn’t a significant hill to climb. In fact, pat with its web UI is really, really easy to use. I recommend it all the time. I also spend some time putting together scripts for people that help them get this stuff running with a single command rather than remembering the other stuff. Top that off with a healthy conversation around modems and, well, yeah. In 2026 Winlink still isn’t a slam dunk. That’s a problem.

Enter MacWinlink!

…

Another trend I’ve noted that’s really taken off in 2026 is many, many new Amateur Radio apps that make operating Amateur Radio much more easy and intuitive thanks to really well-designed user interfaces. Some of this is undoubtedly due to software development getting easier / more efficient / faster from AI assistance. I think another trend is that talented software developers are finding their way into Amateur Radio, and start experimenting with various modes and software, and decide “this sucks; I can do a lot better”.

Mac users are really benefitting from this trend.

MacWinlink is so new it’s not yet listed on the canonical Mac Ham Radio website.

Apple Amateur Radio Bulletin

Andrew Woodward VK2AWN:

Well, if you are going to get the shiny new M6/M5 Mac Mini or the new iPhone Duo, you’re going to want great new and updated amateur radio apps to put on them, right? Well, there’s no shortage of good stuff to choose from. If you have a tip, news, or and good ideas for the bulletin, please contact me, Andrew VK2AWN. You can also download this bulletin as a PDF.

Items are presented alphabetically; mention doesn’t imply endorsement or use, and no listings are paid for or in kind. Items are sourced through social media posts, web sites and online news services. Pricing key (USD) $=1-9 - =10−24−$=25+. ???: Unsure of price. ***: Owned and used by the writer. First edition publishes on the second Friday of the month. The late edition publishes on the fourth Friday of the month.

Speaking of using Apple products in Amateur Radio getting more popular, in addition to the Mac Ham Radio website, we now have the Apple Amateur Radio Bulletin - a new newsletter (via Substack) by Andrew Woodward VK2AWN. One nice thing about Substack newsletters is that each one has a RSS feed, so I’m now following AARB in NetNewsWire.

Plug and Go Allstar Node Z2 with Color Screen, Speaker and Microphone

Mark Herbert G1LRO on g1lro.uk:

New: Download User Guide .

Buy Online

Buy Online: Now shipping with May software release including Allscan built-in:
Preview video from M0FXB:

Introducing the new all-in-one appliance for AllStarLink and similar radio applications.

The unit contains all the required components to operate as an ASL node, fabricated into a sturdy aluminum enclosure with front-panel controls, no PC required.

What’s in the (Radio-less-node) RLN-Z2?

  • A powerful Raspberry Pi Z2 W processor with WiFi

  • 32GB SD card with ASL3 and the G1LRO custom setup firmware pre-installed

  • 1.25 inch color LCD screen with button navigation to select favorite node connections in ASL3

  • Audio interface based on the industry-standard CM108 sound processor

  • Powerful 2.5W amplifier with internal speaker – audio design by Allscan.info

  • Controls for microphone gain to support a wide range of microphone types

  • Line-out for connection to auxiliary audio equipment

  • Manual Bourns volume control and External speaker out

  • Sturdy 88x38x100(mm) extruded aluminum case with rubber feet

  • Front panel ‘K1’ microphone socket with supplied mic.

  • Powered from 5v USB-C (cable provided)

Amateur Radio Over Internet is getting ridiculously cool with products like this. This is a radio… without the complexities of radio circuitry and antennas. Those are “externalities” that are remoted “elsewhere”.

The only thing I would have preferred is a RJ45 connector for being able to use “big” microphones (for my above average sized paws) like those for mobile radios from Motorola or Kenwood, but that’s a very minor quibble.

Beyond Packet Radio: Designing a Modern Radio Broadcast
Protocol (HQFBP)

Loïc Fejoz F4JXQ:

20 August 2026 • Loïc • #radio #satellite #DTN #HQFBP #rust

This is the first post in a series exploring Delay-Tolerant Networking (DTN) and resilient communication stacks built for amateur radio, space payloads, and emergency networks.

The Simplex Noisy Satellite Challenge

The FOSM-1 Mission

The main goal of the FOSM-1 experimental satellite mission is to investigate and experiment the agility of radio communication protocols and onboard software. In addition to beacons, telemetry, and telecommands, one of the primary payloads involves broadcasting images and data captured from the onboard camera. It leverages the open source radio board Spino from Electrolab.

The Problem: simplex, noisy, and unconnected

  • Type of files: Bitmaps, telemetry, vector drawings, sensor logs, etc.

  • Link constraint: No feedback loop (no active ARQ/acknowledgment) due to power or orbit constraints.

  • Noisy channel: Designed for a Bit Error Rate (BER) of $10^{-3}$.

Under these constraints, existing amateur radio protocols show clear limitations:

  • AX.25 / PACSAT PFT: Heavy packet overhead.

  • PACTOR / WINLINK: Require active connected-mode handshakes (impossible in simplex broadcast).

  • FLAMP (FLDIGI): Too verbose for tight constraints.

  • and others

The HQFBP Concept (Hamradio Quick File Broadcasting Protocol)

HQFBP was designed to serve as a lightweight, flexible, and robust file broadcasting layer. This was also a way for me to deep-dive into learning the basic building blocks for a radio protocol.

…

It is very cool that F4JXQ has recognized that current Amateur Radio “data broadcast” implementations are ripe for improvement. PACSAT is a step forward (and I’m looking forward to seeing it for myself in the CubeSatSim at ZRDC 2026). But that’s two decades old now. FLAMP is better, but in researching it, there’s more technology that could be applied to it. Thus I’m looking forward to learning more about Hamradio Quick File Broadcasting Protocol - HQFBP as it seems applicable for terrestrial use, such as Amateur Radio repeaters and mesh networks.

GNU Radio 4: Official GitHub Repository

Josh Mormon on GNU Radio:

We have been working hard getting GNU Radio 4 ready for an official release. Part of this endeavor has been restructuring and refactoring the repositories for future maintainability, better build and CI efficiency, and the flexibility to support different licensing models across the ecosystem.

GNU Radio 4 is now organized around a super-repo builder capable of pulling together foundational projects such as the core runtime and key DSP libraries, modules containing both official and experimental blocks, and applications built on top of them.

We also wanted to make the whole thing really easy to build.

The current super-repo is now live at https://github.com/gnuradio/gnuradio4. It provides the top-level workspace that knows which repositories make up GNU Radio 4, their dependencies, and the order in which everything needs to be built. (Note: the git history from the previous gnuradio4 repo has been preserved in its entirety in the constituent components gnuradio4-core, gnuradio4-blocks, and gnuradio4-library). As discussed in https://www.gnuradio.org/news/2026-05-21-gr4-community-stewardship/ - this repo fully supersedes the earlier prototype implementations.

…

CI Efficiency

There are many ways to skin this cat, and a sufficiently sophisticated monorepo CI system can certainly determine exactly what needs to be rebuilt.

But our previous default was much simpler: a pull request could result in rebuilding the core and essentially the entire block library, even when most of that code had nothing to do with the proposed change.

With smaller, more focused repositories, the natural unit of CI becomes much smaller. If a change is made to a block library, we build and test that block library and its dependencies. A change doesn’t automatically imply rebuilding the entire GNU Radio 4 ecosystem.

…

Licensing

Another important goal of this structure is licensing flexibility.

Our vision for GNU Radio 4 is a permissively licensed core on top of which a healthy copyleft ecosystem can grow.

There are users and organizations that are prevented from using or contributing to GPL-licensed software, or for whom doing so creates enough legal and organizational friction that they simply won’t participate. A permissive core allows those users to build systems using GNU Radio 4 and, importantly, contribute improvements back to the foundational infrastructure.

…

I first learned about GR4 last year at GRCon 2025 and it’s making steady progress. Folks I trust who know GNU Radio have described GR3 “a big pile of assorted code” that is in need of a revamp. It sounds like GR4 is a solution to that issue. Also the more flexible licensing in GR4 seems like it could encourage contributions that were previously discouraged by the GR3 licensing scheme.

Why a Raspberry Pi Shouldn’t be Powered Through its GPIO Pins

82MHz:

…

So now back to the original question, why shouldn’t the Pi be powered by sending 5V straight through the GPIO pins into the 5V power rail? After all, it does work. But it skips all this protective circuitry that we just looked at. And so if there’s a low quality or faulty power supply connected to the GPIO pins, there’s a chance that it will damage the components on the board if something goes wrong, killing the Pi in the process and not just blowing the fuse like it would if it were connected to the proper power input.

So in order to avoid risking damage, a Raspberry Pi and similar boards should always be powered through their dedicated power input.

The exception to this rule of course is if the circuit that sends power into the GPIO pins has the same type of protective circuitry on it that the original power input stage has, in which case the Pi is protected through that and powering it this way is fine.

I wasn’t aware that there was, in fact, significant power conditioning circuitry that this article describes in detail on the (specified) power input of a Raspberry Pi. But the MicroUSB power input is a real Pain In The Asterisk. While this article is dated 2026-08-05, the RPi being discussed is a Raspberry Pi 1, so things may have changed a bit since then, especially on the RPi 4 and 5 which require a lot more power.

TOADS Digital Interface and TOADS DI6 Daughterboard

Somehow I wasn’t aware of these products until last month. TO is Temporarily Offline (website name), but I didn’t find a reference to “ADS” in the product names.

I like this description (emphasis mine):

Many radios are fully capable of digital modes like Winlink, FT8, Vara, APRS or even being an Allstar node - if only there was a small/easy way to connect them up and make that happen. For some reason radio makers don’t seem to know that we want to do anymore than talk on our radios.

What if it were easy?

This is the starter board you need - from here you can wire it in yourself, or you can order one of our daughterboards and a cable and you’re all plug and play like!

Designed by hams, for hams.

The manual for the TOADS Digital Interface is pretty good!

Introducing APRS-WebMesg: A Modern, Free Web Front-End for APRS Messaging

If you’ve ever needed to send someone an APRS message from a browser instead of a radio, you’ve almost certainly ended up on FindU.com. It’s been the go-to gratis option for as long as most of us can remember – and it’s also old, unstyled, and not particularly reliable these days.

I got tired of that being the only free option, so I built something better.

Use It Now

USE IT FREE

Use It Now!

Head to https://aprsmsg.w0chp.radio and send a message – no signup, no cost. If you find it useful, tell a friend who’s still bookmarking FindU.com out of habit.

This is actively developed software, not an abandoned side project – expect it to keep improving.

Use APRS-WebMesg

The Problem

FindU.com’s messaging page has been quietly holding the fort for APRS web messaging for a very long time. Credit where it’s due – it’s been there when nothing else was. But:

  • It looks and feels like it hasn’t been touched since the early 2000s.

  • The UI offers essentially no feedback – did your message actually go out? Did it get delivered? Good luck telling.

  • Uptime and responsiveness have gotten increasingly shaky.

None of that is a knock on Steve Dimse, K4HG, who built and has long run FindU.com. His contributions to APRS and the ham community are enormous, and FindU.com’s messaging platform was genuinely inspirational – it’s a big part of why I knew a free, browser-based way to send an APRS message was worth having in the first place. Credit where it’s due.

But it’s also fair to say the tooling itself hasn’t kept pace, and there wasn’t a modern, actively-maintained, free alternative. So I wrote one.

Cool project by Chip Cuccio W0CHP.

An Open Letter to APRS Software Developers & Hardware Vendors: Stop Misusing TOCALL and Messaging-Capable Packet Flags

Chip Cuccio W0CHP:

APRS works because everyone follows the same small set of rules for how a packet identifies itself. Two of those rules are being violated right now, repeatedly, by multiple pieces of software and hardware still shipping today. This is an open letter to those vendors, and a heads-up to the rest of the APRS community about why it matters.

The Two Violations

There are two separate but related problems I keep finding in the wild:

  1. Unregistered TOCALL collisions – specifically APN000, which is being used as a lazy default/placeholder destination address by multiple unrelated vendors, instead of each registering their own unique TOCALL in the official aprs-deviceid registry.

  2. Misuse of the @ (messaging-capable) data-type flag – packets from non-interactive telemetry senders (weather stations, headless gateways) are being stamped with @, which per the APRS spec explicitly declares the station interactive and capable of receiving text messages. It isn’t, and it can’t.

Important

Every TOCALL used on the air is supposed to be unique to one piece of software or hardware. That’s the entire point of the registry – so that decoders, gateways, and filters can identify exactly what generated a packet. APN000 specifically was never allocated to anyone – other APN-prefixed patterns exist in the registry (e.g. APN0A?, APN102, APN2??), but APN000 itself is not one of them. Multiple vendors picking it independently as a fallback defeats the purpose of having a registry at all.

…

This… seems like exactly the kind of issue that could / should be addressed / coordinated / publicized by an organization like the APRS Foundation.

End of Development of ardopcf (by Original Developer)

Peter LaRue AI7YN on the ardop email list:

I've decided to discontinue development of ardopcf.

While I believe that ardopcf is suitable for continued use, I've also included links at https://github.com/pflarue/ardop to other Ardop implementations, including a couple of new AI assisted implementations. If you know of (or are the author of) an Ardop implementation that you'd like me to add to that list, you can create a GitHub Issue (https://github.com/pflarue/ardop/issues) or post here to let me know about it. That list will not include any fork of ardopcf that still uses that name.

More info about the Amateur Radio Digital Open Protocol (ARDOP) project.

Query - Mac Users of FreeDV?

Mooneer Salem K6AQ on the digitalvoice email list:

I’m curious how many Mac users there are here. If you use FreeDV on your Mac, can you tell me what machine you have and what version of macOS you’re using?

The digitalvoice email list is set for replies to go only to list and thus doesn’t expose individual email addresses. If you’d like to register that you’re a Mac user of FreeDV, all I can suggest is to join the digitalvoice email list, at least briefly.

Or… attend ZRDC 2026, where K6AQ is a presenter!

Book - Packet Radio Old Days (Japan)

One of the few Zero Retries Interesting things I saw in several YouTube videos of the recent Ham Fair 2026 in Tokyo, Japan was this book.

It’s subtitled Internetworking with Packet Radio - 1990 - 1991. The author is Naoyuki Kobayashi JK1FNL.

Per Google Translate of the web page:

Since I’m exhibiting anyway, I’ve decided to create a new book. It’s a book about packet radio, something I’ve wanted to put together for a while. The price is undecided, but I’m thinking it will be around the same price as “Introduction to Overseas Amateur Radio Operation.”

The title is “Packet Radio Old Days.” It’s an homage to the title of the column I wrote from 1993 to 1995, “Packet Radio Today” (although it’s actually strange to pay homage to my own writing).

I believe I started operating a packet radio around 1984. In 1988, I wrote an article titled “The Cutting Edge of Amateur Radio: RBBS is Interesting Now!” for the June issue of “SR Basic Radio” (Seibundo Shinkosha).

After that, from 1990 I was in charge of a series of columns on packet radio for “Mobile Ham” (Denpa Jikken-sha), and after a short break, from 1993 for “CQ ham radio” (CQ Publishing). In other words, I covered the trends in packet radio in the 1990s.

While there are some topics that haven’t been covered much before, such as forwarding RBBS, the magazine also actively covers data communications and the internet beyond amateur radio. Reading it all together gives a good sense of how these technologies and services are developing.

By including articles from the computer technology magazine “bit” (Kyoritsu Shuppan) and proceedings from technical presentation events, we were able to compile everything into a 200-page A5-sized book.

I would enjoy reading this book.

East Coast Reflector Magazine

What is the East Coast Reflector?

Think of a coffee shop. People come from all over and arrive in different ways. Some drive, some walk, some take a bus or a taxi. It doesn’t matter how they got there. They all end up in the same place where they can meet, talk, and enjoy a conversation.

That’s the East Coast Reflector.

Hams from around the world connect to the ECR in many different ways: IRLP, AllStar, Hams Over IP, D-STAR, EchoLink, DMR, or YSF. Different paths, different technologies, but once they connect, they’re all in the same place: the East Coast Reflector.

Yet another thing I wouldn’t have imagined until I encountered it - a magazine that covers a virtual community. But it makes sense - the Magazine kind of “grounds” the East Coast Reflector community.

Hubble Network Raises $200M to Reach $1.6B Valuation as Startup Expands Satellite Bluetooth Network

Kurt Schlosser on Geekwire:

Seattle-based Hubble Network has reached a $1.6 billion valuation after raising $200 million in new funding to power its satellite-based Bluetooth connectivity network. The fresh capital propels the startup into unicorn territory as it works to connect billions of everyday, off-the-shelf devices directly to space.

…

Hubble currently operates six satellites in low-Earth orbit and plans to expand to a full 60-satellite constellation built with satellite operator Muon Space by 2030. The company says its hybrid network — which blends ground-based tracking with satellite coverage — is live for pilot customers today, including software firm Samsara, with data speeds and update frequencies set to increase as more spacecraft launch.

“When we said we’d connect Bluetooth chips to satellites, most of the industry said the physics wouldn’t allow it,” Alex Haro, CEO and co-founder, said in a news release on Wednesday. “Today we’re turning that early skepticism into a global opportunity.”

…

Hubble’s system works via a software update, allowing standard Bluetooth Low Energy (BLE) chips — found in everyday items like package trackers, vehicles, and pharmaceuticals — to broadcast signals directly to space. By pairing a ground-based network of nearly 90 million scanners with its satellite constellation, Hubble aims to replace costly cellular trackers with a setup running on roughly 50-cent chips and $4 monthly subscriptions.

Picking up individual Bluetooth signals from Low Earth Orbit… the mind boggles. Left to my own knowledge base, I’m one of those who say “the physics won’t allow it”. But, apparently, it does.

There is pretty much nothing that’s truly impossible with radio technology with today’s, and especially tomorrow’s technology.

Silent Keyboard - Franklin (Frank) Kuo, Co-inventor of ALOHAnet

University of Hawai’i News:

Franklin Kuo, a pioneering engineer whose work helped lay the foundation for modern wireless communications, died April 14. He was 91.

Kuo, a professor emeritus in electrical and computer engineering at the University of Hawaiʻi at Mānoa, co-developed ALOHAnet in the late 1960s and early 1970s with colleague Norman Abramson. The system, launched in 1971, was the world’s first wireless packet network and introduced protocols that underpin technologies such as Ethernet and Wi-Fi.

IEEE Spectrum: Codeveloper of Ethernet Predecessor Dies at 91:

Kuo helped develop ALOHAnet, a pioneering computer system at the University of Hawaii at Mānoa, in Honolulu. The system went online in 1971 and represented the first public demonstration of a wireless packet data network. It was an inspiration for Robert Metcalfe’s development of Ethernet a couple of years later. In 2020 ALOHAnet was designated as an IEEE Milestone.

Although I cannot find any reference that Kuo was an Amateur Radio Operator, given that he and Abramson created the first (publicly acknowledged) packet radio system, that’s sufficient grounds for a Silent Keyboard mention in Zero Retries.

My thanks to Joe Hamelin W7COM for bringing this development to my attention for inclusion in Zero Retries.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0263. Paid subscribers can comment directly on the web version of this issue.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

ZRDC 2026 Ho!

Zero Retries Digital Conference (ZRDC) 2026 will be here before we (I) know it.

3 weeks until Zero Retries Digital Conference 2026

on Friday, October 16, 2026,

in San Ramon, California, USA.

Partial Success in Highlighting FreeDV RADE as “Just Another Mode” in FlexRadio 8000 and Aurora Series Radios

In Zero Retries 0254, in my story The Remarkable, but Relatively Unsung Achievement of Integrating FreeDV RADE Into FlexRadio’s 8000 and Aurora Radios, I tried, behind the scenes, to get ARDC, ARRL, FreeDV, and FlexRadio to work together to promote what I consider that remarkable achievement. I had no success at that, so I decided to publish that story, from my perspective. Lesson learned - organizations have their own agendas, perspectives, and priorities about working together.

But, eventually, all four organizations have now mentioned FreeDV RADE as “just another mode” on the FlexRadio 8000 and Aurora radios.

ARDC

Rebecca Key KO4KVG wrote FreeDV RADE: A New Approach to Digital Voice over HF, Now Integrated into Popular Radios

Single sideband (SSB) is the most common voice mode for analog communications over HF radio. Its widespread adoption is due in part to its spectral efficiency, with a typical SSB signal occupying ~3 kHz of bandwidth. This efficiency, however, comes with a tradeoff: because only part of the frequency range of human speech is transmitted, received SSB audio sounds less natural than speech heard in person. Improving speech quality while maintaining the characteristics that make SSB effective over HF remains a challenge in amateur radio.

This is exactly the problem that ARDC grantee FreeDV set out to solve. Since late 2023, they have been working to create a digital voice mode that could compete with SSB across varying signal-to-noise conditions on HF while providing more natural-sounding speech. In June of 2025, they released Radio Autoencoder (FreeDV RADE or RADE), their flagship open-source digital voice mode. Building on that milestone, in May 2026, the team worked with radio manufacturers to integrate the mode directly into their radios.

…

ARRL

Richard Moseson W2VU, Editor wrote in ARRL Letter for September 24, 2026:

Will RADE Be the Next SSB?

It’s been a half century since single sideband (SSB) supplanted amplitude modulation (AM) as the most popular voice mode on HF, due largely to its spectrum efficiency, occupying roughly half the bandwidth of an AM signal. Now, there’s a new digital voice mode from FreeDV called Radio Autoencoder, or RADE, that occupies half the bandwidth of an SSB signal and reportedly provides more natural-sounding speech. According to Amateur Radio Digital Communications (ARDC), which funded research that advanced RADE’s development, “FreeDV RADE combines machine learning with classical digital signal processing (DSP) and can operate at signal-to-noise ratios (SNRs) as low as -2 dB. Its design also addresses spectrum use, speech quality, and power efficiency, all important considerations for voice communications over HF.”

Most significantly, ARDC reports that manufacturers are beginning to integrate the mode directly into their radios, starting with a module that can be downloaded and installed on certain FlexRadio models. Users of other transceivers may run the mode through computers connected to their radios. More details are available from FreeDV and on the ARDC website.

…

FreeDV Project

Mooneer Salem K6AQ wrote FreeDV 2.3.0 FlexRadio Integration:

FreeDV 2.3.0 has just been released, and with this comes the ability to upload FreeDV to your Flex 8000 or Aurora series radio using the Docker container feature that is new with SmartSDR 4.2.18. This allows you to use FreeDV with your Flex radio in a manner similar to what you would do with regular USB or LSB modes; no need to set up DAX or CAT with the FreeDV application (though you still can do so if you’d like).

To get started, download the Docker container from here and follow the instructions over in the README. (In short, go to Tools->Waveforms in SmartSDR, make sure Docker is selected and install the downloaded file from the first link; after a bit you’ll be able to select FDVU or FDVL modes on your active transmit slice and begin operating.) The FreeDV FlexRadio integration also includes support for FreeDV Reporter, which means you’ll be able to spot FreeDV signals that you receive over the air and get a live view of what’s currently happening in FreeDV.

This is an exciting development that helps propel us closer to our goal of getting FreeDV embedded within radios (which is a big part of the ARDC grant we received). Hope to hear you on the air on FreeDV!

(BTW for those with a 6000 series radio, you can set this up with a spare Raspberry Pi 4 or newer. More information in the README above.)

FlexRadio

In FLEX-8400 SDR Transceiver:

…

And it’s just as capable everywhere else you’ll want to operate. Legendary FlexRadio transmit audio and 115 dB RMDR keep SSB clean and readable, full break in QSK CW and ultra low phase noise give CW operators the fast, quiet keying they expect, RTTY runs through the same clean digital path with brick wall filtering for crowded contest bands, and if you want to try RADE, the newest digital voice mode from the FreeDV project, this radio’s clean receiver and native digital audio path make it a great platform for that too.

…

My original goal for, what I consider a remarkable accomplishment, would have been to have a joint press release from all four organizations, highlighting the respective contributions of these organizations, such as:

  • ARDC explaining that they funded the work of FreeDV on behalf of Amateur Radio (and open source technology),

  • ARRL explaining that this is a technological development coming out of Amateur Radio development, not a commercial development,

  • FreeDV explaining the unique aspects of FreeDV RADE and how such high voice quality was accomplished in a smaller bandwidth than SSB, and

  • FlexRadio explaining how FreeDV can just be added with FlexRadio’s Docker container feature that is new with SmartSDR 4.2.18.

If this had been one joint press release, in my opinion it would have been much more effective in getting the point across about technological innovation arising out of Amateur Radio.

So, lesson learned that external suggestions like mine for collaboration probably won’t work. Organizations like these four just don’t see the same “big picture” about Amateur Radio technological innovation that I’m seeing.

But, good news, I’ve figured out a workaround for effectively implementing ideas like this in the future.

Converting to NetNewsWire for RSS - The Information Firehose Got Bigger

Using NetNewsWire (NNW) for reading RSS feeds (mostly blogs) is working out fantastically well for me. In the conversion from my previous RSS feed reader, I’m still in the process of manually adding feeds into NNW. I didn’t want to do a bulk import of feeds as I know that there was a fair amount of crap feeds accumulated over the previous decade.

But, in the NNW folders that I have cleaned up, I’m now able to keep up “same day”, and I’m seeing interesting developments that just wasn’t possible to keep up with previously. It’s hard to explain, but I got “bogged down” with my previous RSS feed reader, but I really fly through folders on NNW, and I can zero in on the few items that are worth investing some time in reading and tagging.

Two “folders” that I haven’t yet cleaned up are YouTube channel feeds, and Groups.io email lists. Not all YouTube channels and Groups.io email lists have RSS feeds, but those that do make it possible to “stay on top” of developments and spot things much faster.

NetNewsWire is highly recommended!

GNU Radio Conference 2026 Was This Week

If I had more travel budget, and lack of competing priorities such as Grandson #1’s recent arrival and preparations for ZRDC 2026, I would have happily attended GRCon 2026 in Raleigh, North Carolina, USA this past week.

Attending GRCon 2025 was one of those delightful trying to drink from a firehose of information experiences that happen rarely. At GRCon 2025 I was delightfully out of my element, thus practically everything I encountered was a learning experience. One of the best was learning about many more ways that radio technology was being used, that I’d never heard of, such as body imaging with very low transmit power levels.

In 2026 regarding GNU Radio, I’m still completely out of my element as I never did get GNU Radio set up to experiment with some of my Software Defined Radios… perhaps GNU Radio World (running GR in the browser) and GNU Radio 4 will help with that.

It was cool to glance over some of the GRCon 2026 sessions such as:

I hope that these got video recorded and I’ll eventually be able to watch the presentations on YouTube.

Weekends Are For Amateur Radio!

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0263. Paid subscribers can comment directly on the web version of this issue.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

Founding Members who generously support Zero Retries financially:
Founding Member 0000 - Steven Davidson K3FZT (Renewed 2026, 4th year!)
Founding Member 0001 - Randy Smith WU2S (Renewed 2025, 3rd year!)
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Founding Member 0003 - Don Rotolo N2IRZ (Renewed 2026, 4th year!)
Founding Member 0004 - Bill Arcand W1WRA (Renewed 2026, 4th year!)
Founding Member 0005 - Ben Kuhn KU0HN (Renewed 2026, 4th year!)
Founding Member 0006 - Todd Willey KQ4FID (Renewed 2025, 3rd year!)
Founding Member 0007 - Merik Karman VK1DF / VK2MKZ (Renewed 2026, 4th year!)
Founding Member 0008 - Prefers To Remain Anonymous 08 (Renewed 2025, 3rd year!)
Founding Member 0009 - Prefers To Remain Anonymous 19 (Renewed 2025, 2nd year!)
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Founding Member 0011 - Rick Prelinger W6XBE (Renewed 2026, 3rd year!)
Founding Member 0012 - Ryan Tolboom N2BP (Renewed 2025, 2nd year!)
Founding Member 0013 - Newton White N4EWT (Renewed 2026, 2nd year!)
Founding Member 0014 - Joe Hamelin W7COM (Renewed 2026, 2nd year!)
Founding Member 0015 - Rich Stocking N7OP (Renewed 2026, 2nd year!)
Founding Member 0016 - Chuck Hast KP4DJT (Renewed 2026, 2nd year!)
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Founding Member 0019 - Prefers To Remain Anonymous 0108 (New 2025)
Founding Member 0020 - Prefers To Remain Anonymous 110 (New 2025)
Founding Member 0021 - Prefers To Remain Anonymous 111 (New 2025)
Founding Member 0022 - Prefers To Remain Anonymous 112 (New 2025)
Founding Member 0023 - Prefers To Remain Anonymous 116 (New 2026)
Founding Member 0024 - Rob Bowser (SPOOLTENNA) (New 2026)
Founding Member 0025 - Dave Stewart K7XST (New 2026)
Founding Member 0026 - Prefers To Remain Anonymous 32 (New 2026)

Numerous Annual and Monthly subscribers who also generously support Zero Retries financially!

You thousands of readers of Zero Retries without which there would be little point in publishing this newsletter.

The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries | Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0263 was published on 2026-09-25. This issue was 12,772 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

Long story, but what we now know as the Digital Communications Conferences came out of a merger in 1993 of the TAPR Annual Meeting and the ARRL Computer Networking Conference.

2

Very early on, Tina and I decided to name our conference the Zero Retries Digital Conference to leverage the Zero Retries brand and to indicate strongly that our conference was being independent of the TAPR DCC.

3

Possibly such a “packaging” capability might be one of the improvements implemented in the new GNU Radio 4.x “branch” of GNU Radio.

4

Founding Member 0018 was previously listed, incorrectly, as Prefers to Remain Anonymous 95.

]]><![CDATA[Zero Retries 0262]]>https://www.zeroretries.org/p/zero-retries-0262https://www.zeroretries.org/p/zero-retries-0262Sat, 19 Sep 2026 04:01:25 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its sixth year of publication, with 3600+ subscribers.

Zero Retries Digital Conference 2026 is October 16th in San Ramon, CA
www.zeroretries.org/p/conference

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is likely to be truncated by some email clients. Thus, it might be easier to read in a web browser:

https://www.zeroretries.org/p/zero-retries-0262

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In This Issue:

I-Frame

ZRDC 2026 Update 09/18/2026
Tina Stroh KD7WSF

What’s New at Digital Library of Amateur Radio & Communications — September 2026
Kay Savetz K6KJN

Breaking - New Product - AllScan.info URI50 (AKA AIOC++)
David Gleason NR9V

Successful M17 Transmission Using an Unmodified Retevis C62 Running OpenRTX
Wojciech Kaczmarski SP5WWP

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Comments on This Issue (Redirects to Comments Page)

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

Optional Paid Subscriptions, and especially Founding Member subscriptions to Zero Retries not only help offset various expenses incurred in publishing Zero Retries, but also are a large portion of the “seed capital” that is needed to host Zero Retries Digital Conference (ZRDC) 2026, and future ZRDCs. Thank You!

My thanks to Rick Prelinger W6XBE for renewing as Founding Member 0011 to Zero Retries in the past two weeks (3rd year)!

My thanks to Phil Karn KA9Q for renewing as Founding Member 0017 to Zero Retries in the past two weeks (2nd year)!

Founding members are listed in every issue of Zero Retries!

My thanks to Don Coker KM6TRZ for renewing as an Annual Paid Subscriber (4th year!) to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 10 for renewing as an Annual Paid Subscriber (4th year!) to Zero Retries in the past two weeks!

My thanks to Alex Free N7AGF for renewing as an Annual Paid Subscriber (3rd year!) to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 45 for renewing as an Annual Paid Subscriber (3rd year!) to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 46 for renewing as an Annual Paid Subscriber (3rd year!) to Zero Retries in the past two weeks.

My thanks to Prefers To Remain Anonymous 91 for renewing as an Annual Paid Subscriber (2nd year!) to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 92 for renewing as an Annual Paid Subscriber (2nd year!) to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 94 for renewing as an Annual Paid Subscriber (2nd year!) to Zero Retries in the past two weeks!

My thanks to Brian Wall W1BKW for upgrading from a free subscriber to Zero Retries to an Annual Paid Subscriber in the past two weeks!

My thanks to Prefers To Remain Anonymous 50 for three years of being a Paid Subscriber to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 136 for becoming a Paid Subscriber to Zero Retries in the past two weeks!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Resuming Weekly Publication

As much as I enjoyed the more leisurely biweekly publication schedule (and less stressful Friday publication days) of the last few months, it’s time to get back to weekly publication of Zero Retries. I do expect to take a few weeks off at the end of the year to fully enjoy the holidays, especially with our newly expanded family.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0262. Paid subscribers can comment directly on the web version of this issue.

ZRDC 2026 Update 09/18/2026

By Tina Stroh KD7WSF

This is the fifth in a series of updates leading up to Zero Retries Digital Conference 2026.

With roughly four weeks to go, ZRDC 2026 is looking sparse. Although we have mostly been away from the office for the past two weeks welcoming our first grandbaby (grandson) to the world, I have been remotely checking on registrations for ZRDC. I am not sure if the low attendance is due to the ill founded and totally false rumor that Zero Retries is trying to slight Pacificon or perhaps due to lack of interest. In either case, we are moving ahead and are continuing to plan an outstanding conference. Please remember, there are multiple ways to attend the conference. You can register for in-person attendance, which we strongly recommend, or attend via a live link on Zoom link. If you haven’t already, I would urge you to register ASAP so that I can be assured I have enough supplies on hand.

Zero Retries Digital Conference 2026 Registration - Click Here

New Door Prizes and Sponsor! AllScan.info URI50

AllScan.info URI50 board top and bottom
AllScan.info URI50 board, front and back. Image courtesy of AllScan.info

Also while away, we received a message from David Gleason, NR9V, the owner of AllScan.info stating he is happy to be a sponsor of ZRDC 2026. He will be providing five units of AllScan.info’s new product, the URI50 USB Radio Interface - AKA AIOC++ as door prizes. Please see the article in this issue about this product. We certainly thank and appreciate David’s continued sponsorship and support.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0262. Paid subscribers can comment directly on the web version of this issue.

What’s New at Digital Library of Amateur Radio & Communications — September 2026

By Kay Savetz K6KJN

Around the time I first dabbled in amateur radio in 1989 and started playing with packet radio in 1990, I had an IBM PC XT that ran MS-DOS and had a generous 10 megabytes of hard drive space. At 4.77 MHz, it wasn’t a speedster but it was certainly a workhorse on which I wrote countless school papers when I was working, and connected to packet radio BBSes when I wasn’t. Those DOS programs — from PC Write to packet terminal programs — had a certain look to them, colorful and blocky and (now) quaint. … This month, while adding a passel of classic amateur radio software and source code to the DLARC library, I got to revel once again in the look of those programs. I took a lot of screenshots — officially, for the library, for the metadata. But if we’re being honest, it was mostly because I enjoy looking at those screens. Unregistered version. All files have been processed. Press any key.

We’ll get to the software. First, let’s talk about DLARC’s additions to newsletters, new and old. We scanned 268 issues of The Aerovox Research Worker, which was a monthly publication of Aerovox Corporation, intended to “bring to the Radio Experimenter and Engineer authoritative, first-hand information on condensers and resistances for radio work.” It was first published in 1928 by Aerovox, then a major manufacturer of capacitors and resistors. We have issues from 1929 through 1967.

We also scanned 179 issues of The Cornell-Dubilier Capacitor. This was a technical/service newsletter for the radio and TV repair trade published by Cornell-Dubilier Electric Corp., another capacitor manufacturer. The Capacitor was published from 1937 through 1964; we have issues spanning 1939-1960.

And, 34 issues of The Oscillographer, “devoted exclusively to the cathode-ray oscillograph providing the latest information on developments in equipment, applications, and techniques,” and seven 1959 issues of Du Mont Instrument Journal, “devoted to electronic instrumentation, electronic tubes, and related fields” — both published by Allen B. Du Mont Laboratories. DLARC thanks John Poulton K4OZY for donations of the Aerovox, CD, and Du Mont newsletters.

In addition, we scanned a nice assortment of Hamvention programs from 1986 through 2026.

I also dug out from the backroads of the Internet more than 400 issues of AMSAT Weekly Satellite Report from 2002-2013. It was a weekly update on amateur radio satellites, listing their operating conditions, modes, frequencies, telemetry, and other practical info for satellite operators. Also from our friends at AMSAT: 1,440 (!!) issues of AMSAT News Service bulletins. These bulletins (we have from 1986 through the present) report amateur satellite launches, operations, technical developments, events, and organizational news for the satellite radio community. The two runs of AMSAT goodness were reconstructed from messages scattered across historical Usenet archives, Yahoo Groups, and AMSAT’s official mailing-list archive. Every issue is available as both searchable PDF and plain text.

We also expanded our collection of NZART Break-In, the journal of the New Zealand Association of Radio Transmitters Inc. We’ve added 18 additional issues spanning 2011-2013, available for reading online with the gracious permission of that organization. And we added scripts of 62 episodes of Amateur Radio Newsline published from 1993-2008, bringing our inventory of the weekly news program well past 1,300 episodes.

We added 286 issues of the NAQCC Newsletter, published by the North American QRP CW Club. Based in Georgia, the club promotes low-power Morse code amateur radio operation, QRP equipment building, simple wire antennas, and CW proficiency. We’ve also added an archive of 138 newsletters from the Indiana County (Pennsylvania) Amateur Radio Club, founded in 1963.

Would you like something more … exotic? I found three dozen issues of The Radio News and its continuation Tropical Tuning, an electronic bulletin edited by Manuel Rodriguez Lanza that covered shortwave, tropical-band, and medium-wave broadcasting, especially in Latin America. Our issues span 1993-1995. I also found about 200 scripts/issues of Sweden Calling DXers (later renamed Mediascan), which was Radio Sweden’s news service covering shortwave listening, international broadcasting, DXing, satellites, and developments in global electronic media. Most of what I could find was from the 1980s and 1990s, but a handful of the scripts go back to the early 1960s.

If that’s still not exotic enough, I even found 38 issues of Ham Radio Exchange, a Bulgarian classified ads bulletin edited by Nikolay Babarev, LZ1NG. It offered listings for used transceivers, antennas, parts, test equipment, and other gear. DLARC has issues from February 2005 through January 2007, although the newsletter was published from at least 2001 through 2008.

There’s actually more — a lot more — of various other newsletters. When there aren’t enough issues to warrant a collection of their own, I file them in the inelegantly named Miscellaneous Amateur Radio Newsletters collection. It’s fun to explore: recent additions include FM/TV-News (an English-language newsletter from a German organization), The RTTY Listener, RPT Magazine, Wisconsin Nets Association Bulletin, SWL news, and more.

Government Publications

I found 30 interesting historical publications, guides, and technical materials documenting NBS/NIST Time and Frequency Radio Stations WWV, WWVH, and WWVB. These include a 1951 article on Measuring Time and Frequency in Hawaii, a National Bureau of Standards doc on Time & Frequency Dissemination Services, and the Department of Commerce’s 1976 thoughts on Yagi Antenna Design. One item alone contains 27 editions of NBS and NIST station guides published from 1923 through 2002. Over in the new NTIA/Institute for Telecommunication Sciences Publications collection, we’ve got more than 200 publications spanning 1968 through 2024 documenting radio propagation, antennas, spectrum use, interference, and radio noise.

E-mail and Usenet

I’ve greatly expanded the TAPR E-mail Discussion List archive with group e-mail discussions spanning 1994-2004. Newly recovered discussion lists include APRSSAT, about APRS and packet-radio experiments using the AO-16 satellite; BBSSIG, packet-radio BBS software, forwarding, addressing, and operation; PROPNET, devoted to using APRS networks to observe radio propagation; WXSIG, covering amateur weather stations, sensors, APRS weather data; and 45 other groups.

I wrote about major additions to DLARC’s ham radio Usenet archive last month, and we’ve expanded the Usenet archive yet again with thousands of messages from rec.radio.info from late 1992 through 2013. This group wasn’t for discussion, it was a straight-up information dump: announcements, newsletters, data sources, and so on. If you read Finnish (or you want to learn lol) I also added a couple thousand messages from Finnish Usenet groups about ham radio and shortwave listening.

Software!

DLARC greatly expanded the Software collection. I mean, by a lot. I could go on for another 2,000 words about all the historical amateur radio software we’ve added: some of it vitally important infrastructure, some of it all but forgotten hobby projects. I won’t — but if you’re a programmer, I encourage you to explore, maybe starting with the newest additions. But I must talk about software a little bit. It’s exciting! (And I took all those screenshots.)

Editor’s Note - K6KJN has an editorial “blank check” to provide as many words as wished in future columns.

We’ve dug out source code for more than 80 pieces of software, in assembly language, BASIC, Pascal, C++, and every language in between. When possible, I did my best to find every version of each program’s source code.

The software deep dive started with these 8-inch CP/M floppy disks containing Pascal/Z and Z80 assembly-language source code and executable programs for Hank Magnuski KA6M’s packet-radio beacon and digital repeater. Once I was back in the software rabbit hole, I went deep.

I enlarged the archive of JNOS historical source code. JNOS is one of the enduring descendants of Phil Karn KA9Q’s groundbreaking network software: an early TCP/IP, AX.25 packet-radio, networking, and radio BBS system. DLARC uncovered 57 source code packages, spanning version 1.07b in 1992 through the current JNOS 2.0. And, Linrad historical source code. Linrad is Leif Åsbrink SM5BSZ’s pioneering software-defined radio program, developed for weak-signal work such as Earth–Moon–Earth communication. We have 186 versions (really) reaching back to 2001: the long history makes it a fascinating record of SDR evolving alongside ever-speedier computers.

Early Linux Packet-Radio Software from SunSITE, 1995–1996 is a time capsule from when AX.25 and NET/ROM were becoming part of Linux (much of which has since been removed from modern Linux distros). Its 15 source distributions include modem drivers, digipeaters, routing daemons, satellite download software, and tools for connecting radio networks to the Internet. I also dug deep into TAPR’s files, discovering software and source code for WinAPRS, MacAPRS, even APRS software for PalmOS. I suppose you don’t need to know how the sausage gets made, but the software archaeology involves digging into forgotten web sites in the Wayback Machine, FTP site archives, long-abandoned Linux distributions, CD-ROM collections, and emailing programmers.

Even the U.S. government gets in on the software fun: I added seven software preservation bundles from the National Telecommunications and Information Administration’s Institute for Telecommunication Sciences. The heavyweight is HF Propagation Software: ICEPAC, VOACAP, and REC533: 259 files including source code, DOS programs, Windows apps, and manuals dated 2005 through 2018. These are the tools broadcasters, engineers, and hams used to ask and answer the eternal question: “Will my signal get there?”

Let me digress to talk about one more software find that I thought was particularly interesting: ID LOGIC Shortwave Simulator. It was a 1995 demonstration of a proposed standard for shortwave radios to receive a station/schedule database, letting a listener choose a program and have the receiver select the right frequency at the right time. A consortium including the BBC, VOA, RCI, Philips, Sony, and others explored the idea, but it didn’t work out. Listeners would have needed special hardware in their receivers, broadcasters would need to transmit schedule data in the special format, which standards bodies would have to sort out — none of which happened before the Web came around with easy-to-access online schedules, solving the problem of finding what to tune into.

You can tune in to DLARC to enjoy all of these items, and nearly a quarter million other things.

Digital Library of Amateur Radio & Communications is funded by a generous grant from Amateur Radio Digital Communications (ARDC) to create a free digital library for the radio community, researchers, educators, and students. If you have questions about the project or material to contribute, contact me at kay@archive.org.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0262. Paid subscribers can comment directly on the web version of this issue.

Breaking - New Product - AllScan.info URI50 (AKA AIOC++)

By David Gleason NR9V

Editor’s Note

As Tina mentions in her ZRDC 2026 update above, NR9V reached out to provide a number of URI50s as door prizes for ZRDC 2026. As I think you’ll read, the URI50 is a significant advance in “AIOCs” / audio interfaces intended for use with portable radios such as the higher audio bandwidth available on the URI50. The price is pretty compelling!

I have a new product – the URI50 (AKA AIOC++) – that is now shipping.

This is my lowest-cost USB Radio Interface, that essentially adds a USB interface to any HT (most brands and models that have K1 jacks), supporting packet, digital modes, serial programming, and voice modes such as AllStar and EchoLink.

From my Products page:

URI50 USB Radio Interface - AKA AIOC++

Ultra-compact USB Radio Interface designed for HTs with K1 jacks. Serial data and UART PTT/COS are also supported ensuring the widest possible OS and app compatibility. Functionally equivalent to an AIOC or DigiRig but with better RFI-rejection, more I/Os, comprehensive LED status indicators, and C-Media CM108B USB Audio Controller IC with internal mixer and CD-quality 16-bit DACs and ADC. 1.1”W x 2.0”L. Schematic

URI50 - $39

Includes 6” USB A to C cable w/ferrite filter and 3” 2.5mm & 3.5mm TRS cables

USPS Shipping - $7

This should be of great interest to ZR readers as it is the lowest cost interface available that has professional-grade RFI/EMI-rejection and a CD-quality USB Audio codec IC that is supported as a full sound card interface in all OS’s and applications. Alternatives such as the AIOC or DigiRig have significant limitations in those regards or can require soldering/assembly/modifications.

Editor’s Postscript

One notable feature of the URI50 versus other (“classic”) AIOCs is that the URI50 doesn’t plug directly to a portable radio with integrated plugs on the AIOC board. Instead, the URI50 uses short cables to do so, which probably causes less strain on the audio connectors on the portable radio. That choice also makes it more widely usable for portable (and other) radios that don’t have the same connector spacing standard as Kenwood portable radios, and can probably be connected to nearly any other radio with a customized cable.

While the URI50 (apparently) doesn’t ship with a case, someone will undoubtedly quickly develop a 3D printed case design for the URI50. Alternatively, it’s small enough that a large piece of (clear, so the LEDs can be seen) heat shrink tubing should be a sufficient enclosure for it.

Tina and I are very grateful to David Gleason NR9V and AllScan.info for the donation of five URI50s as a door prize to ZRDC 2026 attendees, and an early insider look at the URI50 for Zero Retries.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0262. Paid subscribers can comment directly on the web version of this issue.

Successful M17 Transmission Using an Unmodified Retevis C62 Running OpenRTX

By Wojciech Kaczmarski SP5WWP

Editor’s Note

This article was posted on the M17 Foundation blog and I’m featuring it in Zero Retries in its entirety because this is a significant achievement of technological innovation in Amateur Radio.

The moment has come! An experimental branch of OpenRTX (Andreas OE3ANC, Marko13, Andrej K8TUN, jki275 et al.) has reached a long-awaited milestone – a successful transmission of M17 signal using an unmodified Retevis C62. Marvelous work, guys!

SDR++ decoding M17 signal transmitted with a C62.

For now, the RF output power is limited due to our lack of understanding on how the calibration data is stored and used. The reverse-engineering work on that is pending. M17 reception does not work yet, but it is expected to be added soon. There is no settings persistence in this model yet.

The most important thing is that the C62 radio is available at about $45 and does not require any hardware modifications to run the M17 mode. This is the game-changer we have all been waiting for. After adding the missing functionalities, this will easily become the go-to radio for everyday M17 use. On top of that, you get all the OpenRTX goodies, such as APRS support and voice prompts.

At this point, I would like to thank everyone involved in this subproject – not only the devs who did some amazing coding work, but also our Ambassador, Mr. Amo Xu BD4VOW for acting as an excellent interface between us and the Chinese manufacturers.

In the meantime, LinHT’s Revision B has been tagged on GitHub. We are working on the Revision C – an order for a test batch should be placed later this month. Big shout out to Vlastimil OK5VAS for his continuous help with this device 🙂

And, as always, there’s more to follow!

PS. We have a very important request. Since LLMs are being heavily used by journalists, bloggers, and other people publishing content on the Internet, some articles covering our activities might not be accurate. Every time you see an error, please take a moment to report it to the author(s). Thank you very much!

Editor’s Postscript

I’m glad SP5WWP clarified:

… does not require any hardware modifications to run the M17 mode.

As significant a development as this is, I think that a development that’s as significant as the M17 transmission capability is the mention of Amo Xu BD4VOW having finally “broken through” to a radio manufacturer1 radio chip manufacturer (ListenAI) to make it possible to implement M17 on what’s otherwise a common, inexpensive FM radio.

I really gotta get some C62s on order to beat the rush, not just for this new M17 capability, but also to beat the rush to have donor units queued up for LinHT version 3.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0262. Paid subscribers can comment directly on the web version of this issue.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

Morse Micro Enables Long-Range Connectivity in Devices with New Wi-Fi HaLow USB Dongle Reference Designs

everything RF:

Image courtesy of Morse Micro / everything RF

Morse Micro, one of the world’s leading Wi-Fi HaLow silicon providers, has introduced two Wi-Fi HaLow USB Dongle Reference Designs that can bring long-range Wi-Fi HaLow connectivity to existing devices via a simple USB connection. Based on Morse Micro’s market leading MM8108 SoC, both of the Morse Micro Wi-Fi HaLow USB Dongles will enable developers to activate Wi-Fi HaLow on many existing devices. Given that Wi-Fi HaLow networks provide native IP connectivity at ranges up to one kilometer, this opens up an exciting range of new possibilities.

The MM8108-RD09 Reference Design provides native Wi-Fi HaLow connectivity to a range of devices including access points (AP) and station (STA) products. OpenWRT drivers are available to enable Wi-Fi HaLow functionality on existing routers and APs with a USB interface. For client devices, native Windows and Linux drivers are available, as well as a MacOS application, which allows for users to easily connect to Wi-Fi HaLow networks, the same as one would for traditional Wi-Fi networks.

…

The MM8108-RD17 Reference Design allows for Wi-Fi HaLow integration into a wider range of client products without the need for drivers to be installed on the host. When plugged in, this Wi-Fi HaLow USB dongle appears as a standard CDC-NCM Ethernet interface to its host, enabling Wi-Fi HaLow connectivity to a wide range of devices including industrial computers, robotics, point-of-sale terminals, tablets and phones powered by Android or iOS. Devices can be authenticated via Wi-Fi Easy Connect (DPP) using a pairing button.

The MM8108-RD09 and MM8108-RD17 reference design schematics and software are available for tier-1 customers via their Morse Micro sales contact.

CNX Software had another story about these units, including some sourcing info for the reference units from Morse Micro:

Morse Micro Wi-Fi HaLow USB Adapters Add 802.11ah Connectivity to PCs and Routers

In “Minimum Quantity 140”, they’re only $40 each.

Ooohhh… very, Very, VERY Zero Retries Interesting! I hope this is the same chipset (or close enough) that AREDN has already been ported to.

I’ve been hoping that there would be eventually be another USB dongle form factor device that we could use for AREDN directly off our laptops. 802.11 based dongles on 2.4 GHz were OK, but AREDN on an 802.11ah / Wi-Fi HaLow USB dongle on 902-928 MHz / 33cm would be even better!

Updating AMBE

Bruce Perens K6BP on a private email list (shared with permission):

Not being satisfied with just re-implementing Codec2, I have driven the AI to do a good deal of work on AMBE today.

See
https://github.com/BrucePerens/hams_open/tree/main/daemons/ham_digital_modes/src/ambe

It's floating-point so far, also in Rust, and it will be a few weeks until I can test it against AMBE hardware to validate it, and then produce a fixed-point version.

This is AMBE 2000 for D*STAR only so far. AMBE 3000 for DMR and System Fusion will have to wait until I get lawyer OK that the patents have expired, this could be up to three years depending on the patent status, which I don't have a call on right now, but [redacted] would have a better idea. In the meantime the documentation on AMBE 3000 is in that directory, but it isn't implemented.

The Codec2 fixed point work is in 0.99996 correlation with the reference David Rowe Codec2 bit-stream, and now includes the 1600+data mode, but hasn't been tested on real radios, etc. This AMBE work is completely untested.

As for the reference to

Not being satisfied with just re-implementing Codec2…

see Zero Retries 0261 - Codec2-mod Fixed-point, and in Rust!

This… is ambitious! And cool! Kudos to K6BP for even considering this. Hopefully with this work AMBE can be reduced to just another library that can be incorporated into Software Defined Radios like Codec 2 and M17 already is.

FCC ISM Rules May Shatter LoRa Mesh Communities

Tom Nardi on Hackaday:

Although everyone has their own reasons for exploring a new hobby, one of the driving factors behind the popularity of Meshtastic and MeshCore has been the incredible accessibility offered by off-grid LoRa mesh networks. You don’t need any expensive hardware or a license to get on the air — armed with a $20 microcontroller dev board and open source software, you could be on the mesh in minutes. Then came the really exciting part, seeing who else was out there. The low barrier of entry and ad-hoc nature of these projects meant there was a good chance you’d soon find yourself exchanging messages with other like-minded folks in the area.

Or at least, that’s how it used to be. With the recent revelation that their default radio configurations have potentially been in violation of the Federal Communications Commission’s (FCC) regulations governing amateur usage of the 900 MHz industrial, scientific and medical (ISM) band, the users and developers of both Meshtastic and MeshCore have been sent scrambling. Getting in compliance isn’t necessarily a technical challenge. In fact, Meshtastic has already introduced changes aimed to address the issue and anyone running the latest alpha release can be sure that their initial radio configuration will meet FCC standards.

But unfortunately, this introduces a new problem. While it’s easy enough to get new installations of Meshtastic and MeshCore operating in a mode that keeps the FCC happy, doing so breaks compatibility with everything that’s already been deployed. The community will be fractured into distinct strata depending on when they first configured their hardware, with an added dash of confusion from the more rebellious users who will undoubtedly refuse to migrate over to the new settings.

What was once easy and accessible has just gotten a whole lot more complicated.

…

This article is much longer than the above excerpt, with much more detail.

Interesting choice of verbiage:

… regulations governing amateur usage of the 900 MHz industrial, scientific and medical (ISM) band.

I interpret that “amateur” as casual / hobbyist / non-professional rather than Amateur Radio, of which the 902-928 MHz / 33 cm band is just another Amateur Radio UHF band for which the Part 15.247 / ISM regulations aren’t applicable.

Yes, adjusting the settings from a bandwidth of 250 kHz to 500 kHz is disruptive, but it’s temporary and the networks will quickly adjust as folks get the word (and access remote nodes to update settings).

It will be interesting to see if the “armchair communications lawyers” get lathered up and start haranguing the FCC, only to learn the mantra of Amateur Radio experimenters that want to accomplish something. That is, generally, “ask for forgiveness rather than permission”. That approach doesn’t always work, and isn’t always advisable, but there are so many technologies I could cite in Amateur Radio that could theoretically run afoul of some nitpicking inessential nuance of FCC regulations.

ARDC 2027 Volunteer Recruitment

Email from ARDC Communications Manager Rebecca Key KO4KVG:

ARDC is now recruiting volunteers for 2027. Applications are open through October 30, and we’re looking for volunteers to serve on five of our committees.

You can find more information about the available volunteer opportunities, eligibility requirements, time commitments, and how to apply in our blog post here: https://www.ardc.net/volunteer-with-ardc-in-2027/.

As always, I recommend the experience of serving on ARDC’s Volunteer Committees. Across the board, ARDC does great work for Amateur Radio and related fields.

The Next Version of the M17 Specification

Jim Ancona N1ADJ on M17 Foundation:

Over a year ago discussions about possible improvements to the M17 Specifications started in the M17 Discord and moved to several Github issues. The goals were to:

  • Allow for expansion: The existing V2 specification has no room for new payload definitions or additional kinds of META content.

  • Make the spec easier to implement and understand.

  • Remove features that haven’t been adopted.

The changes include:

  • A redesign of the TYPE field, putting the various subfields into byte-aligned nibbles. The Payload Contents becomes a 4-bit selector allowing for existing modes (Data, 3200 bps Codec2 Voice and Packet), a reserved version detection pattern, so V3-aware software can properly decode V2 traffic and a bunch of values available for future expansion, e.g. new codec or streaming data modes.

  • Decoupling the META contents into its own 4-bit field, separating it from encryption subtype and allowing room for new kinds of META content.

  • Improve the META Text Data by changing to a different control byte which increases the length of a message from 52 to 195 bytes.

  • Dropping 1600 bps Codec2 Voice+Data mode. This mode has never seen any significant uptake, so removing it simplifies the spec.

So the proposed V3 meets the goals set out for it, but are there any downsides? There is one big one: Compatibility. V2 to V3 is forward-compatible, that is, V3 radios, hotspots, repeaters and reflectors will be able to receive transmissions from V2 devices and software. But it’s not backward-compatible, so V2 devices won’t recognize V3 transmissions, in fact they’ll misparse them. What happens then depends on the contents of the V3 data and the parsing code, but it’s likely to vary depending on the details of both. So the behavior of a V2 radio when receiving V3 is effectively undefined. (There may even be a case where it works!) Indeed, that’s why it’s called V3 – the major version change indicates that it’s not compatible. A lot of thought has gone into mitigating this problem. If we could update hotspots, repeaters and reflectors before radios are updated it’s possible to reduce many of the interoperability problems. But fundamentally, a radio running V2 firmware won’t be able to receive a V3 transmission. Even if the network infrastructure can translate between formats, there’s no way for RF infrastructure (repeaters, hotspots) to do the same. Devices running V3 will still receive V2 transmissions, but if they transmit using V3, any un-upgraded devices won’t hear them. So there needs to be a “flag day” when all the devices in an area switch from V2 to V3. That’s not too bad if it’s just a radio or two and a hotspot, but it would be harder to coordinate in areas with M17 repeaters.

I’ve been concerned that a breaking change might cause problems for the M17 community. So, working with an AI, I came up with a proposal for a backward-compatible change to V2 that accomplishes many (but not all) of the goals of V3. It keeps the layout of the TYPE field in the current spec, but repurposes reserved bits as escapes to allow for expansion.

…

I’m not exactly a dispassionate, uninvolved observer of M17, but one of the things that consistently amazes me about the M17 Project is that its committed, passionate, talented volunteers seem to consistently “punch above their weight” in evolving and improving M17, despite the “nattering nabobs of negativity” (sad Hams) that consistently and ignorantly dump on M17 for aspects of M17 that they just don’t understand… or even try to understand, the most unique aspects of M17. Namely (all from my perspective):

  • It was created as, and has always been, an open source project.

  • Because it’s an open source project, it attracts a “different crowd” than the “just tell me where to buy it” crowd that’s content to use DMR, D-Star, etc. digital voice modes.

  • Its specification was well detailed, and (as shown with the above) continues to evolve.

  • Because it’s entirely implemented in software running on processors / microcontrollers, it can be integrated within other systems.

  • My favorite feature of M17 is that it incorporates a data mode, not a bolted-on, only half compatible data mode as is the case with other digital voice modes.

Kudos to N1ADJ for a great article explaining this development. And kudos to the rest of the M17 team that just keeps creating all things digital, cool, and fun for Amateur Radio! Such as…

A Handful of [M17] News and Updates

Wojciech Kaczmarski SP5WWP on M17 Project:

We have some updates for you:

libsx1255
Significant improvements were introduced saving over 30% of SPI transfer time while writing to / reading from frequency registers. SX1255’s BURST mode is used, reducing the number of bytes being transferred from 6 to 4.

M17_inet
Significant structural improvements were introduced by Tom N7TAE and Jim N1ADJ. On top of that, a new GitHub action was added, rendering a PDF.

CARI
The protocol had two inconsistencies fixed – register writability and the number of subdevices per device.

SX1255 HAT
The project was migrated to KiCAD 10.0.6.

There’s more to follow!

Just… amazing. Again, kudos to the M17 Team!

pigeon: My Experimental PHY (Part 0/12)

Paul R Tagliamonte K3XEC:

Anyone who claims to understand RF is lying to you, doesn’t actually understand RF, or is lying to themselves.

I debated if I should have this be my cold open or not, since I feel like what I’m saying here could easily be read as meaning the opposite of what I actually mean here. I don’t mean to say “you will never understand this because it’s magic”, I’m trying to say “no one understands it, so learn as much as you can”.

I feel like I now know enough that RF is basically just witchcraft. There’s a lot of crystals that those holding the obscure knowledge can use along with rods of specific lengths of specific materials to channelEM fields using earth ground to have a conversation with someone on the other side of the world by sending out specific vibrations through space. Is the resonance of your equipment slightly off? No worries, you can tune it by changing how much electricity you capture in a capacitor made with an electrolyte fluid.

Oh right, also this force is somehow also the same as light (except when it’s not and it’s actually tiny particles, i won’t be taking questions, thank you). Shit, also, heat too. But only sometimes. Oh and it only travels on the surface of things when it’s not going through freespace, cool? Cool. Glad we got that out of the way.

Look, all I’m saying is maybe the witches are onto something, actually.

…

I don’t have anywhere near the bandwidth at the moment to dive into all 12 parts of this (all of which are now published on k3xec.com), but wow… what a richness of understandable explanations about radio technology!

Jeff Davis KE9V, who tipped me off on this said:

This is definitely down-low on the Zero Retries scale of where digital ham radio is going, but it trips my triggers for old school nostalgia. Not sure how or if you’d like to share it with ZR readers, but I find it very cool. FYI - it’s long and detailed but still worth a look. It’s not what’s “new” but it still brings digital joy at the keyboard!

Intro:

https://k3xec.com/pigeon/

Many blog posts later the experiment continues and draws to an end...

https://k3xec.com/pigeon-ip/

Ham radio is supposed to be fun! 😊

KE9V jests, of course. He’s been a reader of Zero Retries since Day 0 and was one of the first of the Zero Retries Pseudostaffers. Thus he couldn’t possibly imagine that I wouldn’t feature this, of course, in Zero Retries!

As always, my thanks to Jeff Davis KE9V for bringing this development to my attention for inclusion in Zero Retries.

Whatcom Radio

Whatcom Radio provides direct online access to locally operated scanner feeds for Whatcom County, Washington. Listeners can follow law-enforcement and fire radio traffic without searching through a nationwide scanner directory.

Coverage includes the Whatcom County Sheriff scanner, Bellingham Police scanner, Western Washington University Police, countywide fire dispatch, and fire talk channels. Feed availability may change as radio systems and active channels change.

This service is independently operated and community supported. It is intended for general awareness, not official emergency instructions.

I stumbled on this service on Facebook2.

What hath AI wrought? This is one example. Thanks to AI, setting up sites and services (including iOS and Android apps “coming soon”) like Whatcomradio.com from a basic template is ridiculously simple by now. Color me… skeptical (but willing to be convinced - if “the entity” is a ZR reader, please get in touch) that “Whatcom Radio” has set up their own infrastructure in (pretty) rural Whatcom County, Washington for receiving two way radio feeds (which, incidentally includes local Amateur Radio repeaters) and serving them out.

The other thing to be cautious if not highly skeptical, is that there is no hint, whatsoever, what individual / entity is behind this service, again, here in (pretty) rural Whatcom County, Washington. I checked just a few small counties in Washington and didn’t seem to find a comparable service, so the entity behind Whatcomradio.com isn’t just creating these services en masse for every Washington county (at least, not yet).

OpenMANET – A Higher-bandwidth Meshtastic Alternative leveraging 802.11ah WiFi HaLow

Jean-Luc Aufranc (CNXSoft):

Image courtesy of CNX Software - Embedded Systems News

OpenMANET is an open-source project for building long-range wireless mesh Mobile Ad-hoc Networks (MANETs) using Raspberry Pi SBCs and Wi-Fi HaLow (802.11ah) chips from Morse Micro.

This came up when we wrote about Morse Micro USB WiFi HaLow adapters, and an X user commented that “OpenMANET is going to explode with these available, no more adapter boards or M.2 cards”. OpenMANET targets search and rescue, disaster response, airsoft events, and other off-grid or infrastructure-failed situations. So it looks like an alternative to LoRa-based Meshtastic and Meshcore, with higher bandwidth, at the cost of more expensive hardware and higher power consumption.

OpenMANET supports field communications, including push-to-talk, sharing GPS positions, cameras/video streams, and ATAK (Android Team Awareness Kit) integration. The mesh network can access the Internet through a single “mesh gate” over Starlink or cellular connectivity.

The project supports a range of hardware platforms including Gateworks Venice, Raspberry Pi Zero 2 W, Raspberry Pi 3 Model B, HaLowLink 2, and Heltec HT-HD01 V2, but for the best experience, a Raspberry Pi 4 kit is recommended since it supports the core network, off-grid communication, the camera, BLOS (Beyond Line of Sight) to securely merge two MANETs in different locations over the Internet, and the new user interface.

…

Mesh networking just keeps getting better, though for my preference, I’m looking forward to running 802.11ah / Wi-Fi HaLow with the mature AREDN firmware and networking.

Amateur Radio ATSC 3.0 and Narrow Band TV

Jim Andrews KH6HTV in the September, 2026 2nd edition, Issue # 218 of Amateur Television Journal mentioned two Zero Retries Interesting developments regarding Amateur Radio (digital) television.

The first was this brief mention:

ATSC 3.0 --- Ron [Economos], W6RZ, of Mountain View, California, also reports doing experimentation on ATSC 3.0. (w6rz@comcast.net).

I’ve been very casually following the development of ATSC 3.0 and remembered that there was a “datacasting” component in ATSC 3.0, so being short on time to thoroughly research this, I asked Claude something like3 “is there a datacasting mode in ATSC 3.0” and it replied:

Yes — data communications is actually one of ATSC 3.0’s headline features, not an afterthought bolted onto video.

The core enabler: ATSC 3.0 broke from earlier ATSC standards by being fully IP-based at the physical/link layer. Instead of carrying only MPEG transport streams, the RF channel delivers generic IP packets, so it can carry video, audio, or arbitrary data in any mix a broadcaster chooses.

”Datacasting” is the umbrella term the industry uses for this, and it covers several distinct use cases:

- Broadcast file/content delivery — non-real-time (NRT) push of files, software/firmware updates, maps, or media to large numbers of receivers at once, with built-in file-repair via the A/331 signaling standard ATSC 3.0 offers datacasting via broadcast television signals with advantages of built-in file repair as described in A/331.

- Streaming/low-latency data feeds — some vendors have built protocols on top of ATSC 3.0 for real-time data streams (e.g., live stats, telemetry) rather than just bulk file transfer one company describes how their protocol allows real-time data streaming using standard ATSC 3.0 broadcasting systems, for pushing streaming information to consumers, IoT devices, and traffic apps.

- CDN/edge delivery and IoT/automotive data transport — broadcasters are aggregating spectrum specifically to sell as wide-area data networks, covering things like CDN offload, geolocation data, digital signage feeds, and wireless data transport for vehicles and IoT devices applications discussed include CDN data delivery, enhanced geolocation, data delivery to the edge, and wireless data transport for automotive and IoT.

- Emergency alerting and positioning — ATSC 3.0’s Advanced Emergency Information (AWARN) and a Broadcast Positioning System (a GPS-independent timing/location signal) are also data services riding on the same physical layer.

Why it’s getting attention commercially: with one-to-many multicast delivery, ATSC 3.0 can move large volumes of the same data to unlimited receivers far more efficiently than unicast broadband, which is why several vendors and even Sinclair’s ONE Media have been building out “spectrum for hire” data networks this has been identified as one of the most potentially profitable applications of NextGen TV.

Given your interest in spectrum policy and mesh/data networking, the interesting angle for amateur radio watchers is that this is essentially broadcast IP over RF at a much larger scale than AREDN — same conceptual territory (efficient multicast data over a shared RF channel), just with broadcast-TV-grade spectrum and infrastructure behind it.

All the AIs always have to add that little pat on the head at the end of every “thoughtful” query.

This is a Zero Retries Interesting development! I had no idea that ATSC 3.0 equipment / systems had been driven downscale to the point where it might be feasible to use for Amateur Radio… though with all things SDR, ATSC 3.0 is probably mostly software. Maybe with the datacasting capability of ATSC 3.0, if it becomes adopted within US Amateur Radio, we could “bridge the divide” between realtime television folks and data communications folks on the same system / spectrum. This potential is actually kind of a SuperPeater.

I’ve emailed W6RZ for more details.

The second Zero Retries Interesting item was a long article about Narrow Band Television experiments in progress:

Summary of 10 meter, NBTV Meeting

Dave, AH2AR

The recent YOU-TUBE presentation by Grant (ZL1WTT) explored his development of a Narrow-Band TV (NBTV) digital mode for HF amateur radio communications. The video outlined the software setup, configuration, and the challenges associated with running high-bandwidth video over limited amateur radio spectrum. In the video, Grant explained that while he has managed to achieve results with bandwidths as low as 200 kHz to 300 kHz, he considers 100 kHz to be the absolute practical limit for his digital NBTV system to maintain the desired resolution and frame rate.

Grant noted that reducing bandwidth for moving images requires significant trade-offs compared to traditional Fast-Scan Television (FSTV), which typically occupies much wider channels. His approach to achieving this involves a hybrid system that uses:

  • OFDM (Orthogonal Frequency-Division Multiplexing): Utilizing 192 carriers to mitigate the effects of phase noise common on HF bands.

  • Digital Multiplexing: Encoding audio and video together into the data stream.

  • Analog-style Visual Compression: Heavily compressing the chrominance signal and motion frames to fit within the constrained bandwidth.

Key Highlights of his Presentation:

  • Software & Setup: Grant demonstrated how to run his custom Gambas and Python-based encoder/decoder system alongside GNU Radio. He emphasizes the importance of setting correct directory permissions and ensuring proper UDP port alignment for system communication.

  • System Requirements: The system is resource-intensive, requiring a modern, high-performance computer. Grant explained that he is currently using an aging i7 system that struggles to maintain the target 12.5 frames per second, often hitting 100% CPU usage. A gaming computer would work much better with this software.

  • Operational Details: The mode uses an OFDM (Orthogonal Frequency-Division Multiplexing) scheme with 192 carriers to minimize phase noise and handle the constraints of HF propagation. The system is a hybrid, combining digital processing with analog-style visual compression to achieve a resolution of approximately 120x96 6 pixels.

…

The two data points that leaped out at me for this development is a 100 kHz bandwidth for full motion television, and that the constraint for realizing that potential is merely “sufficient CPU / GPU horsepower”. That… is a solvable problem - just wait a few more months (and a bit more personal budget). Or buy a decommissioned (but still wicked fast) rack server that’s been outstripped for economical use after 18 months of use.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0262. Paid subscribers can comment directly on the web version of this issue.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

ZRDC 2026 Ho!

Zero Retries Digital Conference (ZRDC) 2026 will be here before we (I) know it.

4 weeks until Zero Retries Digital Conference 2026

on Friday, October 16, 2026,

in San Ramon, California, USA.

Grandson #1 Has Arrived!

Our grandson entered the world on 2026-09-11. He is perfectly healthy, happy, and of course beautiful and smart. I could babble on as any grandparent tends to do, but at the request of the new parents, ‘nuff said.

N8GNJ Running for TAPR Board of Directors

On 2026-09-11, I submitted my self-nomination for one of the three TAPR Board of Directors positions that are open in 2026.

Here is my submitted biographical sketch:

My primary motivation for getting into Amateur Radio in 1985 was TAPR’s development of the TNC-2 and popularizing Packet Radio. I have previously (briefly) served on the TAPR Board, and was also briefly Editor of the PSR. I am Editor of Zero Retries, a free weekly newsletter about technological innovation in Amateur Radio, now in its sixth year with 3600+ email subscribers. In 2025, my wife Tina (KD7WSF) and I created the Zero Retries Digital Conference.

In running for the TAPR Board in 2026, I am not running against any of the incumbents, but to provide some fresh perspective to the Board. From my vantage point in Zero Retries, I am seeing a resurgence in Amateur Radio networking such as AREDN, MeshCore, advanced Packet Radio such as the OpenTNC, and most recently IP400.

Topics I hope to work on in TAPR:

  1. I think that TAPR should (again) provide comments to the FCC when it issues NOIs, NPRMs, Reply Comments - every time.

  2. I hope to get TAPR involved in assisting M17 Project with popularizing the LinHT project - Linux Handheld Transceiver, a fully Software Defined portable transceiver (ANY mode) operating on 70cm, at 5 watts, that runs Linux and GNU Radio.

  3. Get TAPR involved in promoting “mostly digital” Amateur Radio to be more widely recognized as relevant to society and radio technology development in general.

  4. Get TAPR involved (again) in standards coordination like it has done previously with AX.25 and APRS.

Per TAPR, the election (if there are more than three candidates):

An online election will be held from November 7 to November 20, 2026, using ElectionBuddy, if a vote is required.

If you are a TAPR member, I would appreciate your vote.

Resurrecting Old Software

K6KJN’s fantastic, ongoing progress with DLARC, and this month’s additions to DLARC of Amateur Radio software that runs on CP/M from Hank Magnuski KA6M prompted this mental excursion.

There are a lot of gems of software, Amateur Radio and otherwise, that are abandonware. They never stopped being functional (nothing wrong with the software), it’s just that “something” changed in the environment. One big issue was that the hardware older software was designed for aged out and wasn’t perpetuated (even under emulation) such as software developed for Data General minicomputers. Or the prevailing operating system was updated and wouldn’t accommodate the old software (such as the transition from CP/M to DOS), or there was some feature that newer software did better than the old software (such as VisiCalc versus Lotus 123), or the developer just got tired of maintaining it (or died).

Of course, it’s always possible to update software, it’s just not been practical or desirable or cost-effective to do so. Emulation of a computer or OS isn’t always the answer either - the goal was resurrecting the software, not recreating or perpetuating the limitations of the hardware or the OS (though I confess some nostalgia for the incredibly straightforwardness and “intuitiveness” of my brief exposures to DEC VMS).

But now with the endlessly patient and capable and relatively cheap (compared to human labor) AI programming savants… it’s somewhat practical, and with the the right circumstances and some motivation, to redevelop old software at least somewhat practically and cost-effectively. I’m reminded of UI-View32 for Windows which hasn’t been updated in decades (the developer Roger Barker G4IDE became a Silent Keyboard in 2004). Despite the limitation of the source code never being released and thus no updates being possible, UI-View32 is still very popular for use with APRS.

Now creating a UI-View32 workalike / lookalike is feasible because an AI can decompile an app, be instructed to preserve the UI, update to modern OS underpinnings, add new features (but not too many), etc. Those are all things that humans could do… but only at significant expense, time, frustration, boredom, and not much overall motivation to do so. But now, one person can decide to do it, with the assistance of AI.

I’m one of those who thinks the possibilities of AI are just fantastic.

Ribbit Radio and Other Modes Enabled by Inexpensive Audio Adapters

The article on the new AllScan.info URI50 reminds me that there are so many interesting experiments / systems that are possible at very low cost with the combination of an inexpensive, “good enough” portable radio like the Baofeng UV-5R Mini ($38 / pair!) and an inexpensive, but good audio adapter such as the URI50 or the NA6D AIOC.

One often forgotten example is Ribbit. The three most innovative things about Ribbit, in my opinion, are:

  • It’s Open Source - https://github.com/OpenResearchInstitute/ribbit

  • It implemented OFDM over audio bandwidth.

  • It was designed to use unconnected (air gap) audio coupling between a mobile phone (or other device) and any two way radio4 with half-duplex capability. When the Rattlegram app is running it’s constantly listening on the mobile phone’s microphone for a Ribbit transmission coming out of the radio’s speaker and then displays the message. When it’s time to transmit, push the PTT button on the radio and push the transmit button on the Rattlegram app.

Despite no recent updates, the Rattlegram apps continue to be available:

While Ribbit doesn’t require an AIOC, imagine if it were adapted to use one, including automated Push To Talk (PTT) control?

Although there haven’t been any recent updates (that I’ve seen) to Ribbit, the project is open source so it can be easily forked and iterated on (including vibe coding, of course).

Interesting Events in September in the Pacific Northwest

We’ve been blessed (thanks to amazing hard work of individuals and groups) here in Western Washington for a number of significant Amateur Radio events. Two of note that are still badly missed are Communications Academy and MicroHAMS Digital Conference. So it’s encouraging to see that some significant Amateur Radio events are being held in this region, such as:

  • Hams Across the Border - A unique event because it’s held at a unique venue - Peace Arch Park that straddles the US / Washington and Canada / British Columbia border.

  • NWAPRS Summer Gathering - Another unique event - a technical conference held at a campground.

  • Pac Beach 2026 is a new event to me, another technical conference, held on the Pacific Coast of Washington in a few weeks.

Details of these events are on the Zero Retries Guide to Zero Retries Interesting Events page.

Weekends Are For Amateur Radio!

We’ve been out of town for the past two weeks attending the debut of Grandson #1. In preparing for the trip, both Tina and I assumed there would be blocks of downtime in a boring, generic hotel room and packed “a number of” deferred “portable” projects accordingly. Neither of us touched any of our respective projects. Downtime from a bout of flu (mercifully short thanks to “fast flu cure” medications) was part of that.

This weekend is a calm before the storm of the final push and long road trip down to San Ramon, California for ZRDC 2026. The weather in Bellingham couldn’t be more perfect, so it’s catch-up time for some outdoor household projects, and a “doors wide open” weekend for N8GNJ / Zero Retries Labs.

This weekend is also… the big update of my main MacOS machine, a 2020 (!) MacBook Air with an M1 processor. It’s still working amazingly well - best computer I’ve ever owned. I’ll be updating it to macOS 27 Golden Gate with the big feature being Siri AI that promises… (for real and for true this time) to do a good job of understanding the data I have onboard this computer and letting me run useful queries against it.

That said, it can’t be any worse than Claude or the (newly rebranded) Gemini Notebook, which I invested a lot of effort in uploading previous issues of Zero Retries, but a query takes so long (even on the paid tier) that it turns out to be marginally useful in returning a result in a reasonable time to not interrupt my workflow.

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0262. Paid subscribers can comment directly on the web version of this issue.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

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The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries | Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0262 was published on 2026-09-18. This issue was 10,308 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

This is a post publication update. My thanks to Wojciech Kaczmarski SP5WWP for his always careful reading of Zero Retries, and his feedback.

2

Facebook, surprisingly, seems to becoming somewhat more useful of late after a bad period of mostly spammy posts that I was not only uninterested in, but the spam was actively discouraging me from engaging with Facebook at all.

3

My use of Claude is, at the moment, in one of its “I’m stupid and don’t remember what you asked earlier today” modes.

4

Ribbit can be used with any… literally ANY two way radio (and I state that in the most inclusive possible context). There are many radio services / systems that are stated as “voice only” or tightly restricted data (such as position data), such as US (and other countries) Marine VHF, CB, GMRS, FRS, PMR446, broadcast, etc. In this era, with this kind of technological capability… just give up such arcane restrictions such as “voice only”.

My late, very good friend Dewayne Hendricks WA8DZP often offered the thought experiment of imagining situations where arcane, outdated US regulations regarding radio technology wouldn’t apply. He actually did some interesting radio experiments on Tribal Nations making use of that scenario. So, imagine CB (now FM is an option on US CB) plus a reasonable data mode for a reasonable neighborhood data network.

]]><![CDATA[Zero Retries 0261]]>https://www.zeroretries.org/p/zero-retries-0261https://www.zeroretries.org/p/zero-retries-0261Sat, 05 Sep 2026 01:33:08 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its sixth year of publication, with 3600+ subscribers.

Zero Retries Digital Conference 2026 is October 16th in San Ramon, CA
www.zeroretries.org/p/conference

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is likely to be truncated by some email clients. Thus, it might be easier to read in a web browser - www.zeroretries.org/p/zero-retries-0261.

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In This Issue:

I-Frame

ZRDC 2026 Update 09/04/2026
Tina Stroh KD7WSF

Correction - Internet Connectivity for Meshtastic and MeshCore
Steve Stroh N8GNJ

Update on KK7NQN AI Net Logger
Hunter Inman KK7NQN

Zero Retries - Tightening Focus to Data Communications
Steve Stroh N8GNJ

The Use Cases of IP400 Networks
Steve Stroh N8GNJ

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Comments on This Issue (Redirects to Comments Page)

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

Optional Paid Subscriptions, and especially Founding Member subscriptions to Zero Retries not only help offset various expenses incurred in publishing Zero Retries, but also are a large portion of the “seed capital” that is needed to host Zero Retries Digital Conference (ZRDC) 2026, and future ZRDCs. Thank You!

My thanks to Bill Arcand W1WRA for renewing as Founding Member 0004 to Zero Retries in the past two weeks (4th year)!

Founding Member Subscribers are listed in every issue of Zero Retries!

My thanks to Prefers to Remain Anonymous 09 for renewing as an Annual Paid Subscriber (4th year!) to Zero Retries in the past two weeks!

My thanks to Prefers to Remain Anonymous 41 for renewing as an Annual Paid Subscriber (3rd year!) to Zero Retries in the past two weeks!

My thanks to Tom Cain WB8OUE for renewing as an Annual Paid Subscriber (2nd year!) to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 81 for renewing as an Annual Paid Subscriber (2nd year!) to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 85 for renewing as an Annual Paid Subscriber (2nd year!) to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 86 for renewing as an Annual Paid Subscriber (2nd year!) to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 88 for renewing as an Annual Paid Subscriber (2nd year!) to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 90 for renewing as an Annual Paid Subscriber (2nd year!) to Zero Retries in the past two weeks!

My thanks to Conrad Trautmann N2YCH for upgrading from a free subscriber to Zero Retries to an Annual Paid Subscriber in the past two weeks!

My thanks to Prefers To Remain Anonymous 133 for upgrading from a free subscriber to Zero Retries to an Annual Paid Subscriber in the past two weeks!

My thanks to Prefers To Remain Anonymous 134 for upgrading from a free subscriber to Zero Retries to an Annual Paid Subscriber in the past two weeks!

My thanks to Prefers To Remain Anonymous 132 for recently becoming a new Annual Paid Subscriber to Zero Retries. (This acknowledgement should have been in the previous issue of Zero Retries. My apologies for that omission.

My thanks to John Zaruba K2ZA for becoming a new Annual Paid Subscriber to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 135 for becoming a new Annual Paid Subscriber to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 96 for one year of being a Paid Subscriber to Zero Retries this past week!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Zero Retries Summer 2026 Publishing Schedule - Biweekly

During Summer 2026, Zero Retries has being published biweekly. The publication schedule for the remainder of Summer 2026 is:

  • Zero Retries 0262 - 2026-09-18

The reason for not publishing on 2026-09-11 is that next week, Tina and I will be brand new grandparents1, and we’ll spending the week oohing and cooing and cuddling with our new grandchild. Thus publishing Zero Retries will be a distant secondary priority. Thus I choose to recognize that reality in advance and not stress about Zero Retries.

I’ll resume publishing Zero Retries weekly with Zero Retries 0263 on 2026-09-25.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0260. Paid subscribers can comment directly on the web version of this issue.

ZRDC 2026 Update 09/04/2026

By Tina Stroh KD7WSF
Zero Retries Digital Conference Manager

This is the fourth in a series of updates leading up to Zero Retries Digital Conference 2026.

Panel of Speakers Complete

With roughly six weeks to go, the panel of speakers is complete. The panel of speakers is:

  • Dave Platt, AE6EO - OpenTNC - something old, something new, something to build upon.

  • Cale Mooth, K4HCK - New Tech Hams

  • Jeff Scoville, AE5ME - M17

  • Martin Alcock, VE6VH - IP 400 Project

  • Glen Popiel, KW5GP - Microcontroller Communication Technologies and Protocols for Ham Radio

  • Mooneer Salem, K6AQ - FreeDV Project

  • Craig Lamparter, KM6LYW - DigiPi - Data

  • Steve Stroh, N8GNJ - Update on projects and presentations from ZRDC 2025 and LinHT Status in late 2026

  • Panel Discussion - Encryption in Amateur Radio

Registration Has Slowed

I have to say, registration has been very slow. I am not sure if it is just that time of year when we are saying goodbye to summer and vacations or something else. I have sent out a round of press releases and will continue to do so. Please feel free to share any and all information so that the word goes out.

Two New Sponsors - CentyLab and NA6D

To that note, we have also had two additional sponsors support ZRDC 2026 - CentyLab and NA6D. Both have contributed amazing equipment for door prizes at ZRDC 2026. We thank both for their generosity and support.

CentyLab:

  • PocketPD (3)

  • PPsTrigger Board (2)

NA6D:

  • AIOC assembled (5)

  • Open TNC with both cables (2)

As we did last year, the AIOCs will be bundled with Explorer QRZ-1 portable radios donated by GigaParts.

Demonstrations - AMSAT CubeSatSim and M17 Repeater

We are going to have demonstrations at ZRDC.

Steve is a member of AMSAT and read in the most recent AMSAT newsletter that they can make a demonstrator unit of “CubSatSim” available for events like ZRDC. We’re grateful to Alan Johnston, KU2Y and AMSAT for the loan of a CubeSatSim for ZRDC. Steve is happy that it will be able to run a demonstration of “Pacsat”. He’ll be providing more details about that in a future issue of Zero Retries.

Also, Jeff Scoville, AE5ME will be bringing his M17 repeater, so if you have M17 radios, bring them tuned to:

Repeater Output: 441.850
Repeater Input: 446.850.

Steve will be bringing our pair of CS7000 M17 portable radios, and his pair of TNC4s with suitable radios to do M17 data.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0261. Paid subscribers can comment directly on the web version of this issue.

Correction - Internet Connectivity for Meshtastic and MeshCore

By Steve Stroh N8GNJ and Claude (specific model not noted)

In Zero Retries 0260 - A Brief Comparison of Networking - Meshtastic / MeshCore vs Amateur Radio AX.25 Packet Radio, in a footnote, I said:

It is my understanding that there’s no Internet gateways / tunneling / bridging with Meshtastic or MeshCore. There is a technology for LoRa called LoRaWAN that is such an Internet backbone, but LoRaWAN is generally not used in hobbyist use of LoRa.

I received a graceful correction on this point from Conrad Trautmann N2YCH:

When I began with Meshtastic, there is functionality built into the phone app to use your phone’s internet via MQTT to get on an internet backbone. I mentioned that in my qrper.com article [Building an Off-Grid Meshcore Network, One Node at a Time].

I thought you’d want to be aware of that functionality. I did try it with Meshtastic and it was a little crazy, with random messages popping up on the device. There didn’t seem to be any organization to it, and I quickly disabled it.

Apparently Meshcore has a way to use the internet to connect repeaters together, but I haven’t dug in deep enough to speak to that.

Thus, my statement about no Internet gateways / tunneling / bridging in Meshtastic or MeshCore is profoundly incorrect from not doing reasonable research. My apologies to Zero Retries readers. My thanks to N2YCH for pointing out this error.

I mentioned in my brief Post-Publication Update in Zero Retries 0260:

The popular perception (and, in my reading, almost all deployments of Meshtastic / MeshCore) is that Meshtastic / MeshCore networks don’t use, or depend on Internet or other “centrally controllable” infrastructure.

Claude Says About Meshtastic Internet Connectivity…

As is usual these days, to get a fast, general overview of a particular topic or question, instead of doing a web search, it’s often more efficient to consult an AI - Claude, in my case. This is the pretty useful and informative result for Meshtastic.

(This AI answer is not vetted.)

Meshtastic bridges to the internet almost entirely through MQTT, with a few variations on how a node gets that MQTT connection:

1. MQTT bridging (the core mechanism) Any node can be configured to publish/subscribe mesh packets to an MQTT broker, either:

  • Public server — mqtt.meshtastic.org, the default public broker. Encrypted channels stay encrypted end-to-end even over MQTT (the broker just relays ciphertext), but there’s an obvious privacy/traffic-analysis tradeoff to publishing your mesh’s existence publicly.

  • Private/self-hosted broker — point your node config at your own Mosquitto instance or similar, useful if you want to bridge two physically separate mesh islands over the internet without exposing anything publicly.

Per-channel settings control uplink (mesh→MQTT) and downlink (MQTT→mesh) independently, so you can have a channel that only reports out, or one that’s fully bidirectional (letting internet-side traffic re-inject into the mesh).

2. What gets the node onto the internet in the first place The MQTT client has to run on a node that itself has IP connectivity:

  • WiFi-capable nodes (ESP32-based — Heltec V3, T-Beam variants with WiFi, RAK WisBlock with WiFi core) can join a local WiFi network directly and act as an MQTT gateway node.

  • Ethernet — RAK WisBlock with an Ethernet module (or similar) for a wired uplink, handy for a fixed gateway location.

  • Client-side bridging via the phone/desktop app — if you connect over Bluetooth/USB/TCP to a node from the Meshtastic Android/iOS/web app, the app itself can proxy MQTT over the phone’s internet connection rather than the node needing its own radio-side IP link. This is the common setup for a “portable” node that isn’t WiFi/Ethernet capable (e.g., most nRF52-based boards).

3. Downstream integrations Once traffic is on MQTT, it’s trivial to fan it out further — Home Assistant, Node-RED, Grafana dashboards, Discord/Telegram bots, APRS-IS gateways, etc. all just subscribe to the broker. There isn’t a native non-MQTT internet gateway path (no direct AREDN-style IP tunneling built into the firmware) — MQTT is the one blessed bridge point.

One caveat: Meshtastic firmware and MQTT topic/config details change fairly often between releases, and I can’t be certain everything above reflects the current firmware version. Worth a quick check of the official docs or a web search if you’re about to configure this — happy to search now if useful.

Claude Says About MeshCore Internet Connectivity…

(This AI answer is not vetted.)

MeshCore’s answer to this is quite different from Meshtastic’s — there’s no single blessed internet-bridge mechanism baked into mainline firmware. Instead it’s grown organically through third-party bridge tools, mostly modeled after Meshtastic’s approach but running as separate software rather than a first-class firmware feature.

1. Companion app connectivity (not really “internet,” but the base layer) Like Meshtastic, a MeshCore node can run in Companion Radio mode, connected to a phone/PC app over BLE, USB, or WiFi. This gets you a chat client talking to the mesh, but by itself it’s not an internet gateway — it’s just how you interact with a node.

2. Third-party MQTT bridges (the actual internet path) Since MeshCore itself doesn’t ship a native MQTT client in the way Meshtastic firmware does, the ecosystem has produced several separate bridge tools that sit between a MeshCore node and an MQTT broker:

  • meshcore-mqtt — a bridge service connecting to a MeshCore device over TCP, Serial, or BLE, with full MQTT client support including authentication, QoS, retention, TLS, and configurable event monitoring.

  • meshcoretomqtt — a Python script for sending MeshCore debug and packet-capture data to MQTT for analysis, intended to run on a Raspberry Pi or similar device connected to a repeater, useful for tracking a message’s path through multiple repeaters via its unique hash.

  • Meshcore-Repeater-MQTT-Gateway / EastMesh — custom repeater firmware forks with MQTT bridging built directly into the firmware itself (rather than an external script), including bidirectional forwarding, TLS, and NTP time sync required for TLS certificate validation.

3. “Observer” nodes — community mapping/analysis networks This seems to be MeshCore’s most common real-world internet use case. An Observer is a MeshCore node — repeater, room server, or companion device — that listens to nearby mesh traffic and reports what it hears to an MQTT broker over the internet, feeding regional community projects (ChiMesh, NashMesh, LetsMesh, etc.) for coverage mapping and reliability stats. Observers can be configured to share only advertisement packets so they show up on a node map without exposing message contents, and you can stop sharing at any time. Setup is either via a packet-capture install script on a companion device, or via custom observer-enabled repeater/room-server firmware from community builds.

4. Cross-protocol bridges to Meshtastic There’s at least one project, Akita-Meshtastic-Meshcore-Bridge, purpose-built to bridge between Meshtastic and MeshCore networks, enabling communication between the two, supporting direct serial connections plus MQTT as an external transport with per-channel mapping between the two systems.

5. Multi-protocol dashboards Tools like MeshMonitor unify things further — it can connect over TCP, Serial, or BLE to both Meshtastic and MeshCore nodes, and separately connect to MQTT brokers either as a read-only source or by running its own embedded broker with bidirectional bridges to public upstreams, letting you mix protocols in one dashboard rather than picking just one gateway path.

Bottom line vs. Meshtastic: Meshtastic has uplink/downlink MQTT as a native, documented firmware feature. MeshCore’s internet connectivity is more of a bolt-on layer — third-party bridge software or forked firmware, generally organized around either generic MQTT/IoT integration or community-run “observer” networks for mapping. This space is moving fast and fragmented across several independent projects (several updated within the last few weeks), so it’s worth checking each project’s repo directly before committing to one for a deployment.

Now I, and perhaps some of you now know that there are “Internet options” for Meshtastic and MeshCore, when that’s desired.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0261. Paid subscribers can comment directly on the web version of this issue.

Update on KK7NQN AI Net Logger

By Hunter Inman KK7NQN

Editor’s Intro

This article was triggered by Tom Salzer KJ7T’s article in Random Wire 198 - Hunter’s Transcription Script:

I love the graphic, subtitled:

I don’t always listen to nets, but when I do, I like them transcribed!

I can’t always listen to a net, even when I really do want the learning that comes from hearing so many great questions and answers. Then I remembered Hunter Inman’s KK7NQN Transcription Logger project from the first Zero Retries Digital Conference and decided to give it a try on a spare AllStar node. Read Hunter’s overview at https://kk7nqn.net/. It is pretty amazing stuff.

However, getting it working required inferring some information and making some choices. A key choice for me was to use regular expressions instead of an AI for some transcription tasks. The system also tries to detect whether it has captured a net. Just like me, it does struggle with call signs.

Ultimately, I forked Hunter’s code and incorporated some fixes, including some new files. One of those was creating a simple transcript viewer web page. That saves me from having to SSH into the node and run a complicated MySQL query just to see a transcript. The Transcript Viewer lets me use date selectors to set a start and end date/time for the query. The query output is parsed into a table, and the transcript is downloadable as a text file.

Earlier this week KJ7T provided me a preview of his article and that caused me to reach out KK7NQN to mention Tom’s fork, and check in, in general. KK7NQN’s reply was a detailed update on his recent progress, with photos, and thus this article.

…

[Tom’s fork] is really cool to see. Thanks for sending it over!

I actually started on a second major rewrite of the system back in February, although I didn’t get the new version online until around late June. My available project time has been pretty limited lately.

What I find especially interesting about Tom’s project is that he and I seem to have taken the original system in almost completely opposite directions, which is really cool to see.

With the second version, I went much heavier on AI and autonomous operation. I still wanted to preserve the original “everything local” idea, so I built out two dedicated servers in a business location my wife and I own.

I’ve attached some photos of the servers I built out to handle the load of the new system.

KK7NQN Server Rack
Image courtesy of Hunter Inman KK7NQN
KK7NQN server with NVIDIA cards
Image courtesy of Hunter Inman KK7NQN
KK7NQN server
Image courtesy of Hunter Inman KK7NQN

One is essentially a full-time AI server, while the other is the central orchestrator that manages the radio nodes, scheduling, transcription pipeline, database work, and the rest of the backend.

The current system is running at:

https://kk7nqn.net/viewer.html

The central server is an HP ProLiant DL380 Gen9 with dual Xeon E5-2667 v4 CPUs and two RTX 3060 GPUs that handle Whisper transcription. The AI server is an ASUS ESC4000 with dual Xeon E5-2699 v4 CPUs, four Tesla V100 GPUs, and a RAID 0 array of four NVMe drives.

The new version also uses several monitoring AllStar nodes along with three separate SDR sites in Shelton, Potlatch, and Gig Harbor. The SDR sites run KA9Q-radio on Raspberry Pi 4s and feed audio back into the central system for transcription and processing.

Once I got everything running, I basically turned it loose. It has been operating essentially 100% hands-off since then, transcribing and processing several thousand transmissions per day on its own.

So while I ended up moving toward “throw a ridiculous amount of local compute and AI at it and make it autonomous,” Tom seems to be going the other direction: keeping the processing much more deterministic, digging through the original system methodically, finding bugs, fixing things, and documenting exactly how everything works.

I’m genuinely curious to see what he finds and what Parts 2 and 3 turn into. Seeing somebody fork the original project and take it in a direction that different from where I took version two is probably one of the coolest outcomes I could have hoped for.

And thanks again for having me demo it at ZRDC 2025. It’s pretty wild seeing how far the project has spread since then.

Editor’s Postscript

It’s just delightful watching the progress of KK7NQN’s project over the past year. I think it’s the ultimate validation of your work and that you documented it in public, adequately, when someone like KJ7T, in this case, uses your work in a way you never imagined.

In my big picture Zero Retries perspective, I think a synthesis of:

  • KK7NQN AI Net Logger,

  • RepeaterBook’s new capabilities to report on realtime repeater activity,

  • Advanced repeater capabilities such as IP400 and SuperPeater

are going to make Amateur Radio VHF / UHF repeaters even more of an Amateur Radio superpower. With a KK7NQN AI Net Logger, some (additional) embedded AI, the “see which is the most interesting repeater in my area” from RepeaterBook, and the extended capabilities of IP400 / SuperPeater means that NewTechHams can easily get on the air with modest equipment, in data modes, and see what folks on a repeater typically talk about, and join in on the one that’s the most interesting to them.

Kudos to both KK7NQN and KJ7T for their respective work on this concept!

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0261. Paid subscribers can comment directly on the web version of this issue.

Zero Retries - Tightening Focus to Data Communications

By Steve Stroh N8GNJ

The “big three” Zero Retries Interesting topics in Amateur Radio that don’t get much coverage in Amateur Radio media, and thus that I’ve tried to highlight in Zero Retries are Data Communications, Space, and Microwave Communications. Of late, I’ve rethought coverage of the latter two, primarily because those already have dedicated coverage.

Deferring Most Coverage of Amateur Radio Space to the AMSATs

For Space, there are the AMSATs of the world that are entirely oriented towards Space Communications, and many include their own publications, such as the AMSAT Journal. I wish that the “good stuff, such as AMSAT Journal was published for the benefit of Amateur Radio as a whole instead of solely for (paid) AMSAT members, but that’s their choice and I’ve decided to join ‘em rather than fight ‘em with independent coverage. That’s especially true since I’m not yet active on Amateur Radio satellites (other than the occasional passive reception) and the experts on technical aspects of Amateur Radio space are involved, and writing for, the AMSATs. The price of AMSAT (US) membership is reasonable, so I joined and thus have access to AMSAT Journal (including issues earlier than my membership) and I’m enjoying learning in more detail about Amateur Radio space communications.

Some Exceptions About Space That I’ll Continue to Cover in Zero Retries

Exceptions to the above:

  • It’s unfortunate to me that the AMSATs don’t cover the amazing projects of SatNOGS and TinyGS as receive-only ground stations dedicated to downloading telemetry from experimental satellites such as those built as school projects. I think that SatNOGS and TinyGS are particularly relevant to cover because they can be built and operated without an Amateur Radio license. For example, these can be projects of fans of STEM, Makers, Makerspaces, general interest radio technology organizations, schools, etc. Thus I’ll cover SatNOGS and TinyGS in Zero Retries.

  • The AMSATs don’t provide very good coverage of the data communications aspect of Amateur Radio in space, such as upcoming dedicated Amateur Radio data communications satellites (PACSATs). Thus, when I see something about data communications aspects of Amateur Radio in space, I’ll feature it in Zero Retries. An example is the story about the upcoming Pacsat emulation in a future version of software for the CubeSatSim in ZR > BEACON in this issue. I’ll also continue, as a paid member, to encourage AMSAT to consider dropping the paywall for access to AMSAT Journal.

  • The AMSATs don’t provide very good coverage of the potential of a second Amateur Radio payload in Geosynchronous Earth Orbit (GEO), hopefully covering at least portions of North America. Thus I’ll cover Amateur Radio GEO developments in Zero Retries. An example is the story from Open Research Institute in ZR > BEACON in this issue. There’s also very little coverage of data communications used on the QO-100 payload at GEO over Eurasia, so I’ll cover that in Zero Retries.

  • Earth Moon Earth (EME) aka Moonbounce / Lunabounce seems to be its own activity entirely separate from interest from AMSAT. That’s always seemed odd to me because the Moon / Luna is in fact a satellite orbiting Earth and ergo, EME is satellite communications - albeit highly specialized. EME used to be solely the province of those who could build and operate massive antenna arrays, 1 kW of transmit power on VHF or UHF, and slow Morse Code. In this era, EME is achievable with stations as modest as 100 watts of transmit power, an 11 element beam, and data modes optimized for EME. There are many disparate sites of good information for EME but no organization (that I’ve yet found). EME is interesting enough that I’ll probably continue to report on it in Zero Retries, especially “modest station” EME.

  • There are a handful of “big dishes” around the world that that incorporate regular Amateur Radio operation and often radio astronomy, such as those at MIT in Cambridge, Massachusetts, in Wall Township New Jersey, Colorado, and a number of others. I haven’t seen coverage of those in the publications of the AMSATs, so I’ll continue to cover them in Zero Retries.

  • Lastly, there’s no coverage of (what I consider) hobbyist / experimenter use of commercial (or government) Low Earth Orbit (LEO) and Geosynchronous Earth Orbit (GEO) communications satellites such as Starlink or HughesNet. Starlink is particularly interesting for experimentation given its mobility capability, the Starlink Mini unit (small size, easily mobile or portable, can be powered by batteries), and the Starlink Standby service for $10 / month for unlimited data transfer at 500 kbps. While there’s ample coverage of Starlink, that coverage is about using Starlink conventionally, and it’s usually puffed-up regurgitation of information published by Starlink. I think such capabilities are Zero Retries Interesting, and Amateur Radio adjacent, so you can expect ongoing coverage of Starlink in Zero Retries

Why Don’t I Write for AMSAT Journal? The Paywall!

It’s a reasonable question that if I’m going to devote energy to covering the above topics, why don’t I cover them for publications by the AMSATs? Simple answer - those publications are only available behind a paywall, and thus not readable by the vast majority of Amateur Radio Operators, and those interested in hobbyist space communications. Zero Retries is published without a paywall (paid subscriptions are entirely optional). If I’m going to devote time and energy to covering the above exceptions, I’m going to do so for the maximum benefit of Amateur Radio, not sequestered behind a paywall that can only be read by a comparative handful of folks.

That said… Like I recently discovered with ARRL’s publications, writing an article for a publication behind a paywall isn’t necessarily a binary choice. It’s (probably - I haven’t looked at AMSAT’s editorial policies) possible to write an article in Zero Retries and then offer it to AMSAT Journal, so now that I’m a member of AMSAT, I’ll consider that the next time I write a significant article about space for Zero Retries.

Post Publication Update - To be complete, AMSAT also provides AMSAT News Service Weekly Bulletins which is free to subscribe, and regularly feature short stories that are Zero Retries Interesting.

If you’d like more detailed information about Amateur Radio satellite activities that’s not behind a paywall, besides Zero Retries, I recommend the SARC Communicator. In that publicly accessible, bimonthly publication, Amateur Radio satellite news is featured regularly, often written by an Amateur Radio Operator active in satellite activity.

Deferring Most Coverage of Amateur Radio Microwave

Amateur Radio microwave communications also has a dedicated community… actually communities from indepenent, regional organizations and regional interest. That’s understandable because microwave communications and experimentation is inherently a local activity - microwave transmissions don’t travel very far terrestrially.

If one is interested in Amateur Radio microwave communications, and you’re within an area that has an Amateur Radio microwave communications organization - example San Diego, California has the San Bernardino Microwave Society, then you’re all set. If you’re interested in Amateur Radio microwave communications without a local community, you can “tap into” the existing communities and start one.

One exception to the above is that the Amateur Radio microwave communications organizations don’t seem interested in covering, or involvement in Amateur Radio microwave networking.

Since Amateur Radio microwave networking is inherently data communications, (even microwave networking for voice such as repeater linking is data), it falls squarely within the Zero Retries (newly narrowed) focus on Amateur Radio data communications.

Another exception is the potential of “Groundsats” - the idea of using wide(r)band transponders on Amateur Radio VHF / UHF bands such as are used on Amateur Radio satellites, but using transponders terrestrially such as mountains. I suspect that the Groundsat concept isn’t very popular because the most popular VHF / UHF radios don’t offer SSB operation that is required for (narrowband) use on transponders, but that is rapidly changing with the increasing availability of Software Defined Transceivers. Groundsats are rarely mentioned, so when I see coverage of Groundsats, I’ll feature them in Zero Retries.

Continuing Coverage of Software Defined Radio, Especially GNU Radio

Most of the general coverage about Software Defined Radio in Amateur Radio that I see is either:

  • Extolling the features of embedded SDR functionality that’s not modifiable by owners of radios with SDR functionality, and

  • Emulation of existing radio technology that was formerly done in hardware, now done better and less expensively using SDR.

But I rarely see any coverage of SDR in Amateur Radio media that explores what was not previously possible, or at least, not practical in Amateur Radio, but is now possible with SDR. An excellent example of something not previously possible with hardware radio technology, but now possible with SDR is ka9q-radio which allows simultaneous reception and decoding of individual portions of bandwidth (channels). Current Amateur Radio hardware or SDR paradigms “scan” (sequential reception of individual channels) or “bandscope” - displaying an large portion of spectrum but not receiving and decoding individual channels (until the operator selects a particular frequency).

I very rarely see any coverage of GNU Radio technology related to Amateur Radio, thus that’s a good fit for coverage in Zero Retries.

Other Zero Retries Interesting activities such as:

  • Low power operation (QRP),

  • Amateur Radio Television,

  • Digital Voice (VHF / UHF and HF [generally FreeDV RADE],

  • Amateur Radio Over Internet

  • Emergency Communications (EMCOM),

  • xOTA (whatevers On The Air)

  • Field Days

  • Unusual antenna systems, especially for VHF / UHF

… all have reasonable coverage in their own publications / communities -see Zero Retries Directory of Independent Open Amateur Radio Technical Media (recently updated with a number of new publications / communities).

I’m looking forward to Zero Retries being simplified and more focused on data communications.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0261. Paid subscribers can comment directly on the web version of this issue.

The Use Cases of IP400 Networks

By Steve Stroh N8GNJ

IP400, the Advanced Mesh Network Controller (AMNC), OFDM-AB modulation… That’s all cool technology…

but in the big picture of Amateur Radio, what’s it good for?

The following is solely my opinion, independent of Alberta Digital Radio Communications Society (ADRCS), the developers / sponsors of IP400, and my involvement in IP400.

In the 21st century, with nearly ubiquitous mobile networks providing broadband speeds to devices we carry in our pockets, and very recently broadband communications anywhere in the world via satellite… Amateur Radio hasn’t had a “reasonable” data communications system / network that seems reasonably relevant.

Meshtastic / MeshCore

Meshtastic / MeshCore has become wildly popular as a radio communications technology that doesn’t require an Amateur Radio license to participate in and experiment with radio hardware. Within Amateur Radio, Meshtastic / MeshCore has become mildly popular.

My “armchair analysis” of the rapid and rabid uptake of Meshtastic / MeshCore is that it’s easy to experiment with (no license needed), low cost to participate, it works without much effort (lots of nearby nodes), there’s a welcoming community both online and locally, and it has some utility - a messaging system with no reliance on centralized systems or controllable by “bigcorps” or “biggovmint”.

But in the end, Meshtastic / MeshCore is a low data rate technology, and thus generally only usable for text messaging.

Packet Radio in Amateur Radio is Mostly Stuck at 1200 bps AFSK AX.25

The vast majority of Amateur Radio Packet Radio is still 1200 bps using Audio Frequency Shift Keying (AFSK) modulation, using the AX.25 protocol, with “wide area” networking done via digipeaters (and usually, digipeaters “tuned” to the very short packets of Automatic Packet Reporting System - APRS.

Yes, use of 9600 bps Frequency Shift Keying (FSK) using the AX.25 protocol is increasing thanks to it being a built-in mode of new radios like the Kenwood TM-D7502. But, the utility of 9600 bps doesn’t feature modern implementations of AX.25 such as Forward Error Correction and other improvements from the 21st century.

Pockets of Advanced Amateur Radio Data Communications

We have pockets of more advanced types of data communications, such as:

  • Post-publication Update: Internode links in NCPACKET are mostly faster-than 1200 bps (at least 4800 bps and often 9600 bps), and mostly using IL2P Forward Error Correction.

  • AREDN and other microwave networks,

  • New Packet Radio (NPR) and NPR 3.0,

  • VARA FM in conjunction with VarAC,

  • Icom D-Star Digital Data (DD),

But all of those suffer from some drawbacks / restrictions. AREDN and other microwave networks operate at microwave frequencies and thus subject to terrain / foliage issues. D-Star Digital Data is only available on a few high-end Icom radios operating on 1240 - 1300 MHz / 23cm. VARA FM and VarAC are closed source applications written for use on Windows, and only interoperable with some Packet Radio applications via VARA’s basic KISS interface.

To date, NPR and NPR 3.0 is the most “reasonably relevant in the 21st century” Amateur Radio data communications system in the 21st century. Its data interface is Ethernet, its networking protocol is TCP/IP, its data speeds are reasonable - 100 kbps - 1 Mbps, it operates on the 420-450 MHz / 70cm band3, it has a digipeater / repeater mode for wide-area use, and NPR 3.0 provides reasonable transmit power - 7 watts.

Another promising “reasonably relevant in the 21st century” option is AREDN replacement firmware ported to various hardware for the 902-928 MHz / 33cm band. Like NPR, Ethernet, TCP/IP, and reasonable data speeds. 902-928 MHz / 33cm offers reasonable foliage penetration, and reasonable range (more reasonable than microwave).

I’ve covered the details of IP400, the new OFDM-AB modulation, and the AMNC hardware in previous issues of Zero Retries, thus won’t rehash that in this article.

Again, What Can You Do With IP400? Text Chat Like Meshtastic / MeshCore.

Post-publication Update: Commenters on the Zero Retries email list suggested that Raven - the new text chat application running on AREDN nodes is worth mentioning in this context. Notably, Raven is compatible with AREDN, Meshtastic, and MeshCore networks. Hopefully when IP400 is shipping and getting deployed, support for IP400 networks could be added to Raven.

At a minimum, IP400 provides a reasonable alternative to Meshtastic and MeshCore operating in unlicensed spectrum that takes advantage of some of the unique aspects of Amateur Radio:

  • Like Meshtastic, IP400 provides integral autodiscovery mesh networking,

  • Like MeshCore, IP400 provides structured networking (repeaters) for wide area communications,

  • Like Meshtastic / MeshCore (LoRa), robust, reliable modulation,

  • Like Meshtastic / MeshCore, reasonable range with simple antennas (Amateur Radio has no transmit power restriction - 25 watt radios are common)

Thus, (again, at a minimum), IP400 can provide a network to offer very capable, very scalable, short text messaging / chat services the same as Meshtastic does.

One of the attractions of Meshtastic / MeshCore is portability:

  • There are many Meshtastic / MeshCore devices that can be carried on belt, backpack, etc., and

  • The “terminal” is often one’s mobile phone, with using an attractive, easy to use app.

That’s one use case that IP400 won’t immediately be able to provide a direct alternative - an Amateur Radio portable radio plus an AMNC will be bulkier than a portable Meshtastic / Meshcore device. But… watching the progress of the LinHT, it’s feasible that IP400 could eventually be available in a form factor similar to a LinHT

But in the “stationary” or “mobile” use cases, where the combination of a portable or mobile radio plus an AMNC isn’t an issue, IP400 would be completely competitive. Eventually there will be a IP400 converse app for mobile phones, tablets, or perhaps the AMNC operating on a Raspberry Pi could provide a compatible “host environment” to be able to use the same app as Meshtastic or AREDN’s Raven chat app.

Beyond Meshtastic / MeshCore…

From and infrastructure perspective, IP400 can go beyond Meshtastic / MeshCore:

  • Three big improvements beyond the above data communications modes:

    • Faster data speeds4 with higher reliability (using higher power, OFDM, and FEC)

    • Built in mesh networking5. The network figures out who is where, and how to route to them.

    • A not-very-disruptive method to add reasonable data communications to FM voice repeaters that preserves voice functionality.

  • Faster speeds - up to 70 kbps

  • Multi-tier networks - different bands, different frequencies can provide backbones.

  • Can interoperate with other Amateur Radio data communications systems such as Packet Radio, AREDN, NPR / NPR 3.0, and AllStarLink using TCP/IP and KISS.

IP400 Beyond Chat

The use cases of IP400 networks are closest in scope to AREDN networks, including:

  • File transfers in reasonable time (especially text-only like spreadsheets or HTML), including background updates of frequently updated files such as repeater lists, updates to Amateur Radio licensees, tactical maps, node maps updated daily, etc.

  • Firmware updates, including automatic or semi-automatic (user chooses to update, or not) of software for IP400 nodes. Like other systems of similar scope - example, an MMDVM hotspot, you can opt-in for automatic or semi-automatic updates of IP400 software for your IP400 node.

  • File transfer of audio files, or more recently, transcripts of audio files.

  • Email - individual and email lists.

  • Web servers / web browsers (especially simple HTML-only).

  • Flood bulletins.

  • Bulletin Board Servers / clients.

  • Voice Over Internet Protocol (VOIP) - provisionally - IP400 isn’t full duplex.

  • Extensions of wide area traffic handling / bulletins - regional handoffs from NTS and TPRFN to higher speed, high density / high participation IP400 networks.

  • Extension of APRS - port traffic from 1200 bps AFSK APRS on 144.390 MHz into IP400 networks - the difference in speed makes the APRS traffic a “light load” on IP400 networks, especially if aggregated (all traffic buffered for one minute, then ported into IP400 network).

  • Winlink - A local Winlink Radio Mail Server on HF can add a port to the local IP400 network to be able to cleanly route email to / from Internet email using the robust and well-developed Amateur Radio email handling capabilities of the Winlink system.

Community - Water Holes

Generally, IP400 networks can serve the same function, with data communications, as an active voice repeater does - be the infrastructure of an active and welcoming Amateur Radio community. Sometimes this functionality is described as a “water hole” (or in a more modern context, a water cooler) where folks naturally congregate, mingle, and communicate.

This isn’t an either / or - voice repeater or data communications. With the IP400 AMNC, you can do both, and they’re complimentary. For example, if you miss the nightly 21:00 net on your favorite repeater, the repeater club’s local KK7NQN AI Net Logger can email (or flood bulletin) a transcript of each night’s net.

Concluding

I think that IP400 Networks can potentially (there aren’t any, yet) provide a technically superior, more functional, and more accessible (to most Amateur Radio Operators) network system than previous Amateur Radio data communications networks… and Meshtastic / MeshCore networks.

Beyond that technical superiority, I think that IP400 networks can potentially provide a significant incentive for techies curious about experimenting with radio technology to get an Amateur Radio license and get involved in a local IP400 network to have fun and join the community that will (hopefully) form on such networks.

Further Reading:

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0261. Paid subscribers can comment directly on the web version of this issue.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

Breaking! DigiPi 2.2 - Now Available!

Email from Craig Lamparter KM6LYW:

DigiPi 2.2 was just released with exciting new features and hardware support. The new Mercury HF winlink modem is loaded along side JS8Call “Improved”, and support for fully accelerated HDMI and mipi/DSI displays. These new displays look just like your cell phone with large/crisp/fast graphics.

In this video we are going to build a DigiPi from scratch and demonstrate some of the new modes including SMS, E-Mail, APRS, MercuryHF and JS8Call-Improved.

I’m suggesting a Pi3A+ as the new DigiPi base model for $25, and you can get a DSI display for $35. The Pi3A+ is readily available (unlike the Zero2W) and is an ideal platform when joined with a DSI 800x480 display.

All links and documentation may be found at

https://digipi.org/

The DigiPi software is available to Patrons of https://patreon.com/KM6LYW . Anything in the Patreon bucket gets you access to the DigiPi SD card - thank you for your continued support (and for making my videos ad-free!).

I think it’s a great idea to “graduate” DigiPi to be hosted on a Raspberry Pi 3B+ and the larger display format that’s formatted for a larger screen.

With this, I think the Mercury Modem data communications mode for HF now has an appliance for much easier use.

The Communicator: September - October 2026

Communicator Editor John Schouten VE7TI:

Welcome to the September-October 2026 issue of The Communicator. Dive into the latest issue of The SARC Communicator, a bumper edition brimming with technical innovation, operating field reports, and rich radio history for all levels of amateur radio.

A Blend of History and Innovation

This issue opens with a compelling profile of Sir William Stephenson, offering a deep dive into radio history. It then looks forward with “The Future of Morse Code Has a Call Sign,” exploring the enduring relevance of CW in the digital age. For those interested in cutting-edge technology, the feature on “FreeDV RADE” introduces a revolutionary new approach to digital voice over HF, leveraging machine learning for robust communication in noisy conditions.

Practical Projects and Operating News

Practical builders will appreciate “SARC’s NTP Clock Revisited,” which details how to achieve 14 display modes on a single ESP8266, and “Solving the USB charger problem… for good.” Operators can benefit from “An Almost Instant Visual Propagation Tool” and new hams will appreciate “Before You Press the PTT.” The “Radio Heroes on the International Pacific Highway” provides a historical account of the building of that roadway and the role amateur radio played. The issue also covers the latest in satellite news with “LEO satellite news: AMSAT in Canada” and “LEO.space.”

Community and Commentary

Editorial pieces like “Cheap ATV?” and “AI on the Air: Breakthrough, Shortcut, or the Next Tool in the Ham Shack?” provoke thought on the hobby’s direction. Community news includes “What’s New at DLARC,” “The New-Gen Ham,” and a profile of Zero Retries’ Steve Stroh N8GNJ. From “Hunting RF Interference” with the EMF Explorer to the return of packet radio with “New Packet Radio,” this issue is a comprehensive resource for every ham.

So power up, tune in, and turn the page—The Communicator has something for every communicator, now reaching 165+ countries.

The Communicator is the bimonthly newsletterzine of Surrey Amateur Radio Communications based in Surrey (Vancouver metro area) British Columbia, Canada. This issue is a “mere” 96 pages6. As always, this issue is a great mix of tutorials, history, operating tips, technology, and news about Surrey Amateur Radio Communications.

My column Zero Retries in this issue begins on page 66 - Networking, Networking, and More Networking. In this column I discuss IP400 / OFDM-AB / AMNC, LinHT progress, NPR-NG, and the new NA6D OpenTNC. All of those are topics that I’ve discussed in Zero Retries, but this is the “digest” version of those topics for the Communicator readership.

As VE7TI mentioned, I’m the subject of this month’s SARC member profile beginning on page 82:

Profiles of SARC members
Steve Stroh N8GNJ
presented by BLAKE R. WIGGS VA7BWG

I was surprised to see my profile run for four pages given that VA7BWG’s “interview” emails were a short series of questions, and I replied relatively tersely. VA7BWG dug into background information on Zero Retries to flesh out my terse responses. I’m pleased and humbled by the profile. Thanks Blake!

Pacsat Mode in CubeSatSim Software v2.3

The AMSAT Journal, July / August 2026 (paywalled), Educational Relations Update, by Alan Johnston, Ph.D., KU2Y V.P. Educational Relations:

We have some exciting software updates coming for the CubeSatSim! In the upcoming v2.3 software release, we will be adding:

  • Simulated Doppler shift where the transmit and receive frequencies change in real time, just like on a real satellite pass.

  • Pacsat Mode that works with the Pacsat Ground Station https://www.g0kla.com/pacsat/

  • Dashboard for controlling and monitoring your CubeSatSim using a web browser

  • Wi-Fi Hotspot for easy logging into the Pi Zero 2 and configuring your own Wi-Fi network

  • Support for Debian 12 “Bookworm.”

The second bullet - Pacsat mode is particularly interesting to me. At Hamvention 2026, I talked with AMSAT President Drew Glasbrenner KO4MA and explained to him that in my opinion, a standalone Pacsat node would be useful for terrestrial use as it overcomes several known issues in Packet Radio networks.

KO4MA was noncommittal about AMSAT making Pacsat components for non-AMSAT use, but did offer that there would soon be a Pacsat mode in the CubeSatSim. That info was not public at the time, and he asked me not to mention that until it was made public.

On the website Amateur Radio Station VETCP / GOKLA, AMSAT Pacsat Ground Station Software, there is a wealth of reference information on Pacsat technology such as:

  • PACSAT Protocol Suite - An overview

  • PACSAT File Header Definition

  • PACSAT Broadcast Protocol Used for directory broadcast and all downloads

  • PACSAT Broadcast Protocol Update 1 Errata

  • PACSAT Broadcast Protocol Update 2 The case for OLD and NEW dates on directory entries

  • PACSAT Broadcast Protocol Update 3 CL, BL file formats and the PBLIST destinations

  • Pacsat Protocol: File Transfer Level 0 Only used for Uploading Files, ignore Download logic

  • Pacsat Protocol: File Transfer Level 0 - Update

  • PACSAT Data Specification Standards

  • The legacy list of compression types

  • The legacy list of file types.

Codec2-mod Fixed-point, and in Rust!

Bruce Perens K6BP on a private email list (shared with permission):

I am experimenting with a re-implementation of codec2-mod done by Ai at my direction. I had the AI characterize the mathematical domains, there were three, and completely re-implement Codec2 in Rust, using fixed--point. This is an independent implementation observing only the algorithms of the original. The intent is to support M17 on hardware it would not run upon at present.

The codec is at https://github.com/BrucePerens/hams_open/tree/main/daemons/ham_digital_modes/src/codec2_3200

The C-language-compatibility layer is at https://github.com/BrucePerens/hams_open/tree/main/daemons/codec2_3200_capi

This should make it drop-in to M17.

Obviously, copyright means nothing any longer and people like myself with inadequate competence in a field can now direct a machine to do the work anyway.

Caveat - to date, this code is little-tested.

A followup to K6BP’s announcement by Wojciech Kaczmarski SP5WWP:

There is also this:

https://github.com/fenfir/Codec2-mod/pull/1

This is really cool to imagine M17 (which, remember, provides both digital voice and data), on simple(r) computing hardware that doesn’t support floating point.

M17 On Everything!

Cheap/Easy/Light GLOBAL E-MAIL Access! NEW!

Craig Lamparter KM6LYW / KM6LYW Radio on Patreon:

DL2MAN continues dominate the QRP world with not only the (tru)SDX 5-watt HF rig, but also a new standalone web/android Winlink/E-Mail/ARDOP software which leverages the built in cat/audio on a single USB cable! This is easily the cheapest and lightest HF email solution. SOTA operators rejoice! When grams count and your life is on the line, you have email access from anywhere in the WORLD!

https://dl2man.de/ARDOP/ NEW ARDOP Client

https://dl2man.de/

(tr)uSDX 5watt HF rig

https://www.ebay.com/sch/i.html?ssPageName=&_ssn=timortiz Antennas from N9SAB

https://digipi.org/

DigiPi, possibly with trusdx usb support soon?

Danke Schoen Manuel!

See the YouTube video - preview not shown as this issue is already a bit too big for email.

(tr)uSDX support in DigiPi soon? That would be really cool and (more!) Zero Retries Interesting!

Ceefax Station — Teletext Pages Over AX.25 (M7TJF)

Email from Tobias Franklin M7TJF:

I saw your note on the IEEE Spectrum Spectel piece about wanting public ham-teletext code and people to try it on HF. I’ve been running something in that space from M7TJF.

BBC-style Ceefax pages over AX.25 AFSK1200, MIT licensed, with a public map of who’s transmitting and who’s actually decoding.

Live map: https://www.ceefaxstation.com

Code: https://github.com/thaum-labs/ceefax_station

The viewer works with no radio and no API keys. Windows installer or git clone. Alpha. Looking for people to experiment, especially TX/RX on HF or VHF.

I love Zero Retries Interesting projects like this!

SDRoxide - THE RADIO, REFORGED IN RUST

A powerful SDR transceiver client with a GPU panadapter, dual VFOs, neural noise reduction, built-in skimmers, a full stack of digital modes, Winlink radio email, 868 MHz sensor decoding, hands-free satellite operation and a live 3D space-weather globe — running native on Linux, macOS & Windows, or streamed to any browser.

SUPPORTED RADIOS

SDR Oxide supports everything from USB dongles, direct-sampling HF receivers, wideband IQ radios to network transceivers, dongle servers and CAT-controlled rigs — twenty interface families through pluggable backends.

The long list of radios isn’t easy excerptible, so here’s just a couple of common units to demonstrate the breadth of radios supported:

  • Native RTL-SDR

  • ADALM-Pluto

  • HydraSDR RFOne

MODES & MODEMS

Every mode runs in-process — native Rust modems, with the DRM receiver and the RADE codec linked into the binary. No external decoders, no virtual audio cables, nothing to wire up between programs.

The display is really attractive, and Rust seems to be the “new hotness” language of late.

The long list of modes isn’t easy excerptible, so here’s just a couple of common modes to demonstrate the breadth of modes supported:

  • JS8

    Keyboard conversation on FT8’s waveform. All four speeds, JS8Call-compatible.

  • PACKET

    AX.25 at 300 baud on HF sideband, 1200 and 9600 on FM — with a frame monitor and a KISS server for other software.

I’ll guess that both the radios and modes can easily be expanded.

My thanks to Jeff Davis KE9V for (very enthusiastically) bringing this development to my attention for inclusion in Zero Retries.

Dragon Labs CR-8 - An 8-channel Coherent SDR That Doesn’t Sacrifice Performance

New project on Crowd Supply:

Dragon Labs CR-8 is a high-performance, yet affordable, 8-channel coherent SDR receiver. It is capable of 8 MHz per channel with 12 bits of dynamic range and can tune anywhere from 25 MHz to 1750 MHz. That’s more channels, more bandwidth and more dynamic range than the KrakenSDR, giving you more capability.

It can operate with all 8 channels coherently, or with an arbitrary set of coherent and noncoherent groups. This can be used for example to be coherent on two frequency bands at once by having one set of channels tuned to one frequency, and the others to another frequency. If desired, all channels can even operate completely independently while remaining perfectly synchronized in time.

…

Hardware

  • Channels: 8

  • Bandwidth: 8 MHz per channel

  • Sample Depth: 12 bits

  • Tuning Range: 25 MHz to 1750 MHz

  • Coherence: Any combination of channels, up to all 8.

  • Phase Error: Less than 1° at 1750 MHz (More measurements necessary)

  • Timing Error: Less than 100 ps

  • Coherent tuning time: 25 to 50 ms Expected to be reduced to under 10 ms

  • Onboard Oscillator: TCXO, 2.5 ppm over -20°C to +85°C (-4°F to 185°F)

This is cool - 8 receivers @ 8 MHz bandwidth for each receiver, all coherent.

So finally we have the the fabled “All North America VHF / UHF bands” single unit Software Defined Radio Receiver:

  • Receiver 1 - 50-54 MHz

  • Receiver 2 - 144-148 MHz

  • Receiver 3 - 219-220 and 222-225 MHz

  • Receiver 4 - 420-428 MHz

  • Receiver 5 - 428-436 MHz

  • Receiver 6 - 436-444 MHz

  • Receiver 7 - 444-450 MHz

  • 1 receiver for… whatever!

Open Research Institute (ORI) Presentation at futureGEO Community Workshop at HAMRADIO 2026

Michelle Thompson W5NYV in Inner Circle Newsletter Summer 2026:

ORI’s Presentation

Michelle Thompson was the third and final presenter at the workshop, speaking on behalf of ORI’s futureGEO proposal team. ORI is a signatory to the letter of interest (LOI) from AMSAT-DL, participated in the 2025 futureGEO Workshop at AMSAT-DL Symposium, and has submitted a one-page proposal as well as a white paper about ORI’s proposed design. Both of these documents can be found in the futureGEO GitLab as well as at the above links.

Michelle described the working hardware, firmware, and software implementations of Haifuraiya, or “High Flyer”. Haifuraiya is a functional prototype digital regenerative multiplexing amateur radio satellite system, with superior voice quality and integrated voice, text, and data. There are three implementations of the Opulent Voice ground station, and two implementations of the satellite segment. Processing occurs in the satellite. This is not a double-hop system. Uplink is frequency division multiple access Opulent Voice and downlink is DVB-S2 time-division multiplex. The design is carefully engineered and tested, completely open source, and fully documented.

Link - Poster PDF of ORI’s Haifuraiya Digital Satellite System Concept

Haifuraiya’s uplink is 5 GHz, and downlink is 10 GHz. The 5 GHz uplink seems a natural fit for ScaleRF / QuadRF - if it’s powerful enough to do EME, it can do GEO. Unfortunately, I’ve not seen any mention of the potential of using QuadRF with Amateur Radio satellites (except Luna).

TAPR Annual Membership Meeting and Board of Directors Elections

Staną Horzepa WA1LOU on various TAPR email lists:

ANNUAL MEMBERSHIP MEETING

TAPR’s Annual Membership Meeting will be held via Zoom on the afternoon (3 PM EDT, 1900Z) of October 24, 2026. It will run up to two hours. At the meeting, TAPR officers will discuss the current and future state of the organization and will answer questions and comments from the membership.

Nominations for three director positions may be made at this meeting. Anyone who is a member of TAPR can ‘throw their hat into the ring’ and stand for election. If there are more than three nominees, there will be an election by email, following the meeting.

Information on how to access the meeting will be posted on our website approximately one week before the meeting. You do NOT have to be a member to attend.

CALL FOR NOMINATIONS

Three Director positions on the TAPR Board of Directors are now open for nomination and nominations may be submitted now.

TAPR Board members serve three-year terms and their responsibilities include:

1) Attendance at the in-person board meeting that is held at Hamvention in May.

2) Regular participation in the continuous board session, which is conducted over the Internet.

3) Active engagement in TAPR’s management.

To place a person in nomination, please remember that he or she must be a member of TAPR. Also, confirm that the individual is willing to have his or her name placed in nomination. Send that person’s name (or your own if you wish to nominate yourself ), call sign, mailing address, e-mail address, phone number(s), and a biographical sketch (250 words maximum) via contact@tapr.org or via snail mail to TAPR, 1 Glen Ave., Wolcott, CT 06716-1442, to arrive BEFORE October 24, 2026. Nominations can also be made during the October 45th Annual Membership Meeting via Zoom.

An online election will be held from November 7 to November 20, 2026, using ElectionBuddy, if a vote is required.

Website announcement for 2026 Annual meeting:
https://tapr.org/annual-membership-meeting-2/

Website announcement for 2026 Board of Directors Nomination and Elections:
https://tapr.org/call-for-nominations-3/

Happy 50th to PRnet, ARPAnet, and Internet!

Greg Skinner on the Internet-history email list:

50th Anniversary of the First TCP Demonstration
By Don Nielson

Transmission Control Protocol (TCP) is the lifeblood of the Internet. It is the protocol, first defined in 1975, that enabled computer networks of dissimilar nature to seam together in ways invisible to its end users. That transparency and dissimilarity would extend over time to virtually all transmission media. It would also cover the world with a new, affordable web that would bring digital capability to everyone. Although bringing forth the modern Internet involved innumerable far-flung talents, there was one place and time where the Internet first saw the light of day—and SRI was involved.

It was August 27, 1976, and the new DARPA-funded packet radio project, the first mobile digital radio network, was linked through the 7-year-old wired ARPANET to its only hosts speaking TCP, one each in Boston and Los Angeles. The initiating terminal was in the West Bay foothills, and the bridge was the first TCP internetworking gateway located at SRI. Both the ARPANET and the PRNET had lots of contributors that made the connection possible, but SRI was the place of convergence for the PRNET, as it had been earlier for the ARPANET. testing had come to the point a real-life demonstration.

It was Ron Kunzelman, one of the SRI leaders in PRNET development, who suggested Rossotti’s (now Alpine Inn, also known to locals as Zott’s), a popular watering hole in Portola Valley, west of the Stanford campus. SRI’s mobile bread truck van, containing both a packet radio and a TCP-housing microprocessor, had radio visibility from Rossotti’s to a PRNET repeater node atop the ridge on which also sat the big SRI-Stanford dish. It was one radio relay to the gateway and satisfactory for the two networks to work fully in tandem.

The task chosen for the test was the delivery to DARPA of the monthly progress report on the PRNET, a very lengthy transmission. The test/demo was successful, and we buttoned up. It was just a slightly more noticeable day in SRI research that was promptly forgotten. Fortunately, and with little anticipation, I took a few pictures.

Almost exactly two decades later, as the digital world and the Internet blossomed, the inquiries began to appear around its genesis. One of these came to me from the IEEE Spectrum, and I was forced to dig out what I could find. In short, it led to that day at Rossotti’s and to a bigger demo that also included a satellite link and other gateways.

Somewhere along the way, a small bronze plaque appeared on the wall at Rossotti’s commemorating that event, later to be replaced by a larger one, shown here, placed now on the front of the building by the California Historical Society, according to a Rossotti’s manager at a recent event. The event saw me taking a few visiting relatives to lunch there, where I written story of that day. The aim was also to give the somewhat blustery account on the plaque some grounding. For my effort, I am now the proud owner of a Rossotti’s cap and not much else, except serendipitous memories. 50 years have gone quickly.

My thanks to Joe Hamelin W7COM for bringing this development to my attention for inclusion in Zero Retries.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0261. Paid subscribers can comment directly on the web version of this issue.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

ZRDC 2026 Ho!

Zero Retries Digital Conference (ZRDC) 2026 will be here before we (I) know it.

6 weeks until Zero Retries Digital Conference 2026

on Friday, October 16, 2026,

in San Ramon, California, USA.

N8GNJ For TAPR Board of Directors

After serious consideration, I’ve decided to nominate myself for a position on the TAPR Board of Directors. I’ve previously served on the TAPR BoD.

More details in a near future issue of Zero Retries.

Weekends Are For Amateur Radio!

Tina and I and our two cats Fiona and Shrek have decamped to a hotel room in Vancouver, Washington for a couple of weeks. We want to be close to Grandchild #1 (impending, as of publication date) and Grandchild #1’s parents. I packed a ridiculous amount of deferred projects that were “packable”, including a number of projects I want to demonstrate at ZRDC 2026, such as the new OpenTNCs mated and working with some inexpensive portable radios. And yes, one of them is the loaned MeshCore unit.

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0261. Paid subscribers can comment directly on the web version of this issue.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

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The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries | Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0261 was published on 2026-09-04. This issue was 10,577 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

I think the humorous Amateur Radio term for a grandchild is “subharmonic” as children of Amateur Radio Operators are humorously termed “harmonics”.

2

Just… astonishing… that the Kenwood USA Amateur Radio site doesn’t yet mention the TM-D750A. Kenwood folks… It’s for sale and is already in buyer’s hands!

3

NPR 3.0 also has versions for 144-148 MHz / 2m and 1240-1300 MHz / 23cm.

4

Except NPR / NPR 3.0 and (in development) NPR-NG

5

Obviously mesh networking is a feature of Meshtastic / MeshCore, and “kind-of” a feature of Packet Radio for those advanced nodes that implement Net/ROM / TheNET capability.

6

It’s not uncommon for issues of The Communicator to be more than 120 pages.

]]><![CDATA[Zero Retries 0260]]>https://www.zeroretries.org/p/zero-retries-0260https://www.zeroretries.org/p/zero-retries-0260Sat, 22 Aug 2026 00:30:49 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its sixth year of publication, with 3600+ email subscribers.

Zero Retries Digital Conference 2026 is October 16th in San Ramon, CA
www.zeroretries.org/p/conference

Steve Stroh N8GNJ, Editor

steve@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is likely to be truncated by some email clients. Thus, it might be easier to read in a web browser:

www.zeroretries.org/p/zero-retries-0260.

It’s easy and free to subscribe for your own copy of Zero Retries every week:

Subscribe now

In This Issue:

I-Frame

ZRDC 2026 Update 08/21/2026
Tina Stroh KD7WSF

What’s New at Digital Library of Amateur Radio & Communications — August 2026
Kay Savetz K6KJN

Followup on New Packet Radio - Next Generation (NPR-NG)
Steve Stroh N8GNJ and Steffen Heuel DO5DSH

Why Create a New Hardware Module for IP400?
Steve Stroh N8GNJ and Martin Alcock VE6VH

Spectrum is Fungible
Steve Stroh N8GNJ

A Brief Comparison of Networking - Meshtastic / MeshCore vs Amateur Radio AX.25 Packet Radio
Steve Stroh N8GNJ

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

Comments on This Issue (Redirects to Comments Page)

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

Optional Paid Subscriptions, and especially Founding Member subscriptions to Zero Retries not only help offset various expenses incurred in publishing Zero Retries, but also are a large portion of the “seed capital” that is needed to host Zero Retries Digital Conference (ZRDC) 2026, and future ZRDCs. Thank You!

My thanks to Merik Karman VK1DF / VK2MKZ for renewing as Founding Member 0007 (4th year!) to Zero Retries in the past two weeks!

Founding Member Subscribers are listed in every issue of Zero Retries!

My thanks to Prefers to Remain Anonymous 35 for renewing as an Annual Paid Subscriber (3rd year!) to Zero Retries in the past two weeks!

My thanks to Matt Payne N3PAY for renewing as an Annual Paid Subscriber to Zero Retries in the past two weeks! (This is a correction; in Zero Retries 0259 I stated:

My thanks to Matt Payne N3PAY for becoming a new Annual Paid Subscriber to Zero Retries in the past two weeks!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Zero Retries Summer 2026 Publishing Schedule - Biweekly

During Summer 2026, Zero Retries is being published biweekly. The intended publication schedule for the remainder of Summer 2026 is:

  • Zero Retries 0261 - 2026-09-04

There may be some special, focused issues interspersed between the scheduled issues, such as a special issue about Zero Retries Digital Conference (ZRDC) 2026.

After ZR 0261 / 2026-09-04… to be determined.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0260. Paid subscribers can comment directly on the web version of this issue.

ZRDC 2026 Update 08/21/2026

By Tina Stroh KD7WSF
Zero Retries Digital Conference Manager

This is the third in a series of updates leading up to Zero Retries Digital Conference 2026.

Zero Retries Digital Conference 20206 is now open!

Click here to register for ZRDC 2026

With just under 60 days until ZRDC 2026, we have been able to confirm another speaker. Jeff Scoville AE5ME will join the panel of speakers and will be discussing M17. Per Jeff’s message, he will bring an M17 repeater and set up a demonstration of the MSEVEN iOS app running a Mobilinkd TNC4 over the air.

In addition to the panel of speakers , there is a possibility of hosting a panel discussion regarding encryption on Amateur Radio. We had initially planned on doing it in the evening, however it is cost prohibitive. I will speak more about this in the next issue of Zero Retries.

Lastly, I had an email from a ham from whom I sent a message trying to research a speaker/topic for ZRDC. The context of this message was in regard to the date of ZRDC and its connection with Pacificon. His message literally shocked me not just by his audacity but also how misinformed he was. Therefore, as I am about to send out a mailing to many of the amateur radio clubs, I would like to set the record straight so that hopefully everyone can be on the same page, eliminate rumors, and most of all come together as a community to promote Amateur Radio.

We chose to align ZRDC 2026 with Pacificon because last year we were approached by a person associated with Pacificon and they suggested the possibility of ZRDC 2026 in conjunction with Pacificon. Given that we have attended Pacificon for the past two years, we have been impressed with how well the conference was organized and executed, it seemed possible. What has always appealed most to me about Pacificon was the outreach to the youth. Seeing scout troops and school age children at the conference to me is very important as I believe, “you never know where the next great idea will come from”. Based on all that, we made a proposal to Mt. Diablo Amateur Radio Club about ZRDC 2026. But, in the end, the club was unable to accommodate our needs.

That said, in every posting about ZRDC, we have promoted Pacificon 2026. ZRDC is only on Friday, October 16th, not the entire weekend. I specifically chose that date as most techie hams from my surveys do not have an overwhelming interest in antennas and many comments were made about having to take an extra day off work and another hotel night if ZRDC were to be held on Thursday.

Having ZRDC 2026 on Friday leaves Saturday and Sunday open for attendees to attend Pacificon, listen to the various talks and have time to browse the vendors at Pacificon. Zero Retries will have a table again this year in the vendor area as well. In my opinion, it was the best of both worlds.

One last point, we are NOT in competition with Pacificon by any means, although it may appear that way with the overlap. But that Mount Diablo wasn’t receptive to ZRDC may explain why we have not received ARRL sanctioned event status, despite having made numerous attempts, and direct correspondence with ARRL Pacific Division Director John Litz NZ6Q has gone unanswered.

In closing, if anyone from the Mt. Diablo Amateur Radio Club or avid followers of Pacificon have felt slighted because of ZRDC 2026, please accept our sincere apologies as that was never our intent. We sincerely hope that both conferences will be successful, informative and another opportunity for hams to come together and build our community.

ZRDC 2026 Website

Click here to register for ZRDC 2026

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0260. Paid subscribers can comment directly on the web version of this issue.

What’s New at Digital Library of Amateur Radio & Communications — August 2026

By Kay Savetz K6KJN

Greetings from the Digital Library of Amateur Radio & Communications, your free online ham radio library. This month I’m excited to announce significant expansions in the areas of ham radio community preservation, long-lost newsletters, and recovery of (almost) prehistorical technical documents.

Yahoo Groups and Usenet Discussions

Ham radio is all about communications and community, but those things don’t happen exclusively on the air. Since at least the 1980s, radio nerds have used the Internet to discuss and diagnose radios, debate policy decisions, and ask and answer questions.

Do you remember Yahoo Groups? It was a service from Yahoo! that provided e-mail-based discussion groups. In 2010, there were 10 million Yahoo! groups, with people discussing every conceivable topic and interest. But in 2020, the company shut down the groups. Naturally, some of those groups were related to amateur radio topics. I’m thrilled to announce that DLARC has added a searchable repository of radio discussions from Yahoo Groups. And it’s a lot.

We recovered just over 2 million messages across 714 discussion groups, with discussions from 1997 through 2020: an incredible trove of cultural memory.

The discussions are presented as pretty, searchable PDFs: 968 PDF files totaling 2.8 million pages. Some of the largest groups recovered are radioescutas (for Portuguese shortwave listeners), bayscan (for scanning enthusiasts in the California Bay Area), baofeng_uv5r (for users of the popular Chinese handheld), TS-520_820_530_830 (for fans of the Kenwood hybrid HF transceivers), and rda_group (a radio discussion group in Russian). You can explore all of the Yahoo Groups messages here.

A surprisingly difficult part of the job was removing spam from the collection: we removed more than 400,000 spam messages from the radio discussions, 16.5% of the corpus. We certainly didn’t catch them all, but we did our best.

Usenet newsgroups were another popular forum for online discussion, and DLARC has added another 2.2 million messages from 17 newsgroups spanning 1987 through 2013. 563 PDFs totaling 2.8 million pages! These include rec.ham.radio, rec.radio.amateur, rec.radio.amateur.antenna, rec.radio.amateur.space, rec.radio.amateur.digital.misc, rec.radio shortwave, rec.radio.scanner, and ten more discussion groups. This makes an unprecedented trove of intergenerational knowledge searchable, downloadable, and easy to reference.

Newsletters and Podcasts

I’d heard of DXing and island operation, of course, but castles! No one told me you could transmit from castles! DLARC has added 647 issues of ICPO Bulletin — “Islands, Castles & Portable Operations”. It was an amateur-radio newsletter compiled and published by Canadian radio amateur Dave Raycroft, VA3RJ, from 2002-2015. Each issue listed forthcoming on-air activity from islands, castles, lighthouses, parks, portable stations, and DXpeditions worldwide.

And then there’s the ANARTS RTTY News — these newsletters were originally transmitted by RTTY. Now, they’re nice, pretty PDFs. The Australian National Amateur Radio Teleprinter Society (ANARTS) focused on radio teletype and digital communication modes. The group was founded in 1977: DLARC now has an archive of 377 issues of their RTTY Bulletin, which was transmitted via radioteletype on Sundays. News items are related primarily to RTTY and telegraphy. This is not a complete set: let me know if you have access to missing transmissions.

The library also added 225 issues of the Radio H.F. newsletter, which was a monthly electronic publication edited by Sheldon Harvey VE2SHW in Quebec, Canada. It presented annotated links and resources concerning shortwave listening, amateur radio, scanning, broadcasting, and radio equipment. We have a complete run from issue 1 (February 1999) through Volume 19, Number 5 (May 2017). I don’t know if it continued after that.

Also added: 399 issues of the MMMonVHF Newsletter. Published by the Make More Miles on VHF portal, these newsletters document the international weak-signal radio community from 2007 through 2015, with news about VHF, UHF, and microwave amateur-radio activity, including DXpeditions, propagation, contests, and Earth-Moon-Earth communication.

This is a particularly exciting addition: DLARC has added 325 lost episodes of Amateur Radio Newsline spanning 2001-2010! This fills in some gaps in our collection of the weekly news bulletin. The new additions include 90 episodes complete with audio from 2002-2003, and the scripts of 235 more episodes spanning 2001-2010. These episodes contain so much important information and history, including the script for episode 1257, released three days after the September 11 attacks. “Amateur radio took to the airwaves to provide assistance in the wake of apparent terrorist attacks in New York City… More than 300 died in the four highjacked airliner crashes…”

This brings our collection of Newsline to nearly 1,300 episodes, with some dating all the way back to 1992. (There are still plenty more gaps to be filled, listed in the newly updated DLARC Wantlist, as always.)

We’ve also archived nearly 300 episodes of Ham Radio Perspectives, a YouTube channel about ham radio: “Have fun exploring ham radio with K8QS, WA9TDD, and special guests.” — and oh look, they interviewed me about DLARC earlier this month. We’ve also added 30 episodes of Zone Zero, a podcast by VA7ST exploring “HF radio contesting through contest previews, operating tips, propagation talk, and reflections from the shack.”

Packet Radio Temporary Notes

Here’s an update on DLARC’s collection of Packet Radio Temporary Notes. PRTNs were a series of informal technical documents distributed by various technology organizations from 1972 through 1983 to share their research as they created packet radio from the ground up. I’ve worked hard to find as many of these documents as possible, but there are still plenty that are missing from the collection.

An eagle-eyed patron pointed out to me that PRTNs were sometimes buried in longer documents, directing me specifically to Measurement and Evaluation Studies of Packet Radio Telecommunications Systems, which was already in DLARC and which, sure enough, includes 8 PRTNs that we didn’t have as standalone documents.

Then I found several more hiding in plain sight in the Internet Experiment Notes series. I also found a few more published versions of PRTNs (usually slightly more polished versions of the original write-ups, but clearly the same documents). That’s how I added 22 new old PRTNs to the collection, growing the collection to 155.

The newly found material includes On the Performance Analysis of Multihop Packet Radio Systems — a four-part spectacle by Fouad Tobagi; Internetwork Experiments with the Bay Area Packet Radio Network published at Xerox PARC in 1979; and Radia Perlman’s Internet Routing and the Network Partition Problem. I can’t overstate how much of what we rely on for communications today—the Internet, cellular communications, everything—we owe to the foundational research done by these people and their incredible peers. It’s so important to find, recognize, and make available these works.

Digital Library of Amateur Radio & Communications is funded by a generous grant from Amateur Radio Digital Communications (ARDC) to create a free digital library for the radio community, researchers, educators, and students. If you have questions about the project or material to contribute, contact me at kay@archive.org.

Editor’s Note - I’m really thrilled to see the recovery of Yahoo Groups, and USENET, and more PRTNs, and… and… It’s not overstating things to say that DLARC has become a keystone resource for Amateur Radio. I (and I think Amateur Radio as a whole) is indebted to K6KJN for such a singular contribution to Amateur Radio.

Followup on New Packet Radio - Next Generation (NPR-NG)

By Steve Stroh N8GNJ and Steffen Heuel DO5DSH

As mentioned in the original article on NPR-NG in Zero Retries 0258 - What’s New with New Packet Radio, Next Generation (NPR-NG)?, I reached out to Steffen Heuel DO5DSH with some questions, and he responded in detail.

Prototype NPR-NG on display at HAM RADIO 2026
Prototype NPR-NG on display at HAM RADIO 2026. Image courtesy of Steffen Heuel DO5DSH

DO5DSH:
On the 1 MHz [minimum bandwidth], I am in discussion with stakeholders in Germany (as I am also active in CEPT groups for other topics). In Germany it’s not a no-go anymore to keep the legacy 200 kHz bandwidth and things are starting to move, slowly, but are in motion. I am confident that, as soon as Germany clears the way, other countries will have the chance to use 1 MHz BW in 70cm. Hopefully this will propagate.

N8GNJ:
Is there any interoperability with “classic” NPR, including NPR 3.0 (other, than of course, TCP/IP networking via the Ethernet ports)?

DO5DSH:
This is not implemented yet as we make full use of the 802.11ah standard. I did think about it if NPR-NG should implement NPR or vice versa. But it’s probably not so straightforward as I initially thought when deciding for the OpenWrt stack. I need to re-check on the least common mode, e.g. 4FSK and what needs to be done in NPR then. It’s probably easier to update this than mess in the 802.11ah standard… but undecided yet.

N8GNJ:
Is there any actual relationship with NPR-NG with classic NPR given that that NPR-NG is going to be based on OpenWRT?

DO5DSH:
[As with NPR and NPR 3.0, NPR-NG is] a NLOS [Non Line of Sight] end-user entrance for HAMNET (it is for sure used in many more applications already out there). Technically [NPR / NPR 3.0 and NPR-NG] both run a high speed TDMA [Time Division Multiple Access], but NPR-NG scales with higher modulation rates and multi user access. To use an open source OpenWrt was driven by the technical completeness, robustness and open source availability of that stack. Instead of inventing the wheel again I wanted to focus on the missing pieces.

N8GNJ:
Is there a “central node” (repeater / digipeater functionality on a high central node), such as there was for NPR classic that will be incorporated into NPR-NG?

DO5DSH:
That’s one of the beauties we have with the stack now. Already today you can configure it just as your Wi-Fi at home, client, access point, repeater, mesh (!). It’s all the same hardware and the OpenWrt config will do the rest. And if something is missing, OpenWrt is open source and the community can work on this basis.

N8GNJ:
Will the development work you outlined - input / output ports into a single antenna combiner actually go forward or does there need to be a new grant obtained for that work?

DO5DSH:
I did start investigations and tests. I have started to implement the full 802.11ah decoding to measure EVM and next is to work on the amplifiers.

N8GNJ:
What is the anticipated transmit output of NPR-NG?

DO5DSH:
A QPSK requires ~10dB SNR for a BER or ~10^-6. 64 QAM needs ~22-24 dB. So technically I would need 12-14 dB more power for NPR-NG to have a similar SNR as with NPR under the same RF path. In other cases NPR-NG will automatically adapt the MCS [Modulation Coding Scheme] rates to lower speeds or longer guard intervals. Best would be to have something in the 40-46 dBm range, but the OFDM with 64 QAM has a much higher PAPR [Peak-to-Average Power Ratio] than FSK. That requires proper thoughts on the amplifier...otherwise the EVM will become bad. Then you have enough TX power and high RX signal power but still bad connection.

N8GNJ:
Will there be work to create NPR-NG for other bands such as 23cm? I’ll guess 2m is a non-starter given the 1 MHz minimum bandwidth, although here in the US we have 4 MHz in 2m - 144-148 MHz, so it’s a bit more feasible.

DO5DSH:
Step-by-step 😉. The hardware can do 1, 2, 4, 8 MHz of bandwidth and technically up to 32 Mbps. Higher RX bandwidth in turn increases your noise floor. The hardware concept was made in a way that the sub 1 GHz transceiver IF signal can be mixed either upwards or downwards. Mixing upwards would result in 23 cm.

N8GNJ:
What is the anticipated timeline for NPR to be available in a form similar to Localino’s NPR 3.0 products?

DO5DSH:
We have some things to do like updating to latest stable OpenWrt stack, find a proper solution for the PA [Power Amplifier], start testing at longer ranges without direct LOS [Line of Sight]. Unfortunately I have no timeline yet, but we will continue work on this as the solution is just too good to lie around😉.

N8GNJ:
I would like to feature the progress of NPR-NG in Zero Retries if you’d be willing to supply me with periodic updates.

DO5DSH:
Absolutely, it’s a pleasure to read this Sunday mornings at our breakfast and see this great interest from the community!

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Why Create a New Hardware Module for IP400?

By Steve Stroh N8GNJ and Martin Alcock VE6VH

In (slowly… slowly…) developing indexes for previous years of Zero Retries, I came across this brief story:

Zero Retries 0030 - Dedicated Processors for Modems, Versus Software Modems on Host Computers

Rereading it, it offers a substantive explanation for why it makes sense to use dedicated hardware for a high performance data mode instead of a software running on a desktop-class computer with a general purpose multitasking operating system with an audio interface.

…

From his work on the Winlink Development Team, Rick Muething KN6KB knows a thing or six about designing effective modems. I saw this on the VARA-MODEM list and found his perspective on this topic enlightening.

A couple of things I might add that are often overlooked :

  • The trend of the past several years of using “software modems” running on non real time OS machines (Windows, Mac OS, Linux, etc) doesn’t often address the significant problem of real time delays caused by the OS and what other programs may be running. The typical exchange of data with an ACK/NAK involves the requirement of software modems (running on non real time operating systems) to accommodate the delays that are determined by BOTH the decode process (software modem doing DSP) AND the OS latency (this can be 100 ms or more depending on software modem implementation, Sound card latency etc.) This can have a significant impact on throughput since the timing in the Data + ACK/NAK exchange must normally accommodate the worst case anticipated delays.

  • The cost of high performance Dedicated Microprocessors with very good Real time capability (e.g. Teensy 4.x running the Arduino C++ code) has dropped significantly and now rivals or exceeds the DSP capability of some of the earlier Pactor 2 and 3 modems. While a dedicated CPU (e.g. like a Teensy/Arduino) is not a zero cost item (like a free Software modem) it has a number of advantages:

    • Significantly reduces the demands of the host OS response times and CPU loading.

    • Allows the host OS interface to be a much simpler program (and easier to maintain and adapt) since it is not required to do real time DSP and critical Data/Ack/Nak timing. This dramatically reduces the programming support required to “interface” a protocol to multiple operating systems, computers, and OS revisions.

    • Allows building more complex and sophisticated modems (e.g. Dynamic path compensation like used in STANAG and Mil Std 188 modems) that are normally outside the capability of software implementation on non real time OS hosts.

All this should remind us of the “No Free Lunch” theorem!!! (which we too often forget when requesting free software with unlimited free support!)

…

I shared the above with Martin Alcock VE6VH and he added his perspective on the applicability of the above to the IP400 development team’s decision to create the Advanced Mesh Network Controller (AMNC) for managing the new OFDM-AB waveform for IP400, and managing (what may grow to be pretty complex) IP400 mesh networks:

There is some buzz about taking our modem and implementing on a PC sound card, and, apart from the OS issues, there are two GOTCHAs that make it difficult or nearly impossible. The first is a lack of a hardware AGC on receive will limit its ability to decode data from different radios that will be transmitting at different modulation levels, so on the AMNC the CODEC has a hardware AGC [Automatic Gain Control] that takes care of this issue. The second is that and the sample timing is extremely critical. The OFDM symbol requires over 1000 samples, so the sampling offset introduced by the a less than accurate crystal would cause spreading in the receive constellation, making the higher bit rates unusable, and requiring a large amount of forward error correction. In the AMNC we use a PLL sourced from a 0.5ppm TCXO [Temperature Compensated Crystal Oscillator] for sample timing, in contrast a PC sound card will use whatever the cheapest, and probably 100 ppm, crystal.

I asked VE6VH:

So could there be a “slow speed” version of OFDM-AB that could be implemented with “PC sound card” to offer some very limited (slowest modes) compatibility with IP400 and OFDM-AB? Kind of a “training wheels” / very cheap (like students really like)?

He answered:

Theoretically, yes. But - the current development team is fully occupied completing the AMNC, work which extends well into 2027. So, we won’t be the ones doing such a mode, nor do we have the bandwidth to support that and our own efforts. As the source code will be open when we are ready to release it, someone else could tackle such a project independently, but I highly recommend against it. Instead they would be far better off to use the hardware that was specifically designed for this purpose, as it will be supported. They are also ignoring the fact that the modem is only a small part of the mesh network controller, there are other layers for that purpose also built in.

Also as you mentioned in ZR259 about the FPGA:
I’m told it’s currently “lightly utilized” and thus offers ample expansion capability. (sic)
So, there should be a clue there that future firmware development on [the AMNC] will utilize the FPGA resources more extensively. Locking into a sound card implementation is not only a lateral move that excludes these further developments, but it also does not take advantage of the mesh networking capabilities. You would be far better off not re-inventing the wheel on a PC, and using the hardware module that was specifically designed for the purpose, therefore being able to participate in future developments.

Of course, volunteers to join the team are always welcome.

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Spectrum is Fungible

By Steve Stroh N8GNJ

A MHz is a MHz. A brief digression that we can, in fact, use Amateur Radio VHF / UHF spectrum to do higher speed data communications… including using wider bandwidths than is traditional. Also, a brief overview of some attempts to build data radios for Amateur Radio that did so.

In the discussions of starting to use higher speed data - pushing up to 1 Mbps and beyond, in Amateur Radio VHF / UHF spectrum, there’s some confusion that “well, you can only do that up in microwave spectrum”.

That’s a widely held perception, but it’s not accurate. The information capacity of 1 MHz of spectrum at 420-421 MHz is fully equivalent to 1 MHz of spectrum at 2.390-2.391 GHz.

The Perception That High Speed Data “Belongs” on Microwave

The perception that “you can only do high speed data on microwave frequencies” arose from a number of factors:

  • We’ve been using spectrum below 1 GHz intensively for 70+ years now (post World War II), and reasonably wide segments like 1 MHz for fast data communications are relatively rare1.

  • Until the advent of sophisticated high density modulations like QAM (Quadrature Amplitude Modulation) aided by techniques like Orthogonal Frequency Division Multiplexing (OFDM) to provide a “clean channel” for QAM to work, fast data meant a wide channel (often, 1 bit per Hz), with very high Signal to Noise Ratio (SNR) required to work. QAM + OFDM + Forward Error Correction (FEC) means that we can now do fast data with smaller portions of spectrum.

  • It’s easier to do high SNR (better for data) paths on microwave - the antennas are compact and highly directional, often dish antennas.

  • It’s (traditionally been) harder to engineer and manufacture radio equipment using wider (multi MHz) bandwidths on VHF and UHF. It was obviously doable - analog television channels were 6 MHz (and needed all of that). But, that was using very high SNR (some television transmitters were > 1 MW) and poor selectivity (television channels in use in an area were widely spaced out). Current technology has rendered those issues moot, but the perception persists.

  • There’s more spectrum allocated for Amateur Radio on microwave spectrum than VHF / UHF spectrum. The US Amateur Radio allocations around 2.4 GHz is 70 MHz (2.300 - 2.310 and 2.390 - 2.4502), and are lightly used for Amateur Radio, thus the “put high speed data up there” is a widespread perception.

  • The original Wi-Fi standard using 802.11 Direct Sequence Spread Spectrum (DSSS) used a 22 MHz bandwidth, thus couldn’t be used in any spectrum below microwave. Later updates of Wi-Fi chipsets allowed bandwidths of “as low as” 5 MHz, though those were not standardized.
    Post Publication Update - Another 802.11 standard option was Frequency Hopping Spread Spectrum (FHSS), which was not widely implemented except in proprietary systems. The Bluetooth standards use narrower channels on 2.4 GHz using FHSS.

Thus the idea of beginning to use wide(r) bandwidths for fast(er) data communications is not incompatible with Amateur Radio VHF / UHF spectrum. The problem for doing so has (mostly…) been the lack of designed for purpose data radios.

There Have Been Amateur Radio Data Radios

In the 1990s or so we saw a few radios designed for data such as the Kantronics D4-10, with wider audio bandwidths to use higher data rates such as 19.2 kbps. There were other such radios:

  • T7F Data Radio - 430 - 440 MHz / 70 cm. The T7F was more advanced than the D4-10, including frequency agility.

  • Azden PCS-9600D - 420 - 450 MHz / 70 cm. Was notable for featuring separate Phased Lock Loop (PLL) frequency synthesizers for transmit and receive frequencies so the transmit / receive settling time for a synthesized radio was minimal. I think that this radio pioneered the “data jack” / “9600 port” standard that became a feature, for a while, in many VHF / UHF FM radios from manufacturers in Japan.

  • WA4DSY 56 kbps Modem - Used a 100 kHz bandwidth on 28 MHz. The band to operate on was up to the user - just choose a transverter.

  • Doodle Labs DL435-30 - 420 - 450 MHz / 70cm. Data rate up to 8 Mbps (5 MHz bandwidth) or up to 15 Mbps (10 MHz bandwidth).

  • Icom ID-1 - D-Star Digital Data (DD) mode is 128 kbps in a 100 kHz bandwidth, on 1.2 GHz / 23cm. Although the ID-1 is out of production, the ID-1’s “Digital Data” mode is still available in Icom’s ID-RP1200VD repeater, IC-9700 radio, and IC-905 radio.

Attempted Amateur Radio Data Radios

There were also some notable attempts of Amateur Radio data radios which didn’t come to fruition:

  • TAPR packetRADIO - see illustration3. A short lived project. I think that the Kantronics D4-10 removed much of the need and interest for this project. Also was the source of a memorable quote within TAPR:
    Radios… are hard!

  • TAPR 900 MHz FHSS Radio - Designed for 902-928 MHz / 33 cm, up to 250 kbps, and 1-5 watts of transmit power. This project suffered from obsoleted parts before the design could be finalized and productized, twice.

  • FaradayRF - This was a noble effort to develop a new Amateur Radio data radio for the 902-928 MHz band, from 2016 - 2019. It faded out without much notice, but there are elements of it that are still available via the Internet Archive and their Github page.

  • UDRX-440 Software Defined Transceiver / Data Radio - A project by Northwest Digital Radio that came agonizingly close to becoming a product. It was to be a 25 watt multimode (semi Software Defined) data radio with all the features we wanted - flexible modems, full software control of transmit bandwidth, frequency, power, etc.

New Packet Radio

Unlike the above radios, New Packet Radio is in production and available for purchase. Data rate is 100 kbps - 1 Mbps in a 100 kHz - 1 MHz bandwidth, on 420-450 MHz / 70cm. (Assembled and tested version by ELEKITSORPARTS.) For reasonable power levels, a specific amplifier was required. Localino’s NPR 3.0 units are (in my opinion) more practical to use with a transmit power of 7 watts. In addition to the original spectrum for NPR of 420-450 MHz / 70cm, Localino created NPR 3.0 units for 144-148 MHz / 2m, and 1240 - 1300 MHz / 23 cm.

VHF / UHF FM Radios With Flat Audio Connections

Beginning in the same era as the PCS-9600D, manufacturers of conventional VHF / UHF radios began to add “data ports” to be able to use 9600 bps Frequency Shift Keying (FSK) data. FSK signals are distorted if the microphone and speaker connections were used because those are designed for human voice (pre-emphasis and de-emphasis) instead of linear data signals. The “data ports” (which I refer to as “flat audio connections”) bypass the pre-emphasis and de-emphasis circuits in the radio. Radios with “data ports” are the preferred way to use “audio path” data modes such as VARA FM and now, OFDM-AB.

For more details on radios with flat audio connections, see my Zero Retries Guide to VHF / UHF Radios for Data.

But such radios are a stopgap for faster data. VHF / UHF FM radios designed for voice, typically with a radio bandwidth of 12.5 or 25 kHz, and operate in a 2-10 MHz frequency range.

Software Designed (Data) Radios

We now have Software Defined Radios (SDRs) with no such restrictions. We can experience this now, easily, inexpensively with, for example, a SDRplay RSP1B Software Defined Receiver. It can receive any 10 MHz continuous segment of spectrum within its range of 1 kHz to 2 GHz. So receiving wider bandwidths, such as 440 - 450 MHz, is a solved problem. Transmitting wider bandwidths is also a somewhat solved problem using Software Defined Radio technology. For example, the ADALM-PLUTO Software Defined Transceiver can transmit or receive any 20 MHz contiguous segment of spectrum within its range of 325 MHz to 3.8 GHz.

Transmitting wider bandwidths is only somewhat solved because while the transmitters can operate over such frequency ranges and wider bandwidths, the power amplifiers necessary to achieve power levels of 25 watts or so for typical Amateur Radio terrestrial operation haven’t yet caught up4 with the flexibility of the Software Defined Transmitters. We have power amplifiers for individual bands such as the Toptek Communications PA-80U UHF Power Amplifiers PA-80U that operates from 430 - 470 MHz… but it requires an input transmit power level of at least 3 watts, and the typical Software Defined Transmitter only outputs a power level of a few tens of milliwatts.

Obviously this situation is a solvable problem with some radio engineering applied to the problem. We will eventually have Software Defined Transceivers for the Amateur Radio VHF / UHF bands that can transmit at 25 watts or so. We just don’t have them at the moment.

In The US, Arcane and Obsolete Regulations Hamper Progress in Faster Data in Amateur Radio VHF / UHF

The current US Amateur Radio regulations limit bandwidth for data communications:

  • 20 kHz maximum bandwidth for 50-54 MHz / 6m and 144-148 MHz / 2m

  • 100 kHz maximum bandwidth for 222-225 MHz / 1.25m and 420-450 MHz / 70cm.

Thus, US Amateur Radio Operators are mostly, but not entirely out of luck with New Packet Radio, which has a “Silly Arcane US Regulations” mode that restricts NPR to operate with a 100 kHz bandwidth and 56 kbps over the air data rate. But in the US, NPR cannot be used at its full speed of 1 Mbps, which requires a 1 MHz bandwidth.

Thanks to the Arcane, Obsolete, and Just Silly in the 2020s US Amateur Radio Regulations about data communications for VHF / UHF… US Amateur Radio Operators are entirely out of luck with the proposed New Packet Radio - Next Generation (NPR-NG) - (see the related story in this issue) which requires a minimum of 1 MHz bandwidth.

That said, it’s possible for an independent group to petition the FCC for a regulatory change, or perhaps a Part 5 Experimental License to use wider bandwidths on Amateur Radio VHF / UHF spectrum. A primary “talking point” of such a request is the example that video operation on 420-450 MHz / 70cm is at least 1 MHz (digital video) and 6 MHz (analog video), with no issues.

Making Due, For Now, With VHF / UHF FM Radios With Flat Audio Connections - Up to 57 kbps and Mesh Networking

Thus, for now, we can make do with faster-than-9600-bps data communications, using a VHF / UHF FM radio with flat audio connections such as the Yaesu FTM-150R connected to a IP400 Advanced Mesh Network Controller (AMNC), in conjunction with embedded 64-bit computers with four cores operating at 1.4 GHz…

to create Amateur Radio mesh networks across all of our Amateur Radio VHF / UHF bands, at reliable data speeds of up to 57 kbps.

Post Publication Update: Part of the networking, especially local / regional networks, can make use of IP400-enhanced FM repeaters for users to be able to participate in data networks even more easily than they can use repeaters for voice.

And, such networks can be linked with modern HF data communications networks, and multi-megabit microwave networks.

All in all, not bad. Not bad at all. Three decades ago in the heyday of packet radio, when we dreamed of 9600 bps and faster inter-city backbones, and network node routers, we didn’t imagine it would turn out like it has. We also didn’t realize it was going to take so long to have this kind of capability.

But now we do have such capabilities, and it’s now up to Amateur Radio to make use of them.

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A Brief Comparison of Networking - Meshtastic / MeshCore vs Amateur Radio AX.25 Packet Radio

By Steve Stroh N8GNJ

Amateur Radio has always had networks. From the very beginning of Amateur Radio, it has always built networks for passing messages - traffic. In fact, passing traffic was the original mission of the American Radio Relay League (ARRL) more than a century ago. Per Claude AI:

The ARRL was founded in 1914 by Hiram Percy Maxim after he couldn’t reach a fellow ham 30 miles away and had to relay his message through an operator halfway between them. That experience convinced him a formally organized relay system — amateurs passing messages (”traffic”) station to station over long distances — would be essential to the hobby’s usefulness, which became the League’s founding purpose.

The venerable National Traffic System (NTS) still exists. Another organization with a similar (or complementary) mission is Radio Relay International (RRI). But in my opinion, the most modern implementation of Amateur Radio networks on HF bands, the modern implementation of NTS, is The Packet Radio Forwarding Network (TPRFN).

Post Publication Update: The Winlink network and Winlink Radio Mail Server (RMS) stations on Amateur Radio HF bands for exchanging email via Amateur Radio HF should have been included in the same “networking over HF” reference above as the mentions of NTS, RRI, and TPRFN.

Thus, building, operating, and using networks in Amateur Radio is nothing new for Amateur Radio. But two decades into the 21st century, with ubiquitous, broadband, ambient Internet via mobile networks, fiber, and satellite (and very recently, mobile access via satellite anywhere on the planet), Amateur Radio networks seem, to many, especially those not involved in Amateur Radio, an outmoded concept.

In the Mid 2020s, There’s Ample Interest in Independent Networks Via Radio

At least, that’s the way it seems at first glance. But in the mid 2020s, there’s more interest in independent networks via radio, than there ever has been. Witness the incredible interest in Meshtastic, and recently MeshCore (hereafter, Meshtastic / MeshCore5) using LoRa, in unlicensed spectrum6 by experimenters who like the idea of participating in decentralized, independent networks using radio. There’s uncountable thousands, likely tens of thousands of individuals participating in these decentralized, independent networks operating in unlicensed portions of spectrum.

Why this surge of interest in decentralized networks via radio in recent years? Here are my perceptions:

  • Many techies are generally curious about radio technology as an adjunct to electronics, software, hardware, computing, and networking hacking (casual experimentation). Meshtastic / MeshCore on unlicensed spectrum is an inexpensive and easy way to get started with radio technology.

  • Most techies now understand that our incredibly sophisticated, broadband communications infrastructure(s) are generally reliable. But… when there is a failure - a single fiber cut, a widespread power outage in your area lasting more than a couple of hours, a cyberattack on a key Internet resource, or a failure in a far-away data center (like a tornado in the US Midwest), the communications infrastructure fails hard.7 Thus, knowing this happens, techies are open to potential backup systems for communications.

  • Meshtastic / MeshCore is pretty easy, and fun to get started. There’s lots of “join the fun” promotion and there are meetups targeted at techies, such as at Makerspaces and Hackathons on how to set up your new Meshtastic / MeshCore nodes.

  • There’s ample documentation available. For example, see a recent excellent article on QRPer.com - Building an Off-Grid Meshcore Network, One Node at a Time by former ARRL / QST Technical Editor Conrad N2YCH.

  • The hardware is widely available and inexpensive. It’s easy to persuade nearby techie friends to get their own nodes online to join in on the fun.

  • It works - Meshtastic and MeshCore networks do provide a decentralized, independent resilient mesh network for messaging, often with low enough power demands that nodes / repeaters can be powered from small solar panels plus small batteries.

  • Experimenting with Meshtastic and MeshCore is a much lower barrier to entry, and less intimidating, than “Get your Ham Radio license”.8

The Competition for Independent Networks Via Amateur Radio

Those of us already in involved in Amateur Radio networking can easily look at Meshtastic and MeshCore on unlicensed spectrum and think “That’s OK, and I understand the easy and fun aspects. But if they’re serious, they’ll come over to Amateur Radio.”

Yes, and No.

Yes - Amateur Radio has a lot of experience in building radio-based networks (packet radio, though a lot of that knowledge has lapsed), Amateur Radio has more and varied spectrum available for networking than unlicensed spectrum, and has a lot of technology that can (theoretically) applied to networking, such as high profile VHF / UHF repeaters, and even GEO satellites.

No - Amateur Radio doesn’t currently have a networking system that’s directly comparable or competitive to Meshtastic / MeshCore on unlicensed spectrum. Those factors are data-first, easy to deploy, that’s as inexpensive to get involved with, or has the popular, unified support available for Meshtastic / MeshCore.

Amateur Radio Networks Often Depend on Internet

It’s notable that Meshtastic / MeshCore is radio-only. Internet isn’t used and that’s one of the primary attractions of Meshtastic / MeshCore - that it has no dependency on Internet or other “centrally controllable” infrastructure.

Post Publication Update:

As originally published, in the above paragraph was a footnote:

It is my understanding that there’s no Internet gateways / tunneling / bridging with Meshtastic or MeshCore. There is a technology for LoRa called LoRaWAN that is such an Internet backbone, but LoRaWAN is generally not used in hobbyist use of LoRa.

My statement about no Internet gateways / tunneling / bridging in Meshtastic or MeshCore above is profoundly incorrect from not doing reasonable research. My apologies, and I’ll have a correction, amplification, and explanation in the next issue of Zero Retries. My thanks to Conrad Trautman N2YCH for pointing out this error.

The popular perception (and, in my reading, almost all deployments of Meshtastic / MeshCore) is that Meshtastic / MeshCore networks don’t use or depend on Internet or other “centrally controllable” infrastructure.

If Amateur Radio is trying to position Amateur Radio networking as an alternative to Meshtastic / MeshCore… well, a lot of Amateur Radio networking systems depend wholly, or in part, on Internet for their functionality:

  • Winlink’s backbone for exchanging email messages is Internet. Only with careful configuration can Winlink software and radios be used locally / non-Internet.

  • Most of the Automatic Packet Reporting System (APRS) infrastructure, such as linking between APRS digipeaters, messaging, etc. depends on the APRS-IS Internet servers:
    APRS-IS (Automatic Packet Reporting System-Internet Service) is the common name given to the Internet-based network which inter-connects various APRS radio networks throughout the world (and space).

  • The vast majority of voice repeater linking such as AllStarLink (as an example) is done via Internet. (There are a few Amateur Radio repeater linking systems, via radio, such as Puget Sound Data Ring, Rocky Mountain Ham Radio, HAMNET, and various AREDN regional networks.9)

  • All Amateur Radio “hotspots” such as the ZUMRadio Elite 3.5 LCD ZUMspot (as an example) are dependent on commercial Internet access to function.

  • As cool and unique as the all-in-one-device SharkRF M1KE is for participating in Internet Amateur Radio talk groups, it only functions with Internet access (and Wi-Fi).

In mentioning the above Amateur Radio systems’ dependencies on Internet, that’s not to disparage such activity. Amateur Radio Over Internet is a fantastic option for many Amateur Radio Operators, as explained very well by EtherHam and ROTA: Recliners on the Air. But… when Internet access isn’t available, those systems can’t function in part, or in whole.

Also in mentioning the above dependencies on Internet, it’s no longer accurate to say “When All Else Fails, Amateur Radio is the answer”. For many organizations (served agencies), and especially “replacement” for Internet access, Amateur Radio is no longer a good fit. For more on that perspective, see my article Zero Retries Perspective on Emergency Communications (EMCOM) Capability in Amateur Radio.

What About AX.25 Packet Radio Networks?

I said above:

Meshtastic / MeshCore is pretty easy, and fun to get started. There’s lots of “join the fun” promotion and there are meetups targeted at techies, such as at Makerspaces and Hackathons on how to set up your new Meshtastic / MeshCore nodes.

and…

The hardware is widely available and inexpensive. It’s easy to persuade nearby techie friends to get their own nodes online to join in on the fun.

That’s not really the case with AX.25 Packet Radio. There’s a lot of “baggage” with AX.25 Packet Radio on Amateur Radio spectrum.

The first “baggage” of AX.25 Packet Radio that is obtaining an Amateur Radio license. Even if you’re “just curious”, you cannot legally “just experiment a little bit” with AX.25 Packet Radio on Amateur Radio spectrum.

The second “baggage” of AX.25 Packet Radio is figuring out how to get started. In the 2020s, there’s now more than four decades of history with AX.25 Packet Radio, and much of what one finds on the Interwebs is woefully out of date, such as recommendations of “Terminal Node Controllers” (TNCs) that you can’t even buy any more (if their manufacturers even exist).

Much of AX.25 Packet Radio technology is antiquated in the mid-2020s. Most AX.25 Packet Radio operates at 1200 bps. Admittedly that’s faster than LoRa, which is the technology that Meshtastic / MeshCore uses, but just stating up front “1200 bps” is underwhelming to a typical techie. Almost all AX.25 Packet Radio does not use more modern implementations of AX.25 Packet Radio, such as the “single bit error recovery” of Dire Wolf, Forward Error Correction such as NinoTNC (and DIRE WOLF), or faster speeds.

Worst, from a networking perspective, AX.25 Packet Radio doesn’t have a widely used automatic, dynamic (mesh) network system - only digipeaters, or for some more capable AX.25 Packet Radio networks using JNOS which supports the (old, but functional) Net/ROM / TheNet mesh network protocols.

AX.25 is its own protocol, with no easy, well-understood, widely known ways to move TCP/IP over AX.25 Packet Radio networks except for JNOS. There used to be “packet radio drivers” as standard in Linux, but those have been removed. See Zero Retries 0249 - Amateur Radio Drivers Removed From Linux Kernel.

While TCP/IP over AX.25 at 1200 bps does work… it’s not that impressive. I speak from experience.

Another factor is that with AX.25 Packet Radio is that there is no centralized “source of truth” for AX.25 Packet Radio as there is for Meshtastic / MeshCore. There are many AX.25 Packet Radio “tribes”. And if you’re trying to get started with AX.25 Packet Radio… and you don’t want to start from scratch and follow the lead of one of the tribes, it’s tough to get a new branch of a particular tribe started in your area.

Lastly, and perhaps the most pervasive factor that hurts AX.25 Packet Radio is that within Amateur Radio, it’s widely perceived within Amateur Radio as old, tired, done… “Oh, no one does that any more”. That didn’t used to be literally true because Winlink gateways on VHF / UHF almost always used AX.25 Packet Radio, but Winlink access on VHF / UHF has been converting over to VARA FM because it just works better.

Similarly, APRS used to be solely AX.25 Packet Radio, but APRS operation has been migrating to use LoRa technology (and some notable use of VARA HF for APRS on HF bands) because it works better.

Thus, it’s a hard sell for someone to promote Amateur Radio AX.25 Packet Radio as a viable alternative to Meshtastic / MeshCore.

If you are going to try to make the case for AX.25 Packet Radio…

here are some pointers (not a complete list) to some modern AX.25 Packet Radio implementations:

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0260. Paid subscribers can comment directly on the web version of this issue.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

John Portune W6NBC is a Silent Key

Amateur Radio Newsline Report 2546 for Friday, August 14th, 2026 (script):

SILENT KEY: AUTHOR, ANTENNA INNOVATOR JOHN PORTUNE, W6NBC

STEPHEN/ANCHOR: An advisor and mentor to many, and a widely respected expert on antennas, has become a Silent Key. We hear more about him from Paul Braun WD9GCO.

PAUL: Many hams who have wanted to get more out of their antennas - or simply learn more about them - no doubt turned to the words and writings of John Portune, W6NBC. The retired KNBC TV broadcast engineer, an experimenter and an innovator, was always generous with his time and wisdom on the subject.

John became a Silent Key on the 6th of July. Born in 1938, he had been a ham since 1965.

The Los Angeles, California native was a frequent presence - either via Zoom or in person - at club meetings and ham expos needing his expertise on everything from mag loop antennas to stealth antennas that went undetected by homeowner associations.

He was a prolific writer, with bylines in QST and On the Air magazine to his credit. He was also the author of a number of books, including “Slot Antennas for Ham Radio: the Forgotten Antenna.” Many hams turned to John for his advice on how to get on the air from homes in communities governed by home owner associations’ antenna restrictions. He was also known for hosting informal Monday morning chats on Zoom, open sessions where friends gathered to compare notes and, of course, ask questions. Or, as John wrote on his website: “Just fun.”

John was 88.

This is Paul Braun WD9GCO.

(W6NBC.COM WEBSITE, QRZ.COM)

I’ve been a fan of W6NBC since I discovered his genius antenna hack - Efficient 2 meter Disguise Antenna Made From a TV Satellite Dish:

This horizontal “slot” antenna, cut into the reflector of a TV dish, is both the master of disguise and high in performance.

By John Portune W6NBC

47 C.F.R. Section 1.4000, October 1996, “prohibits restrictions that impair… antennas used to receive video… including… satellite dishes less than one meter (39 in.) in diameter”. (FCC Web Site)

I’ve long wondered, is it practical to hide an efficient 2 meter base- station antenna in a TV satellite dish? My CC&R committee couldn’t make me take it down. But what about all the metal in the TV dish?

Wouldn’t that compromise a 2 meter antenna? Finally it struck me, don’t fight the metal; take advantage of it. Cut a “slot” antenna into the TV dish’s reflector.

A slot antenna is a narrow rectangular opening in a large conductive surface, such as a TV satellite dish. Slot antennas are familiar in the commercial radio world, but not to hams. They’re common in TV broadcasting, the skin of aircraft and in radar, microwave and cell phone applications. This disguised TV dish slot is equal to a J-pole (Figures 1 and 2) and is also a great way to learn about slot antennas.

I was lucky enough to converse with W6NBC on a Zoom chat a few months ago . He was charming and informative in casual conversation. I’m glad I got to tell him how much I admired his TV dish slot antenna, and he seemed to enjoy the recognition.

I’m personally, generally, a functionalist (minimalist) on antennas for Amateur Radio. I prefer to do my experimentation with data communications and networking. Thus I’m fine with omni antennas for VHF / UHF, wire antennas for HF, and dish antennas for microwave and (high gain microwave) for space. But, W6NBC’s explanations of different antenna types such as slot antennas is really interesting and informative and gets one thinking that radiation of radio frequency energy at different frequencies is just… weird…. and thus Zero Retries Interesting!

In a presentation / slide deck - TV Satellite Dish Slot Antenna.pdf, W6NBC updated that elegant antenna hack for both 2m and 70cm (different slots / feedpoints, with a duplexer on the back).

W6NBC’s ideas and explanations about “interesting” antennas in Amateur Radio will live on in perpetuity.

NA6D OpenTNC Now Available

The NA6D OpenTNC is now available:

100% Open Source & Extensible: Built on the open-source hardware and software architecture created by Dave Platt (AE6EO), the OpenTNC is designed to keep getting better. Powered by the dual-core RP2040 and Zephyr RTOS, open firmware updates continuously bring new features, protocol enhancements, and performance improvements to your shack.

Why Choose the NA6D Edition?

  • Rugged Aluminum Enclosure: Ditch exposed PCBs and fragile 3D prints. Our custom black anodized aluminum extrusion case shields sensitive RF equipment from digital noise while enduring tough field conditions.

  • Compact Go-Kit Footprint: Sized at just ~64.3 mm x 49.1 mm x 23.7 mm, it fits easily into portable setups and crowded operating desks.

  • Pre-Calibrated Out of the Box: Shipped factory pre-calibrated to 50 mV peak-to-peak (50 mVpp) transmit audio output, offering plug-and-play operation for standard radio microphone inputs (K1 / HTs / Mobile Data jacks) without needing an oscilloscope.

  • Kantronics-Compatible DE-9 Port: Uses standard female DB-9 (DE-9) pinouts for simple radio interface cabling.

Powerful Digital Modes & FX.25 Error Correction

The OpenTNC manages AX.25 protocol processing directly on-board:

  • FX.25 Forward Error Correction: Wraps standard AX.25 packets inside Reed-Solomon RS(255,239) error correction blocks. Reconstructs noise-damaged frames automatically without time-consuming retransmissions, while remaining 100% backward compatible with standard AX.25 TNCs.

  • APRS & Fill-in Digipeating: Track locations, exchange messages, and run built-in WIDE1-1 fill-in digipeater modes with duplicate suppression.

  • Packet Chat & BBS Access: Robust keyboard-to-keyboard QSOs and seamless connection to PBBS emergency mailboxes.

  • KISS Mode & High Speed: Full serial KISS compatibility for Winlink, Direwolf, and APRS clients, supporting 1200-baud AFSK, 2400-baud V.26, and 9600-baud G3RUH modes.

Note: OpenTNC is a hardware AX.25 TNC running on-board modems via serial/KISS. It does not run PC-side software soundcard modes like VaraFM.

Refreshingly, OpenTNC incorporates AX.25 v2.2:

AX.25 v2.2 & Selective Reject (SREJ): Modern link layer enhancements supporting Selective Reject (retransmitting only missing frames rather than the full window) and extended sequence numbers (modulo 128 windowing).

I have… a few… (heh!) legacy AX.25 TNCs of varying vintage and capability, and I bought a pair of NA6D OpenTNCs because it would be refreshing to just have a pair that are modern and plug and play TNCs:

  • Metal case, not bare board or 3D printed case,

  • USB-C for power and comms, so no serial or 12 volt power hassles,

  • Full AX.25 Command Set, not a KISS-only interface that I have to fuss with a host program instead of bog-standard terminal program,

  • Kantronics 9-pin DSUB connector, just about as easy to use for interfacing to a radio as it gets,

  • $99 including a cable (several options).

Kudos to NA6D for pushing out such a polished version of a modern TNC.

AMSAT Canada Begins Offering Membership Options

Amateur Radio Daily 2026-08-16:

AMSAT Canada (AMSAT-CA) has begun offering membership options to further its mission to support amateur radio in space. Those interested in supporting AMSAT-CA through membership can learn more about membership benefits(PDF).

AMSAT-CA promotes, develops, and supports Amateur Radio in space, including via human-made and natural satellites (e.g., the Moon), space stations and planets, and related experiments, as well as new developments in technology, methods and techniques.

AMSAT-CA is expected to play a significant role in the futureGEO geostationary satellite project potentially covering portions of North America.

I’ve filled out my application to support AMSAT-CA.

WhatsPac - Packet Radio Chat Channels and Private Messages App

WhatsPac is a great new application for packet that has chat channels and private messages. Visit http://whatspac.oarc.uk/ for more information.

It is currently in beta and being actively developed but already has a nice user base. There is currently only one server running on MB7NPW, so this is where you will need a route to for the moment (see the UK packet network map to get an idea of possible routes), but there are plans to move to a distributed server model where there will be many servers on different nodes.

Resources:

Updated AREDN® Network Beginner’s Guide - for the Absolute Newbie

Version 28 6/6/2026

What it’s all about

By loading the AREDN®1 firmware in an outdoor wireless access point, you can join a ham radio network. It’s like the Internet but runs on ham radio frequencies, mostly in the 5.8 GHz band.

By joining this network you can find and use all sorts of applications (known as “services”). Anything running on a server, like weather stations, web sites showing site conditions and camera views, email servers, etc can be provided as a service. There are also services that don’t rely on a browser: video streams, chat servers, VOIP PBXs, etc. The network can also be used to host Winlink post offices, D-Star and DMR repeaters, and AllStarLink devices.

Pretty much any kind of service you can put on the Internet you can put on the AREDN® network, subject to the restrictions of the ham radio regulations (FCC Part 97).

This document is a great overview to getting up and running on typical (5 GHz) (Wi-Fi or Wireless ISP) devices, including includes explanations of various common AREDN hardware. It’s written by AREDN Ambassador (and Zero Retries Pseudostaffer) Orv Beach W6BI.

HamSCI Newsletter, Volume 2, Number 2

Gary Mikitin AF8A on the HamSCI email list:

Just in time for the fall academic season, the latest issue of the HamSCI Newsletter has been published, available here on the HamSCI website. Topics include:

Thoughts on HamSCI from Nathaniel Frissell W2NAF
HamSCI in the News
Amateur Profile: Jesse Alexander WB2IFS
2026 Meteor Scatter QSO Parties by Gary Mikitin AF8A
Contributor Column: The Maunder Minimum by Ron Wilcox KF7ZN
Students Learn About HamSCI by Ron Kumon K8DTJ and Ruth Willet KM4LAO
2027 HamSCI Workshop Announcement (Save the date: April 17-18, 2027, coinciding with both Citizen Science Month and World Amateur Radio Day)

Thanks to the hard working Newsletter Editorial/Production Team: Ed Efchak WX2R, Mary Lou West KC2NMC, Vikki Lawhon (University of Scranton), and to all of the contributors and reviewers!

One excerpt:

HamSCI has announced the dates for the 2027 HamSCI Workshop. The 10th anniversary workshop will be held at The University of Scranton on April 17-18. It is worth noting that April 18 is World Amateur Radio Day, and April is Citizen Science Month. More details to follow but make sure that you save the date!

This is a great, thoughtful newsletter! I particularly enjoyed the profile of Jesse Alexander WB2IFS who I was privileged to meet at GRCON 2025 in Everett, WA.

HamSCI Activities - Meteor Scatter and Transmitting Time Signals

It’s just cool to watch the energy and activity of the HamSCI community! I found these two conversations on the HamSCI email list to be Zero Retries Interesting:

Potential HamSCI Project on a Forward-Scatter Meteor Radar Network

and

Utilizing a commercial SWBC station for time signals

SWBC is Shortwave Broadcast station, example WRMI. I enjoyed this terse update from John Ackermann N8UR:

We’re beyond exploratory and into assembling hardware and writing software. Turns out that generating “time at the tone” isn’t as easy as it looks. :-)

Technological innovation in close proximity to, and developed by Amateur Radio!

CHIRP is Still Going Strong With Regular Updates

I don’t remember what caused me to note this, but it’s great to see that CHIRP is actively being maintained and improved.

CHIRP is a free, open-source tool for programming your radio. It supports a large number of manufacturers and models, as well as provides a way to interface with multiple data sources and formats.

Downloads page:

CHIRP-next

This has the latest and greatest set of features and fixes. Drivers that have not been validated with CHIRP-next are denoted by an asterisk (*) symbol on the supported model list on the Home page. This is the only version of CHIRP that is actively maintained. All users should be running the latest version of CHIRP.

Software Modems in Ham Radio — Part 1: Two Kinds of Burst

Great article posted on DigiRig:

How a software modem turns bytes into sound and the sound back into bytes: the modern signal science, examined through a single VARA FM session.

Every digital mode you run uses a modem: something that turns bytes on one end into a sound a radio can transmit, and turns that sound back into bytes at the far end. The same principle powered the early computer networks that sent data over analog telephone lines. These functions can be performed by a hardware device (TNC), or by software running on a general-purpose computer. Today we are looking at the software modem VARA FM — one of the better ones, and the least documented. It incorporates many of the important techniques used in modern digital communications and because of that it is a great case study for this series.

More from Brian Greenforest

I first mentioned Brian Greenforest in Zero Retries 0249 - I Built an FM Receiver With One FPGA Input Pin. That amazing thinking wasn’t a one-off. From his LinkedIn page:

Cartilage At Home: Download One HTML File And Build Circuits Offline

…

Cartilage is an FPGA board: a modular two-dimensional array of FPGA modules with physical I/O, a touchscreen, built-in Vivado, and a touch circuit editor. It works like Logisim, except it feeds the drawn circuits back into the FPGA hardware. Any region can be securely copied and pasted, including nested regions, and circuits can modify circuits. It is a physical, self-modifying Logisim FPGA board with I/O.

…

Cartilage is a modular 2D-array FPGA board with physical I/O, a touchscreen, built-in Vivado, and a touch circuit editor. It works like Logisim, but feeds circuits back into its FPGA modules, securely copy-pastes arbitrarily nested regions, and can modify its own running circuits—a modular, physical, self-modifying Logisim.

…

It’s like Logisim that modifies its own circuits and calls them Turing-complete programs!

At best, I can merely intuit around the edges of this. This seems like a profoundly different way to think of designing… or actually designing circuitry. He’s thinking way different things than I’m used to hearing about how you make use of Field Programmable Gate Arrays (FPGAs).

From a brief look, Cartilage doesn’t seem a good fit for viewing on a Mac running Safari, but I couldn’t take the time to experiment with it on other platforms.

Building an Off-Grid Meshcore Network, One Node at a Time

Conrad Trautmann N2YCH on QPRer.com:

I have a QRP story for you about mesh transceivers using 1 watt or less in the 33-centimeter band. That’s a UHF frequency of 900 MHz, from 902 to 928 MHz. It’s the Industrial, Scientific and Medical (ISM) band and is also able to be used by amateurs as a secondary service.

The story begins with a technology called Meshtastic. You can download Meshtastic firmware and flash it to a Long Range (LoRa) mesh device. LoRa devices are inexpensive and readily available through multiple sources, including Amazon. These devices typically run RF output power of 22 dBm or about 158 milliwatts. The Meshtastic device connects to your mobile phone using Bluetooth along with an app you download, which allows you to send and receive text messages over the mesh network. If you have a few of these devices, you can communicate with each other over short distances. They’re handy to have on a group hike in a park or on a mountain where there’s spotty or no cellular service, for example.

Enter Meshcore. Using the same LoRa hardware technology and frequencies as Meshtastic, the Meshcore developers designed the architecture and operation of the system differently. Meshtastic nodes will repeat a message they hear up to seven times before they stop transmitting, limiting how far it will go on the mesh network.

Meshcore, on the other hand, uses a companion/repeater design, where the device you carry is called a companion, and it will transmit to the closest repeater. The Meshcore companion does not repeat signals like a Meshtastic device does. The Meshcore repeater sends the message from the companion across the mesh network with a life of up to 64 hops (we’re set to 32 hops here in the Northeast). Rather than expiring after seven hops, messages getting onto the mesh network, hopping from repeater to repeater, can travel much further.

I mentioned this article inline earlier in this issue, but it deserves a detailed mention.

N2YCH is the former Technical Editor of ARRL / QST and his departure from ARRL is a significant loss. Of late, the percentage of Zero Retries Interesting content (and even advertisements) in QST has noticeably increased.

Intel just matched Apple Silicon. Seriously.

The Dell XPS 13 in this video is a welcome development. It’s an entry-level, but good, Windows on Intel laptop that Jeff Geerling KF0MYB judges to be equivalent to a MacBook Neo. It’s in the same price class - $700’ish and KF0MYB reports that the display, keyboard, battery life, and overall build quality were equivalent to the MacBook Neo. Previously, lower priced Windows laptops were crap’ish, or used, and if you wanted a reasonable unit (again, equivalent to what Apple accomplished with the MacBook Neo), you had to pay more for equivalent quality and efficiency.

Related - Zero Retries 0241 - Apple’s New MacBook Neo.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0260. Paid subscribers can comment directly on the web version of this issue.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

ZRDC 2026 Ho!

Zero Retries Digital Conference (ZRDC) 2026 will be here before we (I) know it.

8 weeks until Zero Retries Digital Conference 2026

on Friday, October 16, 2026,

in San Ramon, California, USA.

Yikes! Only 8 weeks.

Minor Rant - If You’re Gonna Do Packet Radio in an Expensive New Radio… Do Modern Packet Radio

We’ve now seen that the $1000 (per Ham Radio Outlet) Icom ID-5200A is going to do APRS - eventually:

Supports APRS (Automatic Packet Reporting System) through a future firmware update.

Presumably that’s 1200 bps AX.25 Packet Radio. We don’t know, because as I write this, despite now being for sale, the ID-5200A isn’t on Icom America’s section for Amateur mobile radios.

Similarly, we’ve seen that the $1200 (per GigaParts) Kenwood TM-D750A, with the higher price including (in the North America versions) the 222-225 MHz / 1.25 m band, and some packet radio capability. Giving Kenwood the same ding as Icom, the TM-D750A isn’t on the Kenwood USA Amateur Radio page.

GigaParts’ page on the TM-D750A says:

APRS Ready: Enjoy real-time two-way data communication with full APRS protocol support. Benefit from a wide range of displays and functions for seamless APRS operations. Built-in KISS TNC provides standalone digipeater functionality, and PC connectivity enables 1200/9600 bps packet and iGate operation.

But neither supports modern AX.25 Packet Radio as it has evolved in the past couple of years, as exemplified by the excellent Dire Wolf Software TNC, such as:

  • Vastly improved single bit error recovery technique (single bit flip testing),

  • Support of Forward Error Correction (FEC) - both IL2P and FX.25,

  • Implements AX.25 v2.2

9600 bps Frequency Shift Keying (FSK) has been problematic since it was first introduced. It works, but it’s fussy - really requiring a quiet channel and a good radio. Since you’re trying to push more data than 1200 bps, one little noise burst corrupts a fair amount of data, requiring retransmitting the entire packet. That’s why FEC makes such a huge difference, as does the single bit flipping technique that Dire Wolf implements.

These modern improvements to AX.25 Packet Radio are readily available for anyone to use. All of it is open source. Anyone who’s paying attention would know this. FX.25 is especially a common sense improvement to implement in new units since it’s backward compatible with AX.25. If an FX.25 station is communicating with an AX.25 station, that works. If an FX.25 station is communicating with another FX.25 station, FEC is used for the exchange for a reliable, efficient exchange of data.

So, how silly is it that these $1000 / $1200 radios don’t do these modern implementations of AX.25 Packet Radio? If you want those modern packet radio capabilities, just get a radio with a flat audio connection like the $360 (DX Engineering) Yaesu FTM-150R, and add an $100 NA6D OpenTNC.

That combination gets you:

  • 144-148 MHz / 2m and 440-450 MHz / 70cm radio with up to 50 watts transmit power,

  • Full TNC capabilities (not just KISS or simple APRS-only),

  • 1200 bps Audio Frequency Shift Keying (AFSK) or 9600 bps Frequency Shift Keying (FSK)

  • FX.25 Forward Error Correction

  • AX.25 v2.2

And… the data system is decoupled from the radio. Thus when it’s time to upgrade to better data communications such as IP400 OFDM-AB at up to 57 kbps, you unplug the OpenTNC and plug in the IP400 Advanced Mesh Node Controller (AMNC).

This minor (?) rant spawned a new project that I plan to show off at ZRDC 2026.

Four Years On, My (Then) Ultimate iPhone

In Zero Retries 0046 - 2022-05-13, I wrote:

New iPhone 13 Pro Max With 1 TB of Storage

Funny story that kind of puts technological innovation into perspective. My old phone had given great service for nearly five years, but it was finally time for a new unit. After weighing all the pros and cons of a new phone, I dug pretty deep to, for the very first time, buy a top of the line iPhone - an iPhone 13 Pro Max with 1 TB of storage. Yes, that’s one Terabyte of storage… in my pocket. I was planning to bring a video camera to Hamvention, but after purchasing this phone with its 1 TB of storage, that’s no longer necessary. Technology evolution is amazing, if a bit expensive at times.

I decided to make that purchase just prior to our big trip in May / June 2022, driving cross country from Bellingham to Xenia, to have the best possible communications on the road. To my amazement, despite staying on major highways like Interstate 90, there were many cellular dead spots.

My iPhone 13 Pro Max has been remarkable. The battery still lasts all day. The exception on battery life is when I’m in a dense urban area where it works better to switch from LTE-only (most appropriate here in rural Whatcom County, Washington) to 5G, which starts to slurp battery. Most amazing, despite pouring many videos and photos into the device over my four years of usage, I’m still not even close to using half of that 1 TB of storage.

Along the way I’ve picked up a few accessories - a “selfie stick” and a pair of wireless microphones to make it easier to record video interviews. The one minor nitpick about those (cheap) microphones is that recording an ordinary video doesn’t allow a split between the (external) microphone audio and being able to use my AirPods Pro to monitor the microphone audio10. But with many things Apple, it just seems to work, so I go without monitoring the microphone audio as I’m recording.

One iPhone generation later, the iPhone 14 added the Apple Emergency SOS by Satellite capability.

Two iPhone generations later, the iPhone 15 began using USB-C as its primary external device / charging connector rather than the Apple Lightning connector. USB-C is just so… useful and in the last year, in my experience, it’s become nearly universal, and now you’re a bit handicapped if your smart device doesn’t have USB-C. Think about it - the MacBook Neo is essentially an iPhone (processor) in a laptop body. How much longer until you just have a “shell” like a MacBook Neo and you plug in your iPhone, and that’s the primary computing device.

Those two hardware features are the only things I’m looking forward to on an eventual new iPhone.

Four Years Later, Lack of Connectivity is a Solved Problem

As for those connectivity gaps of no mobile network coverage on portions of major US highways in the Western US, fast forwarding from May / June 2022 to present day, a mere four years later…

  • At no additional cost (to date), Apple’s Emergency SOS by Satellite (iPhone 14 and later) provides some safety communications using the Globalstar satellite system, albeit with some caveats, like you have to be stationary.

  • At an additional cost, T-Mobile now works with Starlink to provide some communications with unmodified mobile phones by equipping their Starlink satellites with additional radios and big antennas for accessing mobile network spectrum.

  • For as little as $55 / month, the Starlink Mini provides no-excuses seamless Broadband Internet anywhere in North America. There are many mounting systems for putting it on top of a vehicle. The rumored Starlink Mini 2 reportedly has built-in batteries, and might not even need a cable to get signal inside the vehicle, especially if the vehicle has a sunroof.

Looking forward, if we were to take another big cross country trip as soon as 2027, there are some potential additional connectivity options via satellite:

  • Having purchased their own mobile network spectrum, Starlink is making noises about creating a hybrid satellite / terrestrial mobile network service. I’m betting that they can, and they will. Unlike the “traditional” mobile network carriers, Starlink can create mobile network cells as entirely standalone. Power via solar / battery, mobile network spectrum within the capabilities of any phone, and most problematic for “traditional” mobile network carriers, use Starlink as low-latency backhaul… literally anywhere on the planet.

  • I’ll further bet that the Starlink Mini 2 (and eventually every Starlink consumer terminal) will likely have a built in mobile network capability (part of Starlink’s Wi-Fi chipset) to act as a mobile network picocell for the (potential) Starlink Mobile service. If not, the Starlink Mini 3 will certainly do so.

  • Amazon Leo will eventually debut, with their own services, likely matching Starlink’s services.

  • AST SpaceMobile intends to launch satellites that are pure “Direct To Device” (D2D) with huge antennas. AST SpaceMobile doesn’t have their own spectrum, so they will partner with terrestrial mobile network carriers to (re)use terrestrial mobile network spectrum.

Converting from NewsBlur to NetNewsWire

It could easily get me bounced from any group of serious Mac users to admit this, but since Google discontinued Google Reader (GR) for using RSS feeds, I have been using NewsBlur.

I don’t remember the specifics now, more than a decade later, but at the time Google forced the exodus from GR, I liked NewsBlur better than NetNewsWire (NNW). I think it was because NewsBlur was (then) web-based like GR, and it had an iOS app (that used the web-based NewsBlur back end), so there was built-in synchronization between “desktop” and iDevices. NNW was local-only (I think).

But in the last few years, subtle, annoying issues have crept into NewsBlur to the point where it’s slowing me down in trying to keep track of RSS feeds, especially in trying to keep up for Zero Retries developments. Every time I’ve asked Mac folks about alternatives, the only answer I get is NetNewsWire! So, I’ve been long overdue to check out NNW circa 2026 on MacOS 26+, on my (current) MacBook Air with an M1 processor.

Oh my gosh, NNW just rocks. Being a native Mac app, by fanatical Mac developers, and being a very, very mature Mac app, it works exactly as any longtime Mac user can expect. Everything I’m doing to move RSS feeds over to NNW is just fluid and (Mac) intuitive.

I wasted way too much time not having migrated to NetNewsWire much earlier.

Huntsville Hamfest is This Weekend

From my inputs, Huntsville Hamfest (HH)11 is getting a lot more attention in 2026 than it has in previous years. The HH organizers have been marketing it very well, including a booth at Hamvention 2026. In the past year, I’ve been seeing mentions of HH in the same “scope” as Hamvention and Hamcation as one of the primary Amateur Radio events to consider attending.

There’s a lot to love about Huntsville, home of the U.S. Space and Rocket Center (go - just go!) and a more recent claim to fame, GigaParts Technology Superstore. Gotta love that GigaParts subtitle is

The Ultimate Technology Superstore. Over 50,000 square feet of PC hardware, Amateur Radio, 3D Printing, Astronomy, and more.

And, of course, we’re very grateful that GigaParts was one of the first sponsors of ZRDC 2026.

Tina and I have dear friends in Huntsville that we’re overdue to visit so perhaps in 2027 we’ll attend (or exhibit Zero Retries) at Huntsville Hamfest.

For other Zero Retries Interesting events, see Zero Retries Guide to Zero Retries Interesting Events page.

Weekends Are For Amateur Radio!

Lots of projects in queue for N8GNJ / Zero Retries Labs. I hope the OpenTNC arrives soon as I’ve promised to get on a local frequency to start playing AX.25 1200 bps Packet Radio, and the OpenTNC is a perfect fit for that.

But… our neighbors literally across the street put on a great Summer Party on Saturday afternoon that will take precedence for that day. Good music, good company, good food!

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0260. Paid subscribers can comment directly on the web version of this issue.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

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The Usual Administrivia

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Zero Retries 0260 was published on 2026-08-21 with some updates on 2026-08-22. This issue was 13,733 14,037 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

Post Publication Update: Exceptions that come to mind are television broadcast channels 2-83, each of which was 6 MHz (including those that were later repurposed for mobile networks) and government allocations.

2

Shared with Industrial, Scientific, and Medical (ISM) - unlicensed systems, of course. Not just Wi-Fi and household microwave ovens, but also industrial use such as drying ovens used in manufacturing plywood.

3

In my opinion, the TAPR packetRADIO (concept) was easily the coolest looking Amateur Radio data radio, but it’s admittedly “retro”. It nicely matched the Retro Coolness of the Altair or the IMSAI computers.

4

Wideband power amplifiers do exist. For example, the AR / AMATEK 50W1000D operates from 80 MHz to 1 GHz, but as I understand it, internally it’s a collection of more narrowly tuned amplifiers such as 80-300 MHz, 300-700 MHz, and 700 MHz - 1 GHz that are switched inline as dictated by frequency of the driver transmitter. Again, that’s my understanding from an explanation by a knowledgeable friend. This company’s broadband amplifier products are designed for government / military use, and are priced accordingly.

5

It’s necessary to mention both Meshtastic and MeshCore. While they’re both “mesh”, they’re two incompatible / non-interoperable systems… akin to D-Star and DMR. Meshtastic is very widespread and popular, but MeshCore is growing and more “stable” with its more structured network architecture.

6

Unlicensed spectrum - In North America, primarily 902-928 MHz (23 cm), and in Europe, 433 MHz (70 cm).

7

“The Internet is down” is a misstatement. The Internet is a network of networks, and that worldwide network of networks never wholly ceases to function (it’s just too big, too diverse). What does go down is Internet access, which does go down all the time. My Comcast cable modem would go down every early morning for some (system / network) reason. In a widespread power outage, cable infrastructure and mobile network nodes typically only have a very limited backup battery capacity of a few hours. Fiber-seeking backhoes are a thing. Wireless ISPs using unlicensed spectrum can experience interference from other unlicensed transmitters. Satellite communications can be disrupted by very heavy and freezing rain coating antennas. Etc.

8

Techies are hearing about Meshtastic and MeshCore on unlicensed spectrum, but they’re not hearing (much) about Amateur Radio. At many technical events, such as Open Sauce 2025, there was an exhibitor promoting Meshtastic. But there was no exhibitor promoting Amateur Radio.

9

Many AREDN networks rely on Internet (tunneling) for linking to other (out of area) AREDN networks.

10

With the iPhone Camera app (on video), if I use my AirPods Pro, the iPhone switches audio output and input to the AirPods Pro. There are other apps that allow the input / output split, and I’ll be checking those out in plenty of time for ZRDC 2026.

11

Kudos to whoever scored hamfest.org for the Huntsville Hamfest.

]]><![CDATA[Zero Retries 0259]]>https://www.zeroretries.org/p/zero-retries-0259https://www.zeroretries.org/p/zero-retries-0259Sat, 08 Aug 2026 00:30:21 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its sixth year of publication, with 3500+ 3600+ subscribers.

Zero Retries Digital Conference 2026 is 2026-10-16 in San Ramon, CA
www.zeroretries.org/p/conference

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is likely to be truncated by some email clients (as usual). Thus, it might be easier to read in a web browser:

www.zeroretries.org/p/zero-retries-0259

It’s easy and free to subscribe for your own copy of Zero Retries every week:

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In This Issue:

I-Frame

ZRDC 2026 Update 08/07/2026
Tina Stroh KD7WSF

Breaking - OFDM-AB - IP400 Refactored
Steve Stroh N8GNJ

ZR > BEACON

Request To Send

Weekends Are For Amateur Radio!

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

Comments on This Issue (Redirects to Comments Page)

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

Optional Paid Subscriptions, and especially Founding Member subscriptions to Zero Retries, not only help offset various expenses incurred in publishing Zero Retries, but also are a large portion of the “seed capital” that is needed to host Zero Retries Digital Conference (ZRDC) 2026, and future ZRDCs. Thank You!

My thanks to Steven Davidson K3FZT for renewing as Founding Member 0000 to Zero Retries in the past two weeks (4 years)!

I’m indebted to K3FZT for his early, formative advice on the decision to offer optional paid subscriptions to Zero Retries, and being the first Founding Member (0000) of Zero Retries!

My thanks to Chris Osburn KD7DVD for renewing as Founding Member 0002 to Zero Retries in the past two weeks (4 years)!

My thanks to Don Rotolo N2IRZ for renewing as Founding Member 0003 to Zero Retries in the past two weeks (4 years)!

I’m indebted to N2IRZ for his friendship spanning decades now, his contributions to Amateur Radio from his Zero Retries Interesting columns in CQ VHF and CQ from which I learned much. Most recently, N2IRZ helped staff the Zero Retries / DLARC booth at Hamvention 2026, and has graciously volunteered (launching himself once more into the breach) as Coordinator of the Zero Retries Digital Conference 2026 Proceedings. Don is a true friend of Zero Retries and is a Zero Retries Pseudostaffer.

My thanks to Chuck Hast KP4DJT for renewing as Founding Member 0016 to Zero Retries in the past two weeks!

Founding members are listed in every issue of Zero Retries!

My thanks to Hugh Vance KW5X for renewing as an Annual Paid Subscriber (4th year!) to Zero Retries in the past two weeks!

My thanks to John Simmons NK0K for renewing as an Annual Paid Subscriber (4th year!) to Zero Retries in the past two weeks!

My thanks to Orv Beach W6BI for renewing as an Annual Paid Subscriber (4th year!) to Zero Retries in the past two weeks! W6BI is a Zero Retries Pseudostaffer.

My thanks to Paul Elliott WB6CXC for renewing as an Annual Paid Subscriber (4th year!) to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 03 for renewing as an Annual Paid Subscriber (4th year!) to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 05 for renewing as an Annual Paid Subscriber (4th year!) to Zero Retries in the past two weeks!

My thanks to Prefers to Remain Anonymous 34 for renewing as an Annual Paid Subscriber (3rd year!) to Zero Retries in the past two weeks!

My thanks to Dave Lounsbury KC1UIX for becoming a new Annual Paid Subscriber to Zero Retries in the past two weeks!

My thanks to Matt Payne N3PAY for becoming a new Annual Paid Subscriber to Zero Retries in the past two weeks!

My thanks to Jonathan Brandenburg, KF5IDY for one year of being a Paid Subscriber to Zero Retries in the past two weeks!

My thanks to Prefers To Remain Anonymous 130 for upgrading from a free subscriber to Zero Retries to a Paid Subscriber in the past two weeks!

My thanks to Jana A KV6BCD for becoming a Paid Subscriber to Zero Retries in the past two weeks!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Zero Retries Summer 2026 Publishing Schedule - Biweekly

During Summer 2026, Zero Retries will be published biweekly. The intended publication schedule for the remainder of Summer 2026 is:

  • Zero Retries 0260 - 2026-08-21

  • Zero Retries 0261 - 2026-09-04

There may be some special, focused issues interspersed between the scheduled issues, such as a special issue about Zero Retries Digital Conference (ZRDC) 2026.

After ZR 0261 / 2026-09-04… to be determined.

3600+ Email Subscribers!

This week the Zero Retries email subscriber count incremented to 3600+. The email subscriber count continues to increase incrementally1, most recently from high profile mentions of Zero Retries Digital Conference 2026 and the recent Call for Papers for ZRDC 2026. Thanks to Amateur Radio Newsline, Amateur Radio Weekly, and AMSAT News Service for these most recent mentions.

As always, I disclaim that the email subscriber count is an inexact measure of Zero Retries “circulation” as there are pass-along mentions between individuals, notification via social media, and especially readers who follow Zero Retries via RSS (no email subscription needed).

Thanks for the measure of support represented by so many continued email subscriptions. That continually growing number indicates that Zero Retries is being read widely within Amateur Radio, and I’m grateful to all you Zero Retries readers.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0259. Paid subscribers can comment directly on the web version of this issue.

ZRDC 2026 Update 08/07/2026

By Tina Stroh KD7WSF
Zero Retries Digital Conference Manager

This is the second in a series of updates leading up to Zero Retries Digital Conference 2026.

As noted in the last issue of Zero Retries, registration is now open!

Click here to register for ZRDC 2026

With just about 10 weeks until ZRDC 2026, all operations are in full gear to get this conference off the ground. Once again, we have arranged multiple ways to attend and participate in the conference. The options are as follows:

  1. Attend in-person. Automatically entered into drawings for door prizes.

  2. Live visual/audio feed via Zoom. We have taken on the additional cost of having the conference set for live audio/visual feed via Zoom so that people can be in their own home, Ham shack, etc. and participate with the speakers and audience.

  3. Order a copy of the video recording. Our Video Director states the recording will be available approximately two weeks after the conference. It can be purchased on the registration page.

  4. Download a free copy after 1/2026.

Please take this opportunity to share with other HAMS who might be interested and who might not subscribe to Zero Retries.

Presentations Update

To date, we have confirmed the following speakers on the roster. They are:

  • Martin Alcock, VE6VH will discuss the IP 400 Project and the exciting new developments explained in the next article.

  • Glen Popiel, KW5GP will be discuss Microcontroller Communication Technologies and Protocols for Ham Radio.

  • Mooneer Salem, K6AQ will discuss the FreeDV Project

  • Craig Lamparter, KM6LYW will present “DigiPi - Data Transceiver Hotspot” and

    other packet projects.

Please note, some of these speakers will also be speaking at Pacificon, which is a separate conference. Their presentations will not be the same as Zero Retries focuses on the more techie side of amateur radio.

Sponsors Update

As we have confirmed speakers, we have also acquired some sponsors. With our gratitude, we thank and welcome ARDC and GigaParts at the present time as sponsors for ZRDC 2026. GigaParts once again has graciously sent five Explorer QRZ-1 portable radios to be given away as door prizes. Each in-person admission is given a free ticket to win one of these radios.

Looking forward, in each issue of Zero Retries Newsletter up until the conference, I will be posting updates regarding the conference as well as on the Conference web page. If you have any questions, please don’t hesitate to contact me at tina@zeroretries.net or 206-618-3511.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0259. Paid subscribers can comment directly on the web version of this issue.

IP400 Logo
Image courtesy of Alberta Digital Radio Communications Society (ADRCS)

Breaking - OFDM-AB - IP400 Refactored

The Amateur Radio Data Communications Revolution of the 21st Century

By Steve Stroh N8GNJ

Highlights of This Story - the TL:DR

I’m trying out this new feature for long stories - a TL;DR with five bullet points, max.

  • This new version of IP400 is based on a new hardware unit - the Advanced Mesh Network Controller (AMNC).

  • This new system uses a new modulation called OFDM-AB. The -AB is for Audio Band.

  • OFDM-AB can be used with any VHF / UHF FM radio. If a radio does not have flat audio connections, connecting via microphone and speaker works fine.

  • On a 12.5 kHz bandwidth radio channel, full quieting, using QAM-256, microphone / speaker connections - potential data rate is 19,360 bps. Using flat audio connections - potential OFDM-AB data rate is 42,353 bps.

  • Mesh networking is integrated in IP400.

Disclaimers

In my previous coverage, I framed IP400 as “The Packet Radio Revolution of the 21st Century”. Per the above, I’ve modified that phrase slightly, and I think it’s now particularly applicable in this new version of IP400.

I was given advance access to this information, and I’m privileged to present it first here in Zero Retries. Although I’m an Honoured Member of Alberta Digital Radio Communications Society (ADRCS) for my initial contributions to scoping and publicizing IP400, I’m not directly involved with the development, or deployment of this project and I’m not speaking for ADRCS or the IP400 developers.

Some features of UFP, OFDM-AB, and the AMNC described in this article are not yet implemented (Fall 2026). All features described in this article are scoped in the development plan and are well within the capabilities of the hardware and overall architecture of the system.

In this article I’ve chosen not to offer comparisons of this new system with AX.25 1200 / 9600 bps Packet Radio, or to VARA FM, as it would quickly get awkward and lengthy in explaining what is comparable, and what is not.

What follows is an introduction to this new, complex system - a new data communications mode / modulation, a new network paradigm (mesh networking in VHF / UHF spectrum), adding data communications to an existing “voice use” FM repeater, etc. There will be follow-on articles in Zero Retries, and more detailed information available from the Alberta Digital Radio Communications Society (ADRCS). Most notably, at Zero Retries Digital Conference 2026 in October, 2026 in San Ramon, California it is planned to have demonstrations of this system and the latest information on this system will be one of the major presentations.

Terminology

The verbiage in this article can quickly get confusing, thus here is a quick reference:

  • IP400 - Intelligent Protocol for the 400 MHz band. Despite IP400 no longer being confined to the 400 MHz (actually 420-450 Amateur Radio / 70 cm) band, the system is (still) called IP400. For background on IP400, see ip400.adrcs.org.

  • Mini Node - The initial radio unit developed in 2025 as a proof of concept and development tool for IP400.

  • Unified Firmware Platform (UFP) - The firmware for IP400 that runs on both the Mini Node and the Advanced Mesh Network Controller (AMNC).

  • Orthogonal Frequency Division Multiplexing - Audio Band (OFDM-AB) - The new modulation method.

  • Advanced Mesh Network Controller (AMNC) - The hardware unit for this newest version of IP400.

Background - 2025 and 1H 2026

Long time readers will recall extensive coverage of the IP400 Project during the first half of 2025. Since then, I haven’t offered much coverage of IP400 - just a few sparse status reports. Out of public view, there was extensive development activity and rethinking… refactoring of the concepts for IP400.

The original goal for the IP400 Project was to create a new radio designed for data communications that would be capable of 100 kbps data rates (minimum) using 4-level Frequency Shift Keying (FSK). That goal was met with the creation of the Mini Node, operating on the Amateur Radio 420-450 MHz (70 cm) band, of which about one hundred were built and distributed.

The Mini Node was successful in proving out the concepts of IP400 mesh networking and as a benchtop development platform.

To be useful for typical terrestrial Amateur Radio use (peer to peer networking), the Mini Node requires a driver amplifier (still in development) and a power amplifier (somewhat expensive) to be usable (25 watts or so). That was going to be expensive. Another issue was for those early IP400 experimenters with IP400 Mini Nodes, the primary barrier to creating new IP400 networks was the “lone node problem”2.

Debut of OFDM-AB - August 2026

During the development in the first half of 2026, it was decided that instead of creating a new IP400 radio capable of OFDM, there would be much wider adoption of IP400 if OFDM could be adapted for use with conventional VHF / UHF FM radios, using OFDM in the audio path of VHF / UHF FM radios3, thus the creation of OFDM - Audio Band (OFDM-AB).

IP400 using OFDM-AB offers compelling attributes:

  • Every Amateur Radio Operator has a VHF / UHF FM radio (or newly purchased inexpensive radios) that can be used for OFDM-AB.

  • IP400 networks using OFDM-AB can be created in any of the Amateur Radio VHF / UHF bands - 6m, 2m, 1.25m, 70cm, even 10m - just buy an appropriate radio.

  • IP400 / OFDM-AB using typical 12.5 kHz FM bandwidth is an easier “fit” in crowded Amateur Radio VHF / UHF bands.

Advanced Mesh Network Controller (AMNC)

Advanced Mesh Network Controller board
Advanced Mesh Network Controller - prototype. Image courtesy of Alberta Digital Radio Communications Society (ADRCS)

One notable feature of the AMNC is the large chip in the lower right corner (Trion). That is a Field Programmable Gate Array (FPGA) and it’s the unit most involved with the (complex) generation of the OFDM-AB modulation. I’m told it’s currently “lightly utilized”, and thus offers ample expansion capability.

The nature of OFDM is that the task of individually managing many subcarriers is computationally intensive. While OFDM for an audio band can be done in a host computer, it’s arguably better to use a dedicated controller without the latency and overhead of a host computer running a typical desktop multitasking operating system.

Thus the creation of the AMNC.

The AMNC can be used in three scenarios:

  • An AMNC can operate standalone connected to a host computer, via a serial connection (USB-C), using the well-developed KISS protocol.

  • An AMNC can be connected to a Raspberry Pi computer (typically a Raspberry Pi 3 Model B+) as a HAT to take advantage of the Raspberry Pi’s capabilities such as Wi-Fi, Bluetooth, Ethernet, general purpose Linux OS, full TCP/IP stack, displays, etc.

  • Adding an AMNC to an FM repeater is a relatively simple upgrade that adds data communications capability and AllStarLink to existing FM repeaters.
    An IP400-enabled repeater using an AMNC creates a Wide Area IP400 network.

The AMNC supports up to two radios, so IP400 mesh networks can be created on multiple Amateur Radio VHF / UHF bands by simply connecting two radios on different bands to an AMNC. The existence of such cross-band gateways in the network is a feature of IP400’s mesh networking.

Data Speeds - Any Radio, Up to 57 kbps

OFDM-AB Bandwidth on 12.5 kHz Spacing chart
Image courtesy of Alberta Digital Radio Communications Society (ADRCS)

In the above chart, “Bandwidths” refer to a radio’s audio bandwidth path.

Narrowband - Any VHF / UHF FM radio can be used with OFDM-AB using the microphone and speaker connections.

Enhanced Narrowband - Some VHF / UHF FM radios provide “better than minimal” audio bandwidth, via the microphone and speaker connections. Such radios are able to achieve higher data speeds than Narrowband.

Wideband - Radios that provide flat audio4 connections (often better known as the “data connector” or “9600 connector / port” - usually a 6-pin MiniDIN connector on the back of the radio).

Enhanced Wideband - Radios that provide an exceptionally wide audio bandwidth; generally those that are specifically designed as data radios. The best-known such radios are Tait radios that were designed for use with mobile data terminals, now widely available as surplus.

See my Zero Retries Guide to VHF / UHF Radios for Data for a survey of various Amateur Radio radios that are suitable for data communications.

OFDM-AB Data Rates chart
Image courtesy of Alberta Digital Radio Communications Society (ADRCS)

As shown on the above chart, the most ideal case for OFDM-AB is with an Enhanced Wideband radio (such as a Tait data radio), on a “full quieting” channel where QAM-256 modulation can be used, can achieve 57,176 bits per second.

Note that the original goal of IP400 was 100 kbps data rate (minimum). Arguably, 57, 176 bps achieves 57% of that goal. But, notably, OFDM-AB uses a 12.5 kHz radio bandwidth instead of the 100 kHz radio bandwidth originally proposed for IP400.

A more typical case is use of a radio such as the Kenwood TM-V71A5 which features flat audio connections, on a “full quieting” channel where QAM-256 modulation can be used, to achieve 42,353 bits per second.

Note that the data rates in the above chart are “raw” data rates. The actual “throughput” data rate will be lower after Forward Error Correction (FEC) overhead is implemented.

Mesh Networking

A highly detailed description of the IP400 mesh networking capability is beyond the scope of this article. IP400 mesh networking will be the subject of future articles after I’m able to have hands-on time with a test network of at least three AMNCs.

The header information in each IP400 transmission is richly detailed, including the maximum data rate of each station, mesh network routing, and many other data elements.

A co-primary goal of the IP400 Project is to provide integral mesh networking, well beyond simple one hop (or user specified multi-hop) digipeating. Header information from each IP400 transmission received is cached by every receiver into its local mesh network table, including routing (if not received directly).

Thus to transmit to any station in an IP400 network, it’s only necessary to specify the destination. The station’s internal mesh network table is consulted (or, if the destination has not been previously heard, the network is queried), any necessary routing is added, and the connection is established.

The primary takeaway about IP400 mesh networking is that IP400 has mesh networking designed in from the beginning and will evolve with real world usage experience and further development.

Adding Data Communications Capability to FM Repeaters

A highly detailed description of the use of AMNCs for providing AllStarLink is beyond the scope of this article. IP400 and AllStarLink capability will be the subject of future articles when I can have hands-on time with a repeater equipped with an AMNC that is on AllStarLink.

One of the primary reasons for development of the AMNC is that this single unit can be used by individual stations and installed in repeaters.

When installed in a repeater that has already implemented AllStarLink for remote (voice) use, installation of the AMNC is largely plug-and-play because AllStarLink capability is already present in the AMNC. Thus an AMNC replaces a AllStarLink unit.

Because the AMNC uses a different audio CODEC than typical AllStarLink controllers, installation of a custom driver is required to access the CODEC capability in the AMNC.

One of the most exciting capabilities of the AMNC is that installing it in a repeater adds data communications capability with minimal impact of voice usage of the repeater.

After installation of an AMNC into an FM voice repeater, the repeater becomes dual mode IP400 data and voice.

In a repeater with an AMNC installed, the one change to voice use is to activate CTCSS6 on the repeater’s transmit signal. Correspondingly, it’s suggested that voice users enable “Receive CTCSS” for the repeater in their radios. Thus when data is being transmitted (without the transmitted CTCSS), the voice user’s radio does not open the squelch, and the data transmission is not heard.

For data, the flow through the repeater is:

Data user 1 transmission —> repeater receiver —> AMNC —> repeater transmitter —> data user 2 reception.

Note that the “data path” through the repeater bypasses the repeater’s controller, and thus CTCSS is not added to the data transmission.

Data users do not transmit with CTCSS. It’s not needed because the AMNC is monitoring for a OFDM sync signal.

In cases of “collisions” when data and voice is transmitted to the repeater simultaneously, the AMNC can be set to defer data communications for an interval to not interfere with voice use. Computers are patient. 😊

This technique of adding IP400 data to FM voice repeaters offers a number of advantages:

  • It’s relatively easy to implement if the repeater already has been set up for AllStarLink.

  • It provides a new / enhanced mission for “quiet repeaters” that are not getting much usage.

  • NewTechHams have a strong preference for data communications over talking. Thus the addition of data capability to a repeater gives them a reason to begin using that repeater.

  • Having a repeater that can retransmit IP400 data makes it possible for lower powered radios to be used to participate in an IP400 mesh network, rather than requiring at least 25 watts for typical terrestrial simplex / mesh network use.

  • The addition of IP400 data capability to a repeater provides a reason for NewTechHams to get involved with a repeater support organization and contribute to the upkeep of the repeater.

  • For those repeaters / organizations that do implement IP400 data capability, that provides a strong differentiation of that repeater / organization versus repeaters / organizations that continue to offer only voice.

Unified Firmware Platform (UFP)

Those early experimenters with IP400 that have Mini Nodes are not being left behind. Since the firmware for the Mini Node and the AMNC is the same, and the IP400 mesh networking is the same in the Mini Node and the AMNC, the Mini Node continues to be useful for IP400 development work, especially testing mesh networking.

ARDC Grant

Much of the development work for IP400 and OFDM-AB was funded by a 2025 grant from ARDC to the Alberta Digital Radio Communications Society (ADRCS). I think7 this development of IP400 and OFDM-AB is an excellent example of ARDC grants enabling significant and unique technological innovation in Amateur Radio, and radio technology in general. There is no commercial work being done (that I’m aware of) for a data communications system using narrow (12.5 kHz) radio bandwidths, with integral FEC and mesh networking.

Open Source Aspects

All of the details of IP400, UFP, and OFDM-AB are publicly disclosed and available as open source. The GitHub repository - github.com/adrcs/ip400 contains released information - specifications, software, and documentation.

Public information such as press releases are on the ADRCS website.

It’s intended / hoped that OFDM-AB will be implemented in other systems as an open source OFDM modulation in the audio band of VHF / UHF radios with integral Forward Error Correction (FEC). It would be ideal for other implementations of OFDM-AB could be implemented to be interoperable with IP400’s implementation of OFDM-AB and IP400’s mesh networking.

The AMNC was privately developed and details of it (other than those aspects necessary for development purposes) won’t be made public.

Development Timeline

The AMNC is projected to be available, in full production, in Q4 of 2026. The distribution and pricing will be released later in 2026.

Feature development of OFDM-AB, and AllStarLink per the chart below, will extend through the first half of 2027.

Planned UFP Releases chart
Image courtesy of Alberta Digital Radio Communications Society (ADRCS)

IP400, AMNC, and OFDM-AB in The Big Picture of Amateur Radio Networking

In my perspective, IP400 and OFDM-AB is the “missing middle” of Amateur Radio networking.

On HF, we now have a good data communications mode, specifically designed for the vagaries of HF, in Mercury (which also uses OFDM). Mercury is already being tested on The Packet Radio Forwarding Network and based on feedback from that real world usage, Mercury is rapidly being improved. Thus Amateur Radio now has a reasonable “long haul via HF” data communications networking capability.

On microwave - 902 - 928 MHz (33 cm), and 2.4 GHz and 5.x GHz, we have the fantastically capable AREDN mesh networking system. (Most AREDN hardware units use OFDM.)

On the Internet for those times when we can’t “just use radio” there has been Amateur Radio’s dedicated corner of the Internet - 44Net. Getting on 44Net has been the realm of wizards, and perhaps your area has one and makes 44Net connectivity easy for you. But if you don’t have a local 44Net wizard, now there’s 44Net Connect which makes it really, really easy to take advantage of 44Net’s capabilities. (And, if you want cheap works anywhere Internet access for Amateur Radio projects and 44Net Connect, it’s hard to beat a Starlink Mini unit running on Standby service of 500 kbps for $10/month.)

But on VHF / UHF… we’ve been muddling through for decades now with AX.25 Packet Radio, mostly at 1200 bps, APRS digipeaters, with Internet-based Winlink and APRS-IS for networking. Recently there has been a resurgence in 9600 bps now that NinoTNC and DIRE WOLF have implemented FEC to make 9600 usable and reasonably reliable. We’ve also had VARA FM which implemented OFDM and FEC, but isn’t really built for networking, more for individual node access file transfers, most commonly used to access Winlink. The closest we’ve come to mesh networking in VHF / UHF is 30+ year old Net/ROM / TheNET capability in some legacy packet radio systems. And, of course, Meshtastic and MeshCore on 433 MHz, at very low data rates from using LoRa.

So, for VHF / UHF, Amateur Radio hasn’t had a very compelling story to tell to the NewTechHams who want to do data communications with their Amateur Radio license. AREDN would be a slam dunk proposition to NewTechHams (and it is, in places where there’s lots of friendly-to-Amateur-Radio hills and a minimum of foliage like Southern California). But in the rest of the world… microwave networks are often problematic, especially if there are trees, or non-optimum terrain.

Thus in many ways, VHF / UHF is the ideal portion of spectrum for NewTechHams - radios are reasonably priced (for reasonable power), antennas are easy to construct and understand and of manageable size, and best of all, VHF / UHF works reasonably well to penetrate foliage and achieve reasonable distances.

What we’ve been missing in VHF / UHF data communications is something exactly like IP400 / AMNC / OFDM-AB - reasonable speeds, reasonable reliability, ability to use existing radios, ability to use our capabilities in multiple VHF / UHF bands, built in mesh networking, a way to leverage repeaters that doesn’t disrupt existing repeater functionality, and… the ability to tinker with it - open source.

Now with IP400 / AMNC / OFDM-AB, if you want to build local networks in Amateur Radio, there is a reasonable story to tell that competes favorably with Meshtastic and MeshCore. Unlike MeshCore, IP400 has the ability to build tiered networks that, for example, could put the fastest networking on 222 - 225 MHz (with Tait radios) and local networks on 144 - 148 MHz. Or whatever. The IP400 mesh networking figures out who is where and how to route to each user.

The N8GNJ Take on the New IP400 With AMNC and OFDM-AB

Whew! This… is a big deal. Bigger than the original idea for IP400. In many ways this new system is as close… as is practical, at this moment… to the ideal Amateur Radio data communications system as I have been imagining / dreaming / scoping for… let’s just say a long time.

The development of OFDM-AB and using existing radios “bootstraps” the ability to build IP400 mesh networks much more rapidly and will prove out IP400 (and improve, with further development).

Using the “pretty fast” data speeds of OFDM-AB, especially with radios that have flat audio connections (the majority of radios I’ve bought in the past five years) is good enough for now. Such radios that are currently in production aren’t common at the moment, but they are available, such as the Yaesu FTM-150R, currently about $360 in the US. (Again, reference my Zero Retries Guide to VHF / UHF Radios for Data for as much as I know about various Amateur Radio data radios.)

I think that it’s reasonably likely that the development of IP400 and OFDM-AB will make it apparent to Amateur Radio en masse, especially manufacturers of Amateur Radio VHF / UHF radios, how “stuck in the past” it is to continue building barely adequate TNCs and AX.25 Packet Radio, especially at 1200 bps and 9600 bps (without any FEC) into radios when there’s much better technology available, like IP400.

Just as a small example, the data communications capability in the new Icom ID-5200 is 1200 bps APRS, and perhaps D-Star DV Fast Data mode (which repurposes most of the 4800 bps bitstream for data). That’s in a VHF / UHF radio that is going to cost nearly $1000. The new Kenwood TM-D750 is slightly better, being able to do 9600 bps APRS and likely a similar price.

One significant difference between those two new radios is that the TM-D750 has a flat audio connection (at least, I think it does, per some early information) which makes it at least a plausible investment for its data communications capability.

But for my purposes, to be able to create / join a IP400 mesh network operating at reasonable speeds, buying a radio with flat audio connections and an AMNC gets me online with IP400 for perhaps half the cost of those two brand new “state of the art” VHF / UHF radios. Oh, the ID-5200 and TM-D750 have Bluetooth and Wi-Fi.
So does an AMNC when mated with a $40 Raspberry Pi 3B+.

It’s probably a fantasy… but it seems at least feasible that the existence of IP400 / AMNC / OFDM-AB could motivate one or more Amateur Radio manufacturers (especially those in China) to create a minimal data radio with minimal “voice featuritis” that would be suitable for use with IP400 / OFDM-AB. A few fantasy features:

  • Flat audio connector, of course.

  • Big heatsink8 rather than a small heatsink with a (Noisy! Always!) fan.

  • Minimal display.

  • Full remote access of radio functions - frequency, etc.

  • Don’t supply a microphone (unnecessary expense).

  • Oversized enclosure that can accommodate an AMNC mated onto a Raspberry Pi.

I’m looking forward to obtaining several AMNCs and mating them with radios that have a flat audio port to do testing in N8GNJ Labs, and showing off a working network (hopefully, at least three nodes) at Zero Retries Digital Conference 2026. Ideally I’ll obtain enough AMNCs to add some radios that only have microphone / speaker connections to demonstrate interoperability. Maybe… even one of my test repeaters will get an AMNC to demonstrate IP400 on a repeater capability.

Longer term, after IP400 becomes more widely known and IP400 networks are established, it becomes more feasible to develop a built-for-purpose IP400 radio, with an integrated AMNC, implementing OFDM in the radio domain, at reasonable transmit power.

Concluding Thoughts

One of the best parts about IP400 is that it’s not done! There’s still a lot… a… lot… of work left to do in developing IP400 more fully and ironing out the inevitable bugs of IP400’s mesh networking and OFDM-AB as it starts getting deployed at scale. The most important parts of IP400 - the firmware, the mesh networking, and OFDM-AB are all open source so there’s plenty to learn from and innovate with and build upon.

Not mentioned above, but important, is that IP400 isn’t entirely a clean sheet of paper system with no backwards compatibility. The available KISS interface on the AMNC makes it easy to use with existing Amateur Radio applications that “speak KISS” (it’s rare when one doesn’t). There’s also the ability to “just add a Raspberry Pi” if you want Ethernet, or a robust TCP/IP stack, or Bluetooth, or running some other network system (even Packet Radio), it’s relatively easy to do so.

Working with other networking systems such as AX.25 and TCP/IP is doable with IP400 via encapsulating their packets in IP400 packets for transport through an IP400 network. For example, a packet radio BBS such as G8BPQ Mail Server could be accessible on an IP400 network, and accessed using a packet radio terminal program such as Radio Messenger (iDevices) or WINTNC (Windows).

Another best part about IP400 is that primary developer Martin Alcock VE6VH is a long time radio technology developer and manager who believes that development isn’t done until there’s good documentation. IP400 is no exception - there is very good documentation.

Yet another best part about OFDM-AB is that it benefited from the knowledge of co-developer of OFDM-AB, Nino Carrillo KK4HEJ. I’ll guess that OFDM-AB benefited a lot from KK4HEJ’s deep knowledge of AX.25 Packet Radio on VHF / UHF gained from development of Improved Layer 2 Protocol (IL2P) forward error correction system first implemented on the NinoTNC.

It’s been dormant during the quiet period of IP400 development, but I’m told that the IP400 email list owned by ADRCS - groups.io/g/ip400 will resume being an official support source for IP400. There is also the dormant IP400-users email list - groups.io/g/ip400-users that may restart (a little diversity is sometimes useful).

For developers interested in contributing to IP400, there is a Developer email list and a Developer GitHub repository. Contact ADRCS if you’re interested in being a developer to get access to those resources.

Lastly, remember that IP400 / AMNC / OFDM-AB will be a significant element of Zero Retries Digital Conference 2026 on October 16, 2026 in San Ramon, California (same weekend as Pacificon 2026 also in San Ramon). Hopefully, there will be ample demonstrations of working hardware.

If you’re interested in contacting ADRCS for interviews such as on YouTube, use the ADRCS contact form.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0259. Paid subscribers can comment directly on the web version of this issue.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

Starlink Mini 2 Will Have a Built In Battery (Rumored)

Michael Kan in PCMag:

Starlink’s ‘Mini 2’ Dish Appears in Firmware With Built-In Battery

Along with a built-in battery, the upcoming Mini 2 dish features a far lower ‘duty cycle’ for uploads, according to a Starlink repair expert.

New Starlink firmware indicates that SpaceX has started producing a “Mini 2” dish, which features a built-in battery and a sign that it supports even lower power consumption.

On Sunday, Ukrainian repair expert Oleg Kutkov reported discovering the “mini2_prod1” in the latest firmware release for the Starlink dish hardware.

The big upgrade is the addition of the built-in battery, which the current Mini model lacks, requiring customers to source the component from third-party accessory makers. Kutkov’s finding confirmed the new Mini boasts a built-in four-cell lithium-ion battery, weeks after a separate researcher discovered signs that a built-in battery for the Mini was in the works.

In addition, Kutkov found that the Mini 2 supports charging over USB-C; the current Mini requires a USB-C adapter for compatibility.

The other notable difference is the Mini 2’s much lower “duty cycle” for uploading, or the percentage of time that a device is operating and transmitting, versus the time off. “The transmit duty cycle has been reduced significantly, from 75% to 11%, which will result in lower uplink speeds. This limitation is most likely driven by the terminal’s power budget,” Kutkov tweeted.

The “Mini 1’s” ability to “power it from USB-C” apparently isn’t very realistic. I’ve tried doing so with two of my battery units and it doesn’t work. My experience is that to power the Mini 1 requires using either the Mini 1’s (optional) 12 volt adapter9 or the Mini 1’s (included) AC adapter.

I was glad to see that my experience with powering the Mini 1 isn’t unique. In his story Fight the Power!, Eric Grumling K0JEG relates his issues trying to power the Mini 1 from USB-C.

I don’t view the lower transmit duty cycle to be a detriment for the Mini 2 - its use case is portability and for the amazing capability of having built-in batteries, this seems to me to be a minor tradeoff.

I hope that the Mini 2 will retain the Ethernet connector in addition to the USB-C power connector. It’s still mind boggling to me that we now live in an era where we have broadband Internet connectivity… anywhere (that you can see the sky).

Starlink Mobile Phone Service

Talk about kicking over a proverbial hornet’s nest in the telecommunications industry…

Starlink Mobile Is Coming for AT&T and Verizon: SpaceX Has Spectrum, Still Needs Towers

I’ll spare you the usual Zero Retries quotage. Yes, of course it’s outrageous and unreasonable and completely unheard of, and impossible, and… and… and…

There’s a (in)famous quote about the debut of the iPhone by Palm’s CEO that comes to mind reading the “industry experts” and their naysaying about the potential of Starlink Mobile:

And so I just would caution people that think they’re going to walk in here and just and do these. We’ve struggled for a few years here, figuring out how to make a decent phone. The PC guys are not going to just, you know, knock this out. I guarantee it.

My thanks to John Gruber of Daring Fireball for the best take on that statement.

But just consider a few bits of speculation on my part:

  • Starlink can install a cell / microcell / picocell anywhere there is sunlight and a view of the sky. Anywhere. Literally. They can use their own satellites as the backhaul, and solar + battery (they have some expertise…) to power it. If Starlink needs to provide coverage in a residential neighborhood, just offer free Internet and mobile service and people start putting up Starlink Mobile infrastructure on their houses.

  • Want in-building coverage for Starlink Mobile? Put up one of those big Starlink Enterprise units on the rooftop of a high-rise and distribute via the built-in Ethernet to every floor of the building with cheap picocells.

  • Some hungry or savvy vendor of enterprise Wi-Fi systems is going to partner with Starlink to add Starlink spectrum to their products. Update to Wi-Fi 7 and Starlink Mobile!

  • Starlink will begin adding picocell radios into every one of their units - right next to the Wi-Fi chipset. It will probably will be one chipset for both functions. I’ll guess that the Starlink Mini 2 will have this feature.

  • Perhaps Starlink will launch as a specialized service for Enterprises, or experimenters, or for existing Starlink customers.

  • One thing that you won’t see is “Starlink Retail Stores” like the big three do so expensively. If you can’t figure it out to buy it and get self-support online, you’re not a target customer for Starlink Mobile.

  • The newest Starlink satellites, once Starship is finally operational, will be able to do pretty reasonable “cell service” from LEO, at least providing service for areas that aren’t very customer-dense.

  • Between the satellites, the phased array antennas (that Starlink pioneered to drive down the pricing to consumer levels), the signal processing… I’m not going to dare to naysay that Starlink can’t parlay a mere 65 MHz of cellular spectrum in the US, that every mobile phone is set up to make use of with a minor software upgrade, into a somewhat credible mobile phone service.

One of the most telling aspects about Starlink is that it is the same system… worldwide. No other telecommunications system or telecommunications carrier10 can say that.

Starlink isn’t building new infrastructure in… Seychelles, or Maldives. They built Starlink with 21st century technology including the management infrastructure. You’re never going to end up in a “Starlink Mobile retail store” watching a bored teenager tap on a keyboard for ten minutes because they have to enter data and cut and paste between multiple systems including mainframes.

Using Starlink as my Internet has been the least frustrating experience I’ve ever had of being an Internet user. If Starlink offers mobile service, I’ll sign up in a millisecond.

We live in very interesting technological times… not just in Amateur Radio!

ARRL to Create an Open Source Contest

This seems to have slipped by unnoticed by most folks in the Hamisphere. In The ARRL Letter for July 30, 2026, in the mention of the recent ARRL Board meeting, there was a link to a “Member Bulletin” (which is claimed to emailed to all ARRL members, but as a paid-up ARRL member, I didn’t receive it) with more details about the board meeting, with this Zero Retries Interesting item:

The Board approved the creation of an ARRL Open Source Amateur Radio Competition to encourage innovation in software, hardware, and open-source development while supporting technical exploration, STEM outreach, and the next generation of radio amateurs. The competition is expected to launch in 2027.

There has been no other mention of this that I’ve seen to date.

In other Zero Retries Interesting ARRL news, in the same Member Bulletin, there was also these two items:

The Board approved the sunset of the Technical Standards Committee, recognizing the successful integration of the Clean Signal Initiative into ARRL Lab operations and thanking committee members for their service and dedication.

It’s sad to me that ARRL has “sunset” the Technical Standards Committee. I had (some, minor) hopes of petitioning the TSC to take on more of a role as I’ve been envisioning for the (fictional, at the moment) Amateur Radio Standards Organization (ARSO). The major story in this issue about the development of OFDM-AB, as exciting and promising as that is, is yet more fragmentation of data modes in Amateur Radio. An ARSO could be a unifying / rationalizing force in Amateur Radio.

Finally, the Board authorized Headquarters staff to work with the Mount Diablo Amateur Radio Club of California to host the ARRL National Convention in conjunction with Pacificon in October 2028. Pacificon annually hosts the ARRL Pacific Division Convention in San Ramon, California.

That’s gonna be cool to have an even larger presence of ARRL at Pacificon 2027. Tina and I are really impressed that Pacificon attracts a higher percentage of Zero Retries Interesting folks than any other Amateur Radio event that we’ve attended to date (other than the now discontinued TAPR DCCs).

Yet another development at ARRL is that they’re hiring for Technical Editor. I got to know the former Technical Editor Conrad Trautmann N2YCH a bit and was impressed with his deep technical background (and he’s a fan of Zero Retries).

ARRL is also hiring for a RFI Lab Engineer.

QuadRF Combined With a Reflector Dish

Martin McCormick K1MCC - The Final Week of Our Campaign:

In our copious free time (ha!), we decided to play with an interesting idea. We all know phased arrays are the ultimate antenna architecture, with instant steering, high gain, and zero moving parts. However, if you are willing to compromise a bit, a single QuadRF can be used for very long-range links when combined with a reflector dish.

With the QuadRF’s four independent channels, it can function as an advanced steering system by digitally combining the four feed elements at the dish’s focal point. This simultaneously generates a central high-gain “sum” beam for main data link, alongside azimuth (left/right) and elevation (up/down) “difference” beams. Using energy detected in these difference beams, the QuadRF knows the precise angular offset of a target. When paired with a motorized mount, this allows the dish to “lock on” and track radio objects in real-time by feeding commands to the motor. It is the fundamental principle of monopulse radar. This nicely solves the parabolic dish typical challenge of needing a calibrated mechanical pointing and a-priori knowledge of a moving target’s exact path.

QuadRF (and K1MCC) just continues to impress me with revolutionary leaps like this for an open source radio technology to put phased array beamforming in experimenter’s hands. The QuadRF crowdfunding campaign has been an overwhelming success and so we’ll see QuadRF emerge later in 2026 or early 2027.

Build a Retro CBBS for Your Shack

Dave Ginsberg N3BKV:

There is a special kind of magic in a blinking cursor.

Before social networks, web forums, Slack, Discord and group chats, there were bulletin board systems. You dialed in, waited for CONNECT, logged in with a handle, read the bulletins, checked your private mail, posted a message and logged off with the unmistakable finality of:

NO CARRIER

For radio amateurs, that world never really disappeared. Packet BBS systems, club bulletin boards, mailbox nodes, Winlink-style messaging, APRS bulletins, repeater status pages and remote station dashboards all come from the same basic idea: low-bandwidth, text-first, asynchronous communication.

That is the spirit behind CBBS_PI — a vintage CBBS-style BBS emulator built in Python for a modern Raspberry Pi, Mac, Linux box or Docker host.

It is part nostalgia project and part platform for experimentation.

What It Is

CBBS_PI is a text-mode bulletin board system that recreates the feel of early BBS systems.

It supports local terminal access, Telnet server mode, SSH access through OpenSSH, selectable baud-rate simulation, ANSI themes, public message boards, private mail, a file area, access levels, daily login bulletins, SYSOP logs and web dashboard administration.

It is intentionally simple. There is no database server. There are no third-party Python packages. The storage is JSON and plain text. The main program is cbbs_pi.py.

That makes it hackable, portable and very much in the amateur radio tradition.

Getting my own Amateur Radio BBS on the air is a serious goal for me in 2026. This… might do the trick.

MMDVM-IQ Released

Jonathan Naylor G4KLX:

For the past few months I have been working on the next generation of the MMDVM, using I/Q based hardware instead of chips like the ADF7021, or using direct taps into the modulator and demodulator like the MMDVM modems do. Our new hardware is based around the Semtech SX1255 which is a 70 cm I/Q based duplex transceiver.

We are definitely not alone in using this chip, and there is TETRA development using it for example. In the case of the MMDVM, I took the standard MMDVM modem firmware and added an I/Q front-end to it, as well as other chip control functions like setting the transmit and receive frequencies. After some testing, often in the context of the MMDVM-CrossMode program, I have decided that this new firmware is now ready for testing by all.

This new program is named MMDVM-IQ and it runs on a Raspberry Pi (the Pi 4 is recommended) with some suitable hardware attached to it. It uses a SoapySDR driver to allow it to access the hardware. This new hardware allows us to use any modulation method that we want to, and this first version supports: D-Star, DMR, System Fusion, P25 phase 1, NXDN, POCSAG, and FM. So we already have one extra mode compared to the standard MMDVM hotspot.

I’m looking forward to talking to Jim Mclaughlin KI6ZUM of ZUMRadio about this at Pacificon 2026. I wish that M17 was one of the supported modes - that would make me much more interested in this development.

A New 10″ Raspberry Pi Touch Display 2, Available Now at $80

…

Physical size is not the only upgrade. Our new 10″ display features a higher 1200×1920–pixel resolution, a more generous 85-degree viewing angle, and a touchscreen controller with support for ten-finger touch, up from five-finger touch in the 5″ and 7″ variants.

As with all our display products, the 10″ Raspberry Pi Touch Display 2 integrates seamlessly with the rest of the Raspberry Pi ecosystem. It is powered directly from the host Raspberry Pi, and comes with all the necessary cables, connectors, and mounting hardware. The capacitive touchscreen benefits from full driver support in Raspberry Pi OS — simply update the operating system and EEPROM bootloader on your Raspberry Pi 5 or Raspberry Pi Compute Module (any model, with a Raspberry Pi Compute Module IO Board or another suitable motherboard), connect the display to the device, and go.

The 10″ Touch Display 2 is not compatible with Raspberry Pi 4 or earlier models, or with the Raspberry Pi Zero series. While previously released Touch Displays use only two lanes of DSI data to communicate with the host Raspberry Pi — which works well with the older display connector on Raspberry Pi 1, 2, 3 and 4 — the higher resolution of the new 10″ variant requires four DSI lanes. This in turn requires our narrower, but higher-bandwidth, ribbon cable and the newer display connector found only on Raspberry Pi 5 and the Compute Module IO boards. For display options you can use with earlier Raspberry Pi computers, take a look at the 5″ and 7″ variants of Raspberry Pi Touch Display 2, or consider the Raspberry Pi Monitor.

This kind of incremental and continuous improvement in the Raspberry Pi ecosystem is what keeps me as a rabid fan of Raspberry Pi, despite issues like increase in prices of units with lots of RAM (not the fault of Raspberry Pi).

At $80… I can imagine equipping a radio desk with an array of these. Someone’s going to quickly slap this together as an inexpensive alternative to iPads, Android, and ChromeOS tablets.

sBitx Version 5.4 Released: New FM Mode and Major Performance Improvements

D. Prabakaran VU3DXR:

…

Cleaner Signal Processing at the Core

Version 5.4 rebuilds parts of the IQ signal handling that sits at the center of the radio. VFO performance is sharper, the complex mixing stage is more precise, and down-conversion runs cleaner than in earlier builds. Together these changes give a noticeable lift to receive quality, especially when pulling weak signals out of noise. The AGC function and AM detector were also updated so they work smoothly with the new DSP pipeline instead of fighting against it.

FM Mode Joins the Feature List

sBitx now supports narrowband FM, complete with squelch and CTCSS tone support. This opens the door to 10 meter FM operation and transverter setups that were not practical before. Squelch has also been added to AM mode, giving operators one more layer of control over what they hear.

There are a number of other improvements mentioned in this article including Controlled Envelope Single Sideband (CESSB) and

Networking With HPSDR Protocol 1

sBitx 5.4 now streams IQ data over Wi-Fi or Ethernet using HPSDR Protocol 1.

With FM operations on 10m, imagine this mated with a IP400 AMNC for IP400 on 10 meters!

How the U.S. Army Built a Telephone Network Across the Pacific in Just 18 Months — 1944 (YouTube)

Apologies in advance. This is yet another “AI” creation, with the usual bad, almost random visuals. My technique for these is to treat them like a podcast - all the information is in the narration, so I open these in the YouTube app on my phone, close the phone, and continue playing just the audio.

The one value of these “videos” is that they’re surfacing interesting stories about technology developed in World War II that I’ve never heard about, including this one. It’s easy to be jaded about the “old” technology of 80 years ago now, but when you factor in the technology they had to work with in that era… especially vacuum tube electronics and computing power measured in kHz clocks and tens of cubic feet, is pretty impressive.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0259. Paid subscribers can comment directly on the web version of this issue.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

Apologies to Bob Witte K0NR

In Zero Retries 0258, Fixing the US Amateur Radio Licenses, I wrote:

I’m a fan (and former colleague doing volunteer work for ARDC) of Bob Witte K0NR. KONR is thoughtful and articulate, and I follow his postings on his blog K0NR Above Average Terrain. K0NR is one of the Directors of ARDC, thus he has a bit more “pull” in Amateur Radio than most of us, thus even more reason to pay attention to what he’s thinking and writing.

I don’t know how I missed this good article K0NR wrote in 2025, but I only recently saw it - The Case of The Shrinking Technicians. It’s a reasonably qualified (he explains the methodology) dive into actual numbers of US Amateur Radio licensees. When there’s some reasonable methodology being applied, despite the apparent rise in overall number of licensees, K0NR argues that the overall number of licensees is declining.

That article, at least in my mind, feeds into his most recent thinking about the US Amateur Radio Technician License - How to Fix the Technician License.

This last paragraph:

Basically… (apologies for oversimplification), K0NR proposes tinkering a bit about the privileges of the Technician class license to “get a taste” of HF operation.

… was a lazy shortcut for what K0NR actually said.

In an email response, K0NR said:

Actually, I proposed a more streamlined VHF/UHF-only version of the Technician license, tagging it the Communicator license. I proposed to lower the barrier of entry for the beginner. The key argument is to create a better on-ramp for folks wanting to get involved in ham radio. Then a number of the commenters said that the real solution was to give beginners more HF privileges, not take them away. Their argument is to include HF privileges (for Technicians) to KEEP new hams on board. I see some merit in this approach, which is close to what you proposed with the two tier licensing: Standard and Extra.

Recall that there is a proposal before the FCC (from 2018 !!!), just laying there in some filing cabinet or server, that would open up HF for Technicians.
See https://www.arrl.org/Technicianenhancement

My apologies to K0NR for my lazy shortcut, and my thanks to him for the graceful and thoughtful followup.

Brian Webster N2KGC is the Newest Zero Retries Pseudostaffer

It’s a long overdue “Honor” to award Brian Webster N2KGC the Exalted Title of…

Zero Retries Pseudostaffer!

Pseudostaffers are those who are fans of Zero Retries and support Zero Retries in many and varied ways - well beyond the occasional comment.

N2KGC is a careful and thoughtful reader of Zero Retries and frequently provides insightful comments. N2KGC is one of the few folks in the Zero Retries readership that are both as long experienced as I am in the glory days of AX.25 Packet Radio and willing to write and comment about it to me to support good coverage of AX.25 Packet Radio in Zero Retries.

Thanks Brian! Your Pseudostaffer badge will soon be on order and on the way.

ZRDC 2026 Ho!

Zero Retries Digital Conference (ZRDC) 2026 will be here before we (I) know it.

10 weeks until Zero Retries Digital Conference 2026

on Friday, October 16, 2026,

in San Ramon, California, USA.

Starlink Is Merely Five Years Old

I’ve been doing a behind the scenes project of creating indexes for each year of Zero Retries. As I write this I’ve been working on “Year 0” - 2021 (now complete!) , and I came across this item in Zero Retries 0018 (2021-11-12) - Starlink Quietly Slips out of Beta Testing. It struck me that we had Plain Old Telephone Service for, what, at least fifty years before we considered it commonplace? Internet for twenty years before we considered that commonplace? Cellular - ten years?

Starlink… a mere five years? What’s astonishing to me is that Starlink has so much capacity that it’s being used as infrastructure for other telecommunications system. I’ve read that it’s now being used as backhaul communications for isolated villages that had been using (very expensive and not very good) Geosynchronous Earth Orbit satellite links as backhaul. With Starlink, these backhaul links are faster, have much lower latency, and much cheaper. The same for remote construction sites, islands that aren’t served by undersea cables, not to mention vessels, airplanes (even private planes), even vehicles that are doing cross country road trips to avoid the dead zones (even on major highways) of cellular coverage.

My favorite Starlink story is a dad that loved to go boating on the weekends but had trouble talking the family into coming along because the teenagers hated not having connectivity after the boat went out of (terrestrial) cellular coverage. But as soon as he installed Starlink on his boat… no problem with the teenagers, because Starlink provided full connectivity and the teenagers were no longer out of connectivity for hours.

Now… it’s not unheard of to bring a Starlink Mini on a hiking trip11, especially as part of a group so everyone can check in with the loved ones, and keep up with sports and emails, and (if you have enough power), stream a movie for the evening’s entertainment. Oh, and of course, share out the day’s selfies and scenery photos.

It seems like there’s even going to be a Mini 2, which will (reported) include a built-in battery. See ZR > BEACON - Starlink Mini 2 Will Have a Built In Battery (Rumored) in this issue.

KB6NU Nice Mention of Zero Retries Email List Discussion About US Licensing Revisions

One lump or two (or three)? - Dan Romanchik KB6NU gives a nice shoutout to a one of the most vigorous discussions on the Zero Retries email list:

Steve, N8GNJ, the fellow behind the Zero Retries newsletter, is trying to re-ignite this debate.

(By the way, if you haven’t already subscribed to Zero Retries, you really should, at least if you’re concerned about the future of the hobby. Despite the way he capitalizes “Amateur Radio,” a la the ARRL, it’s well worth reading. And, it’s completely free, although Steve is very happy to accept donations.)

In issue #258, N8GNJ published an article titled, “Fixing the US Amateur Radio Licenses.” The article, which references a blog post by Bob, K0NR titled “How to Fix the Technician License,” In it, he says that many new hams aren’t all that interested in HF, and consider the current license structure, which is a holdover from the old incentive licensing days, to be a disincentive for upgrading only to obtain more HF privileges. He says that the current licensing structure, “smacks of gamesmanship / hoop jumping / jerking them around, and simply, [new hams that Steve calls “new tech hams] have no patience for such things.” I think that he’s right, up to a point, about this.

Steve proposes that we combine the US Amateur Radio Technician and General Licenses into a single license that has all the privileges of the current General Class license and to promote all of the current Techs to this Standard Class. He would make the test for this Standard Class a bit more challenging technically, adding questions about digital technology and software-defined radio, topics which he feels are more relevant than “arcane radio circuits or formulas that aren’t necessary to operate with current off-the-shelf equipment.”

This article has started an interesting discussion on the ZeroRetries discussion group. There, the idea of a two-tier license structure is quite popular, although the form of that structure varies from person to person.

Several advocate for just a single license class and test. I’m not sure that’s a good idea, as you’d have to make that test quite difficult, and that would discourage many people. One fellow suggested a single class of license with endorsements for things such as “VE/VEC stuff, spread-spectrum operation, high-power operation, encryption, and Operational Compliance Observer (Radio Police).”

KB6NU is a thought leader in Amateur Radio, and one of the few who has the courage to be outspoken about Amateur Radio and its many structural issues. KB6NU is a regular (and early!) source of inspiration for Zero Retries and is one of the Zero Retries Pseudostaffers.

I Missed Open Sauce 2026 and Teardown 2026

Open Sauce 2026 was 2026-07-17 thru 19 at the San Mateo County Event Center in the San Francisco Bay Area, California. It looks like about as much fun as an adult (or young) techie can have, amongst hundreds of like-minded exhibitors and thousands of appreciative fellow fans. Open Sauce seems to me to be the white-hot center of the Maker movement and where techies-for-fun go to seek inspiration (and inspire) their peeps. It seems to have eclipsed Maker Faire and even Burning Man. With family commitments, it just wasn’t possible to attend Open Sauce 2026… but wow, I wanted to. To get a flavor of Open Sauce 2026, there’s ample YouTube videos.

Teardown 2026, sponsored by Crowd Supply, was 2026-07-24 thru 26 in Portland, Oregon was a very near miss for me. We had a family event planned for that same weekend. If not for that, attending Teardown 2026 in nearby Portland would have been a slam dunk. One of the highlights would have been seeing QuadRF there… and asking lots of questions.

Maybe 2027…

Summer Doldrums in Zero Retries Interesting Hamisphere?

I had to add this last bit. I really thought that “things would slow down” this summer in the Zero Retries Hamisphere. There was nothing (that I knew of) trending that was going to be significantly disruptive. That is, until about six weeks ago when Martin Alcock VE6VH got back in touch and began teasing about “something interesting” in IP400, and would I like to be the first to write about it? I had some inkling about OFDM-AB, but had no idea, until the past week, about the IP400 Advanced Mesh Network Controller (AMNC).

All of the sudden… all my expectations and outlook on Amateur Radio networking have been completely reset… and supercharged. I really can’t wait to get my hands on some AMNCs and begin experimenting in N8GNJ / Zero Retries Labs and perhaps seed some of my local co-conspirators with plug and play units for some actual beyond-the-lab experiments.

Weekends Are For Amateur Radio!

Good weather this weekend, and no major conflicting commitments for the moment, so perhaps there will be time spent in N8GNJ / Zero Retries Labs.

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR02592. Paid subscribers can comment directly on the web version of this issue.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

Founding Members who generously support Zero Retries financially:
Founding Member 0000 - Steven Davidson K3FZT (Renewed 2026, 4th year!)
Founding Member 0001 - Randy Smith WU2S (Renewed 2025, 3rd year!)
Founding Member 0002 - Chris Osburn KD7DVD (Renewed 2026, 4th year!)
Founding Member 0003 - Don Rotolo N2IRZ (Renewed 2026, 4th year!)
Founding Member 0004 - William Arcand W1WRA (Renewed 2025, 3rd year!)
Founding Member 0005 - Ben Kuhn KU0HN (Renewed 2025, 3rd year!)
Founding Member 0006 - Todd Willey KQ4FID (Renewed 2025, 3rd year!)
Founding Member 0007 and 0010 - Merik Karman VK1DF / VK2MKZ (Renewed 2025 x2, 3rd year!)
Founding Member 0008 - Prefers To Remain Anonymous 08 (Renewed 2025, 3rd year!)
Founding Member 0009 - Prefers To Remain Anonymous 19 (Renewed 2025, 2nd year!)
Founding Member 0011 - Rick Prelinger W6XBE (Renewed 2025, 2nd year!)
Founding Member 0012 - Ryan Tolboom N2BP (Renewed 2025, 2nd year!)
Founding Member 0013 - Newton White N4EWT (Renewed 2026, 2nd year!)
Founding Member 0014 - Joe Hamelin W7COM (Renewed 2026, 2nd year!)
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Founding Member 0024 - Rob Bowser (SPOOLTENNA) (New 2026)
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The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries | Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0259 was published on 2026-08-07. This issue was 11,053 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

The Zero Retries email subscriber count continues to increment, despite multiple “unsubscribes” that follow the publication of every issue. Zero Retries isn’t for everyone.

2

Lone Node Problem - Purchasing and putting one node of a new system does not a network make.

3

Credit is owed to VARA FM for proving out the use of OFDM in VHF / UHF FM radios in the audio path of the radio.

4

Flat audio connections bypass the (microphone) voice pre-emphasis and (speaker) de-emphasis circuits in a radio that enhance voice, but distort data.

5

I often cite the (out of production) Kenwood TM-V71A as a representative “data” radio with flat audio connections because it is one of the most widely used Amateur Radio units used for data. It’s my favorite “data” radio.

6

CTCSS - Continuous Tone Coded Squelch System - subaudible tones added to the transmitted signal to access a specific repeater when there are other repeaters on the same frequency. Often referred to as “PL” - Private Line, Motorola’s (formerly) trademarked term for CTCSS, now in general use.

7

I think… This is entirely my opinion, and I’m not speaking for ARDC with this opinion (nor do they speak for me).

8

Big heatsink versus small heatsink + fan - I admire Yaesu for doing this and have a preference for Yaesu radios for data use because of this.

9

For a 12 volt adapter for the Starlink Mini, I strongly recommend buying Starlink’s 12 volt adapter for Starlink Mini. I’ve read of some bad experiences using the units on Amazon.

10

Except perhaps Iridium, which was born in the 20th century.

11

Taking a Starlink Mini on hiking or camping trips. Yes, there are lots of folks, perhaps even the majority, who view hiking or camping trips as a way to get away from always-on connectivity. Understood… but some of us would rather at least have the option of having connectivity.

]]><![CDATA[Zero Retries 0258]]>https://www.zeroretries.org/p/zero-retries-0258https://www.zeroretries.org/p/zero-retries-0258Sat, 25 Jul 2026 06:55:41 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its sixth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is likely to be truncated by some email clients. Thus, it might be easier to read in a web browser - www.zeroretries.org/p/zero-retries-0258.

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In This Issue:

I-Frame

ZRDC 2026 Registration Now Open
Tina Stroh KD7WSF

Zero Retries Digital Conference (ZRDC) 2026 Call For Papers is Now Open
Donald Rotolo N2IRZ

What’s New at Digital Library of Amateur Radio & Communications — July 2026
Kay Savetz K6KJN

What’s New with New Packet Radio, Next Generation (NPR-NG)?
Steve Stroh N8GNJ

Fixing the US Amateur Radio Licenses
Steve Stroh N8GNJ

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

Comments on This Issue (Redirects to Comments Page)

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Eric Stammers M0REQ for renewing as an Annual Paid Subscriber (3rd year!) to Zero Retries these past two weeks!

My thanks to Rick Gilmore W3TM for renewing as an Annual Paid Subscriber (3rd year!) to Zero Retries these past two weeks!

My thanks to Scott Honaker N7SS for renewing as an Annual Paid Subscriber (3rd year!) to Zero Retries these past two weeks!

My thanks to Chuck Till K4RGN for renewing as an Annual Paid Subscriber to Zero Retries these past two weeks!

My thanks to Stuart Whiting WS7SW for renewing as an Annual Paid Subscriber to Zero Retries these past two weeks!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Zero Retries Summer 2026 Publishing Schedule - Biweekly

During Summer 2026, Zero Retries will be published biweekly. The intended publication schedule for the remainder of Summer 2026 is:

  • Zero Retries 0258 - 2026-07-24

  • Zero Retries 0259 - 2026-08-07

  • Zero Retries 0260 - 2026-08-21

  • Zero Retries 0261 - 2026-09-04

There may be some special, focused issues interspersed between the scheduled issues, such as a special issue about Zero Retries Digital Conference (ZRDC) 2026.

After ZR 0261 / 2026-09-04… to be determined.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0258. Paid subscribers can comment directly on the web version of this issue.

ZRDC 2026 Registration Now Open

By Tina Stroh KD7WSF
Zero Retries Digital Conference Manager

Click here to register for ZRDC 2026

We are excited to announce the registration for our second Zero Retries Digital Conference (ZRDC 2026) is now open! This year’s conference will bring together Hams and people interested in the technological innovations in Amateur Radio to explore and listen to expert speakers, regarding various topics pertinent to digital communications. Attendees will have the opportunity to participate in engaging sessions, and connect with colleagues from across the industry. In the next few weeks, we will be compiling our list of speakers and will update that list in Zero Retries weekly until the roster is complete.

Registration will again offer in-person access and virtual attendance options to attend the conference. Ticket price descriptions state what is included with each level of participation. Such as, in-person attendance includes access to the conference along with conference proceedings, welcome refreshments, and a chance to win door prizes. Throughout the day, coffee service, lemonade and fruit infused water will be available. There are several food options for purchase at the conference center.

Whether you’re looking to gain new insights, share ideas, or expand your professional network, this conference offers valuable opportunities for everyone. We encourage you to reserve your spot early.

We look forward to welcoming you to another successful year of learning, collaboration, and innovation!

ZRDC 2026 will be held on Friday, October 16th, 2026 at the Roundhouse Conference Center in San Ramon, California. This venue is on the back side of the San Ramon Marriott Hotel where the 2026 Pacificon Conference will the held the same weekend. Pacificon will be held Friday, October 16 through Sunday, October 18th and is one of the largest conferences on the West Coast. Friday, October 16th is the only day the conferences will overlap.

While ZRDC 2026 and Pacificon 2026 are being held the same weekend and in very close proximity, they are two separate events. Please see the links to each event and consider attending both events.

The most current information about ZRDC 2026 can be found at www.zeroretries.org/p/conference (or the Conference link on the top bar of the Zero Retries page).

Please share this information about ZRDC 2026 to your friends that are interested in Zero Retries Interesting subjects.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0258. Paid subscribers can comment directly on the web version of this issue.

Zero Retries Digital Conference (ZRDC) 2026 Call For Papers is Now Open

By Donald Rotolo N2IRZ

Technical papers are sought for the Proceedings of the (second annual) Zero Retries Digital Conference (ZRDC) 2026, to be held at the Roundhouse Conference Center in San Ramon, California, USA on Friday, October 16, 2026. This coincides with the first day of Pacificon 2026.

ZRDC 2026 is being hosted by the Zero Retries newsletter. Papers will be published in the Conference Proceedings of the ZRDC. Authors do not need to present at the conference to have their papers included in the Proceedings, although presenters are highly encouraged to submit a separate technical paper (for the Proceedings). All presenter presentations will also be published in the Proceedings.

A typical technical paper for ZRDC is a short (typically 5-10 pages) but in-depth explanation of a project, experiment, or new technique. A technical paper typically includes the problem(s) to be solved and how the solution was built and tested, and what was learned. Diagrams, data, and code are often included. The intended audience for technical papers are not just the attendees of a particular ZRDC - they’re intended to help others implement or enhance the subject of the technical paper.

A ZRDC technical paper is different from a presentation slide deck:

  • A technical paper is self-contained - all of the needed detail is in the text of the technical paper. A presentation slide deck provides speaking points - the detail is in the presentation narration.

  • A technical paper explains the idea in depth for the long term. A presentation slide deck is a “snapshot” of an idea at that moment in time.

  • Very generally, a technical paper explains the details of how you did something. A presentation slide deck explains (generally) what you did to expose the idea to those who aren’t familiar.

ZRDC 2026 Paper Submission Details

  • Paper submission deadline is Monday, September 28, 2026 23:59 UTC. Submissions received after this date will not appear in the Proceedings.

  • Submit papers via email to zrdcpapers@zeroretries.net

  • Papers must be submitted as a .PDF format, with sufficient resolution for print publication. (Export or Save As… PDF).

  • It is requested that ZRDC papers not use inline web hyperlinks. (Hyperlinks often do not persist through format changes.) In lieu of inline web hyperlinks, simply type out the full URL of the link. For longer URLs, please use footnotes with the full URL in the footnote.

  • Papers will be published exactly as submitted.

  • Paper authors retain all rights.

  • Papers with multiple authors are encouraged.

  • Papers are limited to 12 pages (letter-size).

  • In addition to ZRDC archives, ZRDC technical papers will be archived for posterity in the Digital Library of Amateur Radio & Communications (DLARC), a project of the Internet Archive.

Technical paper topic areas include, but are not limited to digital radio, radio networking, mesh networks over radio, Software Defined Radio (SDR), digital voice/data systems, digital satellite communication, use of LoRa in Amateur Radio, digital signal processing (DSP), HF digital modes, Spectrum Management, Global Positioning System (GPS), Automatic Packet Reporting System (APRS), Linux in Amateur Radio, AX.25 and other protocols, mesh and peer-to-peer wireless networking, emergency and homeland defense backup digital communications in Amateur Radio.

Please share this info to your “Zero Retries” folks that are working on relevant projects, products, and technologies, software, etc. If you have a favorite vendor that is doing Zero Retries Interesting things, perhaps encourage them to submit a paper. A PDF version is included below for easy sharing.

Call For ZRDC 2026 Papers Final
112KB ∙ PDF file
Download
Initial announcement of Call for Papers for Zero Retries Digital Conference 2026.
Download

If you’d like to include this announcement in a newsletter, news release, etc., an .RTF and a .TXT version (for easier copy and paste) is available on the ZRDC page.

The latest information on ZRDC 2026 will be maintained at www.zeroretries.org/p/conference, or just click the Conference link on the top bar of the Zero Retries web page (https://www.zeroretries.org/).

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0258. Paid subscribers can comment directly on the web version of this issue.

What’s New at Digital Library of Amateur Radio & Communications — July 2026

By Kay Savetz K6KJN

Greetings from DLARC World Headquarters, where it’s 99 degrees and there’s a heat advisory: perfect weather for staying inside to play with computers and radios. But — oh no, when you’re cozy and cool indoors, you can’t look up to see the satellites.

DLARC has significantly expanded the AMSAT Symposium archive, adding about 250 new items from AMSAT Space Symposium events. Newly archived material includes audio recordings of the 2007-2008 presentations, matching slide decks, photo albums, and video clips, from 2013-2020, AMSAT-NA proceedings for 2013-2019, and a full set of 2025 symposium papers, slides, and videos.

Especially valuable are the 2007 and 2008 symposium materials, which preserve the talks as they were distributed on AMSAT’s conference DVDs: audio recordings, slide decks, photos, video clips, and schedules. These include presentations on AO-51, ARISS, Eagle, SuitSat-2, digital signal processing, satellite telemetry, CubeSat education, and the state of amateur satellite engineering in the late 2000s.

Bonus: we’ve added the contents of a 2002 ARISS CD-ROM, produced when ARISS was operating under AMSAT, with presentations, ISS and equipment photos, QSL card images, and video of antenna installation and school-contact activity.

Big news: the Manuals Plus project is done. Like, done done, put a bow on it. This massive manual scanning project started more than a decade ago, in 2015 when a company called Manuals Plus went out of business and donated pallets of rare manuals to Internet Archive. Then, a couple of years ago, DLARC scanned four pallets of the radio-related manuals. In September 2025, I announced in this space that we were back for another bite of the apple, with nine more pallets of tech manuals going to the scanning center. There was no way to know ahead of time what products the manuals were for: some would be for radio-related equipment, some wouldn’t. Internet Archive scanned it all, then we separated out the material relevant for DLARC. More than 10,600 manuals were deemed “DLARC-worthy” out of a total collection of 13,046 manuals. You’ll find manuals for rare amplifiers, radios, and all sorts of tools and test equipment. My colleague Jason Scott wrote a blog post titled Manuals Plus: The Wrap-Up that nicely summarizes the whole adventure.

More big news: the DLARC Software collection is expanding! I’ve been on a source code scavenger hunt, finding and archiving historical releases of important amateur-radio software projects. I’ve concentrated on self-contained release tarballs and ZIP files—the source packages people could actually download and build at the time. Some were waiting patiently on old FTP servers. Others were scattered among SourceForge, Debian Snapshot, the Wayback Machine, dusty mirrors, and personal archives.

The heavyweight is the W1HKJ/fldigi family: 184 source archives covering 17 related digital-mode, messaging, file-transfer, logging, and rig-control programs. The collection follows fldigi back to version 1.30 in 2007, filling the early years with tarballs preserved by Debian and continuing through the surviving W1HKJ and SourceForge archives. And there’s Xastir, the APRS mapping and communication program, which uncovered more than 160 source packages beginning in 2002. The early developers released snapshots at a furious pace (sometimes several in a month), so the collection preserves major milestones and also small steps in the program’s evolution.

WSJT and WSJT-X, Joe Taylor K1JT’s family of programs for extremely weak-signal communication, including meteor scatter, Earth-Moon-Earth, and FT8, are represented by 53 source archives, tracing the software from its beginnings in 2005 through present-day WSJT-X.

I’ve also archived source code for Gpredict, a satellite-tracking and orbit-prediction program; Hamlib, the common rig- and rotator-control library used by scores of ham-radio applications; PREDICT, the veteran satellite-tracking and antenna-control program; LinFBB, a packet-radio BBS and message-forwarding system; Thomas Sailer’s Soundmodem, which turns a computer sound card into a packet-radio modem; and the unixcw and cwdaemon Morse-code tools.

Each item includes a chronology, source URLs, and notes explaining gaps, duplicate versions, historical mirrors, and anything DLARC had to reconstruct from an official source tree. I’ll continue these source code scavenger hunts to grow the software collection in the coming months.

On to newsletters! We’ve scanned 40 issues of Cornell-Dubilier Capacitor, which was a technical/service newsletter for the radio and TV repair trade. Cornell-Dubilier, a capacitor manufacturer, began in 1933 when two companies, Dubilier and Cornell Radio, merged. The Capacitor was published from 1937 through 1964.

More club recent reading fare: 146 issues of K9YA Telegraph, the publication of the Robert F. Heytow Memorial Radio Club, based in Skokie, Illinois. The newsletter, spanning 2004-2018, emphasizes Morse code, CW operating, and radio history. And, 142 issues of the Sierra Nevada Amateur Radio Society “Cracklin’ Static” Newsletter. And also, Skywaves, the newsletter of the Sachse Amateur Radio Association, a ham club in Sachse, Texas. We’ve also added 40 issues of QTC Magazine, the publication of the Radio Amateur Society of Australia, from 2020 to the present.

Finally, DLARC has also adopted the SatNOGS collection: observation audio data from SatNOGS, the Distributed Network of Satellite Ground Stations. SatNOGS ground stations observe and receive satellite signals, particularly low-Earth-orbit CubeSats. Initially, SatNOGS focused on retrieving signals from LEO satellites in UHF and VHF bands. Now, SatNOGS is able to retrieve status and telemetry signals, data transmitted by experiments from scientific and research satellites, weather data, and more. The group has been uploading daily observation data since 2021, and now that data has a home in DLARC. More information about the project is at satnogs.org.

Digital Library of Amateur Radio & Communications is funded by a generous grant from Amateur Radio Digital Communications (ARDC) to create a free digital library for the radio community, researchers, educators, and students. If you have questions about the project or material to contribute, contact me at kay@archive.org.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0258. Paid subscribers can comment directly on the web version of this issue.

What’s New with New Packet Radio, Next Generation (NPR-NG)?

By Steve Stroh N8GNJ

Because this is a YouTube “Short”, I’m unable to include it in the Zero Retries YouTube channel playlists, and a lot of the usual amenities of YouTube, such as Substack’s embed a YouTube video feature, aren’t available. Unless you’re a follower of ARDC on YouTube (www.youtube.com/@ardc73) or the algorithm presents it to you (as it did me), you’re likely to miss this video.

This news is easily the fourth1 most Zero Retries Interesting development of 2026 (to date). The title link is to a YouTube video Short posted by ARDC (Thank You, whoever did that interview) is the first inkling I’ve seen about “New Packet Radio - Next Generation”. This interview at HAM RADIO 2026 is with Steffen Heuel DO5DSH of Localino about NPR 3.0 (briefly) and then launches into a discussion of NPR-NG.

I like to think I’m “on top of things” with all things data communications in Amateur Radio… but clearly, I’m not because I had no hint of this, and saw no other mentions of this development other than this video.

NPR-NG is a follow-on to NPR 3.0, which is now available as an assembled and tested series of radios from Localino for 2m, 70cm, and 23cm. Here are the impressive features of NPR-NG as explained by DO5DSH:

  • Will operate on 70cm,

  • Uses OFDM,

  • Modulation index is 64 QAM,

  • Minimum bandwidth is 1 MHz,

  • Data rate is 3.2 Mbps,

  • Operating system is OpenWRT

  • Form factor is a Raspberry Pi HAT

Although NPR-NG is not yet a product, Localino has a great track record with their improved versions of the original NPR, and creating the NPR 3.0 products. The prototype shown has a separate Receive input and Transmit output. D05DSH says future work to be done is:

  • Combiner added for a single Receive and Transmit connector,

  • Add a linear amplifier for higher transmit power,

  • Firmware improvements.

One interesting aspect of NPR-NG is that there was no mention of backwards compatibility with NPR / NPR 3.0. Thus it seems likely that NPR-NG will be a completely new version of (fork?) of NPR.

Another interesting aspect of NPR-NG is that it will be based on OpenWRT. That’s very interesting from the networking perspective because the mature and proven AREDN networking software is also based on OpenWRT. Thus instead of the limited number of nodes that could interoperate in “classic” NPR and NPR 3.0, potentially AREDN networking could make use of 420 - 450 MHz / 70 cm using its robust capabilities to manage many nodes in a network. At 3.2 Mbps, AREDN’s implementation of Babel mesh networking at the beginning of 2026 should operate well with a (potential) “AREDN NPR-NG”.

But… a bummer aspect about NPR-NG for US VHF / UHF data communications experimenters / network builders is that NPR-NG is a complete non-starter for US Amateur Radio Operators. Current US Part 97 Amateur Radio regulations limit the maximum bandwidth of data communications on the US 420-450 / 70 cm band to 100 kHz. Absent such an update of the US Amateur Radio regulations, the only possibility for use of NPR-NG would be an FCC Special Temporary Authority or a Part 5 Experimental License. Applying for those isn’t really feasible until NPR-NG is actually a product that US Amateur Radio Operators could buy… but not be allowed to use in the US.

Postscript

After I finished this article, I reached out to D05DSH and I hope to have some followup from him in a future issue of Zero Retries.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0258. Paid subscribers can comment directly on the web version of this issue.

Fixing the US Amateur Radio Licenses

By Steve Stroh N8GNJ

I’m a fan (and former colleague doing volunteer work for ARDC) of Bob Witte K0NR. KONR is thoughtful and articulate, and I follow his postings on his blog K0NR Above Average Terrain. K0NR is one of the Directors of ARDC, thus he has a bit more “pull” in Amateur Radio than most of us, thus even more reason to pay attention to what he’s thinking and writing.

I don’t know how I missed this good article K0NR wrote in 2025, but I only recently saw it - The Case of The Shrinking Technicians. It’s a reasonably qualified (he explains the methodology) dive into actual numbers of US Amateur Radio licensees. When there’s some reasonable methodology being applied, despite the apparent rise in overall number of licensees, K0NR argues that the overall number of licensees is declining.

That article, at least in my mind, feeds into his most recent thinking about the US Amateur Radio Technician License - How to Fix the Technician License.

Basically… (apologies for oversimplification), K0NR proposes tinkering a bit about the privileges of the Technician class license to “get a taste” of HF operation.

I disagree.

What I’m seeing in the readership of Zero Retries and the NewTechHams that I’m continually encountering is that their interest is mostly in VHF / UHF operation… not HF.

When I’ve discussed HF with NewTechHams that I meet, and mention that they can do interesting things on HF if they “upgrade” to a General class license, the typical response is a variation that I’m talking about a “bait and switch” maneuver. They were encouraged to “get their Amateur Radio license”. And they did! And now, they’re being told, in effect, “well… you didn’t get the good Amateur Radio license”.

With such proposals as “more incentivized licensing” and the reforms that K0NR advocates, what my generation of Amateur Radio Operators just doesn’t seem to get is that there is not a generational “divide” between them and NewTechHams…

There’s a generational chasm. And it’s all about digital / data operation.

A Technician class licensee “venturing into HF” with the ability to operate only CW or a few tiny slivers of HF (such as 10 meters) with voice… is not an “incentive” in 2026. It’s the opposite - it’s a disincentive.

If Amateur Radio writ large wants to increase the number of Amateur Radio Operators operating on the HF bands… then just make it feasible for Technicians to use the HF bands. The current incentive license structure, to this generation, smacks of gamesmanship / hoop jumping / jerking them around, and simply, they have no patience for such things. NewTechHams want to dive in and get on with it. To them, Amateur Radio isn’t a long-term commitment or a lifestyle. It’s an activity that is either quickly engaging and satisfying, or it isn’t.

That Amateur Radio doesn’t prove to be engaging and satisfying because if you’re not a NewTechHam, just an average person who was encouraged to get an Amateur Radio license “to be prepared for emergencies”, you learn enough, pass the test, get the license, buy the portable, try to use it and are generally disappointed (quiet repeaters, poor performance of a portable indoors when accessing a repeater, etc.). The verdict of Amateur Radio from that experience - Meh. I think that experience chain is the primary reason for the decline of Techs licensees discussed in the first K0NR article.

NewTechHams are proving willing to give Amateur Radio a try. They’re getting licensed. As evidenced in the pages of Zero Retries, they’re doing lots of interesting technical experimentation and operation (building networks, developing Software Defined Radio, etc.)

To me, the really damning aspect of this “divide” is that HF can indeed be a lot of fun, especially now that we have engaging new generations of HF radios. My former “most fun HF radio” was the HF Signals zBitx. That had some first generational problems, but those seem to be ironed out with zBitx v2. But the now favorite “most fun HF radio” is the Pebble HF, with the price goal of $50.

Image courtesy of Pebble HF

Darn if that thing is cute! From my reading, t’s developed a good reputation and that seems to be borne out by it being currently unobtanium. If you weren’t in on the crowdfunding campaign (as I wasn’t), apparently we’re in for a long wait. But I’m willing to do that because I want to play with one and take it with me and do some HF operating (digital modes, of course) outdoors away from home.

But again, the damning thing is that the Technician class licensees (that, again, in good faith, jumped through the hoops and got their Amateur Radio license…) only to be told that they can’t do the cool stuff like use a Pebble HF on the 20m HF band.

And that leaves a sour taste. Bait and switch. Hoop jumping.

And for what?!?!?! Answering a few more questions that are mildly more technical on to “qualify” you for a General license?

Here’s my proposal to “fix” Amateur Radio licensing. It’s so laughably simple it couldn’t possible get past the powers that be in Amateur Radio to get passed along to the FCC (which, I believe would say “Fine… whatever.”):

  • Combine the US Amateur Radio Technician and General Licenses into a single license.

  • Call it the Standard license (to differentiate it from the Extra license, which is unchanged).

  • Don’t take away any of the capabilities of the General license.

  • Promote all current Amateur Radio Technician licensees into the same privileges as General licensees.

  • Make the test a bit more challenging with a bit more technical knowledge required - mostly digital technology / SDR which is more relevant than arcane radio circuits or formulas that aren’t necessary to operate with current off-the-shelf equipment.

In summary, if we in US Amateur Radio really want to “fix” Amateur Radio and get more activity from younger folks and newer Amateur Radio Operators… and make Amateur Radio interesting enough to retain them… then we have to stop tinkering / dinking around at the margins and make an Amateur Radio license appear relevant to the current generation.

And… um… we need to finish fixing VHF / UHF bands by removing the symbol rate limitations and maximum bandwidth limitations.

And… we really need to make some changes to accommodate encryption in some commonsense meaningful way like Amateur Radio in Canada has done. Every time you see an https:// in a web browser page that has transited an Amateur Radio link, that’s encryption (and it happens all the time).

For another perspective on this issue, Jeff Davis KE9V has (as usual) a unique perspective, eloquently expressed: FT8 Is a Fad, and Other Heresies.

My thanks, again, to K0NR for some great food for thought.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0258. Paid subscribers can comment directly on the web version of this issue.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

MODEM73

From the web page:

MODEM73 is an open source software modem that works with any HF, VHF, or UHF radio capable of 2400 Hz of bandwidth.

From the GitHub page:

MODEM73 is an open source software modem that works with any HF, VHF, or UHF radio capable of 2400 Hz of bandwidth. All you need is a sound card and audio cable for your radio.

SSB, AM, and FM are all supported. It’s plug and play compatible with any KISS application and works with rigctl, CM108 sound devices, and serial PTT out of the box.

There are three modem families each suited for covering any possible RF setup from clean line of sight FM links to poor HF band conditions. The receiver decodes all of them at the same time, so one station can hear anything another station sends without switching modes.

OFDM, based on the open source COFDMTV modem developed by Ahmet Inan / aicodix GmbH. Modulations from BPSK to QAM4096 with code rates from 1/4 to 5/6 and payloads from 256 to 6144 bytes per frame. Rates run from about 790 bits per second to over 13 kilobits per second in the same 2400 Hz.

ROBUST, a set of slow modes built for fading HF paths such as 40 and 80 meter NVIS. Five modes from 1150 bps down to 149 bps in either 2400 Hz or a 600 Hz narrow variant

MFSK, a non-coherent mode for weak signal propagation and backup links.

Features

  • KISS over TCP so it works with anything that speaks KISS: APRS clients, HamIRC, packet BBS software, Reticulum, custom applications

  • JSON control port API for status and configuration for writing your own programs

  • lightweight UI that runs straight from the terminal and headless mode for embedded use

…

Want to try out a demo of modem73 directly from your browser? Try it out here: https://rfnexus.github.io/modem73-wasm-demo/ Hit “Start microphone” to begin decoding.

I was alerted to MODEM 73 by Georges Auberger WH6AZ who commented:

Looks very promising. The design seems very clean to expose the modem as a service layer. While it does not handle adaptive rate itself, it should allow the app to do it on its own.

I agree. We just keep getting better and better options for digital communications in Amateur Radio as the “software folks” apply better software / signal processing technology on the increasingly capable computer hardware we have access to… like Raspberry Pi 5 and the current generation of mobile phones (aka pocket supercomputers).

Mercury v1.9.10 Released

Pedro Messetti on the hermes-general email list:

We are happy to announce Mercury v1.9.10.

Highlights:

New graphical UI
- Brand-new cross-platform GUI ("Mercury Modem", Fyne-based) embedding
the modem engine (no separate processes needed)
- Self-contained universal macOS .app/.dmg (Intel + Apple Silicon)
- New mercury-ui Debian package
- Windows installer (Mercury_1.9.10_Setup.exe) available for all Windows
users

Modem and ARQ:
- New robust modes: DATAC15/DATAC16, plus DATAC17 and QAM16C2, extending
the adaptive ladder to 6 levels (DATA payload up to 2047 bytes)
- Outer-loop link adaptation (OLLA): SNR + delivery-feedback
gear-shifting, tuned for asymmetric links
- HARQ Chase soft-combining on data modes
- Channel-busy detector with VARA-compatible BUSY ON/OFF reporting
- ARQ timing constants now tunable via mercury.ini
- Many robustness fixes: turn-coordination and TX-ring deadlocks,
fade-cliff stall, last-frame loss on disconnect, ACCEPTING linger

Compatibility and Audio:
- Hamlib 5.0.0 compatibility
- Polyphase FIR resampler (fixes TX clicks), support for
16-bit/mono-only sound cards, ALSA capture wedge recovery

Download Windows installer (still not signed but we are working on it):
https://github.com/Rhizomatica/mercury/releases/download/v1.9.10/Mercury_1.9.10_Setup.exe

Windows binary and Debian packages available.

MacOS release is coming soon.

Full changelog:
https://github.com/Rhizomatica/mercury/compare/v1.9.9...v1.9.10

Thanks to everyone who contributed, tested and reported issues.

Please support the ongoing development of Mercury HF modem:
<https://www.paypal.com/donate/?hosted_button_id=EKY4LRAH64Z9S>

The general release of Mercury is one of the most Zero Retries Exciting developments of technological innovation in Amateur Radio in 2026. The GUI and additional modes are especially exciting in this release.

RadioMail 1.6 - The “Freedom HF modem” Release

I’m happy to announce that RadioMail 1.6 is now available on the App Store.

This release focuses on bug fixes and quality-of-life improvements. One of the biggest usability improvements is bulk message editing. You can now select multiple messages, or select all, to move or delete in one step.

There’s also experimental emoji support. Winlink is limited to the ISO-8859-1 character set, so emojis can’t be transmitted directly. They do display correctly between RadioMail users though. Not exactly standards compliant, but good enough to have a little fun 🤪. Who knows, maybe other Winlink clients will adopt it too. Here’s the supported emoji mapping.

The biggest addition is a built-in ARDOP modem for HF. Supported sound card interfaces include:

  • Digirig Lite

  • AIOC (All-In-One Cable)

  • ICOM IC-705 (USB audio with Bluetooth CAT control)

This is the first HF software modem integrated directly into RadioMail. Along with packet, there are now two open standards for connecting and exchanging email over radio. I’m committed to adding more open modes over time so we can eliminate unnecessary dependencies on external hardware.

This release also includes significant internal refactoring to address changes introduced in the upcoming iOS/iPadOS 27 that were causing crashes. Hopefully there won’t be any further breaking changes before iOS 27 is released later this year.

If you plan to upgrade to iOS 27, you’ll need RadioMail 1.6.

Update on RadioMail 2.0

RadioMail 2.0 will be released as a new app rather than an update to the 1.x series.

The scope of the changes made this the right time for a clean break from the original codebase, provides a stronger foundation for future development. It also gives me the freedom to simplify the user experience by retiring features without taking anything away from existing users.

When RadioMail 2.0 is released later this year, RadioMail 1.x will enter maintenance mode. It will continue to work, but will no longer receive new features or updates.

Existing users who choose to upgrade will be able to perform a one-time migration of their email archive.

If you’ve purchased RadioMail recently, you’ll receive an extended trial period to explore RadioMail 2.0 and decide whether it’s the right upgrade for you. I’ll share more details about migration and upgrade options closer to launch.

B.B. Link sunset

The B.B. Link adapter is now officially sold out.

Thanks to everyone who picked one up and helped clear the final production run. I’m especially grateful not to have a stack of leftover PCBs taking over the linen closet. My wife thanks you too.

Georges Auberger WH6AZ has created a number of delightful Amateur Radio data communications apps for the iOS ecosystem (iPhones, iPads). Be sure to read the section A Passion Project. I hope that he will do extend the ecosystem to MacOS. I’m looking forward to… one of these days… to a clean user experience with my MacBook laptop easily connecting, either via USB or Bluetooth to a mobile radio with good data communications capabilities (reasonable power, reasonable data communications speed).

The same observation I made about in the story about MODEM73 applies to apps like those offered by WH6AZ (running on pocket supercomputers and their larger tablet cousins):

We just keep getting better and better options for digital communications in Amateur Radio as the “software folks” apply better software / signal processing technology on the increasingly capable computer hardware we have access to… like Raspberry Pi 5 and the current generation of mobile phones (aka pocket supercomputers).

AREDN Release 4.26.7.0 Available

The AREDN team is proud to announce AREDN production release 4.26.7.0. Features and fixes are listed below. For the gory details, go to the ChangeLog:
Enjoy!
The AREDN Dev Team.

Major Features

Updated to OpenWRT 25.12.5

OpenWRT 25.12 brings a new package manager - apk. If you are currently using side-loaded .ipk packages, these cannot be updated when AREDN is updated as they are no longer compatible and will be removed.

Faster network changes

You can now add, remove, or update tunnels without restarting the entire network stack. It’s a lot faster and less disruptive.

Improved HaLow 802.11ah support

Updated to the latest Morse Micro 1.17.9 drivers which improves stability and performance of HaLow links.

Support for MediaTek WiFi-6 AX devices

Improved support for AX radio based devices. Note that these radios come with a number of limitations, including only supporting 20 MHz or greater bandwidth.

Zyxel radios

Zyxel is a new manufacturer to AREDN. We support the NWA55AXE. It is the only outdoor rated AX radio supported by OpenWRT, and has connectorized antennas so can be attached to your antenna of choice.

Supernode Babel improvements

Improve the babel configuration for Supernodes. Supernodes handle a lot of routes and these changes get better Babel performance especially on non-x86 hardware.

New Devices Supported

  • Morse Micro HalowLink 2

  • Heltec HT-HD01 V2

  • Heltec HT-H7608 V2

  • Ubiquiti PowerBeam 5AC 300

  • GL.iNet Slate Plus (GL-A1300)

  • Cudy WR3000

  • Cudy WR3000E

  • Cudy WR3000H

  • Cudy WR3000P

  • Cudy WR3000S

  • Zyxel NWA55AXE

  • Vultr Cloud Compute

It is continually amazing that AREDN just keeps getting improved. Look at the umpteen Fixes and Enhancements that have been incorporated!

Kudos to the AREDN Development Team (and AREDN Ambassador Orv Beach W6BI who does such a good job evangelizing and publicizing AREDN.

EastNet Packet Radio Group Quarterly Call Summary

Image courtesy of EastNetPacket

Brian Webster N2KGC on the EastNetPacket email list:

We had a good call this morning with 10 participants. We used the Google Chat video conference system and I had the Gemini AI take notes. I have read through the note and other than a few errors with things like call signs and it calling the TPRFN the Tri-State Packet network, it did a real nice job. The summary is an easy read and it captured all of the topics we covered very well. It time stamps those points in the meeting so you can go to the full transcript for the actual details.

The summary link is here: https://docs.google.com/document/d/1dDso_mep1abFLgKUivzdPYrIMvtD9ohd6_KrTKs5Hms/edit?tab=t.m9uyqifyusei

The full transcript document is here: https://docs.google.com/document/d/1dDso_mep1abFLgKUivzdPYrIMvtD9ohd6_KrTKs5Hms/edit?tab=t.4bqirv4y43n0

Th meeting was held 2026/06/13 08:58 EDT, with Notes by Gemini.

Summary

Technical experts reviewed network integration strategies and protocol efficiency updates for packet radio communication systems.

Network Integration And Configuration
Discussions focused on integrating digital traffic networks with packet radio frequency systems to streamline messaging. The group decided to prioritize configuring BBS software to ensure proper traffic routing and system performance.

Protocol Efficiency And Upgrades
Participants explored AX25 version 2.2 protocol benefits, specifically selective reject features to minimize retransmissions. Future testing will utilize the AGW network interface to achieve necessary hardware requirements.

LoRa Technology Potential
The group evaluated LoRa radio technology for potential use in packet data networks and portable public service connectivity. No formal implementation strategy was established due to technical uncertainties regarding throughput.

Next steps

  • [Ray Adkins] Update Slide Deck: Update the existing PDF slide deck to incorporate Texas Packet Radio Frequency Network integration details. Submit the finalized presentation to Steve Stroh for publication in the Zero Retries newsletter.

  • [Brian Webster, Pat] Develop FBB Instructions: Document the required forwarding rules for National Traffic System traffic on FBB Bulletin Board System platforms. Enable automatic message integration into the Digital Traffic Network.

  • [Brian Webster, Pat] Develop BPQ Instructions: Create setup documentation for BPQ software to handle National Traffic System traffic. Coordinate with system operators to ensure successful network integration.

  • [Charles Hargrove] Provide Routing Assistance: Offer technical guidance to Bulletin Board System operators for implementing packet routing configurations. Assist with troubleshooting specific setup issues.

  • [Brian Webster, Charles Hargrove] Create Speed Test: Design a specific file to measure performance improvements from version 2.0 to 2.2. Distribute this resource to allow users to verify speed gains.

  • [Brian Webster] Contact Craig Lamp: Discuss educational initiatives regarding connected packet modes with the DigiPie developer. Encourage the inclusion of these concepts in the project documentation.

  • [Brian Webster] Record Packet Audio: Visit a hilltop site to capture real-time audio of packet collisions and retransmissions. Use these recordings to create educational content.

  • [Charles Hargrove] Integrate BPQ Applications: Coordinate with Brad Brown to ensure BPQ software components are compatible with additional system environments. Adapt these tools for broader network use.

  • [Brian Wall] Send link: Provide information about mesh comm and the 433 MHz band via the mailing list.

  • [Brian Webster] Contact Jason: Discuss LoRa kiss mode and related use cases with Jason.

  • [Brian Webster] Research LoRa: Investigate how to utilize this technology for connected data networks rather than just APRS.

  • [Brian Webster] Draft suggestions: Write up proposed concepts regarding connected network builds and share them on the mailing list.

  • [Brian Webster] Resolve node issue: Check the K2PUT node status and discuss the connectivity problem with Ted offline.

  • [Brian Webster] Share meeting notes: Upload the meeting summary and documents to the EastNet mailing list.

Details

  • Meeting Access and Connectivity: Participants experienced technical difficulties joining the meeting, specifically regarding a login timeout issue that required a Google account for access (00:00:20). Brian Wall suggested that Brian Webster adjust host controls to allow broader access, which the group addressed to facilitate smoother entry for all attendees (00:03:48).

  • Introductions and Roll Call: Brian Webster [N2KGC] facilitated introductions for the meeting attendees, including Jim [KY2D], John Langner [WB2OSZ], Donald Gouin [K1 CMM], Charles Hargrove, Brian Wall [W1BKW], Misko [YT7MPB], Ted [K1 Y], Pat [WB2CMF], Ray Adkins [N3HYM], and Ray Quinn. Participants identified themselves by their call signs and geographical locations (00:06:46).

  • Tri-State Packet Radio Frequency Network Updates: Brian Webster relayed updates from Glenn [N3MEL], noting that the Tri-State Packet Radio Frequency Network has integrated artificial intelligence services for weather and call sign lookups, a National Traffic System radiogram generator, a Skywarn reporting generator, and a Winlink to packet gateway (00:13:53). The network has grown to 21 full-time hub stations, enabling coast-to-coast radio frequency packet messaging without internet reliance. The group also honored the memory of Jeff [KP3FT], a founding network member (00:15:09).

  • Digital Traffic Network Overview: Jim [KY2D] explained the function of the Digital Traffic Network, formerly known as the National Traffic System Digital. This network serves as the “long-haul” infrastructure for the National Traffic System, handling formal radiogram traffic via packet nodes (00:17:55). Jim described the standardized addressing system, which routes traffic by zip code to appropriate regions, allowing efficient integration between the Tri-State Packet Radio Frequency Network and the Digital Traffic Network (00:19:06).

  • Digital Traffic Network Test Results: Jim [KY2D] provided feedback on a recent test involving approximately 35 radiogram messages. While a few messages were delayed due to incorrect forwarding rules at specific nodes, the majority were processed successfully within a matter of hours, confirming the effectiveness of the current gateway process (00:20:31).

  • Strategic Integration of Networks: The group discussed the Digital Traffic Network’s role as a primary “on-ramp” for radiogram traffic. Jim [KY2D] noted that this integration allows participants to generate official traffic during events like Field Day for bonus points. Brian Webster proposed creating a slide deck to illustrate how these networks collaborate, aiming to increase awareness and utility across the community (00:25:04).

  • Instructional Materials for Network Users: Ray Adkins [N3HYM] offered a PDF presentation regarding the Digital Traffic Network, which Brian Webster recommended updating to include Tri-State Packet Radio Frequency Network integration. The participants aim to refine these materials to educate users on setting up proper forwarding rules for National Traffic System traffic (00:26:28).

  • Forwarding Rule Configuration: Participants discussed the technical requirements for configuring BBS software, specifically BPQ32 and FBB, to handle National Traffic System traffic automatically. Jim [KY2D] clarified the addressing syntax for BPQ32, and Brian Webster committed to assisting FBB users in implementing these configurations to ensure all systems can capture traffic correctly (00:28:42).

  • AX25 Version 2.2 Protocol Improvements: John Langner, author of Direwolf, introduced the improvements found in AX25 version 2.2. The protocol introduces a “selective reject” feature that allows the receiving station to request the resending of only the missing packets rather than retransmitting a full block of data, which greatly increases efficiency (00:33:54) (00:39:19).

  • Testing and Configuration Challenges: Charles Hargrove shared findings from a recent test where an AX25 version 2.2 connection failed because the systems defaulted to the older version 2.0. John Langner explained that this version requires modern hardware capabilities and sufficient memory to buffer up to 62 frames, which was not feasible in earlier decades (00:42:14) (00:45:43).

  • Interface Requirements for Protocol Adoption: John Langner clarified that the “selective reject” functionality of AX25 version 2.2 cannot be achieved through the KISS interface because KISS is designed to bypass the protocol’s connected mode logic. To fully leverage the version 2.2 improvements, users must utilize the AGW network interface (00:47:10). The group agreed to focus future testing on using the AGW interface to ensure the protocol works correctly (00:49:25).

  • Future Implementation and Speed Testing: Brian Webster and John Langner discussed plans to establish speed tests to demonstrate the efficiency gains of AX25 version 2.2 compared to version 2.0. The group aims to encourage broader adoption of these protocols by documenting the process and verifying performance improvements for 1200 baud and 9600 baud packet networks (00:51:31).

  • Nino TNC and Protocol 2.2: Brian Webster and John Langner discussed the Nino TNC, specifically regarding its support for version 2.2; John Langner noted that the device is primarily a KISS TNC. The participants agreed that implementing version 2.2 would improve performance for networks such as the Tarpon network (00:59:08). John Langner explained that implementing the connected mode protocol is a complex task due to the need for state management and queue handling, distinguishing it from simple KISS TNC operations (01:00:15).

  • Educational Value of 1,200 Baud Packet: Brian Webster emphasized the importance of 1,200 baud packet radio as a tool for teaching networking concepts, specifically “hidden transmitter syndrome,” which they noted is a common issue in unmanaged protocols like those used in LoRa mesh systems (01:00:15). Brian Webster suggested that users visit mountaintop sites to listen to the audio on radio digipeaters to better understand how packet collisions and retransmissions occur in real-time (01:01:31). Jim (+1 207-***-**98) supported this, noting that the slower speed allows users to hear acknowledgments and retransmits, making it an effective classroom tool (01:03:52).

  • Hamgate PBX System Status: Charles Hargrove provided an update that the Hamgate PBX system using Asterisk is currently operational following the closure of Hamshack Hotline. Charles Hargrove requested that any individuals managing Allstar repeaters contact them to discuss integrating those systems with the Hamgate PBX (01:07:37).

  • VPN Security and Segmentation: Charles Hargrove clarified distinctions between the ARDC VPN system and the Northeast/Hamgate VPNs. They explained that the ARDC VPN allows all traffic, including non-44net packets, placing the responsibility on the user to secure their system, whereas the Northeast VPN restricts traffic to 44net to maintain security (01:08:58).

  • AXIP and Dynamic IP Connectivity: Charles Hargrove reported that stations utilizing NetRom quality settings recommended in the NEA document have experienced increased reliability and throughput (01:08:58). However, they identified persistent connectivity issues for users attempting AXIP connections who lack static IP addresses and experience failures with dynamic DNS services after local ISP or cable modem resets (01:10:26).

  • Radiogram Routing and BBS Configuration: Charles Hargrove stressed the necessity of proper addressing and BBS routing configurations for the timely delivery of radiograms, noting that improper setups by inexperienced users can hinder network performance. Charles Hargrove and Jim are working with other DTN hub stations to clarify traffic handling procedures and encouraged users to consult the net directory available on the Radio Relay International website (01:11:46).

  • Direwolf Software Implementation: Brian Webster discussed the role of Direwolf in modernizing packet networks (01:13:15). John Langner explained that Direwolf is highly multi-threaded and uses different CPU threads for each audio interface, allowing it to support multiple simultaneous AGW connections if a source code variable is modified. Brian Webster expressed that this capability reinforces the potential for replacing legacy hardware TNCs with software-defined solutions (01:16:55).

  • Service Development and Bandwidth Efficiency: Brian Webster proposed using AI to offer guidance and service information to users on RF-only networks who may lack experience with command-line interfaces (01:20:43). Brian Webster also cautioned that when building services on 1,200 baud networks, developers must prioritize bandwidth efficiency to avoid “lazy” programming that could negatively impact performance (01:21:49).

  • Six-Meter Band Potential: Brian Webster advocated for re-establishing 1,200 baud 6-meter packet links as a viable alternative to the congested HF spectrum for building long-distance, full-time connections (01:21:49).

  • Chat Server Implementation: Brian Webster encouraged participants to implement chat services, such as HubNA, on local BBS systems to facilitate communication beyond a single local node (01:25:10).

  • LoRa and Digital Voice Integration: Brian Webster and Charles Hargrove discussed the potential of using Mobile Link TNCs and LoRa devices for digital voice protocols like M17 (01:26:22). Charles Hargrove expressed interest in using LoRa devices on 433 MHz for mesh networking, specifically to provide portable, handheld connectivity for public service events where operators may not be able to carry a laptop and TNC (01:27:37) (01:32:09).

  • LoRa Technical Specifications: John Langner noted that LoRa devices can function as KISS TNCs and offer adjustable performance through parameters like spreading factors and coding rates (01:33:00) (01:37:16). Charles Hargrove cited research from N7UV, who achieved data throughput of approximately 5 kilobits per second using a 125 kHz bandwidth (01:42:43). John Langner clarified that the confusion often stems from the difference between baud (symbol rate) and bits per second (data throughput) (01:44:03).

  • Instructional Strategies: Brian Webster emphasized the importance of incremental learning and using relatable analogies to explain new technical concepts to audiences without a networking background, rather than relying on theory from a “white sheet of paper” (01:47:55).

  • Future Planning for Connected LoRa Networks: Brian Webster requested further information on how to implement LoRa devices within connected data networks, as opposed to solely for APRS usage (01:49:00) (01:52:01). They noted that they have access to state-managed tower sites in New York and are seeking to modernize these networks with high-gain, point-to-point links (01:50:47).

  • K2PUT Connectivity Troubleshooting: Ted reported an inability to connect to the K2PUT node on 440 MHz despite testing their station with a 50-watt output. Brian Webster agreed to investigate the node status to determine if the issue originates at the K2PUT station or with the connection path (01:55:08).

  • LoRa Integration and AX25 Protocol: John Langner described an unsuccessful attempt to use a LoRa hat on a Raspberry Pi with Direwolf, despite having code to treat it as a built-in modem. Brian Webster questioned whether implementing the AX25 version 2.2 protocol would offer any advantages in this setup or if LoRa functions independently. John Langner clarified that LoRa is a distinct radio technology that serves primarily as a frame transport mechanism, indicating that the AX25 stack is not relevant to the underlying LoRa transmission (01:57:11).

  • LoRa Technology Characteristics: John Langner explained that LoRa was originally developed for the Internet of Things (IoT) to facilitate low-power, long-distance communication for small, occasional data messages. Brian Webster suggested that this technology could be leveraged within amateur radio, similar to how it is used commercially for devices operating on batteries or solar power (01:58:34).

  • Proposed Amateur Radio Packet Network: Brian Webster proposed a conceptual design for a packet network on UHF or 220MHz that adapts commercial LoRa gateway concepts for two-way amateur radio data. The proposal involves using LoRa gateways to allow data transmission to an internet-connected stream, similar to how the APRS system operates, but adapted for broader data use (01:59:40). Brian Webster expressed uncertainty regarding the throughput potential of such a system, questioning whether a model similar to 1200 baud packet radio could be achieved or improved upon (02:01:04).

  • Feedback on LoRa Gateway Concept: Brian Webster solicited input on the viability of using LoRa devices as gateways for an amateur radio data network (02:01:04). John Langner stated they lacked experience with LoRa gateways or the IoT-style implementation Brian Webster described (02:02:10). Ray Adkins N3HYM also indicated they had no experience with the technology (02:03:25).

  • Clarification of LoRa Gateway Functionality: Brian Webster outlined the commercial LoRa gateway model, where gateways on hilltops decode RF data and inject it into an internet stream for server-side retrieval. This was compared to existing APRS operations, where iGates serve a similar role by stripping and injecting packets into the internet (02:04:16). Brian Webster cautioned that LoRa gateways should not be confused with Meshtastic repeaters, as the former are specifically designed for internet-connected routing of commercial IoT data (02:05:34).

  • Meeting Conclusion and Next Steps: Brian Webster thanked the attendees for their input, specifically noting the value of John Langner’s contributions (02:06:44). It was confirmed that the meeting transcript and summary would be emailed and posted to the EastNet mailing list for review. The meeting concluded with an announcement that the next quarterly meeting will be held on a Thursday evening, with details to be shared via the mailing list (02:08:04).

EastNet Packet is one of the longest-lived and most active Packet Radio networks that I’m aware of in the US. Frankly, I’m envious of living in an area with so much Amateur Radio networking activity (though in fairness, I live in an area with a user-accessible microwave network - Puget Sound Data Ring (HamWAN). It was interesting to note EastNet Packet’s research into integrating LoRa links into the EastNet Packet network.

Kudos to President Brian Webster N2KGC and Webmaster Chris Lance WW2BSA for providing good documentation and publicity of the activities of both the group and the network.

Field Day PBX

Eric Grumling K0JEG on his Grand Valley Aviation (and sometimes, Amateur Radio) newsletter:

SIP phones, conference bridges, AllStar integration, and the Asterisk config files that made it work.

This is a followup (more of a sidebar, actually) from May’s article about the Field Day network. We’ll be going into the phone side of the network and how to set one up for your Field Day site, EMCOM communications trailer, or just a way to add some interesting features to your Allstar based repeater.

Allstar on a Raspberry Pi

I started off with the standard ASL3 Appliance image available at AllstarLink.org. I’m using a Pi CM4 with onboard eMMC storage. The board I’m using, the Tofu, is from a Swiss company called Oratek. This board is really nice because it can accept a very wide range of DC input from a coax power connector or two pin screw-down connector. It also includes an M.2 slot on the bottom, on which I installed an LTE modem. For an extra $8 they sell the .stl files for a case, which is functional but the top and bottom plates are pretty thin, so if you go this route make sure to bump up the infill to 75% or higher. I used standard PLA, so it will probably melt a little in a hot vehicle too (Update: It did melt pretty badly, along with the hot glue I used to hold things together).

The setup is powered by a DC-DC power supply that can provide 24VDC to run the MikroTik hAP3 router and mANT access point (on POE passthrough), and +12 to run the server. It also has a set of 18650 LiPo cells to keep the system powered up for some time if the primary power from my Ecoflow solar battery runs out. The Starlink Mini will be powered by its supplied 120V power brick because I’ve had issues with running it on the DC power supplied by the Ecoflow. I was using a USB-C PD adapter that should be supplying enough power to the Starlink terminal, but I’ve had some problems that look a lot like brownout issues that disappeared after I went back to the wall wart supplied.

There’s lots more Zero Retries Interesting detail in this story. I loved reading about all of it, and I love the synergy of setting up a multi-operator field day station with Voice Over Internet Protocol phones running on a “throw it online quickly” wireless local area network. Recommended!

FCC IDs Three Bands for Unlicensed D2D [Satellite Use]

D2D is satellite industry shorthand for Direct (satellite) to Device (mobile phone).

Jeff Baumgartner in Light Reading:

The FCC’s proposal to bring D2D connectivity to unlicensed wireless devices initially keys on three spectrum bands that are already being used for Wi-Fi, Bluetooth and other unlicensed use cases.

The FCC shed more light on a proposal to bring direct-to-device (D2D) connectivity to unlicensed wireless devices, and to possibly include laptops, smartphones and IoT devices that are already accustomed to connecting via unlicensed technologies such as Wi-Fi and Bluetooth.

The FCC announced the general concept last week, including an aim to seek out more than 225MHz of unlicensed spectrum for unlicensed D2D. Days later, it followed with a more in-depth, 38-page draft order that identifies a set of spectrum bands that will be explored, with the option to look into using other bands. The FCC is set to vote on the proceeding at its August 6 meeting.

The draft calls possible Earth-to-space operations in the following bands:

  • 902MHz-928MHz

  • 2400MHz-2483.5MHz

  • 5725MHz-5850MHz

Those bands, the draft notes, are “currently available for use by unlicensed devices under Part 15 of the rules.” The Part 15 rules govern the operation of unlicensed devices, such as those supporting Wi-Fi and Bluetooth connections.

It’s going to be interesting for Amateur Radio’s (and unlicensed users / systems) use of these bands to “get used to the new (satellite based) spectrum users”.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0258. Paid subscribers can comment directly on the web version of this issue.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

ZRDC 2026 Ho!

Zero Retries Digital Conference (ZRDC) 2026 will be here before we (I) know it.

12 weeks until Zero Retries Digital Conference 2026

on Friday, October 16, 2026,

in San Ramon, California, USA.

Our first three presenters for ZRDC 2026 are already confirmed, and we’re actively reaching out to a number of potential presenters that are working on Zero Retries Interesting projects or products or technologies. Tina and I cannot wait to tell you more in the next issue of Zero Retries.

2026 is Definitely the Year of OFDM in Amateur Radio

And with these new Amateur Radio data communications technologies, it seems likely that 2027 will be the year that a buildout of Amateur Radio networks that are relevant in the 21st century could begin.

Orthogonal Frequency Division Multiplexing - OFDM is fast becoming has become the buzzword / coolest technology in Amateur Radio data communications in 2026. It’s starting to eclipse Software Defined Radio, and at the moment, AI / ML in Amateur Radio is still a bit nascent.

I first became aware of how much difference using OFDM made in VARA FM (and VARA HF) a few years ago. Since then, I’m seeing OFDM spring up everywhere.

  • MT63

  • Ribbit / Rattlegram

  • FreeDV RADE (became prominent in 2026)

  • Mercury modem (released in 2026)

  • Hush modem

  • IP400 “Mode B” by IP400 on IP400 hardware and IP400 “Mode B” by Nino Carrillo KK4HEJ for implementation on the NinoTNC, targeted for release in 2026

  • Mesh Operations Protocol (MOP) (in development in 2026)

  • Others that have been mentioned to me under non-disclosure

  • And as of this week…

    • New Packet Radio - Next Generation (NPR-NG)

    • MODEM73

I… can’t… wait for some of these new capabilities to be completed and released for use. VARA FM works well. Ribbit / Rattlegram is pretty cool especially with its acoustic coupling and ability to use on any two way radio. FreeDV RADE is just an amazing leap forward for voice operations on HF. Hush and MOP look really interesting and seem to have energetic and motivated developers behind them. I keep hearing encouraging things about IP400.

It seems like beginning in 2027, we’ll have some significant technical capabilities to begin building substantive, fast, reliable, modern, and integrated networks on Amateur Radio spectrum:

  • Mercury modem for networking on HF,

  • IP400 for “lower speed” (on 12.5 kHz channels) VHF / UHF,

  • NPR-NG for “higher speed” on 420 - 450 MHz / 70 cm,

  • “AREDN-902” on 902 - 928 MHz / 33 cm,

  • AREDN on microwave.

All could be linked together with TCP/IP and perhaps even a unified (we can dream…) addressing scheme using either 44Net IP addresses or IPv6.

Weekends Are For Amateur Radio!

No Amateur Radio fun for me this weekend due to family activities. But August holds some promise for more time for Amateur Radio fun. My condolences to most of the rest of the continental US on their weather. Tina was shocked about the recent tornados in her hometown of Parsippany, New Jersey. In my hometown of Port Clinton, Ohio, tornados touching down was a summer Tuesday.

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0258. Paid subscribers can comment directly on the web version of this issue.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

Founding Members who generously support Zero Retries financially:
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Zero Retries 0258 was published on 2026-07-24. This issue was 10655 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

Preceded by LinHT 2.0, the release of Mercury modem, QuadRF.

]]><![CDATA[Zero Retries 0257]]>https://www.zeroretries.org/p/zero-retries-0257https://www.zeroretries.org/p/zero-retries-0257Sat, 11 Jul 2026 06:31:34 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its fifth sixth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

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In This Issue:

I-Frame

Hamvention 2026 Takeaways: A Record Crowd - and a Signal for AMSAT
Joe Kornowski KB6IGK

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Note to Annual and Founding Member Subscribers

Earlier this year in the attempt to migrate Zero Retries to another publishing platform, I suspended paid subscriptions on Substack in the expectation of paid subscribers starting new paid subscriptions on the other platform.

When I decided that the other platform just wasn’t going to work out, I moved publication of Zero Retries back to Substack and restarted paid subscriptions.

That action of suspending payments (I didn’t cancel payments - just suspended) seems to have… screwed up… at least some Annual Paid subscriptions and Founding Member subscriptions. Monthly paid subscriptions didn’t seem to be affected.

Thus, if you’d like to continue to support Zero Retries financially with an Annual Paid subscription, or a Founding Member subscription, it may be necessary to start a new Annual Paid / Founding Member subscription on Substack. To those of you who have already noticed this issue and started a new Annual Paid / Founding Member subscription, Thank You!!!

Again, paid subscriptions to Zero Retries are voluntary, but very much appreciated to support the expenses of publishing Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Prefers to Remain Anonymous 32 for becoming Founding Member 0026 to Zero Retries this past week! Prior to becoming a Founding Member, Prefers To Remain Anonymous 32 was an Annual Paid Subscriber for two years.

Founding Member Subscribers are listed in every issue of Zero Retries!

My thanks to Prefers to Remain Anonymous 03A for beginning their 4th year of being a Paid Subscriber to Zero Retries as of the past two weeks!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Zero Retries Summer 2026 Publishing Schedule - Biweekly

During Summer 2026, Zero Retries will be published biweekly. The intended publication schedule is:

  • Zero Retries 0257 - 2026-07-10

  • Zero Retries 0258 - 2026-07-24

  • Zero Retries 0259 - 2026-08-07

  • Zero Retries 0260 - 2026-08-21

  • Zero Retries 0261 - 2026-09-04

There may be some special, focused issues interspersed between the scheduled issues, such as a special issue about Zero Retries Digital Conference (ZRDC) 2026.

After ZR 0261 / 2026-09-04… to be determined.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0257. Paid subscribers can comment directly on the web version of this issue.

Hamvention 2026 Takeaways: A Record Crowd - and a Signal for AMSAT

By Joe Kornowski, KB6IGK, Editor [With help from Google Gemini and Anthropic Claude Opus 4.8]

Editor’s Note

This article originally appeared in the May / June 2026 issue of AMSAT Journal, page 17 and is reprinted in Zero Retries with permission.

The final tally is in, and it’s a record. Dayton Hamvention 2026 drew 37,924 attendees to the Greene County Fairgrounds in Xenia — nearly 38,000 hams representing more than 40 countries and every U.S. state. That beats the 2025 record of 36,814 by roughly 1,110 visitors, about a 3% gain.

It’s worth pausing on what that number actually represents. 2026 is the third consecutive record-setting year: 35,877 in 2024, 36,814 in 2025, and now 37,924. Three years, three records, with the flea market and exhibit booths sold out months in advance.

The declining-hobby narrative meets the data

Walk into a typical club meeting, and you might think you’d wandered into a reunion of retired engineers. The age curve is real, and it isn’t going away on its own. But attendance and licensing tell a more interesting story than the demographics alone would predict.

The U.S. amateur population has remained above 750,000 FCC-licensed operators and has trended modestly upward over the past several years, not the steady attrition seen in many other industrialized countries. The headcount isn’t collapsing. If anything, it’s quietly being refreshed.

A bimodal hobby

The clear reading of the Hamvention floor is “bimodal”. On one side, we note the expected graying license base. On the other, however, we find a smaller but visibly rising cohort that the age curves miss entirely:

  • The maker and STEM crowd— Low-cost microcontrollers — Arduino, Raspberry Pi — and affordable software-defined radio have collapsed the wall between computer science and RF. This is a digital-first generation, comfortable with FT8, digital modes, and satellite tracking from day one.

  • University CubeSat and small-sat programs— A growing pipeline of students arrives already fluent in the language of spacecraft, telemetry, and ground stations.

  • The preparedness and off-grid community— A meaningful share of newer licensees treat radio as critical infrastructure rather than a weekend pastime — a steady stream of practical operators in their 30s, 40s, and 50s.

And the youth presence on the floor was unmistakable: kids building FM receivers, Scouting and 4-H integration, the Youth on the Air (YOTA) booth, and the Students on the Air (StOTA) Discord community turning out in person.

Here is the part that matters for AMSAT: **that second cohort is disproportionately interested in exactly what AMSAT does.** SDR, digital modes, telemetry, tracking, working a bird as it arcs overhead — for a maker or a CubeSat-curious student, satellite operation isn’t an obscure corner of the hobby. It’s the most exciting on-ramp we have.

What we do with the signal

The newcomers walking past the AMSAT booth are precisely the operators most likely to stay engaged for decades — if we meet them where they already are. That means accessible demos of live satellite passes, clear paths from “I have a handheld” to “I just worked a satellite,” and continued investment in the educational and university partnerships that keep the pipeline flowing. The cohort exists. AMSAT’s continuing focus is to convert curiosity into operators, and operators into members.

The real threat isn’t age.

If amateur radio faces an existential risk, it isn’t the average age of the license base. It’s the slow erosion of frequency spectrum to commercial interests and the rising noise floor from an ocean of consumer electronics that makes operating from home steadily harder. Those are fights worth having, and they’re fights in which AMSAT— with its direct stake in the bands our satellites depend on—has every reason to stay engaged.

…

Editor’s Postscript

My Thanks to Joe Kornowski KB6IGK for his (very rapid) permission to reprint his article here in Zero Retries.

I eagerly scanned through the rest of the 25 pages of this issue (it’s Zero Retries publication day), and beyond KB6IGK’s article, it was all Zero Retries Interesting. I’m enjoying my membership in AMSAT to have access to each new issue of AMSAT Journal behind the AMSAT paywall as soon as it’s published.

My “slow discovery” of NewTechHams over the past few years has been a lonely… “position” to promote within Amateur Radio. Here in Zero Retries I have posited for several years now that NewTechHams - which view Amateur Radio as a transactional activity (what can it do for me?) trend younger, more techie, prefer to experiment more in software than hardware, prefer digital modes, prefer to operate on VHF / UHF, etc., is a distinct and growing segment of Amateur Radio, that’s unnoticed by the vast majority of “mainstream” Amateur Radio (especially media).

Thus I was gratified to read KB6IGK’s article, which explained the rise of NewTechHams from AMSAT’s perspective. I’m (mostly) in violent agreement with him.

I offer the following “Zero Retries Perspective” on some points:

  • As I’ve explained in previous issues of Zero Retries that in my opinion, beginning in in 2026, AMSAT has become a lot more interesting with the election of Drew Glasbrenner, KO4MA as AMSAT President, and better promotion of the near-term AMSAT satellite payloads that incorporate microwave, Software Defined Radio, and data modes (especially PACSAT), and hopefully a Amateur Radio payload at GEO. In his short time as AMSAT President, KO4MA has been much more open about “AMSAT behind the scenes”.

  • In my observations, the current satellites aren’t intrinsically interesting, once you’ve experienced a few voice contacts via the “flying repeaters”. I think that to attract the NewTechHams into satellites and AMSAT membership, there needs to be a very strong emphasis on digital, digital, digital modes, like PACSAT. Digital voice via satellite is now entirely viable thanks to FreeDV RADE, and for the “flying repeaters” (providing FM), FreeDV’s “other” mode - BBFM. But the most interest by NewTechHams will be in data modes. Potentially, revive an old concept from a previous era of Amateur Radio satellites, gateway stations that allow participation with satellites via a local gateway without individual having to have their own satellite-capable stations.

  • Another very strong interest of NewTechHams is Open Source technology. With anything they choose to get involved with and use, especially something “recreational” like Amateur Radio space activity, they expect to be able to experiment and tinker with it. AMSAT’s perspective on Open Source has been evolving and improving, which is another reason I have changed my perspective about the organization.

  • There’s a lot of potential for AMSAT’s technology beyond actual satellites that it seems to be neglecting. One example is that I explained to KO4MA during our conversation at Hamvention 2026 that the (new) PACSAT project is kind of cutting-edge for packet radio technology, with the incorporation of four 1200 bps uplink channels (from memory…) on 2m, and one 9600 bps downlink channel on 70cm, with a robust and proven queuing mechanism for the four uplinks to be retransmitted. Especially with an integral BBS, a PACSAT unit would be cool to put on the air terrestrially.

  • Another example of an AMSAT product that I think would be well received outside of space use is AMSAT’s SDR Gen2 module:
    … a versatile, programmable GNU Radio transceiver/transponder designed for a 1U CubeSat footprint. The transceiver has 144 MHz – 6 GHz continuous coverage with 10 GHz coverage expected as well. The transceiver will support direct VHF, UHF, L, S, C, and X band operations in all modes – CW, SSB, FT8, NBFM, SSTV, FSTV, etc. and a downlink data rate of up to 1 MBps. This transceiver is being built to fly on GOLF and FoxPlus missions and will be both open source hardware and software.
    What Amateur Radio techie wouldn’t want to experiment with all of that in a single, proven unit?

  • It’s the slow erosion of frequency spectrum to commercial interests and the rising noise floor from an ocean of consumer electronics that makes operating from home steadily harder. Those are fights worth having…
    With all due respect to KB6IGK, no, that particular “fight” about interference from consumer electronics is not worth having. If we try to fight this irrevocable trend, such as complaining about a solar panel installation next door that uses (RF noisy) microinverters on the back of the solar panels…
    Amateur Radio _will_ lose that fight.
    RF noise in Amateur Radio spectrum is an irrevocable result of modern life. We already accept (not that we like it) noise pollution, air pollution, light pollution (of the night sky), microplastics, etc.

    Fortunately, we in Amateur Radio, and Amateur Radio space activities, especially with this coming new generation of Amateur Radio satellites, do have a solution for the issue of increasing RF noise in Amateur Radio spectrum - digital, digital, digital modes. With the use of digital modes, we can “ride through” such interference. We no longer use analog technology in mobile phones, television broadcasting, or other modern telecommunications. Just… go… digital.

  • I know it’s a controversial perspective within AMSAT, but I think that putting AMSAT Journal behind a paywall is a discouraging factor in considering AMSAT membership. Some of the most interesting, exciting, and useful writing about Amateur Radio space activity, and AMSAT’s role in that activity is invisible to those that otherwise might consider (paid) AMSAT membership and involvement. NewTechHams do their own research via the Internet, and if they cannot find “the good stuff” like AMSAT Journal, for them, it doesn’t exist.

Of all the current Amateur Radio organizations that have a charter to be doing Zero Retries Interesting activities in Amateur Radio - technological innovation in 2026 and beyond, I recommend AMSAT, and specifically, becoming a paid member of AMSAT, and serious consideration of donations beyond membership dues.

Again, this is a recently changed perspective on my part because of AMSAT’s previous leadership being opaque, and the change in direction (my perception) of more technically interesting Amateur Radio satellites / payloads.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0257. Paid subscribers can comment directly on the web version of this issue.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

Brevard County ARES® Team (BCAT) Continues to Expand Regional Emergency Communications Capabilities

Brevard County ARES Team website link; this article has been widely shared as a press release.

BCAT’s CTO, Sean Haga KD4WLE, Leads Development of Next-Generation Multi-Network Communications Infrastructure

Brevard County, Florida – The Brevard County ARES® Team (BCAT) continues to strengthen emergency communications capabilities throughout the Space Coast with significant investments in voice, digital, and data communications systems designed to support public service events, disaster response, and emergency management operations.

Leading many of these technical initiatives is BCAT’s Chief Technology Officer, Sean Haga (KD4WLE), who has been instrumental in designing and deploying the organization’s expanding communications infrastructure. Under his technical leadership, BCAT continues to integrate traditional amateur radio with modern IP networking and digital communications technologies, ensuring the team remains prepared for today’s increasingly complex emergency communications requirements.

Expanding Linked Repeater Coverage

BCAT’s linked amateur radio repeater network continues to provide reliable wide-area communications across Brevard County, giving operators the ability to coordinate activities across multiple locations during training exercises, public service events, and emergency operations. The interconnected system provides increased coverage, redundancy, and operational flexibility while enhancing communications resilience when it matters most.

Growing GMRS Communications

In addition to its amateur radio infrastructure, BCAT has expanded its linked GMRS repeater system, providing another valuable communications platform for team members and partner organizations. The growing GMRS network offers an additional layer of interoperability and supports training, community outreach, and emergency preparedness activities.

Modern Auxiliary Communications Equipment

BCAT has also deployed a new fleet of Auxiliary Communications (AuxComm) radios, improved interoperability and ensuring volunteers are equipped with reliable, standardized communications equipment. These additions enhance field deployment capabilities while supporting seamless coordination during emergency activations and public service events.

Continued Investment in AREDN® Mesh Networking

The organization continues its commitment to expanding the Amateur Radio Emergency Data Network (AREDN®) throughout Brevard County. BCAT’s growing high-speed microwave mesh network provides resilient IP connectivity capable of supporting voice, video, messaging, situational awareness, and network services independent of traditional communications infrastructure.

This expanding network represents a critical component of BCAT’s long-term vision for emergency communications, enabling agencies and volunteers to exchange information rapidly even when conventional systems become unavailable.

Advancing Packet Radio, BPQ, and VARA Digital Communications

BCAT continues to invest heavily in packet radio, BPQ networking, and VARA HF/VHF digital communications, expanding resilient messaging capabilities throughout Central Florida and beyond. Through the development of a modern packet radio infrastructure, high-speed VARA connectivity, and Winlink services, BCAT is building dependable digital pathways capable of supporting emergency traffic when internet connectivity is unavailable or compromised.

A key milestone in these efforts is the deployment of BCAT’s new BPQ Live web interface, providing operators with a modern, browser-based portal for accessing packet radio services. The interface streamlines access to packet messaging, bulletin boards, node information, network monitoring, MHeard statistics, and Winlink-related services, making packet radio more accessible to both experienced operators and those new to digital emergency communications.

The BPQ Live platform represents a significant step forward in modernizing packet radio operations while preserving the resilience and independence that have long made Amateur Radio digital communications an essential emergency communications resource. Combined with Winlink, VARA, and the organization’s expanding packet network, BCAT is creating an integrated digital communications ecosystem capable of delivering formal emergency messages, resource requests, situational reports, and operational information across multiple communications paths.

First Deployment of Multi-Site Tactical Communications Plan

During a recent operational deployment, the Brevard County ARES® Team successfully implemented its first multi-site tactical communications plan, utilizing tactical call signs across multiple operating locations while integrating Winlink messaging into the operational workflow.

The deployment demonstrated BCAT’s ability to coordinate voice and digital traffic simultaneously across multiple communications platforms while maintaining organized message flow between field operators and command locations. The exercise represents a significant milestone in the team’s ongoing commitment to developing interoperable communications capabilities that mirror modern emergency management practices.

Building for the Future

The Brevard County ARES® Team remains committed to expanding volunteer training, enhancing communications infrastructure, and fostering partnerships that strengthen emergency preparedness throughout Brevard County. By combining traditional amateur radio with modern digital technologies, including linked repeaters, GMRS, AREDN® mesh networking, packet radio, VARA, and Winlink the team continues building a communications ecosystem capable of supporting communities when reliable communications are needed most.

As technology continues to evolve, the Brevard County ARES® Team remains focused on providing dependable, innovative, and interoperable communications solutions that serve the citizens of Brevard County during emergencies, disasters, and community events alike.

About the Brevard County ARES® Team

The Brevard County ARES® Team (BCAT) is a State of Florida 501(c)(3) nonprofit volunteer organization of licensed Amateur Radio operators dedicated to providing emergency communications, technical innovation, training, and public service throughout Brevard County, Florida. Working in cooperation with served agencies and community partners, BCAT develops and maintains resilient communications systems—including voice, digital, data, and mesh networking technologies to support emergency response, disaster recovery, and community events while advancing the Amateur Radio Service. Visit www.n4tdx.org for more information.

I wasn’t familiar with the term AuxComm - apparently there is a formal definition. auxcomm.radio:

AUXCOMM encompasses amateur radio, RACES, CERT Team communications, citizens band, and other non-public safety communications services. AuxComm is the Department of Homeland Security (DHS) National Incident Management System. AUXCOMM stands for Auxiliary Communications and often considered a Primary Emergency Communications asset which is overseen by qualified amateur radio licensed personnel.

This announcement (and system) is really refreshing in that it’s a balance of traditional voice (repeater) technologies coupled with modern data technologies.

The BCAT network is an interesting integration of different Amateur Radio data communications technologies at different tiers of technology / capability / speed:

  • An apparently well-developed Packet Radio network,

  • VARA HF and FM - reasonably fast, highly reliable data communications via HF and VHF / UHF,

  • AREDN - High speed, native TCP/IP, via microwave

  • Web technology - “BPQ Live web interface”,

  • Winlink as Internet email interface

Kudos to BCAT CTO Sean Haga KD4WLE and the rest of the BCAT team. They’re doing all the right things!

Regional Network of VarAC or SafeComLink Nodes?

Frustratingly… I think… that in the past two weeks I read about another EMCOM group that had built up a regional data communications network as a network of either VarAC (Amateur Radio) or SafeComLink (Commercial / Government) nodes. But apparently I didn’t bookmark that story, and now I cannot find a reference to it. If a Zero Retries reader can provide a pointer to that group / network / story, please let me know and I will write that up in a future issue of Zero Retries.

2026 DARKWIRE

LAXNORTHEAST website:

Executive Summary: 2026 DARKWIRE Exercise

Pasadena, Jun 2, 2026 by Oliver Dully (K6OLI), District Emergency Coordinator, ARES LAX Northeast

The 2026 DARKWIRE Exercise, conducted on May 30, 2026, successfully demonstrated the critical role of amateur radio in maintaining hospital communications during a total infrastructure collapse. We are pleased to provide this report detailing the technical achievements and collaborative efforts that ensured stable situational awareness for our hospital partners.

Exercise Scenario: “The Digital Quake”

The exercise was built around an escalating “Dark Wire” scenario. It began with a simultaneous cut of major fiber optic cables, triggering a widespread internet and cellular outage across Southern California. The crisis deepened with a cascading power grid failure, forcing hospitals to switch to generator power, followed by civil unrest. The final inject was a powerful M 6.3 earthquake in the San Fernando Valley, which added physical structural damage and a massive surge in trauma patients to the existing utility failures.

…

Key Successes

…

4. High-Speed, Congestion-Free Digital Transmissions The implementation of the new offline HTML forms (which export data as tiny JSON files) worked exactly as intended. Because the file sizes were so microscopic, it prevented radio traffic jams and “pileups” on the frequencies, allowing operators to send their forms almost instantly.

…

Operational Results and Technical Milestones

Our operators successfully maintained a stable communications network using VHF/UHF digital modes

throughout the operational period. The following data reflects the high volume of critical traffic processed:

  • VARA Chat Digital Traffic (JSON): 33 JSON forms were successfully transmitted via VARA Chat, providing high-speed, error-free data. These included:

    • LA County & ICS-213 Resource Requests: Critical requests for diesel fuel and Starlink terminals.

    • HAvBED Reports: Real-time facility status and bed availability updates.

    • Capacity Polls: Two comprehensive surveys capturing hospital preparedness and emergency service status.

  • Winlink Digital Messaging: A robust total of 53 Winlink messages were processed:

    • 6 JSON via Winlink: Provided as a fallback for high-priority data.

    • 47 Winlink Messages: Comprehensive traffic including Check-ins/Check-outs, Welfare messages for out-of-area contacts, and USGS “Did You Feel It?” earthquake reports.

  • Real-Time Situational Awareness:

    • APRS Hospital Service Level Reporting: Operators utilized PinpointAPRS to provide hourly visual status updates (Green/Yellow/Orange/Red) directly on the map, allowing for immediate visual assessment of hospital service levels across the region.

It’s cool to see EMCOM via Amateur Radio VHF / UHF being brought into the 2020s by using modern data communications technology like VARA FM and the tiny files resulting from using (local) HTML forms. Since they’re “just text”, it’s probably a bit more efficient to send that text as a chat element rather than queuing it up as a file.

When a network like this is set up appropriately to let the data communications system work (and handle the contention issues of a busy channel), there’s no need for manual intervention such as a (human) net control on a separate supervisory voice channel as a “traffic cop” managing who and when data transmissions can be sent.

It’s unstated in this sitrep, but pretty much mandatory for a scenario such as this to have worked as well as it did, but all the stations have to be able to hear each other reliably - no hidden transmitters.

My thanks to Franco Venturi K4VZ for bringing this development to my attention for inclusion in Zero Retries.

Drones Used As Airborne Relay / Nodes

Obviously, don’t treat a YouTube video as authoritative - I don’t. But a recent YouTube video clarified something I had been wondering about - that in a drone swarm, was it feasible to use some of the drones, operating at higher altitudes, as relays to establish a long-distance link? Apparently, yes, at least per this video:

I used the “Ask about this video” feature to find the particulars about drone-to-drone communications relay:

Find the section about relaying between drones

and this is the output:

The segment discussing the use of relay drones for this long-range mission occurs between **(02:02 - 05:20)**.

Key details regarding this process include:

* **The Role of Relay Drones:** Ukrainian forces utilize *Warog TRN* relay drones to maintain signal connectivity over long distances. Because the FPV drones use **5.8 GHz** video transmitters for minimal latency, they require these relays to be positioned approximately every **5 km** (02:35 - 03:11).

* **Contingency Strategy:** The mission employs a chain of three relays at different altitudes. The primary drone flies at **1,800 ft**, while backups fly at **700 ft** and **330 ft** to evade detection and maintain signal if a primary relay is destroyed (04:38 - 05:12).

* **Operational Resilience:** During the mission, when the first relay was hit by a Russian *Jirean 2* missile, the backup relay system automatically activated to ensure the attack drones could still receive commands (02:02 - 03:40).

I had known that this was feasible… possible… but I didn’t know if it was practical. Apparently it’s not only practical, but common, and well developed to the point of failover capability if… when… one of the relay drones is disabled. There’s a brief snippet in this video where the drone is not only relaying, but using a flat panel directional antenna to do so.

So… tie this development together with ScaleRF’s (eventual) follow on products to the initial QuadRF - low cost, easily hackable phased array antenna systems for the 5 GHz band. For drone-to-drone relay networks, instead of a flat panel directional antenna on a drone (that’s a big wind load and thus hard to keep aimed), you can use the much smaller, and much easier to maintain a high gain point to point link (you’re steering the beam electronically rather than physically), such a “solid state directional antenna” would, in theory, work better than the flat panel antenna. If you don’t think this is feasible, note that all the capabilities of the QuadRF to date are being done on a Raspberry Pi 5 - relatively light, relatively cheap, relatively power efficient.

Fast forward a couple of years. Need a quick tactical network? Need a repeater for a tactical exercise? Need to improve your receiver range? Field Day / Meadow Day? Winter Field Day? Put the radio - HF / VHF / UHF and the antenna(s) on the drone and downlink / uplink the I/Q to your laptop.

I can imagine that “communications relay drone” will very quickly become just another product available from “Ukraine Industrial Drones, TOB”.1

varaip — IP-over-VARA Network Driver

varaip is a cross-platform userspace daemon that exposes a virtual network interface (Linux TUN, macOS utun, Windows Wintun) and tunnels IP packets over a VARA soft-modem ARQ session, giving you TCP/IP connectivity between two amateur-radio stations. It works with both VARA FM (VHF/UHF FM) and VARA HF (HF SSB): the two modems share the same TCP command/data protocol, so the same driver drives either. VARA HF adds a channel-bandwidth command — set it with --bw (see the flags table).

It connects to a locally running VARA modem over its TCP command/data ports, manages the radio ARQ session (connect/listen, flow control, reconnect), and pumps IP packets between the OS network stack and the radio link. By default it runs as a transparent TCP proxy (--mode pep) that keeps the chatty TCP ACK stream off the half-duplex air; a classic raw tunnel mode is also available (see Modes).

This is pretty cool, and further evidence of the utility of VARA (especially VARA FM) in Amateur Radio. This reminds me of the utility of the Icom ID-1 in transferring TCP/IP (actually, Ethernet) data over a half-duplex radio link. It would be really interesting to see this in action.

The author provides some real world guidance of using varaip:

Nature of the link

VARA is a half-duplex, single-carrier ARQ modem. Like PACTOR, only one station transmits at a time and the link “turns around” (changeover) whenever the direction of data flow reverses. Every changeover costs real time — keying delay, sync, and ACK exchange. This shapes everything about how IP behaves over it:

  • Bulk, one-directional transfers are the best case. A large file moving mostly one way lets VARA keep transmitting, ramp its modulation up, and amortize changeovers. Expect steady low-kbps throughput.

  • Chatty, bidirectional, interactive traffic is the worst case. A protocol that ping-pongs small messages forces a changeover in each direction and spends most of the airtime turning the link around instead of moving data. Interactive latency is measured in seconds, not milliseconds.

Yep. That’s going to be a showstopper for netheads - seconds of latency.

It would be really cool to see this ported to the Mercury data modem as a transparent TCP/IP bridge2.

Cascade-SDR: A Web-Based Multimode Receiver App For RTL-SDR Dongles

RTL-SDR.com:

Over on GitHub, developer Jens Engfors has released Cascade-SDR, a free and open source web-based receiver app designed specifically for RTL-SDR dongles. Cascade-SDR uses a Python backend that owns the dongle and handles all the DSP, paired with a browser frontend for the UI, waterfall, audio, and maps. The two communicate over a WebSocket, which means you can run the backend on a Raspberry Pi or mini PC and access it from any browser, phone, or tablet on your network.

Cascade-SDR has a live waterfall and spectrum scope view, with click-to-listen demodulation for WFM, NFM, AM, SSB, and CW, complete with RDS decoding, FM stereo, and a Morse decoder. CascadeSDR also includes a wideband Sweep mode, a channel Scanner, IQ recording and replay, and a built-in antenna helper that tells you how to set up the RTL-SDR.com dipole kit for your tuned frequency.

It also supports decoding of various digital modes, including ADS-B, AIS, APRS, ACARS, DAB+, NOAA APT weather satellite images, SSTV, POCSAG/FLEX pagers, and 315 to 915 MHz ISM band devices like weather stations and TPMS sensors. However, to decode most of these modes it is necessary to install various decoder software that it is dependent on such as dump1090, AIS-catcher, direwolf, welle-clide, multimon-ng, and rtl_433.

Cascade-SDR runs on Windows, macOS, and Linux/Raspberry Pi. The readme includes instructions on installing the software on the various OS platforms.

AI-Disclaimer: This software has used Claude for development.

Cascade-SDR Screenshot
Cascade-SDR Screenshot

This is Zero Retries Interesting because of the low cost of the RTL-SDR.com Software Defined Radio receivers and that this can be used on Raspberry Pi, and uses a browser as the display, and the display and receiver / server can be separate units running over a network.

M17 Foundation - Report: Friedrichshafen HAM RADIO exhibition 2026

Wojciech Kaczmarski SP5WWP on the M17 Foundation website:

This year’s Friedrichshafen booth was busier than ever, with noticeably higher visitor traffic than last year. Many visitors encountered M17 and the wider open-source amateur radio ecosystem for the first time. The Nokia 3310 demonstration running OpenRTX+libm17 proved to be an excellent conversation starter, while the LinHT display allowed visitors to explore the project’s evolution and preview the upcoming Revision C hardware.

Throughout the event, we answered countless questions about LinHT and discussed why open hardware and open protocols matter in amateur radio. We often compared LinHT and M17 to Linux: unlike proprietary digital voice systems and commercial radios, they give users complete insight into (and control over) the technology they use. This is especially significant when one wants to use this technology for education purposes – the code and hardware can be inspected and analyzed by anyone. Many visitors were particularly interested in the possibility of running an open-source TETRA RF stack on our hardware, especially the SX1255 full-duplex hotspot.

We were also pleased to share the exhibition hall with our long-time neighbors from OpenRTX, continuing the strong collaboration within the open-source amateur radio community.

Another highlight of the event was being interviewed by a prominent amateur radio journalist Tobias DL3MHT (a co-host of The European Ham Radio Show). During the interview, we discussed the ongoing development of LinHT, its role within the M17 ecosystem, and our vision for open hardware in amateur radio.

We also had the opportunity to meet Vivian Xu, BI6KSS, from Retevis in person after nearly five years of corresponding by email. Although the language barrier made detailed technical discussions challenging, it was a pleasure to finally put a face to the name. We hope this meeting will strengthen our collaboration and eventually lead to Retevis sharing the schematics for some of their new radio models with us, which would be a valuable step toward supporting their gear within the OpenRTX/M17 open-source ecosystem.

We were delighted to meet so many people interested in our work. If you’d like to help us continue developing open hardware and open-source amateur radio technologies such as LinHT and M17, while also making our visit to Friedrichshafen next year possible, please consider supporting the foundation with a donation.

Interview with the LinHT Development Team

M17 Project (Wojciech Kaczmarski SP5WWP) on Mastodon (@m17_project):

LabCat (Tobias DL3MHT) uploaded his interview with the LinHT development team: Wojciech SP5WWP, Vlastimil OK5VAS, and Andreas OE3ANC. Check it out :-)
^SP5WWP

The above YouTube embed is supposed to start at 16:37, skipping to the LinHT team interview.

I can’t wait to watch this one.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0257. Paid subscribers can comment directly on the web version of this issue.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

Zero Retries Begins Its Sixth Year of Publication

On 2021-07-09, I published Zero Retries 0000, thus this issue begins Zero Retries’ sixth (!) year of publication. The Zero Retries email subscriber base on Substack seems to have settled in at around 3500+. (It’s been (unusually) stable at that number for the last several months.)

When I began Zero Retries, I didn’t expect it to have this long a run. When I was imagining Zero Retries then, it seemed like there was perhaps a year’s worth of “Zero Retries Interesting” topics to discuss. While I did imagine publishing weekly for a few months to clear out the “backlog”, afterwards I’d convert to publishing biweekly or monthly.

To my amazement, then, and continuing to the present day, “Zero Retries Interesting” things keep happening that continually justify publication of weekly (mostly) issues. A former employer described their company as “a hobby that went terribly, terribly wrong”, and Zero Retries is kind of like that, only a “hobby that took over my retired life, but in a good way”.

As I relate in a story in this issue, the perspective on Amateur Radio that I related in Zero Retries 0000, that Amateur Radio is inexorably changing to a more technical activity - use of Software Defined Radio, digital modes becoming predominant, networking becoming mainstream (again), etc. seems more prominent in Amateur Radio with each passing month. My one regret with Zero Retries is that inevitably I spend more time writing than I do experimenting with Amateur Radio or just operating on the air… which I hope to rebalance, at least in part, in Summer 2026.

I had an email exchange with an a trusted advisor this week and they offered their perspective that some of the technologies / modes / projects / products that I project here in Zero Retries that will become mainstream… aren’t likely to so, in their opinion. They just don’t see enough movement in some (many?) of those.

But to that trusted advisor’s general point, that I’m sometimes overenthusiastic in my advocacy… yep, guilty as charged! Much of what I discuss here in Zero Retries isn’t on the leading edge, it’s on the bleeding edge of Technological Innovation in Amateur Radio.

But also some of what I discuss here in Zero Retries is actually “the wave of the present”, not even the wave of the future. One example is Amateur Radio data networks, some of them based on Packet Radio technology, and many not, such as AREDN, HamWAN, VarAC (as a network system), and MeshCore are active in my places (worldwide). As in present day, not “rising” or “emerging” or “soon”.

Here’s the secret business model of Zero Retries - Irrational Exuberance about Technological Innovation in (and adjacent to) Amateur Radio. Zero Retries only exists because I was frustrated that only a very tiny bit of the technological innovation that I was seeing occur in Amateur Radio was being mentioned in the vast majority of Amateur Radio media. To me, the Amateur Radio media (then, and now, mostly) was boring same old, same old. Thus starting an independent publication like Zero Retries to feature technological innovation in Amateur Radio, even a token effort would be better than the few tiny mentions of technological innovation that were (then) being mentioned in the vast majority of Amateur Radio media. With fortuitous timing, Substack came along as my ideal publishing system - I could write, hit publish, and “a system” took care of the rest - managing the fights with email delivery, payments, web hosting, etc.

Along the way I discovered that there were a lot of folks that had the same perspective as I did, that the most interesting part of Amateur Radio was the technological innovation that was possible, and occurring in Amateur Radio, and finally they could read a dedicated publication about that. To those of the 3500+ email subscribers, and the extended community beyond those that choose not to be an email subscriber, that have reached out to me that Zero Retries really resonates with you, Thanks! As any author will relate, mostly they write to scratch their own itch… but if no one seems to care about what you write, a lot of the fun and motivation goes out of it. Thus the ample positive feedback of the past five years of publishing Zero Retries is very much appreciated.

Not Much (Zero Retries Interesting) Heard From HAM RADIO 2026

I was kind of surprised that I haven’t heard of any Zero Retries Interesting “new” news coming out of HAM RADIO 2026. The M17 Foundation apparently had a good conference with lots of exposure, especially the LinHT in progress.

The only other thing of note that I heard was that there was another planning meeting for “FutureGEO”, a possible Amateur Radio payload at GEO that might bridge between Amateur Radio Operators in North America and Eurasia.

But I haven’t done much research either, digging into the vendor list from HAM RADIO 2026, or spending some dedicated time watching YouTube videos from HAM RAIO 2026 such as the one immediately above. I wasn’t aware of that YouTube channel, but now subscribed in the Zero Retries YouTube channel and added to the Zero Retries Interesting Videos playlist.

If you Zero Retries readers are aware of any Zero Retries Interesting developments / announcements, products, etc. from HAM RADIO 2026, please let me know.

Thinking More About the MorseNexus DitStorm Cypher

In Zero Retries 0256 - MorseNexus DitStorm Cypher Version 3.0 - Cypher Mail, I mentioned the MorseNexus DitStorm Cypher as essentially a CW modem. I know that it’s anathema to many, but I view CW as just another, and perhaps the original, data mode over radio (and landlines).

For some reason, since then, the idea of having and using a DitStorm Cypher has grown on me. A couple of Zero Retries readers that brought the DitStorm Cypher to my attention feel that the manufacturer’s claims for it to be the best such unit for automated CW decoding and display are valid.

That said, undoubtedly there are gazillions of approaches to machine decoding and displaying CW. I remember reading about microprocessor based CW decoders back in the early days of microprocessors in Amateur Radio in 73 in the late 1970s, now more half a century ago. Thus there’s ample prior art. But what’s mildly compelling about the DitStorm Cypher is that MorseNexus is making CW / Morse Code much more prominent than “just another mode selection on the HF rig”. At first, MorseNexus’ approach was a bit of a novelty. But admirably, they’ve kept at their central premise of “Good CW operation with no tears” and have continued to improve their products.

And, admirably, MorseNexus has continued to improve their marketing of the company and their premise. It was interesting when they pivoted from their original company name of PreppComm to MorseNexus - the new name just sounds cooler and more high tech. Put simply, MorseNexus is doing a good job at making CW / Morse Code operation sexy in Amateur Radio again. Unlike the hard work and (sometimes, really) heartbreak (some people take it really seriously) of trying to “get your code speed up”, with the DitStorm Cypher, you need not fear that you’re not going to be good enough when you “wade into CW”. The DitStorm Cypher is, from accounts, a well engineered, capable appliance to do the heavy lifting of CW decoding and display, especially if you don’t have the requisite skills for it.

I think what triggered these musings was listening to the hosts on the Ham Radio Workbench podcast extoll how much fun they have with using CW on Parks On The Air (POTA) activations, and reading other folks like Jeff Davis KE9V about his almost exclusive use of CW. That “world” on Amateur Radio HF is largely foreign to me as I simply haven’t tried to develop my CW receiving and transmitting skills.

Thus, it’s tempting to think about getting a DitStorm Cypher… and with it just plunge into the world of expert CW operators on the Amateur Radio HF bands.

I know - I’d just be “pointing the money gun” at what many consider to be a human skill. But so was cursive writing for much of our human history, and we don’t do much of that any more either. From my way of looking at the issue of CW… with the DitStorm Cypher, I’d just be using technology that, much like radio technology in general does, amplifies my human abilities through the use of technology.

So, perhaps sometime this Fall / Winter, you’ll hear N8GNJ in the CW portions of the HF bands calling CQ.

N8GNJ Column In May / June 2026 Issue of The Communicator

My regular column in this issue of The Communicator is titled Interesting Emerging Trends Summer 2026 on Pages 81 - 85. I discuss:

  • Voice Repeaters (and Net Operations) Migrating Into the 21st Century

  • HF Digital Capabilities Improve

  • Software Defined Radio Advancements

and more.

As always, I strongly recommend the entire issue, which, as I always posit, is easily the equal of any other Amateur Radio magazine with a great mix (as always) of Amateur Radio content - introductory, history, operational, technical (my favorite), and humor… and a recipe or two! Honestly, I don’t know how other Amateur Radio magazines, that are only accessible behind a paywall, compete given that The Communicator is available exclusively online, and is free to read worldwide.

Kudos, as always, to The Communicator’s amazing Editor, John Schouten VE7TI.

ZRDC 2026 Ho!

Zero Retries Digital Conference (ZRDC) 2026 will be here before we (I) know it.

14 weeks until Zero Retries Digital Conference 2026

on Friday, October 16, 2026,

in San Ramon, California, USA.

Tina KD7WSF (and I) continue to be impacted by Tina’s recent surgery and her resulting lack of mobility and impact on her overall office productivity. By this issue, we had hoped to finalize some details about ZRDC 2026 that we could publish… but we didn’t.

Rest assured that such details are coming very soon, such as registration details, confirmed speakers, call for papers, etc. We both think that the change in venue to the Bay Area, California, USA, overlapping with Pacificon 2026, and the many exciting technological innovations in Amateur Radio that have / will occur in 2026 will culminate in ZRDC 2026 being an even more exciting and impactful event than ZRDC 2025. Thanks for your patience!

Weekends Are For Amateur Radio!

As is the usual season, we’re now receiving no rain and mild temperatures for the past two weeks. It’s been (welcome) light overcast / broken cloud cover which has kept the temps comfortable, especially at night (we’re still sleeping with windows open and under a comforter).

Although I have one big yard work project promised, beyond that, the weekend should indeed be mostly about time in N8GNJ / Zero Retries Labs for Amateur Radio, sunny, mild, with all of the big shop doors open.

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0257. Paid subscribers can comment directly on the web version of this issue.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

Founding Members who generously support Zero Retries financially:
Founding Member 0000 - Steven Davidson K3FZT (Renewed 2025, 3rd year!)
Founding Member 0001 - Randy Smith WU2S (Renewed 2025, 3rd year!)
Founding Member 0002 - Chris Osburn KD7DVD (Renewed 2025, 3rd year!)
Founding Member 0003 - Don Rotolo N2IRZ (Renewed 2025, 3rd year!)
Founding Member 0004 - William Arcand W1WRA (Renewed 2025, 3rd year!)
Founding Member 0005 - Ben Kuhn KU0HN (Renewed 2025, 3rd year!)
Founding Member 0006 - Todd Willey KQ4FID (Renewed 2025, 3rd year!)
Founding Member 0007 and 0010 - Merik Karman VK1DF / VK2MKZ (Renewed 2025 x2, 3rd year!)
Founding Member 0008 - Prefers To Remain Anonymous 08 (Renewed 2025, 3rd year!)
Founding Member 0009 - Prefers To Remain Anonymous 19 (Renewed 2025, 2nd year!)
Founding Member 0011 - Rick Prelinger W6XBE (Renewed 2025, 2nd year!)
Founding Member 0012 - Ryan Tolboom N2BP (Renewed 2025, 2nd year!)
Founding Member 0013 - Newton White N4EWT (Renewed 2026, 2nd year!)
Founding Member 0014 - Joe Hamelin W7COM (Renewed 2026, 2nd year!)
Founding Member 0015 - Rich Stocking N7OP (Renewed 2026, 2nd year!)
Founding Member 0016 - Prefers To Remain Anonymous 77 (New 2025)
Founding Member 0017 - Phil Karn KA9Q (New 2025)
Founding Member 0018 - Prefers To Remain Anonymous 95 (New 2025)
Founding Member 0019 - Prefers To Remain Anonymous 0108 (New 2025)
Founding Member 0020 - Prefers To Remain Anonymous 110 (New 2025)
Founding Member 0021 - Prefers To Remain Anonymous 111 (New 2025)
Founding Member 0022 - Prefers To Remain Anonymous 112 (New 2025)
Founding Member 0023 - Prefers To Remain Anonymous 116 (New 2026)
Founding Member 0024 - Rob Bowser (SPOOLTENNA) (New 2026)
Founding Member 0025 - Dave Stewart K7XST (New 2026)
Founding Member 0026 - Prefers To Remain Anonymous 32 (New 2026)

Numerous Annual and Monthly subscribers who also generously support Zero Retries financially!

You thousands of readers of Zero Retries without which there would be little point in publishing this newsletter.

The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries \ Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0257 was published on 2026-07-10. This issue was 7859 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

It wasn’t clear if “Warog TRN” was a description of a type of drone, or an actual product name. Thus this corporate name is entirely imaginary, as far as I’m aware. I made it up for this article.

2

It’s not obvious to me if “transparent TCP/IP bridge” is (currently a capability of Mercury).

]]><![CDATA[Zero Retries 0256]]>https://www.zeroretries.org/p/zero-retries-0256https://www.zeroretries.org/p/zero-retries-0256Sat, 27 Jun 2026 06:34:17 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its fifth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is likely to be truncated by some email clients. Thus, it might be easier to read in a web browser:
www.zeroretries.org/p/zero-retries-0256.

It’s easy and free to subscribe for your own copy of Zero Retries every week:

Subscribe now

In This Issue:

I-Frame

QuadRF is LIVE on Crowd Supply!

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Kurt Geisel N3JTW for renewing as an Annual Paid Subscriber to Zero Retries this past week!

My thanks to Prefers to Remain Anonymous 75 for one year of being a Paid Subscriber to Zero Retries as of this past week!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Zero Retries Summer 2026 Publishing Schedule - Biweekly

During Summer 2026, Zero Retries will be published biweekly. The intended publication schedule is:

  • Zero Retries 0256 - 2026-06-26

  • Zero Retries 0257 - 2026-07-10

  • Zero Retries 0258 - 2026-07-24

  • Zero Retries 0259 - 2026-08-07

  • Zero Retries 0260 - 2026-08-21

  • Zero Retries 0261 - 2026-09-04

There may be some special, focused issues interspersed between the scheduled issues, such as a special issue about Zero Retries Digital Conference (ZRDC) 2026.

After ZR 0261 / 2026-09-04… to be determined.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0256. Paid subscribers can comment directly on the web version of this issue.

QuadRF is LIVE on Crowd Supply!

By Steve Stroh N8GNJ

QuadRF is the first “hackable” Phased Array Antenna technology for radio experimenters, including Amateur Radio.

Martin McCormick K1MCC via email to the distribution list for the MoonRF project:

An update since May... the wait is officially over: the QuadRF is available on Crowd Supply!

To everyone who recently joined our community specifically for QuadRF--welcome. This kit functions right out of the box as a real-time 4x4 MIMO RF camera, rendering a live, augmented-reality heatmap of the wireless signals around you at 30 frames per second.

Designed for developers, educators, hardware hackers, and amateur radio enthusiasts, QuadRF replaces tens of thousands of dollars of bulky lab equipment with a single, portable device. It completely lowers the barrier to entry for spatial RF, beamforming, and phased-array development.

With the QuadRF Kit, you get the complete RF tile, four dual-polarization antennas, an active-cooling enclosure, and an integrated Raspberry Pi 5. It’s pre-assembled and also ready to go mobile with the extended battery pack.

And for our long-time followers, you know that QuadRF is also the foundational building block for the massive 240-antenna MoonRF architecture. Our ultimate goal is to make scalable phased arrays affordable for Earth-Moon-Earth communication, radio astronomy, and custom spatial RF projects.

Since our last email, we’ve started working on certifications and export for global shipping, prepping our 100% open-source software stack (GPLv2), and cleaning up the antenna hardware files for release (CC BY-SA 4.0). The final QuadRF design is really slick, reliable and production ready! It’s wild to see how far it has come after three dozen iterations.

How you can help!

By picking up a kit (or two) today, you are directly helping us fund the mass manufacturing of these RF tiles. Once we hit volume production, building large MoonRF arrays becomes significantly cheaper for everyone. Plus, when you are ready to scale up, you can pull the RF tile right out of your kit enclosure to use in larger array builds.

Check out the live campaign, watch the AR demo videos, and secure your kit on Crowd Supply to grab a spot in our initial 1,000 unit batch, shipping early Fall:

https://www.crowdsupply.com/scale-rf/quadrf#

Thanks for all the incredible support, ideas, and feedback so far. Let’s go phased-arrays!

In the meantime, keep the questions coming in the Discord: https://discord.gg/QPGVFTsNS4

Two caveats about this project:

  • This version of QuadRF operates only on the 5 GHz band - 4.9 - 6.0 GHz. That’s likely to be the case for the foreseeable future so that it can be scaled to an eventual full array.

  • The entire project / product is not entirely open source1 - see the Support & Documentation section:

    QuadRF uses a hybrid open model. We have open-sourced the elements where users are most likely to modify, extend, and build, while protecting the RF-core implementation that makes a low-cost 4x4 MIMO SDR possible.

    Our open source software is available right now in our GitHub repository, and our Antenna design files and simulations will be opened before the campaign completes. We have guides and schematics for easy DIY and will be working with the community to make them even more accessible, and compatible with a wider range of SDR tools.

    Specifically:

    Protected RF Core: The production RF-core and official factory DSP bitstreams are proprietary. However, we provide source-available RF schematics for debugging, education, and academic research.

I don’t view this as a disqualification for experimentation, because QuadRF is the most advanced phased array technology that radio experimenters have ever had access to, at anything approaching an “experimenter” price point. QuadRF is especially useful for engineering students because its initial application, when it ships, is a visualization of radio technology. It could easily be ported to display to a virtual reality display to visually display sources of radio energy (within the 4.9 - 6.0 GHz band).

As with all such decisions about open source and proprietary technology in Amateur Radio, I respect the creator’s choice, and I’m grateful for innovative new technology to be made available to radio experimenters and Amateur Radio even with some proprietary restrictions. It might be that with the example of QuadRF someone will decide to create additional capabilities, such as a QuadRF workalike for the 2.x GHz band.

Another potential extension might be other radio receivers using more conventional approaches such as highly directional antennas such as dishes or yagis that could be overlaid on the “viewing application” for QuadRF. It won’t be as elegant as QuadRF, but might be workable.

As I’ve explained in previous issues of Zero Retries, I expect that a significant application of this technology will be for low-cost outdoor point to multipoint broadband communications systems, both Amateur Radio (especially AREDN) and unlicensed experimentation… or quite possibly, commercial systems / applications. Imagine a mesh network that not only could separate its communications by frequency and time domains, but also the spatial domain. That’s done now with large (and micro / pico?) cellular systems, but very, very expensively.

LEO Satellite Plans?

There’s no mention of the potential synergy of QuadRF (or the largest array) for satellite operations… other than “the biggest one” - Luna, the Moon, or as some long time EME experimenters refer to it - OSCAR-0.

Thus I’m mildly puzzled why there is an apparent disconnect between the potential for Amateur Radio satellites such as AMSAT’s that are in the planning stages to use a 5 GHz uplink to LEO satellites (that move rapidly across the sky, thus requiring a azimuth / elevation focused antenna) and the QuadRF / MoonRF project. The ground station requirements for such a satellite are a bit daunting for an average Amateur Radio Operator, thus QuadRF seems like an ideal technology that would make such satellite uplinks very practical, perhaps requiring only basic azimuth / elevation capabilities in conjunction with a QuadRF handles the finer tracking requirements.

Back QuadRF

The complete Quad RF Kit for advanced SDR applications. Includes the main QuadRF board, a custom antenna assembly, a custom enclosure, a Raspberry Pi 5, an international power supply, a tripod, a 32 GB microSD card preloaded with SDR software, a fan, and all necessary cables so you can get started immediately

$499 Free US Shipping / $12 Worldwide

Orders placed now ship Sep 30, 2026.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0256. Paid subscribers can comment directly on the web version of this issue.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

JNOS 2.0 - Working on AX25 V2.2

Maiko Langelaar VE4KLM on the nos-bbs email list:

Working on it, living updates in development repo ...

Need to find myself an ax25 v2.2 client and set that up I guess

This will take a bit of time I’m sure :|

This is great news about implementing AX.25 version 2.2 in JNOS! For background on the significance of AX.25 version 2.2, see Zero Retries 0244 - AX.25 Version 2.2 by John Langner WB2OSZ.

Further discussion about how to test new builds of JNOS with AX.25 version 2.2, it was suggested to use Direwolf which already supports AX.25 version 2.2 (implemented by the same WB2OSZ), and use QtTermTCP as a terminal program front end for Direwolf:

QtTermTCP is a multi-platform version of BPQTermTCP. There are versions for Windows, Linux and Android.
It supports TCP access to a bpq32 node either over a local LAN or the Internet. It connects to the BPQ32 TelnetServer in FBB mode, so you must define an FBBPORT in the BPQ32 Telnet Configuration.

It can also be used as a terminal for programs like UZ7HO's Soundmodem that support the AGW API, with KISS TNCs and with the VARA Modem. KISS TNCs can be connected via a serial port or a TCP connection. It can be used with the AGWPE emulator in BPQ32/LinBPQ though that has no significant advantages over the normal TCP interface.

It supports the YAPP protocol to allow you to send and receive files.

Mention of QtTermTCP is a handy bit of knowledge on working with Direwolf which is largely command-line driven, with configuration via config files.

Case Study - SafecomLink Cluster

Email from SafecomLink:

Shattering the ARQ Barrier with SafecomLink Pactor Clusters

Pioneering Real-Time, Cross-Band Multi-Station Chat/Data-Exchange on HF

For decades, HF data communication over ARQ modes like Pactor has been bound by two hard limits: it is point-to-point, and both stations must share propagation on a single frequency. The SafecomLink Cluster feature breaks both, enabling real-time, cross-band ARQ data exchange and the world’s first multi-party ARQ-based live chat.

EXECUTIVE SUMMARY

Breaking two limits that have bound HF data for decades

In critical off-grid communication, ARQ protocols are the gold standard for error-free delivery, but their traditional use has always carried two structural constraints. SafecomLink disrupts both with the Cluster feature, deploying a unified, multi-node “connected brain” architecture that enables real-time, cross-band ARQ data exchange and introduces the first multi-party ARQ-based live data-exchange/chat on HF radio.

Other data communications systems term this capability a gateway, bridge, or router (or similar terminology) as the capability to move messages or data between networks.

I can understand how this is being marketed as a new capability of commercial / government / professional communications systems using HF communications.

At the risk of oversimplifying the comparison, SafecomLink the commercial / government / professional version of VarAC which is offered for Amateur Radio use. “Cluster” is also a feature of VarAC (called multi-node cluster). In VarAC, see Setup > Cluster.

MorseNexus DitStorm Cypher Version 3.0 - Cypher Mail

The MorseNexus DitStorm Cypher is (as I read it) essentially a Morse Code “modem” appliance (hardware), much like a TNC, but the data communications protocol it transmits and receives is Morse Code instead of AX.25.

Now it has a very interesting new, unique capability:

DitStorm™ Version 3.0 adds the following significant improvements:

• Cypher Mail. A store-and-forward messaging system for Cypher-to-Cypher communication. You compose a message to another station and the Cypher delivers it as a sequence of Morse frames, with the recipient’s Cypher confirming receipt automatically.

Messages are stored on the device, retried automatically until delivered, and require no live, real-time contact between stations. Cypher Mail is described in full in Section 8.

There are other improvements in the Version 3.0 software, but that’s the big new feature.

It’s fascinating to think of composing an “email” message in Cypher Mail (via a computer, communicating to the DitStorm Cypher via Wi-Fi) and then having it queued and sent automatically using Morse Code. I wouldn’t have imagined such a capability… but hey, why not? Morse Code is a data communications protocol, and it’s unique that its the only such protocol that’s interoperable2 between humans and computers.

The only issue I see is that since it’s only “Cypher-to-Cypher communication”, it can only communicate between two (or more) DitStorm Cypher units? But the communications bitstream is in Morse Code, so it shouldn’t be too terribly hard to reverse engineer any unit-to-unit handshake protocols.

MorseNexus has taken the automated use of Morse Code paradigm to entirely new dimensions with their increasingly sophisticated and capable products, and now DitStorm Cypher and Cypher Mail. Kudos!

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0256. Paid subscribers can comment directly on the web version of this issue.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

Early Summer Writing Doldrums

This is the third sequential issue of Zero Retries where I started a substantive article, now three such articles, that I didn’t complete in reasonable time to be able to (barely, again) publish Zero Retries on Friday (Pacific time). And I nearly missed an important contribution deadline and a couple of other significant writing commitments. Sometimes, writing is bleh, and the only “cure” is self-imposed mandatory butt-in-chair time. But perhaps, with a laptop, the writing environment can be made a bit more pleasant, like outdoors in the open air.

The weeks have flown by, consumed by… stuff. Fortunately this week was a bit lighter for breaking news, but doubtless there will be some Zero Retries Interesting news or presentations from HAM RADIO this weekend.

Thanks to all the Zero Retries readers who have suggested topics for Zero Retries. That you didn’t see your suggestions mentioned to date speaks to the “Doldrums”. Apologies, and I’ll try to catch up, but from experience, I can’t promise.

Unless there is major breaking news to justify an “early” issue (or a single topic Zero Retries Bulletin issue), the biweekly Summer 2026 schedule will resume, and Zero Retries 0257 will publish in two weeks - 2026-07-10.

Happy US Independence Day to US Readers

Since I don’t plan to publish Zero Retries next Friday, I’ll take a parochial moment here in (US-based) Zero Retries to wish my fellow US readers of Zero Retries a Happy 250th Independence Day next Saturday - 2026-07-04. This US holiday is often (and incorrectly, in my opinion) referred to as the “4th of July” or “July 4th” holiday, but my Dad always bristled at those references, pointing out that we’re not celebrating the 4th day of the 7th month… we’re celebrating the anniversary of US Independence Day.

The US is a (horribly imperfect at times) experiment in progress in democracy. But one thing that we can (and I am) be proud of is that however imperfect we are at times, we keep striving to be a more perfect union. The vast majority of us do the best we can, with what we have, with what we know at the time, and try mightily to be good neighbors, apologize when we’re not, and strive to do better.

ZRDC 2026 Ho!

Zero Retries Digital Conference (ZRDC) 2026 will be here before we (I) know it.

16 weeks until Zero Retries Digital Conference 2026

on Friday, October 16, 2026,

in San Ramon, California, USA.

Weekends Are For Amateur Radio!

(ARRL) Amateur Radio Field Day is this weekend, and in our corner of the world and North America, it will be damp. For the next week we’ll be getting what is usually the last gasp of significant precipitation for the Summer, typically until mid-September. In this area, July and August are usually sunny, dry, and mild. This week’s “damp” is welcome as it gives us perhaps a month’s grace of minimal wildfire danger before the heat and dry conditions combine to increase the wildfire danger to “likely” at some points in the vast forests of the Pacific Northwest.

This week has been more hectic than I anticipated and thus Meadow Day 2 might not happen, but pretty much by design, a Meadow Day exercise, especially with the Starlink Mini, only requires perhaps an hour of “grabbing stuff”, so perhaps it will work out.

Have a great weekend, HAM RADIO, and Field Day all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0256. Paid subscribers can comment directly on the web version of this issue.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

Founding Members who generously support Zero Retries financially:
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Founding Member 0004 - William Arcand W1WRA (Renewed 2025, 3rd year!)
Founding Member 0005 - Ben Kuhn KU0HN (Renewed 2025, 3rd year!)
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Founding Member 0008 - Prefers to Remain Anonymous 08 (Renewed 2025, 3rd year!)
Founding Member 0009 - Prefers to Remain Anonymous 19 (Renewed 2025, 2nd year!)
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Founding Member 0012 - Ryan Tolboom N2BP (Renewed 2025, 2nd year!)
Founding Member 0013 - Newton White N4EWT (Renewed 2026, 2nd year!)
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Numerous Annual and Monthly subscribers who also generously support Zero Retries financially!

You thousands of readers of Zero Retries without which there would be little point in publishing this newsletter.

The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries | Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0256 was published on 2026-06-26. This issue was 3235 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

I have previously characterized open.space / MoonRF / QuadRF product and project as “entirely” open source. That characterization is not correct. I was corrected about that characterization by a Zero Retries reader with deep experience in open source.

2

Arguably, other than (very recently) automated speech recognition and generation.

]]><![CDATA[Zero Retries 0255]]>https://www.zeroretries.org/p/zero-retries-0255https://www.zeroretries.org/p/zero-retries-0255Sat, 20 Jun 2026 03:01:06 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its fifth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is too big for email clients. Thus, it might be easier to read in a web browser - www.zeroretries.org/p/zero-retries-0255.

It’s easy and free to subscribe for your own copy of Zero Retries every week:

Subscribe now

In This Issue:

I-Frame

LinHT Rev B Status: What Works, What Broke, and Why Rev C is Next

Mercury Proven Useable as an HF Data Communications Mode

Ham.Live is Going Away; N5SAC, the Sachse Fire Station Ham Radio Club is Trying to Save It

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Prefers To Remain Anonymous 129 for becoming a new Annual Paid Subscriber to Zero Retries this past week!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Zero Retries Summer 2026 Publishing Schedule - Biweekly

During Summer 2026, Zero Retries will be published biweekly. The intended publication schedule is:

  • Zero Retries 0255 - 2026-06-26 2026-06-19

  • Zero Retries 0256 - 2026-07-10 2026-06-26

  • Zero Retries 0257 - 2026-07-24 2026-07-10

  • Zero Retries 0258 - 2026-08-07 2026-07-24

  • Zero Retries 0259 - 2026-08-21 2026-08-07

  • Zero Retries 0260 - 2026-09-04 2026-08-21

  • Zero Retries 0261 - 2026-09-04

There may be some special, focused issues interspersed between the scheduled issues, such as a special issue about Zero Retries Digital Conference (ZRDC) 2026.

After ZR 0261 / 2026-09-04… to be determined.

This Issue is a Week Early

In Zero Retries 0254, I stated that “the plan” was for this issue publish next Friday. But, the three stories about technological innovation in and adjacent to Amateur Radio - LinHT, Mercury, and Ham.Live weren’t amenable to such a schedule.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0255. Paid subscribers can post comments on this issue.

LinHT Rev B Status: What Works, What Broke, and Why Rev C is Next

Vlastimil Slinták OK5VAS on the M17 Project Website:

LinHT display - Image courtesy of Vlastimil Slinták OK5VAS / M17 Project

Before Friedrichshafen, we want to put the current LinHT development status in one place. We have published many short updates over the last months, and the project moved through several phases: Rev A proof-of-concept testing, Rev B design, manufacturing, first boot, RF tests, audio bring-up, GNSS debugging, and now Rev C planning.

This post summarizes that progress. It starts with what Rev A proved, then goes through what we changed in Rev B, how we built the first boards, what worked during testing, what failed, and what we need to fix before Rev C.

If you want the longer background, start with my older text about the first LinHT prototype: LinHT – Open SDR Handheld for Radio Amateurs. That article describes the Rev A board, the Retevis C62 donor-radio approach, and the basic idea behind LinHT: a Linux-based SDR handheld transceiver, open enough that the radio can be changed in software, not only programmed from a vendor tool.

Rev A was our proof of concept. It showed that the architecture made sense and that the device could work the way we imagined. An i.MX93 system-on-module could boot Linux inside a handheld radio body, run a Yocto image, expose USB networking, talk to the display, run GNU Radio flowgraphs, and use the SX1255 IQ RF front end. We decoded M17, tested TETRA receive, displayed spectrum data on the small screen, and ran enough hardware and software tests to be sure that the concept was valid.

Rev B is the revision where we tried to turn that proof of concept into a much more complete handheld.

This is a very comprehensive update on LinHT, probably a ten minute read. Click on the title link for the complete article.

The development progress outlined in this update is remarkable, in my opinion. Just as one example, the completely independent development of LinHT is running rings around all the China-based Amateur Radio manufacturers that are endlessly iterating on mundane “advances” in their products, such as embedded 1200 bps TNCs accessible via Bluetooth. That’s… nice… but hardly competitive in the mid-2020s, and just another copycat feature. LinHT represents a leap forward in (Amateur) radio technology.

Very Talented Developers

In my opinion, the three developers of LinHT:

  • Andreas Schmidberger OE3ANC

  • Vlastimil Slintak OK5VAS

  • Wojciech Kaczmarski SP5WWP

(and the supporting team) are “punching above their weight”, developing a significant new radio project that could easily justify the resources of a company and a team of ten or so developers. (In saying this, I’m not intending to “sabotage” the LinHT project… but offering credit where due…) Each of the three developers are proving their respective talents in radio technology development. Thus any company that is doing radio technology development would be fortunate to employ any of them. A comment by a company that was represented at GNU Radio Conference 2025 that had open positions for radio technology put such demonstrated capabilities into context - “Don’t tell me what skills you have, show me what skills you have on a project that you’ve executed on.” The LinHT developers are doing so.

Rev C May Well Be Buildable by Amateur Radio Operators

What struck me after reading this update is that there don’t seem to be any “unknown unknowns”. The remaining issues, for example - the placement of the GNSS receiver, seem understood. Thus it’s “just” “straightforward” engineering to fix the remaining issues.

Thus a Rev C board could be put into production and sold to brave experimenters to create their own LinHT:

  • Buy a Retevis C62 radio,

  • Buy a Rev C LinHT board,

  • Disassemble the Retevis C62,

  • Scavenge the required components from the Retevis C62 board (display, etc.)

  • Add the scavenged components to the LinHT board,

  • Reassemble the radio with the LinHT board,

  • Flash the current images onto the components.

  • Enjoy your bragging rights of having a very rare, very cool, bleeding edge piece of Amateur Radio technology that can do things no other portable Amateur Radio unit can do.

That last bullet is no small thing. We all like to brag about something cool in our personal Amateur Radio sphere. For example, there is a large manufacturer of commercial portable radios that can be very expensive. Amateur Radio owners of such units enjoy bragging about them and showing them off. Admittedly those units are nice. As for me, I would be much more impressed by someone showing off their LinHT. Just as one minor point… a LinHT can run M17, and Single Sideband (SSB). That last one will undoubtedly impress, because even the $$$ commercial portable radio can’t do SSB.

Another example of the much greater capabilities of the LinHT versus typical commercial Amateur Radio portable radios - because LinHT is Open Source, all of the text on the display can be customized for one’s language preference. Instead of defaulting to common languages such as English, the LinHT can display in, for example, German, Czech, or Polish.

A Few Speculations About the LinHT as Disruptive Technology

The market for the LinHT will be larger than the Amateur Radio market. Remember that LinHT runs unmodified GNU Radio v3 flowgraphs. Thus the practical form factor of the LinHT will be attractive to GNU Radio developers who are also Amateur Radio Operators1 for testing and using their experimental GNU Radio flowgraphs.

In looking ahead at the potential future of the LinHT as a commercial product, I’m reminded of PacComm being founded by licensing the TNC-2 design from TAPR. PacComm went on to be a successful company by developing unique products for both the Amateur Radio and commercial markets. Another example is FlexRadio was founded on the basis of a project that was published in a magazine. FlexRadio “came from behind” to provide bleeding edge products such as the Aurora series and currently being unique in the ability to add in FreeDV RADE as “just another mode selection”.

The “not invented here” perspective of all of the Amateur Radio manufacturers, especially the China-based radio manufacturers towards the LinHT to date seems to me to be a classic example of The Innovator’s Dilemma. That is, those radio manufacturers are all doing well, selling derivatives of their current products, into (what they perceive as) a largely static, undemanding market. They are the “Blackberry” versus the LinHT “iPhone”. For example, Icom’s extension of their popular IC-7300 into the IC-7300MK2. FlexRadio is another such example, creating new products only for the (well understood, to them) market for very high end HF transceivers rather, than, for example, developing a new product line for VHF / UHF / Microwave bands.

The Amateur Radio manufacturers can easily justify their deliberate ignorance of the LinHT because there is no “threat” to their “business as usual”. LinHT is “merely a minimally funded project” by three persons. But make no mistake…

the LinHT is disruptive technology within (and beyond) the Amateur Radio market.

There are many instructive parallels of successful companies choosing to ignore alternatives to their dominant products and technologies until a challenger specializing in those alternatives becomes a threat to their business. By time the threat to their business is apparent, it’s often too late and the inertia of the larger, successful company works against them.

Some person, some company, or perhaps some non-commercial organization is going to figure out the large and lucrative market waiting for a LinHT (and, I’m convinced, the development of a LinMobile).

When a technology like LinHT has unlimited potential to scale upward and fix the many problems existing in the current Amateur Radio paradigm… you know it’s just a matter of time. That’s the exciting thing about the development of a radical new technology like LinHT challenging the current paradigm of fixed function radios by current Amateur Radio manufacturers. It’s fun watching for “the breakout”.

Many of us have seen such disruptive technology ascend into dominance. Examples abound:

  • OFDM versus earlier forms of dense modulations,

  • iPhone versus the then-dominant Blackberry,

  • Linux versus Windows,

  • Personal computers versus minicomputers

  • The Internet versus the telephone network.

We’ve seen these disruptive technologies “come from behind”, thus we know how such stories eventually play out when the disruptive technology (LinHT in this case) offers compelling advantages over the currently dominant technology.

The technological capabilities of a fully software defined radio, in a portable (and eventually, mobile) form factor, are just too profound for it not to become the dominant paradigm in radio technology. It might take time… it will probably come (at scale) from a source no one would have expected… but it is inevitable.

I… cannot… wait! Goodspeed LinHT team! And Thank You for taking this big leap and incredible amounts of work to move Amateur Radio forward beyond the “same old, same old” technology that the Amateur Radio manufacturers would prefer to offer us.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0254. Paid subscribers can post comments on this issue.

Mercury Proven Useable as an HF Data Communications Mode

By Steve Stroh N8GNJ

Mercury is an Open Source project by Rhizomatica to create a high performance data communications mode for use on the High Frequency (HF) bands below 30 MHz. The HF bands pose unique challenges for data communications including fading, significant potential for interference, and many other conditions that necessitate data communications modems (and digital voice modes) to be uniquely adapted for HF.

The primary differentiation between VARA HF (currently the highest performance HF data mode running as software on a host computer via an audio interface) and Mercury is that Mercury is Open Source, free to use, and can be used on computer systems other than Windows. In contrast, VARA HF is proprietary, requires the payment of a license fee to “unlock” full performance, and runs only on Windows or Windows workalikes such as WINE.

Similar to VARA HF (which Mercury was modeled2 on):

  • Mercury is software on a host computer via an audio interface,

  • Mercury uses Orthogonal Frequency Division Multiplexing (OFDM) modulation,

  • Mercury implements Forward Error Correction,

  • Mercury implements dynamic “upshift” and “downshift” amongst its variable parameters to attempt to maintain a continuous data communications connection for the length of the data transfer.

In some mentions of Amateur Radio media, Mercury is stated as being “compatible” with VARA HF. Yes, and No.

Yes, Mercury implements the same software (TCP Sockets) interfaces as VARA HF. This enables Mercury to be used in the same way as VARA HF is used with applications software such as the Pat Winlink client, and (at least experimentally) the powerful VarAC application that incorporates text chat, bulletins, file transfers, and email.

No, Mercury is not interoperable with VARA HF over the air. A VARA station cannot communicate with a Mercury station.

At the moment, this incompatibility reduces the immediate utility of Mercury because it cannot be used to communicate with the large number of Winlink Gateway Stations (Radio Message Servers) that use VARA HF.

But there are many other uses of data communications over HF that Mercury is well suited for, including the increasing popularity of Automatic Packet Reporting System (APRS) beacons over HF, short messages or emails peer to peer (such as using Pat in peer to peer mode, rather than connecting to Winlink). Given that Mercury is free to use, I think it’s probably a matter of time, with some improvement in performance, that Winlink Gateway Stations (Radio Message Servers) will add Mercury in addition to VARA HF.

KM6LYW Demonstrates Mercury

I think that Mercury is ultimately more useful than VARA HF for the simple expedient that it can be run natively on a Linux system as minimal as a Raspberry Pi, as demonstrated by Craig Lamparter KM6LYW on the KM6LYW Radio YouTube Channel:

KM6LYW provides some context for this development on his KM6LYW Patreon page / blog:

Better Than VARA: First Winlink Email Sent over MERCURY on RF! (DEMO)

The guys at Rhizomatica just made a better VARA than VARA. Unlike VARA, it’s free, open-source, runs on Linux and Raspberry Pi. While not directly compatible with the proprietary VARA encoding, it does use the same API so existing VARA-HF clients (Pat, Winlink Express) can immediately leverage this exiting new HF radio transport!

In this video, we use “Pat” (http://getpat.io) Winlink email client on “DigiPi” (http://digipi.org) and Mercury (https://github.com/Rhizomatica/mercury ) send an email message over RF from one Raspberry Pi to the other.

The radio on the right (ic705) is the client running pat client (pat http), and the radio on the left (ic7300) is running pat server (pat --listen=vara http).

This is a first-ever technology demonstration and proof-of-life. Much more is to come, in fact, I think I’ll create a MERCURY Winlink Server that everyone can run along side VARA, Packet, ARDOP, etc.

Both VARA and MERCURY leverage “Orthogonal Frequency Division Multiplexing” which is the foundation for modern/commercial RF transports, including WIFI. That’s how we get our speed and reliability. MERCURY includes “gear shifting” dynamically adapting to conditions and fading SNR.

Project MERCURY https://github.com/Rhizomatica/mercury

DigiPi https://digipi.org/

Kudos to KM6LYW for doing this demonstration of Mercury, that it is viable.

I hope that KM6LYW will eventually incorporate Mercury into DigiPi equivalent to ARDOP being included as a mode in DigiPi.

I have hopes that Mercury will be incorporated as a “standard mode” into Open Source Software Defined HF radios such as the HF Signals sBitx and zBitx (I have suggested this to HF Signals). I hope that the Mercury developers will reach out to FlexRadio to make Mercury available as “just another mode selection” on the FlexRadio 8000 series and Aurora, as is now the case with FreeDV RADE.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0254. Paid subscribers can post comments on this issue.

Ham.Live is Going Away; N5SAC, the Sachse Fire Station Ham Radio Club is Trying to Save It

Email from Lonnie Webb KG5WHQ:

The beloved Net logging and chat service is going away. I love Ham.Live as it is SO easy to use that even your Uncle Fred can work the chat from the VA! N5SAC - the Sachse Fire Station Ham Radio Club decided Ham.Live is too valuable to lose. We have built a private instance to test it prior to it being shut down.

Our goal is to continue Ham.Live (probably under a different domain name) as a hosted service for anyone to use without the complexity of creating their own hosted version of Ham.Live.

N5SAC (www.sachseraces.org) is a ham club, we aren’t going away. But we do badly need publicity and beta testers. We aren’t asking for sponsors, but we wouldn’t turn one down. Our club is open to the public and have FD members in our club.

The push is to be golden for July 1, when the original Ham.Live service will go offline.

The beta test URL for N5SAC’s version of Ham.Live is:
www.sachseraces.org/ham-chat/

I put more details on a post on Facebook:
www.facebook.com/share/p/1JWDtuZ1vJ/

I hope you can help us bring more publicity to our project with clubs around the world.

Here’s the text of the Facebook post for those (like me) who sometimes cannot access individual Facebook posts:

Ham.Live goes away at the end of the month, and I will be sad to see it go. BUT--KK6BEB did such splendid work that we at N5SAC, the Sachse, TX Fire Station Ham Club, have given it a new home!

Be a beta tester and help us iron out the bugs! Visit https://tinyurl.com/n5sac-chat to learn more. Share out the URL and QR code to your ham club.

We ask you to give up an email address so we can notify you when we go out of beta. Your data should persist unless we find a terrible bug.

This is an instant text chat and logging software for YOUR ham radio nets. You can share links to files, images, etc. It’s faster, and no actual training is needed to use it. Your Uncle Fred--who cannot operate Discord--can even use it without coaching.

Log in and set up a new net in about 5 minutes. This is EASY. It even works on HF nets

😉

The best feature: you can “whisper” privately to anyone on the net in a side-chat!

N5SAC says, “Be a ham and have fun!”

Context on Ham.Live

Ham.Live logo
Image courtesy of Ham.Live

From the main page:

Ham.Live is now open source

Every club can run its own instance — free, MIT-licensed, and fully documented. View & self-host →

Hosted service retires June 30, 2026

From github.com/Constant-Digital-Holdings-LLC/hamlive-oss:

Ham.Live (Open-Source Edition)

Self-hostable web app for running amateur radio nets.

Ham.Live is a browser-first application that helps amateur radio operators discover, join, and run nets — coordinated on-air meetups where stations check in, exchange signal reports, and follow a moderated agenda. This is the community open-source edition, intended to let clubs and groups run their own instance.

This repository is the MIT-licensed sister project to the original hosted Ham.Live service, shared for the amateur radio community to run and carry forward.

Project status

Ham.Live is released as-is for the community to self-host and carry forward. It’s the code that powered the hosted Ham.Live service, which is winding down — I’m stepping back from day-to-day operation, not taking on a support desk.

What that means:

  • No guaranteed support, SLAs, or maintenance. Running an instance is do-it-yourself.

  • Issues and pull requests are welcome but handled on a best-effort, time-permitting basis — they may not be answered or merged, so please don’t expect a quick response.

  • Forks are encouraged. If someone wants to drive this forward as a community maintainer, that’s the goal — not a worst case.

  • The MIT license already says it: provided without warranty. The same applies to support.

If your club depends on it, treat it like infrastructure you own: read the docs, keep your own backups, and plan for self-reliance.

Features

  • Real-time net participation — live presence, ordered station lists, and interactions (hand, highlight, check-in/out, signal reports)

  • Net control (NCS) tools — start/stop nets, assign roles, and run moderation via shell-style commands

  • Net discovery & following — find active nets and follow the ones you care about

  • Real-time chat (optional, via GetStream) with inline images

  • Email + Google sign-in — magic-link email login, with optional Google OAuth

  • No front-end framework — native ES modules, Custom Elements, and reactive stores

I confess I was not aware of Ham.Live until KG5WHQ’s email.

Assistive applications like Ham.Live make trying to keep track of fast-paced nets, especially to those that are new to the experience, a bit easier and less intimidating.

I hope that some Zero Retries readers can assist the Sachse Fire Station Ham Radio Club in creating a new hosted version of Ham.Live for the benefit of those who prefer not to, or or cannot, host their own version of Ham.Live.

Another Assistive App for Running Nets - KK7NQN Transcription Service Node (TSN)

Another assistive application for running a net is the KK7NQN Transcription Service Node (TSN):

As the name indicates, KK7NQN TSN attempts to transcribe the conversation on the net (and much more), especially the callsigns that can come fast at a net control operator during a busy net. KK7NQN TSN uses some web services, but the core functionality isn’t dependent on web services. KK7NQN TSN can be run on hardware as modest as a Raspberry Pi, including the AI features.

For long time Zero Retries readers who are already aware of KK7NQN TSN (which was publicly debuted at the Zero Retries Digital Conference 2025 - video link), a new look at the kk7nqn.net website is warranted. KK7NQN has put a lot of work into better explaining the TSN concept and how it’s used.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0254. Paid subscribers can post comments on this issue.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

Join ARDC on Discord!

Email from Rebecca Key KO4KVG of ARDC

We’ve launched an ARDC Discord Server!

Whether you’re a grantee, volunteer, 44Net user, member of the amateur radio or digital communications communities, or simply interested in learning more about ARDC, we invite you to join us on Discord.

The server is a place to discuss grants, project updates, 44Net, and related topics while connecting with others across the community.

You can join us here: https://discord.ardc.net.

Sigh… I held out as long as I could given my disadvantage of not being good at continuous partial attention that realtime group chat systems such as Discord require. But, the combination of ARDC and the new Spectrum Community Group of Cascade STEAM having community interactivity on Discord… well, I can no longer resist. I feel compelled to get back on Discord to feel connected (yes, pun intended) to these groups, and also join the IP400 Discord group to see what’s happening with IP400 these days.

HAM RADIO 2026 International Amateur Radio Exhibition is Next Weekend

2026-06-26 thru 28 in Friedrichshafen, Germany.

It’s been nearly five laps around Sol since I began Zero Retries and thus began trying to pay closer attention to Amateur Radio technological innovation in Europe. Thus I wanted to attend HAM RADIO to get a reasonable sense of the companies, groups, and technology that aren’t well represented in the US. This year’s event is even more interesting:

HAM RADIO 2026 meets ASTRO

Amateur Radio meets the Stars: New Astronomy Exhibition opens alongside HAM RADIO

Under the motto “Discover the Sky: Amateur Radio meets Astronomy,” HAM RADIO 2026 takes it a step further and shines even brighter with the Astro trade fair, held in parallel for the first time. The trade fair dedicated to astronomy, astrophotography, and modern observation technology is a perfect complement—featuring its own lecture program, an astro flea market, numerous technical exhibitors, and various connections to amateur radio.

The reduction of international participation at Hamvention 2026 was noticeable, even from 2025. There just weren’t very many international exhibitors at Hamvention, other than Radio Society of Great Britain (RSGB) and HAM RADIO. Purely from vague memory, there seemed to be a lot more international exhibitors at Hamvention 2025. Such lack of participation of companies willing to travel to the US in 2026 is understandable, of course. There’s also the factor that in 2026 the expenses of international travel, and shipping exhibits, etc. increased significantly. So, perhaps in 2027, things will have calmed down to a dull roar and Tina and I can avail ourselves of a standing offer from a friend of Zero Retries to act as a guide and escort for us to travel to Europe (finally), do some touristing, and attend HAM RADIO 2027. Perhaps even exhibit Zero Retries and Zero Retries Digital Conference, and some cool Zero Retries Interesting projects from North America.

(ARRL) Amateur Radio Field Day 2026

The other big event next weekend is (ARRL) Amateur Radio Field Day 2026 (PDF), held from 1800 UTC Saturday and ending at 2059 UTC Sunday on the air.

The most Zero Retries Interesting aspect of (ARRL) Amateur Radio Field Day is AMSAT Field Day 2026 on the Satellites. That sounds like a fun, and a more technical aspect of participating in (ARRL) Amateur Radio Field Day 2026. Despite my years of “Satellites… Real Soon Now…”, I’m not yet active on Amateur Radio satellites.

From Random Wire 187

On the off chance that there are some Zero Retries readers that don’t yet subscribe to the other excellent Zero Retries Interesting technically focused Amateur Radio weekly newsletter, Random Wire by my friend and colleague Tom Salzer KJ7T, there were three very Zero Retries Interesting items mentioned in this week’s issue:

  • 09 Keeping Every Ham at the Table
    This excellent article discusses the use of a local AI for aiding Amateur Radio Operators in remaining active in Amateur Radio activities despite physical challenges. KJ7T provides an excellent rundown, and explains his own project to address such issues. In an email to KJ7T, I mentioned that there is an organization called Courage Kenny Handihams Program whose mission is:
    The Courage Kenny Handiham Program provides tools for people with disabilities to learn Amateur Radio and technology skills, and to earn their Amateur Radio licenses.

  • I’ve been wanting to stand up a small fill-in digipeater, but I rarely have a lot of time to dig into projects like this. That’s why I was very pleased to see the LightAPRS Gateway by QRP Labs. I have one on order and am looking forward to getting it on the air.
    I wasn’t aware of this device, but I agree with KJ7T that this looks like an excellent APRS appliance with the bonus that all of control and display is designed to be accessed remotely via network. Thus it’s almost ideal for remote mounting near an external antenna, but the enclosure doesn’t look weather-resistant. That’s easily solved by mounting it into a weather-resistant (larger) enclosure. The power input is USB-C, so to remote it, at minimum, there needs to be an external voltage over Ethernet to USB-C power converter. Not to mention, it’s a product of QRP Labs which makes very good stuff. The N8GNJ / Zero Retries experiment budget has been replenished, so maybe this will find its way to the overflowing future projects pile in N8GNJ / Zero Retries Labs.

  • The Great Plains Super [balloon] launch event is gearing up for the weekend. Many balloons beaconing on APRS.
    As in     this weekend, in Pella, Iowa, USA. If you’re anywhere near the central portion of North America, you may be able to receive some of the telemetry from the highest altitude payloads. GPSL is yet another Zero Retries Interest event that I’d love to attend one of these years.

Again, Random Wire is highly recommended. Like Zero Retries, Random Wire is a free Amateur Radio newsletter and I can’t think of any reason why, if you’re reading Zero Retries, you wouldn’t also want to read Random Wire.

Hilberling UDL-16 Multi-Transverter

Enthusiasm for Ham radio is one of the foundations that led to the formation of Hilberling GmbH.

The know-how gained through years of experience in the development and series production of industrial and maritime high-frequency products flows directly into very special products for Ham radio.

Cutting-edge technology developed and manufactured in Germany!

UDL-16 Multi-Transverter

Up / Downlink Transverter for Satellite Communication on QO-100 / P4-A NB Transponder

Hilberling GmbH UDL-16
Image courtesy of Hilberling GmbH.

That… is one sophisticated piece of Amateur Radio technology! As is the other products on that page of Amateur Radio products by Hilberling.

This is an example of Zero Retries Interesting products that aren’t widely known outside of Europe. The PT-8000A - VLF / HF / VHF Ham Radio Transceiver is pretty impressive also.

Hilberling GmbH PT-8000A VLF / HF / VHF Ham Radio Transceiver
Image courtesy of Hilberling GmbH.

I really like the front panel layout / user interface of the PT-8000A. It seems very functional and straightforward with a minimum of distracting, over-complicated “eye candy” that’s so prevalent on Amateur Radio HF radios in this era.

Hilberling also offers a 2.4 GHz transverter for uplinking to the QO-100 Amateur Radio payload in Geosynchronous Earth Orbit (GEO) above the Eastern Hemisphere which has driven a lot of technological innovation about Amateur Radio satellite communications in Europe and Asia.

It’s really cool to see a really solid acknowledgment from Hilberling about the value of providing unique, technologically innovative products into the Amateur Radio market, and especially the acknowledgement that participating in Amateur Radio is a core value of the company.

My thanks to Steve Monsey N0FPF for bringing this development to my attention for inclusion in Zero Retries.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0254. Paid subscribers can post comments on this issue.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

Zero Retries Bulletins

Given that I had planned for this week to be an “off week” for publishing Zero Retries, this issue almost became the first Zero Retries Bulletin. However, the three significant stories combined were enough justification to make this issue into a full issue of Zero Retries.

Zero Retries Bulletins will (generally) be a brief post / email on a single subject, published whenever there’s a story that’s more appropriate to publish sooner than the weekly (or biweekly) cadence of Zero Retries. My model for Zero Retries Bulletins is the relationship between Amateur Radio Weekly and Amateur Radio Daily, with the latter being a single subject, published whenever appropriate.

Substack Sponsorships

Email from Substack:

You’re invited: early access to sponsorships on Substack

We recently announced Creator Kits for Substack bestsellers. These are a way to let us know you’re interested in using sponsorships and brand partnerships to add value for your subscribers.

The idea is simple: brands can support your work directly in ways your subscribers benefit from, like unlocking a paywalled post, co-hosting an event, or backing a series you care about.

If you’d like to participate, publish your Creator Kit: a media kit that helps us introduce your publication to potential brand partners.

Participation is entirely optional. Turning on your Creator Kit simply lets us know you’re interested. You’ll always choose whether to work with a brand, set the terms, and keep the vast majority of the revenue. We’ll handle the rest.

I was apparently an early invitee because Zero Retries has more than 100 paid subscribers. Substack isn’t very specific about exactly how Substack sponsorships work, other than how to create the “Creator Kit”. But, presumably, there will be some form of sponsorship message… ads… inserted into Zero Retries. It’s unlikely that there are any Zero Retries Interesting Amateur Radio advertisers on Substack, so likely the ads, er, sponsorship messages will be directly relevant.

This is an intriguing possibility, given that there has been zero, zip, nada interest from Amateur Radio sponsors, other than the wonderful Paid Subscribers and Founding Members, to help financially support Zero Retries. Thus this might be worth a try.

One feature that I hope will be available (and if it isn’t, I’ll request that it be added) is an option that Paid Subscribers and Founding Members not be shown sponsorship messages (ads).

YouTube Short - N8GNJ’s Brief Mention of Radio on the Titanic

Jane McConnell via email:

People have watched and liked the short I put on line a few hours ago with you talking about the Titanic.

https://youtube.com/shorts/TVQZD4feiXo?feature=share

Just wanted to let you know!

This is a (AI animated) brief excerpt of my interview with McConnell earlier this year - Steve Stroh – Zero Retries, Amateur Radio and the 21st Century.

EtherHam - Build Your Own Substack Archive Search

EtherHam is Random Wire’s “sister” publication, where KJ7T publishes longer-form, less topical articles. Of particular interest to me on EtherHam was today’s article Build Your Own Substack Archive Search. KJ7T is absolutely correct that Substack’s search capability, especially as your archive grows (such as more than 250 issues of Zero Retries) can only (charitably) be described as “poor”. I tried using Google’s NotebookLM as an archive query tool, but I’ve not been impressed with it, especially the minutes-long lag in just doing a simple query. I’m going to have to carefully consider whether KJ7T’s “simple” solution:

… standard shared hosting with PHP and SQLite — no special server setup required.

is within my capabilities to create and maintain. But, I really do need a search capability for Zero Retries that works!

Technological Innovation in Radio Technology in World War 2

The algorithm (or full blown AI now, I guess) on YouTube has begun presenting me with World War 2 “mini documentaries”. In reality, these are essentially AI generated podcasts with random… at times laughable… slideshows of photos to qualify as a “video”. Because of the droning AI voices don’t vary much in intonation, I’ve found that they’re relaxing audio as I’m trying to go to sleep. Some are really bad. Some are… not terrible. A handful have been reasonably good and informative about things I never knew.

A subset of these World War 2 videos discuss radio technology that was developed or perfected during World War 2. I’m now beginning to look around for books that better explain this incredible period of innovation in radio technology.

The biggest revelation, to me, about radio technology developed during World War 2 was how a Proximity Fuze artillery shell works - and was developed with early 1940s electronics technology. Would you imagine that a vacuum tube could be developed that could withstand the incredible acceleration and centrifugal force within an artillery shell? Also remarkable was that the US development of a workable Proximity Fuze was a technology development program second only to the Manhattan Project in secrecy, complexity, and overall cost. Another groundbreaking aspect of the Proximity Fuze program was that the requirements for quality control and reliability of electronic components was exponentially higher for use in Proximity Fuzes. That industry experience became a significant advantage in developing reliable electronics for the space use.

Those two aspects boggled my mind. Things you have no idea about…

The Proximity Fuze development program helped fill in a gap in my knowledge base of electronics history, that (glass) vacuum tube circuitry was gradually displaced by more reliable, more capable, and (finally…) cheaper transistors. But in that transition, there was an odd almost-hybrid of the two - the Nuvistor, which at a glance could easily be confused as a transistor, but was actually a miniaturized vacuum tube in a metal can, like early transistors. Where did the Nuvistor come from? It was barely mentioned in all the voracious reading I did as a teenager about electronics. But after learning about the development of the Proximity Fuze, and the need for highly ruggedized, highly miniaturized, highly reliable vacuum tubes, Aha! Now I understand the Nuvistor a lot better.

Very slightly related to Amateur Radio - the Doppler RADAR function of the US Proximity Fuze developed during World War 2 operated at 180 – 220 MHz. (In North America, the 220-225 MHz band was allocated to Amateur Radio. Later, 220-222 MHz was allocated to other services.)

Some other radio-related technologies developed / perfected in World War 2 (most by the Allies):

  • FM modulation and VHF / UHF became much more widely used for tactical communications, especially in tanks, jeeps, and “man portable”:

    • The SCR-536 handheld “Walkie Talkie” was so revolutionary that (per the videos), the first few units found by the Germans were considered a propaganda tool, in part because it used FM, which was not used by the Germans.

    • The SCR-300 backpack FM radio was revolutionary - radios (in sufficient quantity) with reasonable range and reliability could be placed wherever needed, included forward observers spotting for infantry.

  • Crystals began being widely used making radio much more reliable,

  • Radio Teletype (RTTY) became widely used,

  • LORAN was developed for aviation and marine navigation,

  • Germany developed Knickebein (”Crooked Leg”), X-Gerät (”X-Apparatus”), and

    Y-Gerät (”Y-Apparatus”) to navigate their bombers over the UK.

  • Direction Finding systems became much more widely used for rapid location of transmitters,

  • RADAR of course, especially the UK’s Chain Home network and microwave RADAR that was used to locate surfaced submarines,

  • Single Sideband (SSB) came into widespread use because HF frequencies became very heavily used and SSB was more efficient than AM,

  • Mobile communications (including backpack radios) became much more widely used, driving the development of more rugged electronics and better power efficiency,

  • And, all of this radio / RADAR technology created Electronic Warfare, from simple strips of aluminum foil “chaff” to jam RADAR, to active electronic jamming of RADAR, radio communications, land radio location.

One video mentioned that the three highest priority consumables for logistics support to the front line were:

  1. Artillery shells and ammunition,

  2. Vehicle fuel,

  3. Batteries for the portable radios.

Feather Ruffling

This week a Zero Retries reader pointed out to me that in my call ‘em as I see ‘em candid style of discussing Amateur Radio organizations, projects, and (rarely) individuals, I don't exactly endear myself to those organizations, projects and individuals.

The reader observed that in my article in Zero Retries 0254 - The Remarkable, but Relatively Unsung Achievement of Integrating FreeDV RADE Into FlexRadio’s 8000 and Aurora Radios, I have, at times, given (always intended as) constructive criticism to each of the four organizations I suggested that could (should?) work together to promote FreeDV RADE.

That’s a fair point, and quite possibly why none of the four organizations have responded substantively to my suggestion to jointly promote FreeDV RADE.

The freedom to be able to do so - offer such suggestions, candidly, in detail, is one of the benefits, and perhaps responsibilities, of being a fully independent publication. I understand why other publications / media choose a different path - never saying anything that potentially might offend organizations or individuals.

But in the big picture of Amateur Radio in the 2020s, a “never potentially offend” perspective isn’t what’s needed for Amateur Radio to continue for the long term. Especially in this era where Amateur Radio is transitioning not only in technology, but there is a substantive change in orientation of Amateur Radio Operators - from “traditional” Amateur Radio Operators to the NewTechHams. Not to mention Amateur Radio’s tenuous perception of being relevant to society in the 21st Century. I’m fond of offering this quote:

Ultimately, amateur radio must prove that it is useful for society.
Dr. Karl Meinzer DJ4ZC.

Here in Zero Retries, I’m an unabashed advocate of NewTechHams. There’s no one… no organization, that is willing to speak “truth to power” about the growing population and influence and eventual dominance of NewTechHams within Amateur Radio. I really, really wish there were. So, I try to do so… despite the ruffled feathers that result. I hope that those whose feathers are ruffled will try to understand the bigger picture.

Meadow Day Experiment 2 - With Starlink Mini

It’s probable that next weekend I’ll attempt a Meadow Day Experiment 2, this year with a more realistic scenario of using my Starlink Mini, battery powered, of course, and connected to my now-ancient 100 watt cheap solar panel.

Why a Meadow Day Experiment 2 rather than participating in (ARRL) Amateur Radio Field Day? I explain my perspective in this article - Zero Retries Perspective on Emergency Communications (EMCOM) Capability in Amateur Radio.

ZRDC 2026 Ho!

Zero Retries Digital Conference (ZRDC) 2026 will be here before we (I) know it.

17 weeks until Zero Retries Digital Conference 2026

on Friday, October 16, 2026,

in San Ramon, California, USA.

Weekends Are For Amateur Radio!

Barring unforeseen events, this weekend just might be the first time in more than a month that there’s uncontested time in N8GNJ / Zero Retries Labs. A pickup / reorganization / project time in the Labs is long overdue. My brother just sent me a wonderful surprise present of my Dad’s old wooden tool chest. That tool chest evokes wonderful fond memories in childhood and my early teen years learning how to use tools and build small projects at Dad’s workbench in our garage during the summer. Dad’s tool chest deserves a prominent place of honor near the N8GNJ Labs workbench.

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0254. Paid subscribers can post comments on this issue.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

Founding Members who generously support Zero Retries financially:
Founding Member 0000 - Steven Davidson K3FZT (Renewed 2025, 3rd year!)
Founding Member 0001 - Randy Smith WU2S (Renewed 2025, 3rd year!)
Founding Member 0002 - Chris Osburn KD7DVD (Renewed 2025, 3rd year!)
Founding Member 0003 - Don Rotolo N2IRZ (Renewed 2025, 3rd year!)
Founding Member 0004 - William Arcand W1WRA (Renewed 2025, 3rd year!)
Founding Member 0005 - Ben Kuhn KU0HN (Renewed 2025, 3rd year!)
Founding Member 0006 - Todd Willey KQ4FID (Renewed 2025, 3rd year!)
Founding Member 0007 and 0010 - Merik Karman VK1DF / VK2MKZ (Renewed 2025 x2, 3rd year!)
Founding Member 0008 - Prefers to Remain Anonymous 08 (Renewed 2025, 3rd year!)
Founding Member 0009 - Prefers to Remain Anonymous 19 (Renewed 2025, 2nd year!)
Founding Member 0011 - Rick Prelinger W6XBE (Renewed 2025, 2nd year!)
Founding Member 0012 - Ryan Tolboom N2BP (Renewed 2025, 2nd year!)
Founding Member 0013 - Newton White N4EWT (Renewed 2026, 2nd year!)
Founding Member 0014 - Joe Hamelin W7COM (Renewed 2026, 2nd year!)
Founding Member 0015 - Rich Stocking N7OP (Renewed 2026, 2nd year!)
Founding Member 0016 - Prefers to Remain Anonymous 77 (New 2025)
Founding Member 0017 - Phil Karn KA9Q (New 2025)
Founding Member 0018 - Prefers to Remain Anonymous 95 (New 2025)
Founding Member 0019 - Prefers to Remain Anonymous 0108 (New 2025)
Founding Member 0020 - Prefers to Remain Anonymous 110 (New 2025)
Founding Member 0021 - Prefers to Remain Anonymous 111 (New 2025)
Founding Member 0022 - Prefers to Remain Anonymous 112 (New 2025)
Founding Member 0023 - Prefers to Remain Anonymous 116 (New 2026)
Founding Member 0024 - Rob Bowser (SPOOLTENNA) (New 2026)
Founding Member 0025 - Dave Stewart K7XST (New 2026)

Numerous Annual and Monthly subscribers who also generously support Zero Retries financially!

You thousands of readers of Zero Retries without which there would be little point in publishing this newsletter.

The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries \ Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0255 was published on 2026-06-19. This issue was 7471 words (almost terse 🤣).

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

If GNU Radio experimenters aren’t Amateur Radio Operators, they’ll likely get licensed to be able to use the LinHT in its full capabilities on the Amateur Radio 70 cm (420-450 MHz [in the US]) band.

2

Based on its years-long development, and steadily improving capabilities, Mercury was not reverse engineered from VARA. Mercury was an independent development of an HF data communications modem. Mercury (independently) implemented some of the capabilities of VARA HF such as use of Forward Error Correction (FEC), Orthogonal Frequency Division Multiplexing (OFDM) (the OFDM modem implemented by FreeDV was used) and “upshifting” and “downshifting” the combination of speed, modulation, etc. as HF band conditions change to provide a data communications connection.

]]><![CDATA[Zero Retries 0254]]>https://www.zeroretries.org/p/zero-retries-0254https://www.zeroretries.org/p/zero-retries-0254Sat, 13 Jun 2026 07:59:53 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its fifth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is likely to be truncated by some email clients.

Thus, it might be easier to read in a web browser:
www.zeroretries.org/p/zero-retries-0254.

It’s easy and free to subscribe for your own copy of Zero Retries every week:

Subscribe now

In This Issue:

I-Frame

What’s New at Digital Library of Amateur Radio & Communications — June 2026
Kay Savetz K6KJN

The Remarkable, but Relatively Unsung Achievement of Integrating FreeDV RADE Into FlexRadio’s 8000 and Aurora Radios
Steve Stroh N8GNJ

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Prefers to Remain Anonymous 30 for renewing (three years!) as an Annual Paid Subscriber to Zero Retries this past week!

My thanks to Prefers to Remain Anonymous 73 for renewing as an Annual Paid Subscriber to Zero Retries this past week!

My thanks to Andrew Moskowitz N6AMM for upgrading from a free subscriber to Zero Retries to an Annual Paid Subscriber this past week!

My thanks to Prefers to Remain Anonymous 128 for becoming a new Annual Paid Subscriber to Zero Retries this past week!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Minor Enhancement - Index Link on Navigation Bar

On the top (navigation) bar of the Zero Retries web page, I’ve added an Index link for easier navigation / search of Zero Retries issues published in 2026. I’ve found this index to be very useful when I remember just one keyword in the title of an article.

Zero Retries Summer 2026 Publishing Schedule - Biweekly

Summer 2026 promises to be unusually busy for our household. For a few details, see this issue’s Request To Send at the end of this issue.

Thus for the remainder of Summer 2026, Zero Retries will be published biweekly. The intended publication schedule is:

  • Zero Retries 0255 - 2026-06-26

  • Zero Retries 0256 - 2026-07-10

  • Zero Retries 0257 - 2026-07-24

  • Zero Retries 0258 - 2026-08-07

  • Zero Retries 0259 - 2026-08-21

  • Zero Retries 0260 - 2026-09-04

There may be some special, focused issues interspersed between the scheduled issues, such as a special issue about Zero Retries Digital Conference (ZRDC) 2026.

After ZR 0260 / 2026-09-04… to be determined.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0254. Paid subscribers can post comments on this issue.

What’s New at Digital Library of Amateur Radio & Communications — June 2026

By Kay Savetz K6KJN

Greetings from DLARC World Headquarters, where I still have a stack of business cards from Hamvention to sort through. Your free online ham radio library has added a massive amount of reading material since my last update. Whether it’s for casual reading or deep research, you’re sure to find something of interest in the stacks.

First, an update: In April, I mentioned the addition of many public domain issues of CQ Amateur Radio to DLARC, but listed a bunch of issues that we lacked from that publication’s first four years. Daniel Bateman KK4FOS, at Buckmaster International / hamcall.net, stepped up with the digital goods, delivering all of the missing issues! Now DLARC has a complete set of CQ from its first issue in 1945 through 1963. (A bit of free advertising: If you need issues from 1964 through 2022, HamCall’s CQ Magazine Archive is the only legit place to get them.)

In addition, DLARC has added a new collection of Review of International Broadcasting newsletters. Review of International Broadcasting was a newsletter devoted to the shortwave listening hobby, covering notable content heard on the air, news about legitimate broadcasters and pirate radio stations, program schedules, and radio hardware tips. The new collection includes 107 issues published from 1978 through 1997. 83 of those issues are new to DLARC, thanks to a box of issues generously sent by the publisher, Glenn Hauser.

We’ve added many other electronics and communications magazines to the library as well including 146 issues of Electrical Communication, from issue one in August 1922 all the way through 1961. It began as the journal of the International Western Electric Company, passed through being called the journal of the International Standard Electric Corporation, and ended in 1961 as the technical journal of the International Telephone and Telegraph Corporation. The entire time, though, it was a fascinating journal of “progress in the telephone, telegraph and radio art.”

We’ve added 565 issues of Electronics magazine, from the first issue in April 1930 through the end of 1961. It covers all aspects of electronics, and there’s lots and lots of amateur radio content. 1946: The Collins 30K transmitter, 1956: An SSB station in a train car.1961: Hams orbit their own satellite.

Also, a collection of 60 issues of Electronic Servicing (well, technically it’s called “P.F. Reporter Including Electronic Servicing” — rolls right off the tongue, doesn’t it?) spanning 1961 through 1967. It was a trade journal covering electronic equipment maintenance, published by Howard W. Sams. Some fun amateur radio content is buried in these pages.

We’ve added 26 issues of FM Bulletin, which was a magazine chronicling early amateur FM on VHF/UHF, was published from 1967 to 1969. Edited by Ken Sessions K6MVK and Mike Van Den Branden WA8UTB, it was renamed to FM Journal sometime in 1968. These scans are courtesy of Florida Amateur Spectrum Management Association.

DLARC has added a small collection of historical documents from the Case Amateur Radio Club (W8EDU) at Case Western Reserve University in Cleveland, Ohio. The club was founded at the Case Institute of Technology in the 1940s. And, we have a new Texas A&M University Amateur Radio Club (W5AC) collection, including newsletters, QSL cards, meeting minutes, and meeting slides. Founded in 1912, W5AC is one of the oldest student organizations at Texas A&M University, and is one of the oldest university radio clubs in existence.

In a post-Hamvention frenzy of reaching out to many many ham clubs, DLARC has added newsletters from many regional ham radio groups: the Vaca Valley (California) Radio Club, the East Greenbush (New York) Amateur Radio Association, the Peekskill/Cortlandt (also New York) Amateur Radio Association, the Northern Ohio Amateur Radio Society, the Radio Association of Erie (Pennsylvania), the Ole Virginia Hams (in Virginia, obviously), the Rockford (Illinois) Amateur Radio Association, and the Cuyahoga Amateur Radio Society (in Independence, Ohio).

If I was giving out awards for these clubs (which I am not! We don’t play favorites!) they would be to Ole Virginia Hams for sheer number of newsletters to archive — 472; to Cuyahoga for best newsletter name — “Wobbly Oscillator”; and to Rockford for uploading 360 newsletters all on their own. I was delighted to see them show up at Internet Archive, I simply created a collection for them.

So that’s a lot of reading and research material. We’ll finish with a treat for your ears: DLARC has a new collection of Amateur Radio News And Notes, a weekly news roundup by Ed Cabic N2EC for the Mount Vernon (Alexandria, Virginia) Amateur Radio Club, covering DX, contests, propagation, club activities, and notable developments across the hobby. Ed’s been at it since March 2025, and we have all 62 episodes so far.

Digital Library of Amateur Radio & Communications is funded by a generous grant from Amateur Radio Digital Communications (ARDC) to create a free digital library for the radio community, researchers, educators, and students. If you have questions about the project or material to contribute, contact me at kay@archive.org.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0254. Paid subscribers can post comments on this issue.

The Remarkable, but Relatively Unsung Achievement of Integrating FreeDV RADE Into FlexRadio’s 8000 and Aurora Radios

By Steve Stroh N8GNJ

Introduction

I think that the inclusion of FreeDV RADE, now available as a “just another feature” in FlexRadio’s recent 8000 series and Aurora units (hereafter, 8000 / Aurora), is a remarkable achievement for Amateur Radio as a whole, and deserves more awareness in Amateur Radio than it has received to date.

Amateur Radio began to use SSB for voice communications on the HF bands in the 1950s. At that time, SSB was a considerable improvement over Amplitude Modulation (AM), the primary voice mode then in use on the HF bands. Not only was SSB more spectrally efficient than AM (smaller bandwidth), but it enabled longer range communications for the same amount of transmit power, and enabled smaller, more power efficient transmitters.

In the succeeding seven decades since the introduction of SSB, the primary innovations for SSB was the development of Polar Modulation, and greater receive sensitivity thanks to Digital Signal Processing (DSP).

In contrast SSB, FreeDV RADE is a voice mode that is more spectrally efficient than Single Sideband (SSB) and it’s more reliable than SSB because it incorporates Orthogonal Frequency Division Multiplexing (OFDM) and Forward Error Correction (FEC). FreeDV RADE was developed in the 21st century, in this decade, and incorporates state of the art technology.

FreeDV is software, and most significantly, Open Source software. Thus, FreeDV, as software, can continue to evolve and improve to take advantage of ever greater compute and signal processing technologies embedded into current and future generations of radios… not just endlessly re-implementing seven decades old SSB technology.

FreeDV RADE Development

FreeDV RADE (Radio Autoencoder) is a digital voice mode developed for use on the Amateur Radio High Frequency (HF) bands. There are a number of notable aspects to FreeDV RADE:

  • It was developed by Amateur Radio Operators,

  • It was developed specifically for use on the Amateur Radio HF bands,

  • It is entirely Open Source - software implementation, the algorithms, the training models, etc.

  • The on-air bandwidth of FreeDV RADE is 1.5 kHz, but the speech bandwidth that is transmitted is 8 kHz. This compares with a typical Single Sideband (SSB) on-air bandwidth of 2.7 kHz.

  • The speech quality of FreeDV RADE is much better than SSB.

  • The “noise tolerance” of FreeDV RADE is much better than SSB, because FreeDV incorporates Orthogonal Frequency Division Multiplexing (OFDM) and Forward Error Correction (FEC) techniques.

  • Because it is entirely created in software, and is Open Source, FreeDV will continue to improve and expand its capabilities, perhaps expanding to incorporate messaging, telemetry, or data1.

FlexRadio’s Refreshing Choice to Provide User Initiated Modifications to its 8000 Series and Aurora Series Radios

There are a number of notable aspects for it to be possible to install FreeDV RADE into 8000 / Aurora, and after installation, FreeDV RADE being “just another mode choice” in those units:

  • From its founding, all of FlexRadio’s products have been true Software Defined Radio technology. The performance of every FlexRadio product is primarily defined by software, rather than fixed circuitry radio hardware.

  • FreeDV RADE being able to be installed into 8000 / Aurora was made possible by FlexRadio’s progressive attitude about what a modern Amateur Radio should be. Of the major Amateur Radio manufacturers2, FlexRadio is unique in actively facilitating such features3 by providing an Application Programming Interface (API) and a “container” environment for “external” applications to be run in without affecting the basic (software) functionality of the radio.

  • FlexRadio was willing to undertake the considerable (and undoubtedly expensive professional software development) work make it possible to add capabilities such as FreeDV into FlexRadio units.

  • 8000 / Aurora uses a standardized “compute engine”4 that is well understood and the easy to program for. A year ago, I was told that the compute engine in 8000 / Aurora is a Raspberry Pi Compute Module 4. As I understand it, if there’s need for more compute capability in the 8000 / Aurora, the Raspberry Pi Compute Module 5 is plug compatible with the Compute Module 4 and provides is even more compute power and up to 16 GB of RAM.

  • FlexRadio was willing to work with the FreeDV team to work out the issues of its API and container system to enable FreeDV RADE to be installed into 8000 / Aurora and be integrated into the user interface of the radio and use the standard interfaces such as the radio microphone and speaker, with no need for external devices such as separate microphone, speaker, computer, or other hardware.

Apart from FreeDV RADE, FlexRadio’s Aurora series of radios are groundbreaking technology for Amateur Radio, offering incredible power efficiency. By using Polar Modulation, Aurora can transmit up to 500 watts, but only requires a standard 15 amp, 120 volt circuit (or 240 volt outside the US) circuit. Thus the combination of 500 watts of transmit power, combined with the superior voice performance of FreeDV RADE results in an amazing new communications capability using the HF bands.

ARDC Grants Enabled Extensive FreeDV Development

Beginning in 2023, the extensive, and intensive development of FreeDV was enabled by a significant grant from Amateur Radio Digital Communications - Enhancing HF Digital Voice with FreeDV. In my opinion, the grant for FreeDV is one of ARDC’s major success stories. ARDC helped create significant new radio technology:

It was pointed out that RADE V1 is the first known real-world deployment of a neural codec – an important milestone that the Ham community can be proud of.

As Open Source technology, FreeDV RADE can be used anywhere, not just for Amateur Radio. In addition to 8000 / Aurora, FreeDV RADE could also be embedded into other radios and systems, with the only limitation being sufficient computing power in the radio or system.

In addition to the overall FreeDV RADE system for digital voice, FreeDV’s Orthogonal Frequency Division Multiplexing (OFDM) technology has been used in another ARDC grant funded project - Rhizomatica’s Mercury (data) modem:

… uses field-proven FreeDV digital data modes…

ARRL Could Be, Arguably Should Be, Promoting FreeDV RADE

In my opinion, the development of FreeDV RADE, integrated into 8000 / Aurora should be promoted by ARRL as a significant new capability in Amateur Radio. Again, because FreeDV is Open Source, promotion of FreeDV as installed into 8000 / Aurora is not promotion of a company, but rather it is general promotion of significant new technological innovation in Amateur Radio.

ARRL’s promotion of FreeDV could (should?) include:

  • Any ARRL activity such as contests and Field Day that includes voice modes used on HF - Single Sideband (SSB), Amplitude Modulation (AM), Double Sideband (DSB), etc. could / should be extended to include FreeDV RADE.

  • ARRL’s W1AW voice transmissions:
    Frequencies are 1.855, 3.99, 7.29, 14.29, 18.16, 21.39, 28.59, 50.350, and 147.555 MHz.

    Voice transmissions on 7.290 MHz are in AM, double-sideband full-carrier.
    …     could (should?) be extended to incorporate some voice transmissions in FreeDV RADE.

  • FreeDV RADE could (should?) be incorporated into ARRL’s Clean Signal Initiative (CSI) program to promote better performance of HF transmitters. FreeDV should be a “peer” mode to (analog) SSB in all CSI standards, testing, and reporting.

  • Because FreeDV RADE’s performance is superior to SSB, ARRL Lab’s review criteria could (should?) begin including whether a radio incorporates (or can be updated with, such as is the case with 8000 / Aurora) FreeDV RADE. The result of that “checklist item” should be reported in the new online QST Product Review Database. Finding radios that incorporate (or can be updated to) FreeDV radio should be a “click to compare” item.

  • ARRL could (should?) promote the development and existence of FreeDV RADE in its communications to FCC staff and its responses to FCC Requests For Comments as a significant example that Amateur Radio can significantly contribute to the state of the art in radio technology, especially HF radio technology where there is little commercial development.

  • ARRL could (should?) update its guidance of HF band plans by mode to promote that FreeDV RADE is a voice mode, and thus can be used in the (larger) band segments recommended or assigned to voice modes. There is still significant controversy, and at times, acrimony that some consider FreeDV to be a “digital” mode and thus can only be used in the portions of bands recommended / assigned to digital modes. In my opinion, it’s obvious that FreeDV is a mode for transmitting voice… that happens to use a different modulation technique - digital.

    Such angst about FreeDV as a voice mode could perhaps be understandable if FreeDV RADE’s bandwidth were wider than SSB, but the bandwidth of FreeDV RADE is nearly half that of SSB. Thus the use of FreeDV RADE for voice communications is a net gain for voice communications - more voice conversations per band, and better quality of voice conversations.

Perhaps a Joint Promotion Between ARDC, ARRL, FlexRadio, and FreeDV?

Disclaimer 1 - I have suggested the following idea via email to some individuals in the named organizations, with only tepid responses. Admittedly my email was long on concept and short on detail. This article is attempting to rectify that shortfall, and if a joint promotion doesn’t happen, at least I have publicly celebrated what I consider a significant accomplishment of technological innovation in Amateur Radio.

Disclaimer 2 - I am currently a volunteer member of ARDC’s Grants Communications Team (GCT). Other than that, I am not involved in ARDC’s decision making processes. In the following, I am not speaking for ARDC, formally or informally. Similarly, ARDC doesn’t speak for me (other than my work on the GCT), or have any influence on the content of this article or Zero Retries.

In my opinion, ARDC, ARRL, FlexRadio, and FreeDV could (should?) work together to jointly promote FreeDV RADE as an example that Amateur Radio can be a source of technological innovation in radio technology in this era. A development such as FreeDV RADE is not a technology that’s suitable only in Amateur Radio - it’s usable for other radio services, even VHF / UHF. The audio quality of FreeDV RADE is remarkably good, easily as good as some Digital Voice systems used on VHF / UHF. If spectral efficiency for voice communications is taken into consideration, D-Star and NXDN the most “narrow channel” Digital Voice systems currently in use for VHF / UHF use a 6.25 kHz channel. In contrast, FreeDV RADE uses a 1.5 kHz channel - more than 4x more spectrally efficient than any Digital Voice system in use on VHF / UHF.

Not only is FreeDV RADE more spectrally efficient than any other system, it’s Open Source, thus there are no proprietary elements of FreeDV RADE, thus even more usable for new voice communications systems than any of the existing Digital Voice systems5.

Promote FreeDV RADE and Mercury Together?

If FreeDV RADE isn’t a “big enough deal” for considering such a joint promotion promotion, then perhaps “make a bigger splash” by incorporating the other recent remarkable achievement in Amateur Radio technological innovation - the Mercury modem developed by Rhizomatica for HF data communications. In my opinion, Mercury is equally significant to FreeDV RADE, with a similar level of commitment going into its development. While it cannot be claimed that Mercury was developed by Amateur Radio for Amateur Radio, Mercury is certainly useable and useful for Amateur Radio. Like FreeDV RADE, the development of Mercury was the result of grants from ARDC, and like FreeDV RADE, Mercury is entirely open source. With further development, Mercury could replace the use of VARA HF, which is currently the most popular data communications mode used on HF for connecting to Winlink and other emergency communications. Unlike VARA HF, being Open Source, Mercury is free to use, Mercury can be enhanced and developed by others, it can be embedded into appliance units6 such as the popular NinoTNC or new OpenTNC.

And, like FreeDV, Mercury could be “just another mode selection” on 8000 / Aurora, or any other HF radio that chooses to be user-modifiable like FlexRadio has chosen to do.

A joint FreeDV RADE / Mercury promotion could deliver more of an impact than FreeDV RADE or Mercury individually. Both were developed as new software-only modes in this era, capable of significantly enhancing HF communications capabilities, not just for Amateur Radio but for other users of HF communications such as government, marine, air transport, etc.

I’d be happy to help in such a project.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0254. Paid subscribers can post comments on this issue.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

The Machine Learns to Listen

Great essay on the evolution of Amateur Radio… and radio technology in general by Tom Salzer KJ7T on EtherHam:

There’s a smell to a warming vacuum tube that you don’t forget. If you’ve ever powered up an old tube-type radio, you know what I mean. It is somewhere between hot dust and ozone, with a faint suggestion of the RF itself. You see the needles jump. The glow behind the dial steadies. And then you get to work — not by typing a frequency, but by listening, watching, coaxing. Peak the power. Dip the plate. You feel the radio respond.

That’s not nostalgia talking. That’s a description of a relationship between an operator and a machine that required genuine skill to maintain. The radio demanded something of you. You had to meet it halfway to operate it well.

I’ve been thinking lately about how far we’ve traveled from that moment, and about where we appear to be heading. I’m not alarmed, exactly. It is more like that particular feeling of a person watching a landscape change from a moving train — aware that you’re seeing something important, but not quite sure yet what it means.

The Arc

The history of amateur radio hardware follows a pattern reflected in other technologies.

Early systems encoded all their intelligence in physical structure. Wires, tubes, relay positions. The circuit was the logic. Operating skill meant understanding what was happening at the component level, because if something went wrong — or if you wanted to optimize — you had to intervene physically. The operator was part of the circuit. If something broke, you could find it and fix it.

Then transistors arrived, and with them, automation of the tasks that had required the most operator attention. You didn’t have to dip the plate anymore. The radio handled more of its own housekeeping. Skill shifted from manual tuning to understanding the system well enough to configure it. Repairs began to shift away from fixing circuits to replacing modules.

Then software entered the picture — first augmenting hardware, then replacing whole subsystems. The modern Icom IC-7300 runs a sophisticated touchscreen interface and a real-time spectrum scope. It is a fundamentally different object than the TS-520S, even though both sit on a desk and connect to an antenna. The 7300 is more capable by almost every measurable standard. It is also, if I’m being honest, more sterile. More clinical. Something has been gained. Something has also been traded away.

And then came Software Defined Radio, which pushed the logic further still. What is SDR but an antenna connected to an analog-to-digital converter, with everything else — filtering, demodulation, decoding, display — happening in software? The hardware becomes a substrate. The intelligence lives in code. Software has eclipsed hardware.

KJ7T absolutely nails this subject.

I don’t want to “steal his thunder” by reprinting KJ7T’s entire essay here in Zero Retries, tempting as that is. KJ7T’s observations are fantastically on-point for Zero Retries, and he wrote this essay with an admirable conservation of prose.

Frankly, I’m envious of KJ7T’s ability to frame the incredible evolution of radio technology, in text, this well.

Strongly recommended!

RADIANT — Radio Amateur Delay-tolerant Interplanetary Networking Testbed

From amateur packet radio to CubeSat relay to cislunar networking.

RADIANT brings Delay-Tolerant Networking (DTN) to amateur radio, enabling store-and-forward messaging across disrupted links from terrestrial ground stations to Low Earth Orbit (LEO) and ultimately to cislunar space. Current status: two-node terrestrial DTN operational (Raspberry Pi, Mobilinkd TNC4, Yaesu FT-817, 9600 baud G3RUH GFSK over VHF/UHF). All subsequent phases are in design or planning.

The project implements Bundle Protocol version 7 (BPv7) over amateur radio links using LTP wrapped directly in KISS framing. The architecture is DTN-implementation-agnostic — a common abstraction layer supports multiple DTN engines (NASA Glenn’s HDTN, JPL’s ION-DTN, µD3TN, and Hardy) through a unified interface, allowing operators to select the engine best suited to their platform and mission phase. Station identification is achieved through callsign-embedded DTN Endpoint Identifiers (e.g. dtn://g4dpz/spacecraft) carried in every bundle’s metadata, ensuring regulatory compliance while using numeric ipn:// addresses for efficient routing.

RADIANT — Radio Amateur Delay-tolerant Interplanetary Networking Testbed

With the modest hardware requirements:

  • Raspberry Pi

  • Mobilinkd TNC4

  • Yaesu FT-817

  • 9600 baud G3RUH GFSK over VHF/UHF

(x2 or x3 for a testbed system)

… there seems to be a low barrier to entry for participating in RADIANT experimentation and development.

The primary qualification of the Yaesu FT-817 for experimentation / development of RADIANT seems to be that it provides a “data” (flat audio) connection suitable for 9600 bps G3RUH GFSK transmission and reception. The HF capability of the FT-817 does not seem to be a consideration for RADIANT. Thus any VHF / UHF FM radio with a flat audio connection would seem to be suitable for experimentation with RADIANT. For suitable radios, including those that are currently in production, see Zero Retries Guide to VHF / UHF Radios for Data (now updated to include the FT-817).

Despite the focus on space communications, RADIANT is applicable to terrestrial Amateur Radio use because of the many disparate networks in use in Amateur Radio, from BBS forwarding (latency can run to days between message transfers) to 10 GHz microwave networks operating at hundreds of Mbps (latency could be as short as a few mS). For context on disparate Amateur Radio networks in use, and projected, see Zero Retries 0250 - Networking, Networking, Networking.

Thinking ahead, as Hank Magnuski KA6M did in 1981 by requesting IP address space for amateur packet radio networking from Jon Postel for what became AMPRNet (later better known as 44Net)…

Some entity in Amateur Radio will ultimately be in charge of issuing Amateur Radio Network IDs. For example, as the article cites, dtn:// (Delay Tolerant Network) and ipn:// (Inter Planetary Network) network identifiers are already in use.

It may not be too early to start discussion of establishing arn:// (Amateur Radio Network) network identifiers.

As for which entities… perhaps International Amateur Radio Union (IARU) as the most international of all Amateur Radio organizations? Or perhaps Amateur Radio Digital Communications (ARDC) given its history with 44Net?

SkyFox Labs BusCORE Groundstation Terminal

Image courtesy of SkyFox Labs

The BusCORE™ Groundstation Terminal is a Full Space-to-Earth, Earth-to-Space Radiocommunication Infrastructure, with 50 W Output Power, Excellent Sensitivity, Variable Bitrate Modulator/Demodulator, Superfast Solid State RX/TX Switch and RF Monitoring Output port for the external Spectrum Analyzer monitoring activities and USB port for a single cable connection to the control PC station.

Change the Bitrate during Pass.

The unit provides data rates in variable settings during the flight over the groundstation from long range 1200 bps up to 38 400 bps maximum, depending on the link quality. Automatic Bitrate Fallback function sets the modem to nominal 4800 bps in case the mutual bitrate negotiation attempt fails. Standard bitrate settings is optimized for LEO operations with 4800 bps.

Upgrade your system to a Brand New Rig and Get your data down!

PRODUCT SUMMARY

  • State-of-the-art Hardware Accelerated Satellite Communication System

  • UHF 435.000 - 438.000 MHz, Amateur Radio Band Operations

  • 1200 - 38 400 bps 2GFSK, Variable Bitrate (1200, 2400, 4800, 9600, 19 200, 38 400 bps)

  • Standard International Amateur Radio xxxxxx 6-letter Format Callsign plus unique 65k ID Addresses Available for Swarm Operations

  • Automatic Bitrate Fallback to 4800 bps (nominal)

  • Automatic AFC with no need for Doppler Shift Compensations (4800, 9600, 19 200, 38 400 bps)

  • Harmonic Filter

  • Solid State Power Amplifier (SSPA) with 50W RF output @ 50 Ohms (no hybrid used)

  • Forward Power, Reflected Power measurements

  • No antenna connected Tolerant SSPA

  • 2-line LCD with RGB backlight indicating key statuses (Transmission, Valid packet reception, Nominal reception, Overtemperature)

  • Indicating LEDs for a quick status overview

  • Volume Settings for audible RF demodulated sound via Embedded Speaker

  • Squelch Gate with indicating LED

  • USB status indicating bi-color LED, optically isolated USB interface

  • Basestation Power Connector + Grounding stud with quickWing Nut

  • Since March 2026: Full Standalone Hardware support for Bidirectional 9600’s GFSK AX.25 Framing G3RUH Scrambling Legacy Amateur Radio Satellite Systems Support, -106 dBm @ 5% PER

  • Sensitivity: up to -120 dBm @ 1200 bps 5% PER

  • Sensitivity: up to -106 dBm @ 38400 bps 5% PER

  • 1/2 Duplex

  • Input Antenna Port Noise Floor (no antenna connected -133 dBm typical)

  • Up to 3000 km operational slant range

  • Intended to: LEO up to h = 1000 km

  • Power Requirement: 13.8 V @ 8 A (50 W RF Power Out)

  • 1 250 000 bps Virtual COM Port PC Data Interface

  • Cooling Fan with temperature control

  • USB Data Port

  • 1x N-Female UHF Antenna Port

  • 1x N-Female UHF Monitor Port

  • Amphenol Base Station rated 60V/26A Two pole Input Power Connector

  • Dimensions: Rack Mount 3U 19”

  • Wide Temperature Range: 0˚C to +70˚C

This… would look really cool in the Radio Rack in N8GNJ / Zero Retries Labs, either above or below a similar sized rack unit for an automatic Azimuth / Elevation antenna controller with a cool display of current antenna pointing status (with an integrated camera with its own display).

As you can see from the photos, despite this product targeted at “Amateur Radio” satellites (based on the frequency range of this unit) in Low Earth Orbit, this is a serious satellite ground station radio. With the big rack mount enclosure and a big fan implies that it’s capable of a reasonably high duty cycle on transmit for data uploading.

Thus this unit seems ideal for an Amateur Radio ground station for organizations that have a research or Amateur Radio satellite in orbit and need to do command and reliable downlinking of telemetry. It also seems a good fit for Amateur Radio clubs that want to get involved in Amateur Radio satellite communications.

See the About page for more interesting detail on the origins and perspective of the company, which is based in Czech Republic.

My thanks to Steve Bossert K2GOG for bringing this development to my attention for inclusion in Zero Retries.

QuadRF (by MoonRF) is Now a Crowd Supply Project

QuadRF

A 4x4 MIMO SDR tile for spatial RF vision and beamforming that scales as a phased array

This project is launching soon.

Coming Soon

QuadRF democratizes modern phased array technology, bringing it down to Earth in an accessible, hacker-friendly, and programmable kit. At its core, QuadRF is a modular 4x4 MIMO software-defined radio tile with an open antenna architecture. Powered by an integrated Raspberry Pi 5, it functions out of the box as a real-time RF camera, expanding SDR exploration from the traditional time and frequency domains into the spatial domain.

While a single QuadRF is a complete, fully functional phased array development platform, it is also designed from the ground up as a building block for much larger arrays. Beamforming computation is distributed across each tile’s Lattice ECP5 FPGA, meaning users can link boards together to scale into square-meter scale phased arrays, such as our open-source 240-antenna MoonRF design.

Apparently MoonRF has been accepted at Crowd Supply as an official project, thus the crowdfunding campaign will begin soon. Sign up for direct updates on this project via email. I have!

Programing the USB Transceiver Model 50

Mark Herbert G1RLO:

The G1LRO USB Transceiver Model 50 is built around 2 discrete elements:

  • AIOC Sound card and serial interface

  • SA818 UHF transceiver module

Both of these need setting up individually before use.

The setup process is :

  • Flash the firmware into the AIOC processor

  • Configure the AIOC processor for COS settings

  • Configure the SA818 for the required frequency and CTCSS settings

  • Configure ASL3 to easily recognize the AIOC processor.

All of these steps are executed via a PC and Web browser, no command line access is needed.

This gives the impression that the G1LRO USB Transceiver Model 50 is a combined radio transceiver and audio interface (equivalent to an All In One Cable - AIOC).

But there’s no USB Transceiver Model 50 listed as a product in G1LRO’s Shop. I try to follow G1LRO, but perhaps this was a project (that he doesn’t sell as a product) that I’m not aware of.

But if there were (or will be) a USB Transceiver Model 50, it sounds like a really cool product.

One Decoder for All Battlefield Networks: DARPA Moves Toward Universal Codec

Ethan M. Encarnacion in NextGenDefense:

DARPA is developing an adaptive military codec that automatically adjusts error-correction methods to keep transmissions reliable across contested networks.

The Defense Advanced Research Projects Agency (DARPA) is pursuing a universal codec that would allow military radios, satellites, and data networks to adapt how they protect transmissions from errors.

Through a special notice, the agency announced the Leveraging Universal Codecs (LUC) program, which seeks to develop a next-gen encoder-decoder pair capable of adapting to different error-detection and correction methods during data transmission.

The effort builds on DARPA’s earlier Guessing Random Additive Noise Decoding (GRAND) research, which works by reverse-engineering interference in a transmission channel to reconstruct the original signal.

Under the LUC program, a GRAND-based decoder will be paired with a new adaptive encoder capable of automatically selecting the most effective error-protection method based on signal conditions and mission priorities in real time.

DARPA said the approach could improve bandwidth efficiency, make adaptable coding methods more difficult to exploit, and allow data to move more reliably across different military communications systems.

In pointing out this article, K0JEG noted:

Looks like hams aren’t the only ones with transcoding issues.

I agree. In imagining how voice (or data) would transit different US military systems, each with their own protocols, error correction, encryption, latency issues, etc. - radio, satellite, wireline, local, wide area, etc. I can easily imagine negotiating all of that, especially for realtime voice or video could begin to increase latency and interoperability issues.

My thanks to Eric Grumling K0JEG for bringing this development to my attention for inclusion in Zero Retries.

Tests Suggest Russian Satellites Can Jam GPS on a Continental Scale

Jeremy Hsu in Ars Technica:

Mystery of GPS interference across Europe raises questions about Russian motives.

Russian satellites have been identified as the cause of mysterious, seconds-long bursts of GPS interference across Europe—a rare example of human-made GPS interference coming from space. But uncertainty still hangs over whether such interference is intentional and if it could be more powerfully weaponized as GPS jamming with continental reach in the future.

The discovery came from an investigation detailed in a June 2 preprint paper by Todd Humphreys and his student Zach Clements at The University of Texas at Austin, along with Argyris Kriezis at Stanford University in California. By sifting through public data from ground-based stations with global navigation satellite system (GNSS) receivers, they identified a pattern of high-powered interference lasting less than 10 seconds each time but simultaneously detectable by ground stations across Europe from Norway to Spain to Poland, and even reaching as far west as Greenland and Canada.

By analyzing the ground station data from January 2019 to April 2026, the researchers found 75 days with at least one widespread GNSS interference event overlapping with the GPS L1 frequency band centered on 1575.42 megahertz. That represents the main band used for signal transmission by the US-made GPS satellite constellation and GNSS constellations from other countries.

Such interference patterns happened mostly on Tuesdays, Wednesdays, and Thursdays during business hours in Europe, Humphreys told the YouTube channel Veritasium. Because such “continental-scale” interference was simultaneously affecting GPS receivers across Europe and beyond, Humphreys and his colleagues calculated that the source had to be at least 1,200 kilometers above the Earth.

By examining which satellites were above the horizon over the affected region during each interference event, the researchers narrowed their search to a handful of suspect satellites. But they couldn’t go further because they only had data processed by the GNSS receivers of the ground stations—they needed to capture the raw radio signal data from the interference source.

Although this article specifically relates to jamming of the (US) Global Positioning System (GPS), the overall issue of susceptibility to jamming and spoofing is applicable to all of the Global Navigation Satellite System (GNSS) implementations.

It was naive of me to not imagine that this was a possibility. I’ve discussed GNSS jamming / spoofing in previous issues of Zero Retries, generally concerning the loss of precision timing from GNSS that is required for many Amateur Radio systems such as Weak Signal Propagation Reporter (WSPR). Of course there would be satellite-based interference, outright jamming, or spoofing of GNSS signals - terrestrial, regional, even aircraft-based (long duration drones) wouldn’t be nearly as effective as a satellite… though as the article points out, any such effects from LEO satellites are only effective during relatively short passes overhead.

I continue to posit that Amateur Radio, as radio technology “experts” (compared to the general public) could have a role to play in detecting GNSS signal interference, jamming, or spoofing. Participation could be as simple as a having highly accurate survey done of the location of a “prosumer” grade GNSS receiver. Then, monitor the position that the GNSS receiver is reporting, and flag any significant deviation of the location reported by the GNSS receiver. IE, if your GNSS reports movement or a different location than where you know it is located, to the meter, ergo something is going on, and not necessarily deliberate interference, etc. Atmospheric conditions can affect GNSS signals, which is the basis for Wide Area Augmentation System (WAAS).

Perhaps an Ad Hoc Amateur Radio GNSS Disruption Detection Network?

Harold Feld House Energy and Commerce Oral Testimony on Next-Gen GPS

Public Knowledge Senior Vice President Harold Feld testified before the U.S. House Energy and Commerce Subcommittee on Communications and Technology. His testimony in the hearing on “Where Are We?: Examining Positioning, Navigation, and Timing Capabilities (PNT) in the United States” urged Congress to preserve the current GPS system while ensuring a basic tier of PNT for free to the general public even as GPS continues to evolve. Public Knowledge contends that next-generation GPS should serve the public interest. View the written testimony for more information.

In the same week as the previous story breaking…

Harold Feld is an expert on regulatory-related radio technology issues. I’ve known of him for decades, from my earlier career writing about the wireless industry and Wireless Internet Service Providers. Feld’s knowledge, and testimony on issues such as this is deeply sourced and rock solid.

With all the other… issues… in play in the US Congress, if it’s having hearings about PNT, and are hearing from Subject Matter Experts such as Feld, that’s ample evidence that there is very serious concern within the US government (not just the US military) over the reliability and day-to-day usability of GNSS systems.

Amateur Radio is More Than a Hobby

Dustin Gray KR4MBZ on his LinkedIn page:

Amateur Radio is More Than a Hobby.

It is one of the best hands-on ways to learn how communication really works.
You learn about RF, antennas, propagation, power, troubleshooting, operating discipline, and emergency communication. More than that, you learn by doing.

You test an idea.
You make adjustments.
You try again.
You keep improving.

That same mindset applies to IT, networking, wireless technology, AV, and technical problem-solving. In a world where most communication feels instant and invisible, amateur radio reminds us that understanding the fundamentals still matters.

Ham radio is not just about making contacts. It is about learning, experimenting, and staying curious.

Any other hams, GMRS users, or wireless tech folks in my network?

I’ve been sayin’…

I dropped a brief comment about Zero Retries.

I hope that KR4MBZ begins following Zero Retries and is able to connect with some of the 3500+ other “hams, GMRS users, or wireless tech folks” readers of Zero Retries.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0254. Paid subscribers can post comments on this issue.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

Busy Summer 2026 in the N8GNJ / KD7WSF Household

As mentioned in I-Frame, Summer 2026 will be unusually busy in our household. The biggest factor is that Tina and I will be grandparents sometime in September. Thus there is a baby shower (actually, two) to be planned and executed. Complicating the logistics for the baby showers is that Tina had surgery on her foot a week ago. The surgery went very well, but post-surgery, she is not “allowed” to bear weight on her foot for five more weeks, so I’m the legs and arms, and driver, and errand-runner of the family at the moment. Tina is a retired Registered Nurse / Complex Medical Case Manager, and readers who have medical professionals in their family can commiserate with the challenges of being a caregiver for such folks.

In between baby showers, there are the preparations for Zero Retries Digital Conference (ZRDC) 2026 to be kicked into high gear. Expect full details on ZRDC 2026 in the next issue.

I also have a book to complete in time for ZRDC 2026 and that will require more butt-in-chair time than I can otherwise allocate at the moment if I were to continue publishing Zero Retries each week. Thus the decision to change to biweekly publication of Zero Retries for the remainder of Summer 2026.

In my sparse “spare” time this Summer, my dedicated office area in N8GNJ / Zero Retries Labs is long overdue for a major remodel for upgrades on electrical and networking, painting, new shelving, etc. Because this much work will require emptying the entire office, that’s feasible in the good weather of our generally rain-less summers. I can move things around in N8GNJ / Zero Retries Labs and park some of the bigger pieces outside without damage.

And of course there are many, many long-deferred projects for N8GNJ / Zero Retries Labs. I want to get at least a few more antennas up in the air to improve my activity in Zero Retries Labs. Antenna activity is going to include HF and a major investment in an HF radio. More on my plans for HF in a future issue.

There has been a considerable uptick in Zero Retries Interesting activity here in Bellingham / Whatcom County, including MeshCore on 902-928 MHz, 1200 bps Packet Radio (thank you W9CPZ!), and VARA FM / VarAC. There is also some potential on-air activity resulting from the Cascade STEAM Spectrum Community Group (Special Interest Group) that may be Amateur Radio, or perhaps unlicensed - to be determined.

I’m long overdue to connect into the Puget Sound Data Ring (PSDR) microwave network (HamWAN), and I want to get working on creating some connectivity on “AREDN-900” (my terminology for AREDN networks operating on 902-928 MHz using repurposed 802.11ah / Wi-Fi HaLow equipment. I want to get in on all of that activity, and soon. There are also many receivers to put online - I really want to get a SatNOGS and a TinyGS LEO satellite receivers online, as well as my KiwiSDR. All of that will be tied together with 44Net static IPv4 addresses that is made very easy now with 44Net Connect.

But, one of my favorite “Dad Wisdoms” is:

Want to hear God laugh? Explain your plans. 🤣

But, we do the best with what we have, and useful bit of “Dad Wisdom” comes from my dear friend Harold Sprinkle who said:

Plan the work… then work the plan. 🫤

Yep.

ZRDC 2026 Ho!

Zero Retries Digital Conference (ZRDC) 2026 will be here before we (I) know it, especially given the action-packed Summer this one promises to be in our household. It’s useful to me to put the countdown prominently on display in Zero Retries. Thus I am beginning a Hamvention-esque countdown to ZRDC 2026 in this issue.

18 weeks until Zero Retries Digital Conference 2026

on Friday, October 16, 2026,

in San Ramon, California, USA.

Weekends Are For Amateur Radio!

Well, not this weekend, at least directly. Our shed kit didn’t get assembled as planned a month or so ago due to a bad back. But most factors have aligned - good weather, availability of a handy, strong friend, and an absence of other complicating factors. Perhaps, eventually, the shed will support its own radios and solar panel and other geekery.

And, in between shed-building and a needed gas-powered7 motorized lawn scalping, I was delighted to discover that Project Hail Mary is now available on a streaming service. It’s about $20, but that’s a reasonable price to pay for being able to watch it on my big living room video display8, from the comfort of my recliner. Next to getting the shed-building off my HoneyDo list, watching Project Hail Mary will be the highlight of this particular weekend.

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0254. Paid subscribers can post comments on this issue.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

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The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries \ Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0253 was published on 2026-06-13. This issue was 8221 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

As I’ve related in previous mentions of FreeDV, in a conversation with David Rowe VK5DGR, he confirmed there is nothing “structural” in FreeDV that precludes FreeDV from incorporating messaging, telemetry, or data. The primary reason for not doing so, to date, is that those capabilities were not in the scope of the ARDC grant, and so no (grant funded) work was done on those additional capabilities.

2

Major Amateur Radio manufacturers (in my opinion) that manufacture significant Amateur Radio product lines, mostly Amateur Radio HF radios: Alinco, Elecraft, FlexRadio, Icom, Kenwood, Yaesu, and most recently Xiegu.

3

My descriptions and understanding of exactly how “external” software / features are accommodated in 8000 / Aurora is admittedly vague. My (self assigned) deadline for this article didn’t allow me to vet these descriptions with FlexRadio. If, after publication, I got some significant descriptions wrong, I will update the online version of this article.

4

What I refer to as the “compute engine” of the FlexRadio 8000 and Aurora radios is the computer that runs the overall functionality of the radio - the display, the controls, etc. The “heavy lifting” of the digital signal processing is done with Field Programmable Gate Arrays (FPGAs).

5

M17 is also Open Source, but it uses a 9 kHz channel.

6

Appliance units, similar to PACTOR 4 modems which are also used for connecting to Winlink, and other emergency

7

One of the big differences in perspective between my wonderful wife and I is that she considers mowing the nearly 1 acre of grass with a noisy, fume-spewing lawn tractor to be “relaxing”. I’ve tried to make my case to invest in a lawn mowing robot that keeps the lawn continuously trimmed 24x7, other than rain or recharge cycles. But, Tina doesn’t want to give up her “fun”, so lawn duties fall to me during her recovery (at the peak of grass growing season, of course). Fortunately there’s always the latest Ham Radio Workbench podcast to listen to as I mow.

8

Not a television, because I no longer have any use for classic “linear” television entertainment.

]]><![CDATA[Zero Retries 0253]]>https://www.zeroretries.org/p/zero-retries-0253https://www.zeroretries.org/p/zero-retries-0253Sat, 06 Jun 2026 04:31:05 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its fifth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is too big for email clients. Thus, it might be easier to read in a web browser - www.zeroretries.org/p/zero-retries-0253.

It’s easy and free to subscribe for your own copy of Zero Retries every week:

Subscribe now

In This Issue:

I-Frame

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Craig Dale W9PAX for renewing as an Annual Paid Subscriber to Zero Retries this past week!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Reopening Substack Comments to Paid Subscribers

Optional Paid Subscriptions to Zero Retries, such as W9PAX this week, help offset the expenses of publishing Zero Retries. Tina and I are indebted to all of the paid subscribers and Founding Members.them. From the beginning of Zero Retries, the content of Zero Retries is the same for free and paid subscribers. Recently, I was asked by one of the Paid Subscribers if I would reconsider my policy of closing comments on Substack and steering comments to the Zero Retries email list, and

The Paid Subscriber noted that when they feel moved to comment, it’s a bit more “friction” to send an email to the Zero Retries email list versus posting a comment on Substack. To post a comment on the Zero Retries email list, one issue is that you have to be subscribed to the Zero Retries email list to be able to send an email to it.

That was a fair point, and I decided that being able to post a comment on Substack will be one minor “perk” for the Paid Subscribers.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0253

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

[MoonRF] Phased arrays 🌕🔵 Blue Moon update!

Email from Martin McCormick K1MCC on the supporters email list:

With two full Moons in May, a MoonRF / open.space update is officially overdue!

Last week we applied to Crowd Supply to help us launch QuadRF, our 4-antenna / 4x4 MIMO SDR tile. It’s the core of the 240-antenna MoonRF architecture, the building block for the larger arrays.

The QuadRF Kit is one RF tile + four dual-polarization antennas, an integrated Raspberry Pi 5, and a preloaded software stack so you can start experimenting right away.

Complete Kit

One exciting thing about QuadRF is that it moves software-defined radio beyond time and frequency and into the spatial domain.

This is most obvious in the real-time RF camera mode, that gives an augmented-reality heat-map of all the RF signals around you..

QuadRF Overview
QuadRF Overview

Check out our full application video about it here:

That shows our literal first attempt with the augmented-reality RF overlay on a cellphone! It’s cool to watch, but even more amazing in hand, as the visualization is quite immediate and responsive.

Besides shooting nerdy YouTube videos, we’re,

  • cleaning up the software/drivers/docs/examples so more people can build on the code

  • adding a battery and cellphone holder feature to the enclosure for AR

  • preparing antenna, mechanical, and simulation files for the open source larger arrays for those who want to build their own early

  • working on our CCATS commodity-classification request so we can confirm the proper export-control treatment before launch and make shipping availability clear for backers

We are not live on Crowd Supply yet. They let us know they received the application and are excited to work through the details early this week. One nice thing about Crowd Supply is they handle all distribution / shipping / VAT / export etc.. which let’s us focus on the actual technology and support, so it will be great to work with them.

We’ll keep you posted! Assuming the project gets approved, help support us by picking up one QuadRF Kit (or two)! You can then reuse the kit’s tile as part of the larger MoonRF phased arrays which will become cheaper to build when we start shipping mass RF tiles!!

In the meantime, please join the Discord if you have questions, ideas, demo requests, or just want to follow along,

Discord: https://discord.gg/QPGVFTsNS4
Update website: https://moonrf.com/updates/

OK, back to work!
Martin
Founder, Scale RF Inc.

There is a very similar update posted on the MoonRF website with slightly different info:

May 31 2026 - QuadRF is headed toward Crowd Supply!

For additional context, see Zero Retries 0245 - open.space - Moon Launch Update!

In that article:

Post Publication Update: Email from Martin McCormick K1MCC:

The QuadRF [kit] is likely to be $399, not $2000.

Wow. Just… Wow. That’s an incredibly reasonable price point.

While K1MCC attracted my attention with an open source, hackable, phased array antenna system that, oh yeah, could be ganged together to do Earth Moon Earth (EME) communications at 5 GHz, there are many other applications for a phased array antenna system that’s hackable. One of the most interesting and potentially useful is:

… augmented-reality heat-map of all the RF signals around you.

After my meeting with the Cascade STEAM Spectrum group a couple of weeks ago1, the QuadRF is the kind of tool / capability that really helps newcomers to radio technology get a jump start on viscerally beginning to understand RF… because with an radio energy heat-map, they can finally “see” radio energy, not just try to visualize it in their mind. Another effective demonstration, when you do have the ability to “see a radio energy heat-map is to demonstrate attenuation of various materials, and reflectivity of materials.

I predict MoonRF will eventually sell a… lot… of QuadRF to Electrical Engineering programs and EE students.

TAPRX-888

Paul Elliott WB6CXC presentation (pages 3, 4, 5) at Hamvention 2026 TAPR Forum:

First, About the TAPRX-888

Based on Oscar Steila’s BBRF103, the RX-888 SDR has been a game-changer:

  • 100 kHz – 60 MHz continuous coverage

  • Wide dynamic range – 16-bit ADC

  • Full-bandwidth digitized spectrum sent to host computer for

  • processing by ka9q-radio

  • Adopted as the preferred receiver for wsprdaemon and the HamSCI Personal Space Weather Station

But:

  • Can be hard to find, especially with the prevalence of clones and scam-sellers on AliExpress

  • Internal anti-alias filter is marginal

  • MF, LF sensitivity is poor

  • Thermal issues, requiring mechanical heat-transfer improvements

  • For precision frequency measurements it needs an external reference clock adaptor

  • Hardware design (schematics and PCB) are not open-source

So we decided to design a new SDR

  • Based on the BBRF103 → RX-888

  • Eliminated VHF converter and other unused components.

  • Improved and flexible filtering and low-frequency performance.

  • Input for external reference clock

  • Input for time-synchronization source

  • Improved thermal design

  • Larger PCB, allowing easier future development

  • True open-source from TAPR

I’m glad to see this significant new project from TAPR. The HamSCI community has been making good use of a network of RX-888s, but at HamSCI 2026, when I first heard of this project (apparently at the very early stages), there was a lot of frustration expressed that buying a RX-888 to participate in HamSCI research was, essentially, pretty random chance that any given unit purchased could result in a usable unit, or a poorly built unit, or an outright scam. There are no “brand names” of RX-888 units.

I hope TAPR begins some real marketing for this unit to build interest. At the moment, the existence of this project is essentially word of mouth. There is no dedicated mention of this project (that I can find) on the TAPR website, and to date, it hasn’t been featured in the TAPR newsletter (that I recall reading).

AIOC Update – New Hardware COS for Low Cost HTs Coming Soon

Mark Herbert G1LRO on his website:

New AIOC Hardware Coming This Summer

I’m refreshing my AIOC project with new hardware and software, and I’m excited to share what’s coming.

COS (Carrier Operated Signal) is used by applications like AllStarLink (ASL3) to indicate that a radio carrier is present, it not based upon the sound received, but on the carrier being present (even is there is no speech at the time). Good COS performance is important so that the ASL3 (or similar) software knows when to be sending the signal to the other party, and when to stop sending.

This new AIOC hardware version stays true to the original AIOC form factor and dimensions while integrating new circuitry to provide several meaningful improvements. It uses the standard v1.3 or later firmware:

Hardware COS — Speaker Bias Method For low-cost HTs in the Baofeng class, the new board includes hardware COS detection using the speaker bias method to reliably detect an open squelch. This delivers consistent hotspot performance that virtual COS implementations simply can’t match — no more dropped keying or intermittent behaviour.

Hardware COS — Logic-Level For HTs with logic-level COS support, such as the Tidradio H3, a dedicated logic-level COS input is included. This also opens the door to other use cases like integration with an SA818 module or an APRS repeater.

Improved Voltage Regulation The dual regulator has been replaced with two discrete regulators, offering better short-circuit protection — particularly useful given the open, “naked” nature of the AIOC board — along with improved overall reliability.

Circuit Layout Refinements Vulnerable tracks have been moved away from plug solder joints, and pads have been made larger and easier to work with, reducing construction risk and making the build more beginner-friendly.

New Setup Scripts for ASL3 AllStarLink v3 supports the AIOC, but currently requires manual file editing. I’ll be releasing a single-line setup script that handles all the necessary modifications to ASL3, eliminating errors and making the process far more accessible.

New ASL3 How-To Documentation Configuration guidance on this blog has drifted out of sync with the current state of ASL3 and AIOC over the years. I’ll be publishing a definitive how-to guide covering a complete simple hotspot build using the G1LRO AIOC card and a low-cost HT, with full use of the advanced COS functionality for reliable, professional-grade performance. Video walkthroughs are planned too, and I’ll be sending sample boards to some YouTube friends for independent reviews.

Watch this space.

G1LRO’s addressing of the COS issues with portable radios is welcome relief. That’s one of the most frustrating aspects of using inexpensive portable radios for data communications.

AIOC is All In One Connector is an open source project for a single unit that combines the (previously, separate) audio interface and programming interface hardware. AIOC is in a form factor suitable for just plugging into many portable radios with a pair of 3.5mm “audio” jacks. There are many versions of the AIOC available for retail sale, including one that’s called All In One Board, not intended for use with portable radios. My personal favorite is a version by Nigel Armstrong NA6D, who generously donated a number of AIOCs for Zero Retries Digital Conference 20252.

An AIOC mated to an inexpensive portable radio is an easy, low-cost low-risk way to experiment with Amateur Radio data modes. However, there are two significant “gotchas” for those new to data modes using portable radios.

  • Some portable radios are slow (electronically) to switch from Receive to Transmit mode (and back to Receive) - hundreds of mS versus tens of mS. If you have such a radio, data modes can be frustrating to set up because you have to configure each application (data or voice) that you want to use to provide adequate switching time before attempting to transmit data or voice. In Packet Radio, this parameter is called TXDelay (TXD). One easy workaround for this issue is to buy a Baofeng UV5R Mini for data experimentation; see Zero Retries 0237 - Is The “Mini” Better for Data Modes? (Video) for context.

  • Because the transmitted radio energy is being radiated close to the data device (the AIOC) because of the “rubber duck” antenna on the portable radio, radio energy can cause unintended operation, usually by induction into the data cables as they act as receive antennas. The usual cure is to use a high quality (good shielding) data cable, or add ferrite coils onto the data cable to suppress the radio energy from being conducted by the cable.

If you’d like to see an illustration of using an AIOC, see Bring Your Old Handheld to Life With an AIOC by Mike Tatum M0AWS.

It’s frustrating to see the “latest and greatest” radios proudly debuting their built-in 1200 bps (and occasionally 9600 bps) TNCs… that are basically 30 year old technology. Audio interfaces like AIOC combined with very capable software such as Dire Wolf running on the host computer or RadioMail on an iPhone are much more capable and flexible than any (fixed function) internal TNC on a portable (or mobile) radio.

Thought experiment: Instead of integrating a TNC into a portable (or mobile) radio, integrate an audio interface such as an AIOC instead. I’d be much more inclined to buy such a portable radio as opposed to yet another “meh” portable radio “featuring” an internal TNC.

Do One Thing Well: A 24/7 Remote JS8 Station for 40m

Michael Clemens DK1MI on the rz01.org blog:

…

Thanks to my satellite station, my shortwave station was suddenly available for experimentation. The idea arose to find a digital mode robust enough for my situation with the interference and offering true keyboard-to-keyboard communication. I’ve had quite a bit of success with FT8 so far, but it’s quite far from real QSOs. However, there’s JS8 with the accompanying software JS8Call. This digi mode is like FT8 but for real QSOs and has many other great features such as relaying messages, sending heartbeats, querying which other stations are able to hear, and more. After some research, it turned out that the main activity takes place on 40m. This is perfect because I have a 10-meter-long vertical antenna right behind the garden shed that is tuned to 40m.

The Station

My idea was to build a JS8 station that’s as simple as possible, so it can also be operated remotely. I’ve already tried remote operation with the Hermes Lite 2, though back then I was still using a power amplifier and an antenna tuner - with only moderate success. The whole setup is far too complex, with too many variables. So I came up with the following setup:

  • QRP Labs QMX+ with the 10W mod (putting out 7W on 40m)

  • Raspberry Pi 5 running Debian Linux with JS8Call and a VNC server

  • 10m long vertical antenna

  • 40m band pass filter

  • no antenna tuner

  • no amplifier

I’ve already described the station’s setup here: https://rz01.org/qmx. To summarize the linked post, I’ve installed the QMX+ and the Raspberry Pi in a 19-inch rack inside the garden shed.

This is another facet of a trend I’ve been seeing that I’ve begun calling RadioServer. Formerly, I’ve also called this idea Station Server, and before that I think I might have called it “RadioLab” a few times as an allusion to Information Technology (IT) experimenter’s HomeLab. Just as DK1MI describes with his remote JS83 station, generically a RadioServer is a radio / computer “stack” that’s within your household, but “sits in a corner unattended”. A RadioServer isn’t intended to be used locally; only rarely (troubleshooting) would you sit in front of the RadioServer. Instead, you access it remotely via your home network from your lap / laptop, your couch / tablet, or even a mobile phone. A RadioServer isn’t the same as a remote station (though, I guess it is, from a purely technical perspective - an IP address is an IP address).

Another well-developed example of a RadioServers is DigiPi which modifies data modes intended to display locally and reroutes display, keyboard, and pointer into a web browser interface.

The most well-developed example of a RadioServer is by Paul Schwan N4FTD, explained well on his website Recliners On the Air (ROTA). He has put a lot of work into creating his concept of a RadioServer (which he terms Radio Engine).

My thanks to Amateur Radio Weekly Issue 422 for bringing this development to my attention for inclusion in Zero Retries.

NodusNet - Community Radio Activity

NodusNet About Page:

See what’s happening on the air — without sitting in front of a radio.

NodusNet is a community-powered ham radio activity dashboard. It observes local FM traffic in real time, identifies operators by callsign, tracks nets, and builds a shared picture of what’s happening on the air. Whether you’re a licensed ham or just curious about what’s on the airwaves — you’re welcome here.

What is NodusNet?

Ham radio is a blind medium. Unless you’re parked on a specific frequency at the right time, you have no idea what’s happening on the air. New hams get licensed and hear silence. Net controllers run sessions without participation data. Clubs can’t tell which members are actually active.

NodusNet makes local ham radio activity visible, measurable, and shareable.

Listener nodes — each one just an RTL-SDR dongle and a small app — monitor local repeaters and feed activity into either a local (your own) or shared dashboard — your choice! NodusNet detects transmissions, identifies operators by callsign, recognizes net sessions, tracks participation, and surfaces patterns across your local bands.

  • Live activity feed — See who’s on the air right now across all monitored frequencies

  • Net tracking — Automatic net detection with check-in counts and participation trends

  • Leaderboards & badges — Community recognition for active operators

  • Interactive map — See where activity is happening geographically

  • Repeater profiles — Which repeaters are active, when they’re busiest, who uses them

  • Club directory — Find and join local ham radio organizations

  • Notifications — Get notified when a callsign you follow is heard or a new ham keys up

  • New ham welcome & connect — Automatically greets newly licensed operators heard on the air and connects them with locals who share their interests

  • Privacy controls — Don’t want your callsign publicised? No problem — claim it and opt out with one click

How It Works

STEP 1

Plug in an RTL-SDR dongle

$25–35, any RTL2832U-based USB stick

STEP 2

Enter your zip code

Local repeaters populate automatically from RepeaterBook

STEP 3

Watch your dashboard

Activity appears within minutes

STEP 4

Sign up

Unlock leaderboards, operator profiles, and community features

Each node monitors multiple frequencies simultaneously using FFT channelization, transcribes speech locally using AI, and extracts callsigns from the audio. All processing happens on your hardware. If you want more — connect to NodusNet!

This is an interesting system. It seems to be very early days for it:

Where is NodusNet available?

NodusNet is live in Omaha, NE. Each new metro requires at least one listener node — no code changes. If you’re interested in bringing NodusNet to your area, reach out.

Despite the similarities, NodusNet seems to be an independent development from RepeaterBook’s Project Apollo, although NodusNet uses RepeaterBook for repeater data lookups.

I didn’t find any information about the person(s), group, or company behind NodusNet.

Interesting project!

My thanks to Dave Stewart K7XST (Founding Member 0025) for bringing this development to my attention for inclusion in Zero Retries.

Hot Iron #133

Frank Barnes W4NPN via the Hot Iron distribution email list:

Issue #133 of Hot Iron is now available on the website at this link.

I’m a day late distributing this May 31st issue, due to making some home repairs that my missus said “would not wait.” Message received and understood. Home harmony now reigns.

As usual, this issue covers a wide range of topics and wanders over the ham radio landscape. Since we are the “Constructors” (”builders”) club, it tends toward building projects. I’m constantly looking for simple solid state and/or digital projects that can be easily constructed at home, as well as tube designs (which I’m partial to). I’m not a trained digital technician so must rely on others for this info. Not being very digital, I tend toward older analogue designs. Please send info you might have regarding digital projects.

This issue mentions

  • The sad cessation of CHU transmissions,

  • BBC’s 198 KC long-wave cessation,

  • A reminder about DLARC,

  • The 76 year- old 555 timer chip that just won’t stop tickin’,

  • Aluminum chassis construction,

  • Some antenna thoughts,

  • A favorite antenna tuner,

  • Much more

Hot Iron is always a delightful read, and is one of media listed in the Zero Retries Directory of Independent Open Amateur Radio Technical Media. Hot Iron is free, and to be notified of each new issue:

… send an email to me at fbw4npn@gmail.com, requesting addition. Make the subject field say “Hot Iron Subscription.”

My thanks to Frank Barnes W4NPN for bringing this development to my attention for inclusion in Zero Retries.

MSeven IOS App - TNC4 Users Sought for Testing

Gregg Wonderly W5GGW on the M17-Users email list:

I am in the process of integrating the use of the TNC4 with my iOS app to allow an RF path out from the iOS environment. If you have an iOS device, a TNC4 and a capable 9600baud KISS mode radio (see the Mobilinkd website for insights), you may be able to help verify this feature. Please reply to this email if you are interested in helping to test and prove out this capability.

The Mobilinkd TNC4 is a KISS TNC with Bluetooth (that can connect to both Apple IOS and Android devices ) as well as a USB-C connection. It’s battery powered and pretty small, thus it works well with portable radios. One of the TNC4’s unique features is that it supports M17 data modes. Please help W5GGW if you can.

Experimental New Packet Radio Node Map — Now Live

Josh Hicks KK6SEN on the 145050PacketNetwork email list:

I‘ve put together a live coverage map for the 145.050 MHz packet network. You can check it out at map.kk6sen.com.

https://map.kk6sen.com

It shows all the stations my AUBNOD hears with the correct tag in real time, plotted on a proper map with active/stale status and a sidebar to browse through.

Getting on the map is simple. Just include a location tag in any packet beacon you send and get it to a point my node can hear in south Auburn. I hear KBANN the best

The format is:
<MAP:lat,lon,callsign,nodename>

or

<MAP:lat,lon,callsign>

It can be part of a larger message — doesn’t need to be a standalone beacon. If AUBNOD hears it (usually relayed through KBANN), you’ll appear on the map within about 30–60 seconds.
More instructions on the top of the webpage under “How to”

A note on the stations already showing. I imported the digipeater nodes from the old maps so you can see what’s out there, but they’re on the same timer as everyone else:

Green = heard within the last 24 hours,
Gray = last heard 1 day to 2 weeks ago,
Disappeared = no activity for over 2 weeks,

If you operate a node and want it to stay visible, just make sure it sends a beacon through every so often. At least once a day to make it not turn stale.

Let me know what you think. Good idea? Bad idea? I’m also open to suggestions.

From the 145050PacketNetwork email list home page:

145.050 Packet Radio Network

In California, Nevada, and Oregon:
The VHF Ham Frequency at 145.050 is the home to an extensive NET/ROM Packet Radio Network.

It still rocks my world that the 145.050 Packet Radio Network is perking along using NET/ROM as its networking protocol. Note that NET/ROM was the original… and powerful… mesh networking protocol for Amateur Radio Packet Radio. When it was introduced, NET/ROM was horribly constrained by running it on TAPR TNC-2 hardware… a 1 MHz Z-80 system, with 32kB ROM and 32kb RAM. I can’t imagine how well it works now with 1 GHz (and multi core) processors, and pretty much as much RAM as you could use.

Good thing folks like the 145.050 Packet Radio Network aren’t paying any heed to those that consider Packet Radio no longer used, interesting, or relevant.

My thanks to Joe Hamelin W7COM (Founding Member 0014) for bringing this development to my attention for inclusion in Zero Retries.

The 5 Things That Have Revolutionised my Radio Shack

Mike Tatum M0AWS on his blog M0AWS Amateur Radio:

The articles I write for the blog are mostly technical but, I thought it was about time that I wrote this article as it’s been buzzing around inside my head for some time now.

So, what are the 5 things that I have found revolutionary in my shack that have brought new, exciting ideas and projects to life making amateur radio more enjoyable.

1: A RaspberryPi Single Board Computer

2: A 3D Printer

3: An AllStarLink Node

4: Node-Red

5: A Hermes Lite 2 HF SDR Transceiver

M0AWS offers a compelling, detailed justification for all of these Zero Retries Interesting items. I agree with all of them.

PacketRF

Vlastimil Slinták OK5VAS

PacketRF is firmware for building IP-capable radio nodes that behave like ordinary network interfaces from the host side and like proper amateur radio modems on the air side. It is open source, it runs on RP2350 hardware, and it is designed as a platform — meaning it does not stop at one protocol or one board.

The project currently focuses on New Packet Radio by Guillaume F4HDK, because NPR is the most interesting actively deployed data-radio system on the 70 cm band and because there is a real opportunity to move it forward without breaking what already works. Beyond NPR, PacketRF is intended to grow into a more general experimentation platform for packet networks over RF, including classic AX.25 audio packet radio, additional transceivers, and eventually delay-tolerant networking on top of all of that.

What it actually is

A PacketRF node connects two worlds. On one side it speaks standard IPv4 — the HW shows up to your operating system as a regular network interface, gets an address, takes part in routing, and carries any traffic you care to push through it. On the other side it speaks whatever air protocol the firmware is currently running, today NPR over an SI4463 transceiver. There is no proprietary modem in the middle, no special tool to capture and forward the data; once the node is up, the radio link is just an interface like any other, and the rest of the stack does not need to know it is there.

Configuration and status live on a separate management interface, reachable both locally over USB and remotely over IP, including over the radio itself. That management interface uses CoAP and CBOR, requires authenticated writes, and is designed to be safe to leave it reachable on a real an open network. More on it in Quick Start, the Management CLI, and the developer-side Control Module.

Why this project

Existing amateur data systems sit at two extremes. Traditional packet radio is universal but slow and hard to extend past the assumptions it was built on in the 1980s. WiFi-derived systems like HSMM/Hamnet are fast, but they need bands and conditions that not every operator has access to and that not every experiment fits inside.

Between those two points there is a useful middle: usable IP throughput on lower bands, narrower channels, modest hardware, and a clean network model. NPR already lives in that middle. PacketRF is an attempt to give it a modern, maintainable codebase, a proper management options, and room to grow into more than one protocol family.

There is also a more personal motivation. Building a packet radio platform turns out to be a very direct way to learn, in detail, how IP networks actually behave when the link underneath them is genuinely constrained — a shared TDMA channel, narrow bandwidth, real latency, occasional silence or noise. That kind of environment is exactly where most modern “Internet networks” stop working, and where amateur radio can experiment and be interesting to use.

This bit was inspired:

Between those two points there is a useful middle: usable IP throughput on lower bands, narrower channels, modest hardware, and a clean network model.

I’ve met folks who can’t imagine such a “useful middle”. They’re advocates of either “TCP/IP is only usable on 1 Mbps+ networks” or “Packet Radio is its own networking system, and has no need for TCP/IP”.

Kudos to OK5VAS for thinking this through and presenting it so well.

From AFSK to Goertzel

(Another great article from) Vlastimil Slinták OK5VAS

Some time ago I started implementing “classic” packet radio into PacketRF. Not the fancy NPR stuff, not high-speed links, but the old and simple AX.25. The one that runs at 1200 baud over a narrow FM channel and somehow still works over surprisingly long distances.

And as soon as I decided to support 1200 baud packet radio (often called PR1200) in PacketRF, I ran into a problem that many people before me had already solved, but I had never really thought about in detail: how do you efficiently decode Bell 202 AFSK on a small embedded system without wasting half your CPU on it?

This post is a write-up of what I learned. Part refresher, part rediscovery, part “wait, why does this even work?”. I ended up making a bunch of small visualizations along the way, mostly out of curiosity, and at some point I realized this is actually a very nice way to look at DFT and Goertzel that I personally had never seen presented this way.

So this is not a textbook explanation. This is more like: I needed this for PacketRF, I looked into it, and this is what finally made it understandable for me. And I also wanted to share my fancy animated GIFs :)

What are we trying to decode?

Let’s start from the beginning. Packet radio is one of those things that “everyone knows”, but if you ask three people what PR actually is, you will probably get three slightly different answers.

Classic packet radio (on VHF/UHF) is basically a stack of very simple building blocks layered on top of each other:

  • AX.25 on the link layer (HDLC-like framing)

  • NRZI encoding of bits

  • AFSK modulation at the physical layer

And specifically for 1200 baud, this is Bell 202, which uses two tones:

  • 1200 Hz → mark (logical 1)

  • 2200 Hz → space (logical 0)

So the whole chain looks like this:

1 TX: HDLC frames → NRZI → bits → AFSK (1200/2200 Hz) → audio → radio

2 RX:radio → audio → detect tones → bits → NRZI decode → HDLC frames

The part we care about in this article is just one small piece of that chain: detect tones and turn them into bits in the receiver path. So the question we will be solving in the rest of this text is:

Given a chunk of audio samples, how do we decide whether it contains 1200 Hz or 2200 Hz?

That’s it. That’s the entire problem.

At that point, OK5VAS begins a deep dive into signal processing, applied to the “simple” problem of decoding a packet radio 1200 bps transmission that consists of two tones.

The Mesh Is the Plan

“MUSTAFA@TERRAKINESIS.COM”:

Why a self-healing UDP/multicast data mesh simplifies your PACE plan, defeats jamming, and makes cheap drones lethal.

The Department of War (DoW) builds communication plans around a framework called PACE — Primary, Alternate, Contingency, Emergency. Four pathways. Four separate systems. Four failure modes to manage under fire.

Every layer assumes a different radio, a different waveform, a different piece of kit strapped to the warfighter or bolted onto the vehicle. When the Primary goes down, the unit switches to Alternate. When Alternate goes down, they switch to Contingency. And so on, until they reach Emergency — which usually means voice over HF and a prayer.

This model made sense when every pathway was a single point of failure. A radio. A satellite link. A frequency. One jammer pointed at the right frequency and the link was dead.

This model was a compromise. It made sense when compute at the edge did not exist, when processors on tactical nodes could not encode, decode, or repair data in real time, and when the gain from a smarter transport layer was not sufficient to justify the engineering effort. The technology was simply not there for COTS processors at the edge. So the military solved the problem with hardware redundancy instead of software intelligence — at the cost of increasing the warfighter’s fighting load.

That compromise is no longer acceptable. Edge compute is here. Processors that fit inside a cheap drone can execute forward error correction in milliseconds. The gain from a self-healing transport layer is no longer marginal — it is the difference between a formation that survives jamming and one that does not. Modern warfare demands mesh-scale communication across thousands of nodes in contested spectrum. The current model was not designed for that fight.

But what if the data link itself could not be killed with a single jammer? What if the mesh healed itself faster than the adversary could disrupt it? What if taking down the mesh required an emission signature so large that it became a target worth more than the data it was trying to silence?

That is the argument for a self-healing UDP/multicast data mesh. And that is what changes the PACE equation.

The Problem

Today’s military data links are point-to-point. One sender. One receiver. One pathway. Jam the path, interfere with it, or destroy a node along it, and the message does not arrive. Hub-and-spoke does not solve this. It scales it. Each spoke is its own point-to-point link to the hub. The hub is a single point of failure managing dozens of single points of failure. Take down the hub and every spoke goes dark.

The military compensates by layering redundancy. PACE is that redundancy. But PACE is expensive. Each layer requires its own hardware, its own spectrum allocation, and its own logistics supply chain. The four-system model is a SWaP-C problem, whether on a soldier’s rucksack or on a deployed drone.

The result is predictable. Drones today rely on a single data link. If that link gets jammed, the drone is lost. The warfighter loses situational awareness. The mission degrades.

This is not a technology problem. We have the technology today, ready to be fielded. It is an architecture problem, and it begins with a change in perspective.

Self-Healing Changes the Math

A UDP/multicast mesh does not rely on a single path. Every node in the mesh is both a sender and a receiver, and data propagates across multiple paths simultaneously. If one node is jammed or destroyed, the mesh routes around it automatically. No operator intervention. No switching to Alternate. No time wasted by the warfighter switching hardware or configurations.

This is the power of self-healing at the transport layer. The mesh detects losses. The mesh repairs them. It does both in microseconds — not the minutes it takes a human to recognize a link failure, diagnose the cause, and switch to a backup system.

PULSE is built with the single goal of accomplishing this: a true UDP/multicast mesh. This is done by building a full protocol from the bits up, based on NACK-based repair, forward error correction encoding and decoding in under 50 microseconds, and Beehive clustering that organizes nodes into self-managing groups.

Every node carries the logic to detect, repair, and reroute. No central controller. No single point of failure.

The mesh may still need a PACE plan, but it is far more resilient before it ever reaches for one. A self-healing mesh at the transport layer absorbs jamming, reroutes around lost nodes in DDIL environments, and restores data flow — all before a frequency hop is necessary. The mesh exhausts its own redundancy first. Primary, Alternate, Contingency, and Emergency are embedded in the topology itself. Every path is Primary. Every route is Alternate. The mesh provides all four layers simultaneously without four separate hardware stacks. When the mesh finally does jump to another frequency, it is a deliberate step — not a panicked fallback.

This Substack newsletter is apparently a marketing vehicle for TerraKinesis and their product called PULSE:

Distributed Computing up to 1,000 nodes. Real-time. No Servers. No SATCOM.

1,000+NODES AT SCALE

<1ms LOCAL REPAIR

95-99%

Allowing myself a bit of snark… the Substack newsletter and the website of vague claims is what is passing for “marketing” of this product in this era of white hot interest and ample available investment funding of anything related to drones used in defense systems.

I’m including this in Zero Retries to illustrate how much we Amateur Radio Operators can do / experiment with in Amateur Radio and how cutting-edge mesh networking is in the real world of radio technology. It wouldn’t take much to create a mesh network such as what’s proposed here using software defined radios operating in Amateur Radio spectrum, deployed by a bunch of Amateur Radio experimenters.

Announcing kiss-tnc-bridge

Jared Crapo K0TFU:

I just created and released a new piece of open source software called kiss-tnc-bridge. This daemon bridges Bluetooth KISS TNC clients to TCP KISS TNC servers. Here’s why I created it, how it works, and how you can use it.

Why does this exist?

If you already have a KISS TNC server running on TCP, why would you want it to work via Bluetooth?

  1. In a scenario where power consumption matters more than range, Bluetooth Low Energy uses less power than WiFi.

  2. On Apple’s iOS, the aprs.fi app cannot use WiFi when it’s not the foreground app. But it can use Bluetooth, allowing it to remain connected in the background.

  3. I created a portable APRS station using Graywolf on a Raspberry Pi. Graywolf can be configured to create a TCP KISS TNC so multiple apps can use the radio set up in Graywolf. kiss-tnc-bridge lets a mobile device use Graywolf’s TNC without having to have any WiFi available.

How I use it

I have built a setup I call an APRS Command Center. I’ll do a more detailed write up soon. To summarize, I want an APRS station that supports some or all of these functions, depending on the scenario:

  • portable (i.e. work in a car, easy to set up in a remote location)

  • flexible radio/antenna options (digirig connected to a 50 W mobile radio and an X300 on a 25 foot mast, or my TH-D75 connected via USB cable)

  • multiple options for power (solar, USB-C battery, 12V power, 13.8V power)

  • doesn’t require internet access

  • can be an igate if internet access is available

  • shows a live map of APRS stations, which needs to work with no internet access

  • can beacon my location, as well as objects and locations of other assets

I want a station I can use at a race event where there is no internet access.

This station will be most useful when co-located with net control. In that setting, it is likely that other devices, like a phone running aprs.fi, may want to connect to the station to send/receive their own APRS packets using the radio connected to the APRS Command Center. Graywolf can easily offer a TCP KISS TNC. This new kiss-tnc-bridge also offers another method to connect, and has the important benefit that it doesn’t require WiFi to work.

Feedback welcome

If this software is useful to you, I’d love your feedback. Open an issue on GitHub or contact me directly.

The creativity and energy going into apps and Amateur Radio data communications is just amazing.

APRS World (aprs.world)

About page:

What is APRS?

APRS (Automatic Packet Reporting System) is a digital ham radio protocol that broadcasts live position, telemetry, weather and short messages over VHF — and worldwide via the APRS-IS gateway network. Licensed amateur-radio operators have used APRS since the early 1990s as a real-time situational awareness tool.

APRS World is a modern visualization platform for the worldwide APRS network used by amateur-radio operators. Free, open-source, no ads — a live ham radio station locator and callsign lookup, all in your browser.

APRS in practice

Once a station beacons a position, every digipeater within RF range repeats it; one of those digipeaters typically forwards it to APRS-IS, the global internet backbone for APRS. APRS World subscribes to that backbone so the moment a beacon hits the network, it lands on the live map you see at the homepage.

Features

  • Live worldwide map of APRS stations

  • Per-station detail with position history, telemetry, weather, raw packets

  • Read and send APRS messages over APRS-IS (licensed callsign + passcode)

  • Follow friends and stations, multi-SSID support

  • Dark/light theme, multilingual UI

APRS World (apparently) has three elements - Web app, a cloud back end, and an Android app. The Android app has some paid features, such as ability to use a KISS TNC. The basic functionality on the web app (viewing) is available at no cost (as far as I could tell).

There’s an interesting comparison chart of the APRS World Android app and APRSdroid - Switching from APRSdroid to APRS World:

APRSdroid is a hugely valuable 12-year-old project — its KISS TNC and phone-mic AFSK depth is real. This page isn’t a hit piece; it’s a head-to-head on the things modern web + cloud can do that APRSdroid hasn’t touched.

Apparently an IOS app is planned - from the FAQs:

When is the mobile app?

Native iOS + Android, shipping to App Store + Play Store + F-Droid once Apple Developer + Google Play Console accounts are live. Soon.

It’s an interesting looking project, and apparently a new entrant into Amateur Radio APRS.

I didn’t find any information about the person(s), group, or company behind APRS World other than it seems to be based in Turkey, per the two contributors in the Credits page being Amateur Radio Operators in Turkey.

There’s Plenty Happening in the Apple Amateur Radio Land With Some Great New And Updated Apps Across Mac, iPhone, iPad, AppleTV And Watch (May 2026)

Andrew Woodward VK2AWN on his blog:

In recent months there’s been a plethora of apps coming to Mac, iPhone and iPad for amateur (ham) radio. I have tried a few of them and in the list below comment where I feel I can do so credibly.

If there are some apps I have missed, please share them in the comments on the social media posts or contact me directly and I will update the list. I will link this post to my Apple Amateur Radio page and the Apple Amateur Radio Subreddit.

There are many other great web based services that could be included in this list but they have no specific Mac, iOS, iPadOS or other Apple aspect and are therefore not included. Apps are presented in alphabetical order.

I wasn’t sure what criteria VK2AWN was applying, but there were several data related apps in development or in the process of being updated including RadioMail and Packet Commander, both from Island Magic / Georges Auberger WH6AZ. (I couldn’t find a comment section on that post on VK2AWN’s blog.)

Both RadioMail and Packet Commander are listed on Mac Ham Radio, which is a comprehensive website for all things Amateur Radio and Apple products. I don’t know why I didn’t check previously, but it has an RSS feed, now added, so I can more easily stay up to date on Mac and iDevice Amateur Radio apps.

My thanks to Amateur Radio Weekly Issue 423 for bringing this development to my attention for inclusion in Zero Retries.

rapel - Chunked Resumable Downloads in Unstable Networks

Chunked HTTP downloader with resume support.

A modern, cross-platform implementation with improved state management and progress tracking.

What caught my attention is that you can tune the parameters for smaller chunks (for slower networks), and many other actions / tuning parameters. Just another tool that you can use over Amateur Radio networks that support TCP/IP.

JS8Call Waveforms “Wrapper” for Arbitrary Data (and Your Own Software)

Jeff Francis N0GQ on his QRZ page:

Speaking of JS8Call, I’m also the author of js8net (now js8net-legacy), which is an open-source python API layer that makes JS8Call easy to interface with your own software. The current version is for the legacy JS8Call software. I started working on fixing and rebuilding the JS8Call API for JS8Call-Improved, but had two big deaths in the family in close succession, and had to drop out of that effort and focus at home for a while. It looks fantastic, though, and I wish them well. I’ve build js8net-improved that does the same thing as the old js8net, only for the new js8net-improved.

I’ve also written my own version of JS8Call called JF8Call from scratch. It’s early in the process, so it’s still alpha code, but it does work, and I’ve had multiple QSO with other ham using JS8Call. I started with a version of the 8FSK library extracted from JS8Call-Improved (see 8FSK Modem), but now it’s got its own written-from-scratch 8FSK modem (see 8FSK Modem-clean). It also supports Olivia (with the modem code extracted from FLDigi) and a PSK soundmodem that supports BPSK, QPSK, and BPSKF at various speeds that I wrote from scratch. Oh, and also the codec2 modem. JF8Call was designed from the ground up to run headless (using an API), with a Qt interface, or with a curses-based text interface. The websocket API supports 100% of the functionality of the software, and has a corresponding Python3 SDK called jf8net.

The title is my (probably imperfect) description of what N0GQ is describing in those two paragraphs.

N0GQ is a friend from when we both lived in the Lesser Seattle area and both involved in Amateur Radio data communications (and discovered that we were both involved in Experimental Aircraft and both were fans of Zenith kit planes).

I saw N0GQ at Hamvention 2026 and we caught up a bit. As you can see from the above, N0GQ “forged his own path” in Amateur Radio data communications. I think that his utilities are an elegant method to use the robust FT8 / JS8Call waveforms for data communications moving arbitrary data.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0253.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

Zero Retries Guide to Zero Retries Interesting Events Updates

I maintain this guide to attempt to keep track of the many Zero Retries Interesting events that are relevant to or adjacent to technological innovation in Amateur Radio. Recent additions include:

  • 2026 AMSAT Space Symposium & Annual General Meeting 2026

  • ARRL Field Day 2026

  • HOPE 2026

  • GNU Radio European Days 2026

  • North Star Radio Convention 2026 / ARRL Dakota Division Convention 2026

  • Winter Field Day 2026

  • Zero Retries Digital Conference 2026

There are a few more events to add to it and then it will be complete for 2026, and it will soon be appropriate to add some big events for 2027.

Followup on Zero Retries 0250 - Networking, Networking, Networking

For context, see Zero Retries 0250 - Networking, Networking, Networking.

Gareth Howell M5KVK posted some thoughtful feedback to this article:

The piece “Networking, Networking, Networking” contains this paragraph.

But none of the current Amateur Radio networks are big enough, successful enough to be considered the data networking solution for Amateur Radio. Thus, Amateur Radio can’t really cite a “success story” for Amateur Radio networking.

I think I understand the reasoning behind the piece, but I do push back against the notion that there needs to be “the data networking solution”, or a “success story”, and therefore the need for a “networking strategy”.

Amateur Radio is an experimental hobby. Note the emphasis on hobby: it’s not a business or a profession: it’s a wide-ranging technical hobby. Everything from construction to moon bounce with stops along the way for [B,I,M,P,S]OTA, DXing etc. Do any of these have “success stories”? If they do, I’m not aware of any. Do they have a “strategy”? No.

Amateur data communications is no different. It’s an opportunity to see what can be done and to experiment. There’s no business plan, no strategy, and no success measures beyond simple things like “how far did that message/packet get?”

Having said all that, I can see the merit in somebody trying to inter-network all the islands: after all, the inspiration for the “Internet” was to inter-network those islands of proprietary network protocols. But it’s still a personal endeavour - like climbing a mountain - because it’s there; and not because it’s of any practical use.

Also, using the voice network analogy is odd. I look around in my local area and I see analogue FM, DSTAR, DMR, and C4FM repeaters. Hardly ubiquitous unless they are all connected to AllStarLink.

M5KVK had some fair points. I replied:

The following are my opinions. Your opinions may vary. Reasonable people can agree to disagree in their respective opinions.

Amateur Radio in the US isn’t a hobby that can be enjoyed equivalent to… woodworking, for example. That is, anyone can do woodworking with tools as simple as a saw, or as expensive as an entire shop, limited only by one’s time, interests, and budget, and skills. How you do your individual woodworking is completely up to you, unregulated, requiring no other inputs.

In contrast, Amateur Radio is a radio service regulated in the US by the FCC. The spectrum used by Amateur Radio is allocated by the FCC (and international treaties for some spectrum). Without allocated spectrum, there is hobby radio that can make use of limited, unlicensed portions of spectrum, such as CB, FRS, MURS, ISM, etc. Hobby radio is not completely equivalent to Amateur Radio. There are severe power limits, no access to portions of spectrum such as HF, and many other significant differences.

Thus Amateur Radio does not exist solely as a hobby activity. The spectrum allocated to Amateur Radio is at the expense of that “Amateur Radio” spectrum being withheld from other uses of spectrum. In some cases, Amateur Radio operation in some portions of spectrum is at the forbearance of primary users, such as the US Government / Military.

Thus, for Amateur Radio to continue to exist as we know it… to have dedicated or shared spectrum allocated to Amateur Radio, requires some justification. I posit that “allocate spectrum for hobbyist use” may not be sufficient justification by those that make the decisions of how to allocate spectrum amongst competing uses.

The most prominent, relevant, present / future such justification for the continuation of dedicated or shared spectrum allocated to Amateur Radio, is providing examples of networking over Amateur Radio and more generally, networking in many different forms and capabilities, via radio.

In my article, I cited many examples of different forms and capabilities of networking occurring in Amateur Radio.

I cited Amateur Radio voice repeaters as an example that Amateur Radio knows how to deploy infrastructure to the point of having achieved near-ubiquity. No, Amateur Radio voice repeaters are not heterogeneous, but that wasn’t my point. My point was that all but a vanishingly small number of Amateur Radio Operators are within the coverage pattern(s) of “Amateur Radio infrastructure” (voice repeaters). Thus we know how to deploy Amateur Radio infrastructure. To date, we’ve chosen to do so only for voice communications.

I also posted a more general reply:

In a more global response to Gareth M5KVK and Orv W6BI about why not try to create a global network within / for Amateur Radio…

I think part of the problem is most of Amateur Radio doesn’t understand how much… how good… networking we can (now) do. A great example is the high capacity networking that’s now possible on the Amateur Radio 10 GHz band that Orv W6BI cites.

We’ve had low capacity, fragmented networks for so long, that many of us in Amateur Radio feel that’s the best Amateur Radio networking can accomplish.

  • We know about Winlink, accessed via packet radio, VARA, or PACTOR 4 via VHF / UHF and HF,

  • We know about networks of APRS digipeaters,

  • We know about pockets of packet radio networking such as OhioNet, EastNet, the 105 network in California,

Or that the only way to bridge disparate Amateur Radio networks is via Internet.

If most of us in Amateur Radio don’t know what’s possible in Amateur Radio networking… we accept the status quo of low speed, fragmented networks that we’ve had for decades now.

I posit that now that we have the technology of interconnecting Amateur Radio networks… I think we should try to interconnect Amateur Radio networks.

And, that doing so will have a side effect of demonstrating Amateur Radio is relevant and useful and interesting in the 21st Century.

…

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0253.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
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The Usual Administrivia

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Zero Retries 0253 was published on 2026-06-05. This issue was 9383 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

See Zero Retries 0252 - Cascade STEAM Spectrum Community Group.

2

I was a fan of NA6D’s AIOC products before the ZRDC 2025 donation.

3

DK1MI is the only one I’ve seen refer to this mode as JS8. The creator and all other references I’ve seen refer to this mode as JS8Call.

]]><![CDATA[Zero Retries 0252]]>https://www.zeroretries.org/p/zero-retries-0252https://www.zeroretries.org/p/zero-retries-0252Sat, 30 May 2026 02:30:49 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its fifth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

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In This Issue:

I-Frame

LinHT Rev B – Hardware Testing Status [2026-05-23]
Andreas Schmidberger OE3ANC

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Scott Johnston KD4EBL for upgrading from a free subscriber to Zero Retries to an Annual Paid Subscriber this past week!

My thanks to Prefers To Remain Anonymous 127 for upgrading from a free subscriber to Zero Retries to an Annual Paid Subscriber this past week!

My thanks to Prefers to Remain Anonymous 74 for one year of being a Paid Subscriber to Zero Retries as of this past week!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0252.

LinHT Rev B – Hardware Testing Status [2026-05-23]

By Andreas Schmidberger OE3ANC

Editor’s Note

LinHT is Linux Handheld Transceiver. It is an open source Software Defined Radio transceiver operating on the Amateur Radio 420-450 MHz (70cm) band. Three primary characteristics of LinHT are that it’s designed to be used as a handheld radio (initially based on the Retevis C62 portable radio), it runs GNU Radio 3.x flowgraphs, and it runs on Linux. You can shell into your LinHT.

For technical details on LinHT, see linux-radio.eu and the M17 Foundation Wiki page on LinHT - wiki.m17foundation.org/index.php?title=LinHT.

LinHT is the most important hardware project in Amateur Radio today. - Bruce Perens K6BP, 2025-08-12. (I agree wholeheartedly with this statement.)

This article is excerpted from the M17 Project webpage.

It took us some time, but here’s a quick update on where we’re at with the LinHT Rev B hardware tests:

What‘s working?

  • Variable RF input attenuators

  • RF switch – switching between TX/RX paths

  • RF PA (Power Amplifier) – functional, delivering about 4.5 watts (CW)

  • GNSS connection – UART interface (NMEA)

Still requires testing

  • GNSS receiver’s antenna path

  • PMU (Power Management Unit) – battery voltage measurements

Known problems

  • Audio codec IC – reset and I²C communication issues needing a bit of investigation

  • The button below PTT not triggering USB boot sequence correctly

Test setups

RX path (RF switch, attenuators)

For testing, I used a simple GNU Radio flowgraph, based on the M17 flowgraph used in LinHT, to check the signal levels.

A “simple” flowgraph for plotting RF spectrum/waterfall

LinHT provides Ethernet via USB, so the received baseband socket can be accessed remotely by forwarding it via SSH:

ssh -o StreamLocalBindUnlink=yes -L /tmp/bsb_rx:/tmp/bsb_rx root@10.17.17.17

BTW, it would be awesome to have CARI support for such things in LinHT at some point!

With the flowgraph running, I toggled the RF switch and adjusted the attenuators while observing signal levels.

Editor’s Note - The image of a spectrum plot, illustrating the above paragraph, was too large for Substack. See this link for the image or the original article by clicking on the title link.

TX path

For the TX path test, I kept it simple. I’ve set the RF switch to “transmit” using the new controls of the web UI and transmitted M17 with the gui_test program (included in the LinHT image).

Transmitting M17 at 3.5W

I was able to hit my repeater OE3XOR with the M17 RF transmission.

Software changes

There were some required software changes to get the new hardware components working.

Device tree updates in meta-linht-hardware:

  • New audio codec

  • RF attenuators

  • RF switch

  • RF power amplifier

  • Updated changed GPIO pins

Experimental driver support in liblinht-ctrl:

  • RF attenuator control

  • RF switch control

  • RF PA control

  • Corresponding linht-web controls added

linht-web control panel

You can find more information about LinHT in the M17 Foundation’s wiki.

Enjoy experimenting with M17!

Editor’s Postscript

It’s exciting to read this update! The Rev B hardware version of LinHT sounds like there aren’t any “showstoppers”, just straightforward additional development and debugging.

A number of Zero Retries readers stopping by the Zero Retries / DLARC booth at Hamvention 2026 commented that they’re looking forward to the LinHT, and hoped that M17 / LinHT could be exhibited at Hamvention 2027.

It’s the nature of ambitious open source hardware projects such as LinHT to have extended development cycles when the developers can only work on such projects “as we have time and resources available”.

If you’d like to help the development of LinHT, the project is sponsored by the M17 Foundation, and you can donate to M17F (donate link in upper right corner) and add a note that you’d like to support the development of LinHT.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0252.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

Experimental Radio News 15

Image courtesy of Experimental Radio News
Image courtesy of Experimental Radio News

In this issue: Laser power in space, scanning thousands for hidden weapons, batteries from nuke waste; asteroid mining, burritos, broadband, speech without talking, shortwave stations: hints of what’s next – and a plea for peace through Bluetooth jamming.

One of the things I most appreciate about every new issue of Experimental Radio News is that ERN Editor Bennett Z. Kobb (AK4AV), in parsing through the gamut of experimental radio licenses issued by the US FCC, features many uses of radio technology that aren’t about communications. In Amateur Radio, we think of radio technology in the context of communications. But there are a myriad of other uses for radio technology such as power transmission, which is featured prominently in this issue of ERN.

Experimental Radio News is highly recommended!

[PocketPD] Firmware V2.0 Released!

Louis Law on the PocketPD project website on Crowd Supply:

We just released V2.0.0 of the PocketPD firmware, a complete rewrite from the ground up. PocketPD turns any PPS-capable USB-C charger into a pocket-sized bench power supply, with a rotary encoder and two interface buttons for precise V/I control and monitoring. The V2 update keeps all that functionality while adding a slew of improvements and bug fixes that address long-standing user pain-points.

Why a Rewrite?

Firmware support for PocketPD started as a small open-source demo and outgrew itself fast. Due to its monolithic nature, adding features meant adding branches, and adding branches meant breaking unrelated ones. Unit testing was non-existent because everything imported Arduino headers. Simply put, V1 was painful to develop on and just wasn’t feasible long-term.

V2 splits the firmware into three layers:

  1. HAL adapters own the hardware APIs,

  2. Stages own local views and environment,

  3. Tasks own I/O cadence and general-purpose logic.

At a high level, it’s a state machine + cooperative scheduler + event bus. Each layer can be replaced or mocked, and the codebase today has over 150 unit tests and counting.

On screen, it looks similar, but you’ll notice much improved overall responsiveness and, most importantly, many bugs fixed.

What’s New?

Multiple PPS Profile Detection Fixed

Modern PD chargers often expose multiple PPS bands. For example, a low-voltage, high-current band around 3.3–11 V at 4 A alongside a high-voltage, low-current band like 3.3–21 V at 3 A. Until now, a bug in the PD controller library prevented detection of multiple profiles. We’ve fixed that, and V2 now surfaces every PPS profile the charger advertises.

Simplified Profile Picker

V1 split the charger’s capability list across two screens, CapDisplay and Menu, with subtly different rules for which button did what. V2 combines them into a single screen. The encoder scrolls through the profile list, and long-pressing the encoder confirms the selection. You can reach the Profile Picker at any time by long-pressing the "L" button.

Added Safety When Switching Profiles

Switching to a different PDO profile now disables the output automatically by default. We think this is a good default behavior, as different profiles have different V/I capabilities, and a sink device configured for the old profile could end up drawing more current than the new profile is capable of, which can lead to an unexpected power reset.

Input Lock

Long-press both "L" and "R" buttons together to freeze the screen against accidental presses. You’ll notice a padlock icon now appears in the top-right corner. To unlock the device, long-press both buttons again.

Redesigned Energy Screen

The previous energy screen lacked screen real estate for the padlock icon, so we took this opportunity to redesign it while keeping the functionality. The new layout provides a more focused view for the Watts reading. From the Normal screen, long-press the "R" button to show the energy view; the same gesture takes you back.

More Stable Live Readouts

We’ve applied oversampling and EMA smoothing to reduce jitter on small deltas, while larger changes still snap to their new values quickly.

Snappier Buttons

Buttons now run at 30 ms debounce and 500 ms long-press, down from V1’s 50 ms and 1500 ms. You no longer have to wait an eternity for long-presses and the experience is now closer to using a smartphone, it’s just snappier overall!

Tina and I are very proud that Zero Retries Digital Conference 2025 was the public debut of the PocketPD. With this update, the two cofounders are well on their way to future success in their next project(s).

M17 Packet Mode Data

Gregg Wonderly W5GGW on the M17 Users email list:

In my MSeven app, I have added support for SMS messaging in packet mode. I am also adding NTS RadioGram support. I am wanting to do several things with other data types. I’d like to solicit comments/ideas around the use of OpenTrac data packaging as one of the available packet mode data types. I am using the leading byte pair, 0x24, 0x42 to designate my specific use of OpenTrac. OpenTrac is already something in use and in different devices, and so I think it’s an interesting choice for packing multiple data values into packet mode frames.

Any thoughts on this would be appreciated.

Jim Ancona N1ADJ replied:

Your email inspired me to check out MSeven even though I don’t have an iPhone. I was pleasantly surprised to see that it runs pretty well on my MacBook.

How do you envision NTS RadioGram support working?

I’m not familiar with Opentrac, but I found the spec at https://opentrac.org/ and this thread, which gave me a little idea of its relationship to APRS: https://lists.tapr.org/pipermail/aprssig_lists.tapr.org/2023-August/049584.html

I don’t understand what you mean when you say you’re using the leading byte pair, 0x24, 0x42 to designate your specific use of OpenTrac. Is that the M17 Packet Mode Protocol Identifier (section 3.3.2) or something else?

I’m curious how you see OpenTrac being used. AFAIK, there’s no broader network infrastructure in place for Opentrac. Do you envision M17 becoming a transport layer, the way AX.25 is for APRS, with M17 reflectors taking the place of APRS-IS?

W5GGW replied:

Currently, what I am providing is the ability to craft an NTS radiogram, and transport it using the M17P packet mode. The idea behind using OpenTrac, which has been supported in a few different devices, is to use something that already has support and documentation for encapsulating various details that I will add to MSeven support through BLE interfaces.

Where I am going with MSeven, is to provide a very capable first responder application, that will allow certain scenarios to play out, readily. Much like any support effort using ARES resources or just people on the scene with HAM radio equipment, I want to enhance information gathering and forwarding through MSeven’s capabilities.

Today, it does voice and messaging. In addition, I have a contact mapping feature set so you can see where people are “from”. I include QRZ navigation information so that you can find out more about a contact through the use of their callsign on QRZ.com or callook.info web services (when available). What I am really thinking through, is someone rolls up to a disaster with a starlink dish, some batteries, and erects an AP routed through starlink. If they have a reflector setup that they can put on that network, local traffic can start right away with just a WiFi AP and a reflector and external comms can come later.

The radiogram support allows people to go out and collect information that can be received by another device, which could be taken, carried or just forward the radiograms once internet, or some other connectivity (I will add winlink support soon too), so that we have a path and a system for using our devices.

Still to come in MSeven will be photo transport and as I said, winlink transport. Also, I am working on Mobilinkd TNC4 use for M17 transport out of the iPhone to an RF deck. This would allow you to have your phone connected to an HF link out of an area local to you. I am also working on another application that is providing FT8 use from my phone as well to see how that might work out (no CAT/PTT controls without MFi or external BLE connected serial port etc.)

DVSwitch and other such systems that can cross M17 over to Vara FM or other transports is what we would want to flesh out.

This is really about how to make M17 and Codec2 something that can become very useful and attractive to many more ideals so that manufactures can start to think more about how can they support more advanced features.

There’s a lot of things in here that are still just ideas, but there is quite a bit that I have working and not yet visible in the Apple Store version.

Anyone interested in helping me test the TNC4 integration in particular can let me know their iCloud email address and I can set them up for TestFlight access to the things I am testing.

This sounds like a really fun, Zero Retries Interesting project!

The M17-Users email list is sponsored by Zero Retries, and that offsetting that (admittedly minor) expense is thanks to Zero Retries readers who are paid subscribers.

John Draper Website Update: Wavewatch, Ham Radio, And AI Development

The past several weeks have been extremely busy for me as development continues on my new project called WaveWatch. I am not quite ready to reveal all the details publicly yet, but I can say that the project has been moving forward rapidly, especially with the help of modern artificial intelligence development tools.

Recently, I attended meetings with the Henderson Amateur Radio Club and had the opportunity to talk with fellow amateur radio operators about the WaveWatch project. The response was very positive, and several members suggested that I create a dedicated Discord server where I can post updates, technical discussions, development progress, and eventually coordinate testing with members of the ham radio community.

That idea makes a lot of sense because projects like this benefit greatly from collaboration between radio operators, SDR experimenters, software developers, and electronics enthusiasts. Amateur radio operators have always been at the forefront of experimentation, innovation, and emergency communications, and I believe AI-assisted software development will become an important part of the future of ham radio technology.

To encourage collaboration and technical participation, I have also posted portions of the WaveWatch source code to GitHub. At the present time, however, access is intended primarily for individuals who are genuinely interested in helping contribute to the project and assist with development, testing, experimentation, and improvement of the system. My goal is to build a collaborative technical community around WaveWatch consisting of radio enthusiasts, SDR experimenters, programmers, and researchers who share an interest in advanced communications technology and AI-assisted development.

For background on Draper, and why he’s Zero Retries Interesting, see Draper’s Wikipedia page. I believe that Draper is KK7YQS.

Just a quick web search found wavewatch.io which says:

Remote RF Spectrum Analysis

Access your equipment from anywhere, collaborate with your team, and never miss critical RF events. WaveWatch is open source and free to use.

Sounds like an interesting project, and KK7YQS is an interesting character, so I hope to learn more about WaveWatch when more info is made public.

rpitx-ui: A Modernized, Easier To Use Fork Of The RPITX Raspberry Pi Transmitter Software

RTL-SDR Blog:

Thank you to Ihar Yatsevich for writing in about his release of rpitx-ui, a modernized fork of F5OEO’s popular rpitx project. If you were unaware, rpitx is software that turns a Raspberry Pi (most Pi hardware apart from the Pi 5 is supported) into a low cost RF transmitter by generating signals directly on a GPIO pin, requiring no extra hardware beyond a wire antenna. Ihar writes:

rpitx-ui started as a fork of F5OEO’s rpitx and has evolved into a modernized, easier-to-use version of the original Raspberry Pi RF transmitter project. The goal is to make rpitx easier to build, install, use, and extend on modern Raspberry Pi OS systems.

In rpitx-ui, the build system has been migrated to CMake, the project installs system-wide, and it has been adapted for 64-bit Raspberry Pi OS (Debian Trixie). Most transmitter binaries have been rewritten in modern C++20 with shared DSP, audio, and CLI libraries. SSB and AM now use an internal DSP chain with direct DMA output instead of shell pipelines (removing the large SSB startup delay), NFM is a standalone transmitter with wide/narrow deviation presets, WFM with RDS has configurable PI, PS, RadioText and 50/75 us pre-emphasis, CW/Morse has safer parsing with adjustable WPM, and a new RFgen mode supports noise, sweep, and multitone generation. Audio modes also now accept any libsndfile compatible format rather than only WAV.

The UI itself has been improved with file selection for common modes, loop or once playback, custom messages for POCSAG/RTTY/CW, Opera call sign input, SSB sideband selection, NFM deviation selection, and RDS parameter setup. Full source and build instructions can be found on the rpitx-ui GitHub page.

Wow - I wasn’t aware of all those different modes. This is one of my most oft-cited examples of Zero Retries Interesting radio technology that’s easily accessible to those who want to experiment with radio technology without obtaining an Amateur Radio license. (Obviously, with the disclaimer of “don’t do stupid things with this”.) Like

Cool logo for rpitx-ui:

Image courtesy of rpitx-ui

WWV Amateur Radio Club

About the WWV Amateur Radio Club

The WWV ARC is an amateur radio club based in Fort Collins, Colorado. The club was created in January 2019 to help facilitate the 100th Anniversary of radio station WWV, which is located just north of Fort Collins.

Our Mission Statement:

The WWV Amateur Radio Club (WWVARC) exclusively promotes and celebrates the historic, scientific, and cultural importance of radio station WWV and amateur radio by conducting club educational programs and activities related to WWV, time and frequency measurement, and amateur radio.

The club re-organized in April 2021 and now has an international membership. We look forward to sharing our knowledge of WWV and the NIST Time and Frequency services in addition to taking part in current research utilizing the WWV and WWVH HF broadcasts.

…

The Enhanced WWVB Broadcast

The next meeting for the WWV Amateur Radio Club is on Thursday, May 28, 2026, at 6pm MDST via Zoom.

The May 28 meeting will feature Dr. Oren Eliezer. His talk reviews the history and technical details of the enhanced WWVB broadcast, which was introduced by NIST in 2012 to allow for more reliable reception of the station’s broadcast throughout North America. It will include the background for the enhancement, the communication theory behind it, the speaker’s personal experiences leading the engineering effort and interacting with NIST, the architecture of the receiver IC for the enhanced broadcast, photos from the station, and some entertaining stories.

The Zoom meeting will open at 5:30pm MDST for shooting the breeze for about 30 minutes until our meeting STARTS OFFICIALLY AT 6PM MDST.

This meeting is open to all amateurs. CLICK HERE for a description and Zoom info.

Zoom information is forwarded in emails to the membership a few days before each meeting.

WWVARC (club callsign WW0WWV) doesn’t seem to have a YouTube channel.

WWVARC is a Zero Retries Interesting Amateur Radio club!

My thanks to Scott Honaker N7SS for mentioning the above article.

CHU To Shut Down 2026-06-22

NRC shortwave station broadcasts (CHU)

As of June 22, 2026, the shortwave radio broadcast of the NRC’s official time signal will no longer be available.

The NRC’s official time can still be found in the following ways:

For those looking for shortwave radio time signals, they are available from the Bureau International des Poids et Mesures.

NRC is National Research Council Canada.

The above… is the entirety of official information available (that I’ve been able to find) about the impending shutdown of time reference radio transmitter CHU located near Ottawa, Ontario.

A discussion about this development ensued on the HamSCI email list. One post by Robert Mazur VA3ROM offered his perspective as a former government employee:

This follows on the heels of the termination of Environment Canada’s shutdown of the VHF Weatheradio Canada transmitter network and the “Hello Weather” telephone service (March 16, 2026). As a former Canadian government employee (35-1/2 years), I’ve seen the budgetary spending of my one organization, where over 75% was for salary and associated expenses at just one centre, and only 25% was devoted to the actual equipment and maintenance/upgrades. As a result, well into the 21st century, we were still using 1990’s radio and computer technology. Many of the services we were providing to the public, at great expense, were essentially obsolete, unknown or little used. Maintaining analog systems, archaic computers and operating systems (new ones couldn’t be interfaced with the out-of-date equipment), and landlines is very, very expensive. Another fact was that replacement technicians coming out of college had no training on Harris kilowatt (tube) transmitters (or any tube-based training) or how to use and program archaic MSDOS, IBM O/S 2.1 and PL/M-80. The looks they gave us. Needless to say, most moved on as fast as they could get their technologist’s tickets punched. Our nearing retirement technicians were sourcing NOS parts from eBay to keep things working! Long story short, 44 centres became 22, then 11 and the public couldn’t care less. But the savings to the federal government (and taxpayers) were in the billions. I suspect that, like our service was, CHU is in bad need of a “makeover”. But makeovers are expensive. Be it AES weather radio, NRC CHU, or CBC services, reducing spending on climate change research, or simply ending AES in-person training for the Canadian Weather Amateur Radio Network (CANWARN), and switching to a remote (Zoom) training, all those nickels and dimes saved add up. Especially more so now, when AI will reduce redundant staff and their salary benefits to the bone. So 11 centres eventually become 1, and can we reduce the clerical, technical and operational staff by 90%! If I’m a Canadian superintendent in charge of, say, NRC, and told by the Minister (my boss) to cut expenses or else find a new job, do I really care about low-handling fruit like CHU? Does the Canadian taxpayer really care about CHU (99% don’t even know what a “CHU” is)? Will their world be any different on June 23rd?

VA3ROM also hosts an interesting website - www.va3rom.com (but, alas, no RSS feed to be able to easily keep up with new postings). Several of VA3ROM’s archived articles for The Canadian Amateur such as The Road to Radio series (all parts not yet posted), Telemetry Over WSPR, and FM Voice & Data & the ISS look Zero Retries Interesting. Be sure to browse the link bar on the left side of the page - I found links there to a number of small Amateur Radio manufacturers (mostly kits) that I’d never heard of.

VA3ROM’s perspective rings true. While I’ve never worked for (US) government, I did briefly work for on a military project. Some of that project’s technology was decades old (and the equipment we used outlived the manufacturer). The expense to maintain “archaic” equipment and technology, as it ages out of widespread use, is significant. And no, updating the decades-old technology wasn’t as simple as “port it to Linux”.

One Zero Retries reader noted that CHU is often easier to receive in the Eastern portion of North America than WWV’s transmissions from Fort Collins, Colorado.

Earlier this year, Canada also shut down its nationwide Weatheradio service, a network of VHF transmitters.

My thanks to several Zero Retries readers, especially Wes Plouff AC8JF, that brought this development to my attention for inclusion in Zero Retries.

UberSDR - Open Source Web HF SDR

2000 Channels · No GPU

UberSDR is a free, super powerful, web-based Software Defined Radio platform for amateur radio enthusiasts, providing real-time access to the entire HF spectrum and multi-band WSJT-X skimming. Support for third party software via SoapySDR as well as a native desktop client. Based on the affordable RX-888 MKII and generic PC hardware. Powered by ka9q-radio.

I took a glance at the Zero Retries 2026 Index and I don’t seem to have mentioned UberSDR, at least in 2026. Update - It was mentioned in late 2025, but it’s been a few months, thus it’s worth a repeat.

This mention was triggered by VA3ROM’s mention on his web page:

May 4, 2026

May the Fourth be with you! “ Added link to the new & amazing UberSDR. If you hate Linux, as I (still do, but...) this Linux-based SDR platform (standalone or cyberspace shared) is something for you to check out! It’s not your usual browser-based SDR because you do some serious radio science with it. If you can never get enough TMI then UberSDR is for you!

Packet Radio is Making A Strong Comeback

Mike Thompson WB8ERJ on Mike’s Tech Blog WB8ERJ:

Fellow hams, if you think packet radio is a relic of the 1980s and 90s BBS era, it’s time to tune in again. This resilient digital mode is experiencing a notable resurgence, driven by its proven reliability in off-grid scenarios, modern software tools, and renewed interest in resilient emergency communications.

For operators who remember connecting to distant nodes with clunky TNCs, everything is now done with software. All you need is a computer with a sound card, free modem / TNC software such as Direwolf, and you are good to go. I have several Packet stations running on Raspberry Pi’s. My WB8ERJ-1 packet BBS runs on a Raspberry Pi 3B+ and a USB sound card.

Why The Comeback?

Packet radio, built on the AX.25 protocol, breaks data into packets for efficient transmission over VHF/UHF (and sometimes HF). While the internet boom reduced its everyday use, recent events—natural disasters, infrastructure concerns, and a broader focus on grid-independent operations—have highlighted its value.

Modern implementations use sound card modems like DireWolf, and software such as BPQ32, making setup far easier and more powerful than the hardware-heavy days of old. Clubs and regional networks are reviving or expanding packet infrastructure, with active BBS systems and forwarding links.

Here is a map of some of the Packet BBS nodes in Ohio. For a complete list, OhioPacket.org has a list by county.

Packet Radio Is Making A Strong Comeback
Packet Radio Is Making A Strong Comeback

Operators report renewed activity on traditional frequencies like 145.010 MHz for BBS traffic. High-profile emergencies have demonstrated packet’s role when cellular and internet services collapse. The WB8ERJ-1 BBS is on 145.030 mHz in the Mansfield Ohio area with a backhaul link on 223 mHz to KB8UVN-1 in Johnstown as well as to KD8FTR-1 in Ashland Ohio.

Be sure to click on Page 2 at the bottom of the page where WB8ERJ discusses BBS forwarding.

It’s heartening to see the map in this post as when Tina and I relocated from the Cleveland, Ohio area to the Seattle, Washington area in late 1987, a statewide packet radio network in Ohio was barely in discussion. And, argh, I was just in the Mansfield, Ohio area (passing through); had I seen this post prior to Hamvention 2026, I might have been able to stop and meet WB8ERJ.

In my review of ARRL’s new book Digital Networking for Ham Radio, in my conclusion, I said:

A Suite of ARRL Amateur Radio Networking Books?

…

Similarly, a book that’s a fresh treatment of Amateur Radio Packet Radio and Packet Radio networking in the 2020s is badly needed, including the use of Winlink. Although VARA FM, Icom DD Mode, and (again, in development) MMDVM-TNC aren’t Packet Radio, they would fall within the overall scope of such a book. Such a book would be mostly about VHF / UHF operation.

I received some knowledgeable feedback about this idea. Apparently ARRL considers Amateur Radio Packet Radio to be old, tired, and largely irrelevant at least when it comes to justifying a dedicated book on (modern aspects of) Amateur Radio Packet Radio. After all, ARRL has already published the most up-to-date book on Packet Radio available on Amazon - Your Gateway to Packet Radio… albeit being published in 1989.

But as WB8ERJ posits, Amateur Radio Packet Radio is making a comeback (and follow-on technologies for data communications on VHF / UHF bands) and it continues to be relevant.

Thus I posit that there is an opening for such a book. Such a book is on my list of writing projects1, if someone else doesn’t beat me to it.

CQ FD 2026

Eric Grumling K0JEG on his Grand Valley Aviation newsletter:

ARRL Field Day is June 28, 2026. Part One

…

Site Communications

As Field Day operations have become more computer-driven, the site itself has started looking less like a few radios under pop-up tents and more like a temporary communications campus. This year we’re finally going to do what I’ve wanted to do for about a decade, but never had enough time or motivation. We’re going to have a network for all the tents to use. We set up 3 primary stations based on operating mode: CW (Morse code), SSB (Voice) and Digital (sound card tones). We also set up two auxiliary tents, the “Get On The Air” (GOTA) tent and a VHF tent. In the past we’ve not paid much attention to either, because the rules say that the GOTA tent is worth 100 points and the VHF tent is “free” in that we don’t need to include it in our normal exchange and report. But points is points, and we want to make sure to get the most possible1.

In years past we’ve used a computer logging program called N1MM+. It’s an old workhorse of a program that has gathered hundreds of features that most people never touch. One of these features is to share logs across a LAN as both a real-time way to back up the logs and so each station can keep a real time status of how we’re doing. The logs can also be used to run a dashboard that can show everyone how we’re doing. This year I’ll be leading the buildout of a site-wide WiFi network that will tie all the tents together.

Network Requirements

One of the surprisingly difficult problems at Field Day is keeping all the computers synchronized. In the high country, temperatures range from the upper eighties during the afternoon to below freezing at night. The extreme shift will cause computer real time clocks to drift, leading to problems. N1MM+ wants a fairly accurate real time clock, especially when running in network mode. The digital modes require precision timing to work properly. As clocks drift with temperature they need to get back in line. Luckily I have a stratum 1 NTP time source available, thanks to my Starlink Mini. In years past we’ve had issues with keeping clocks accurate as temperatures changed, so just having accurate time available is probably worth the effort.

Tent-to-tent communication is also something that has been lacking in years past. N1MM+ has a chat service built in, and I set up a portable PBX using Asterisk and Allstar. The tents will have SIP phone extensions that can call each other, call out to other Allstar nodes such as the club repeater, and even get dialtone if they want that late night pizza delivery. This traffic will all be isolated on its own VLAN and separate SSID, so we shouldn’t have any issues with interlopers interloping.

In addition, I’ll set up another VLAN/SSID for the public to provide information about field day, our club and links about ham radio. This will probably be where the dashboard application lives too. It will run over Starlink so I will probably put some serious access controls on the VLAN to make sure we’re being good netizens and not burning up my monthly data allocation.

Finally I’ll have my own VLAN/SSID for my devices, because… well, I built the thing so why not? I’ll have both an HT and my WiFi SIP phone on my belt so tents can call me to help coordinate fixes to problems and vice versa.

Basic network diagram (ChatGPT)

Hardware

I’ve been working with MikroTik routers and switches for years (time flies). Their hardware isn’t necessarily the fastest for moving packets around, but it is pretty great for amateur use and still at a great price. I will be using the same hAP ac3 I installed in my camper van but with the addition of an external WiFi radio (MikroTik mANTBox ax 15s). This will be the access point for the tents. Each tent will have a MikroTik SXTsq 5 pointed back to the access point, and supplying Ethernet to the laptop and a SIP radio. These will be powered by a small DC UPS that will keep the connections up while refueling. The primary router and other network gear will be stationed at my camper van and should run on my Ecoflow Delta Max the whole time -and if not I’ll have the Ecoflow Smart Generator available too.

Overkill? Probably. But also gives me a chance to stretch my networking skills. Not only that but I’m now pretty familiar with MikroTik’s RouterOS operating system, which is widely used in ham radio for repeater linking, point-to-point networking and other general use. They aren’t the fastest routers out there, but they’re extremely capable and at a price point that’s extremely ham friendly. Normally the hAP ac 3 can also use my iPhone tethered to its USB port for a backup but T-Mobile service at the Field Day site is pretty much nonexistent.

Network Topology

I’m building in three separate VLANs. First will be my normal VLAN that has access to everything. This way I’ll be able to monitor and troubleshoot any issues that may come up. This is also where the Allstar/Asterisk/dashboard server lives, and it will have full access to the Starlink feed. It is basically unchanged from my normal set up, using the hAP ac3 integrated WiFi and switch. The second VLAN will be the tent network as described above. And the third subnet will be for the public to get information about Field Day, the Ski Country ARC and some of the nuts and bolts of the site. I will probably include limited Internet access to a few websites like APRS.fi and the ARRL.

Now that is a Zero Retries Interesting kind of Field Day. VOIP phones at each tent? Cool! If I was located near K0JEG, I’d show up just to learn more about the temporary networking.

I’m beginning to think that there should be a Meadow Day 2 using my Starlink Mini operating at 500 kbps.

Starlink Standby Mode Price To Double to $10/month

Speaking of Starlink and Amateur Radio, I received an email from Starlink stating that price increases for Starlink service coming in June. The price increase that is most Zero Retries Interesting is Starlink’s Standby Mode pricing will increase from $5/month to $10/month. That’s a non-issue for me - at 500 kbps2, Standby Mode at $10/month remains a great deal especially for Internet connectivity that I can dedicate / firewall solely to Amateur Radio activities.

There is a single satellite launched by the US Navy in 1964 that is still in orbit, still transmitting, and still being used by amateur radio operators around the world — and nobody at the Navy has been in charge of it for decades

Space Daily Editorial Team:

On December 28, 1964, a Thor-Able-Star rocket lifted off from Vandenberg Air Force Base in California and put a small US Navy satellite into a low polar orbit.

On December 28, 1964, a Thor-Able-Star rocket lifted off from Vandenberg Air Force Base in California and put a small US Navy satellite into a low polar orbit.

The satellite was called Transit 5B-5. It weighed about 70 kilograms. It was part of the first satellite-based navigation system in human history — the predecessor to GPS, designed to help American submarines fix their position anywhere in the world. It was given a working lifetime of a few years. Maybe five, if everything went well.

That was sixty-one years ago.

Transit 5B-5 is still up there. It’s still in orbit. It’s still transmitting. And somewhere right now, an amateur radio operator with a backyard antenna is listening to a signal that was first beamed down from space when Lyndon B. Johnson was president.

Nobody at the US Navy has been in charge of this satellite for nearly thirty years. The program that launched it was officially retired in 1996, when GPS took over the job. The Navy walked away. The satellite did not stop working.

How it’s still alive

The reason Transit 5B-5 has lasted this long is genuinely remarkable.

Most early satellites ran on chemical batteries or basic solar panels that degraded quickly. Transit 5B-5 carried something different: a SNAP-3 radioisotope thermoelectric generator — a small nuclear power source that converts the heat from decaying plutonium-238 into electricity.

Plutonium-238 has a half-life of about 88 years. That means a SNAP-3 RTG launched in 1964 should still be producing somewhere around 65% of its original power output today. The satellite isn’t using sunlight. It isn’t using a battery. It’s using a small lump of slowly decaying radioactive material that simply continues to give off heat, year after year.

The radio transmitter on board doesn’t need much power. Just enough to keep broadcasting a signal at around 136.65 MHz — a low-frequency telemetry beacon that, against all reasonable expectation, has never stopped.

There are no moving parts left to wear out. No fuel to run dry. No on-board computer to crash. The whole satellite is essentially a power source connected to a transmitter, drifting along in an orbit that itself doesn’t require maintenance. It just works. It has worked for sixty-one years.

Fascinating story! On a previous job that predated Global Navigation Satellite System (GNSS) technology, passes of the Transit satellites were received several times per day as one element of a custom precision navigation system. That would be cool to set up a SatNOGS station to receive Transit 5B-5 when it’s not otherwise in use.

New Book - Satellite Operating for Amateur Radio

New book from ARRL by Tony Milluzzi KD8RTT:

Work the Birds!

Ever wanted to operate amateur radio satellites but thought tracking the “birds” was too complicated—or weren’t sure you had the right equipment? This book is for you. Written in a clear, engaging style, Satellite Operating for Amateur Radio shows just how exciting, approachable, and fun satellite operating can be.

Your journey begins with the simple act of listening—the first step to every successful satellite contact. With just a handheld radio, you may already have everything you need to get started. From there, author Tony Milluzzi, KD8RTT, guides you through making your first satellite contact, sharing practical tips and proven advice to build confidence as you explore new modes of operation.

For experienced operators, the book dives into digital modes like FT4 and D-STAR®, plus roving, award chasing, and advanced techniques to sharpen your skills and become a stronger satellite operator.

Explore antennas, modern tracking and operating apps, and the vibrant amateur satellite community. Whether you’re just getting started or ready to take your skills to the next level, Satellite Operating for Amateur Radio will help you get on the air and point your antenna at the sky.

Inside You’ll Discover:
Listening to Your First Amateur Satellite Pass
Making Your First Satellite Contact
Digital Satellite Operations
Linear Transponder and Digital Satellite Operations
Antennas for Satellite Operating
Ground Station Considerations
Software and Mobile Applications
Connecting with the Amateur Radio Satellite Community

ARRL is on a roll in 2026 with a couple new Zero Retries Interesting books. Arguably they’ve hit all three of the Zero Retries trifecta (data communications and microwaves in the same book, and now space).

Completeness requires me to note that if you’re really interested in Amateur Radio satellite operation, AMSAT is an entire organization focused on Amateur Radio satellite operation and membership is pretty reasonable. I’ve seen a lot of good progress at AMSAT of late, and when I joined AMSAT earlier this year, a “signing bonus” was a free download of their excellent book, revised annually - Getting Started with Amateur Satellites (PDF), otherwise $15.

Findings from the 2026 [ARDC] Grants Evaluation Team (GET)

Rebecca Key KO4KVG on the ARDC website:

As ARDC’s grants program continues to evolve, understanding the outcomes of funded projects remains an important part of our work. The Grants Evaluation Team (GET), now in its third year, helps support this effort by reviewing completed projects and evaluating how well grantees achieved their stated goals. We’re pleased to share highlights from their latest report with the community.

For this year’s report, the GET reviewed 49 final reports submitted between June 2025 and February 2026 from ARDC-funded projects. Throughout their meetings, the team discussed trends, identified recurring themes, and worked collaboratively to evaluate project outcomes and broader program learnings.

As in previous years, the GET approached this work reflectively, looking at projects from multiple perspectives. Their discussions focused on these primary questions:

  • Were these grant projects successful?

  • Were they a good use of funds?

  • Are the process changes we’re implementing having an impact?

  • What information should we be sharing back with our community?

There were some interesting takeaways from this report such as financial and time estimates from grantees for installing antenna systems are frequently too optimistic about time required, complexity (engineering and organizational), and the expense to install them.

Video - Can you help the Arika 2 CubeSat team? Amateur radio operators needed!

HamShack TV YouTube channel:

The Sakamoto Laboratory in Tokyo is calling on the global amateur radio community to assist with tracking its Arika 2 CubeSat. Launched in late April, this 2U CubeSat is currently transmitting CW signals on 436.830 MHz and requires signal reports from operators worldwide. While the satellite is focused on capturing Earth and aurora imagery using machine learning, it also aims to demonstrate real-time alerts for astronomical events. Future plans include transitioning to GMSK transmissions, with updates expected via the AMSAT bulletin board and social media. This mission highlights the vital role hobbyist radio operators play in supporting satellite research and space data collection.

This sounds like a perfect job for the SatNOGS network!

Video - Hamvention 2026 - FreeDV!

Interview with Walter Holmes K5WH of the FreeDV Project. It’s a good basic intro to FreeDV, but this interview is most notable that it was recorded and posted by Ham Radio Outlet, a US Amateur Radio retailer who normally doesn’t promote “experimental” systems that they cannot sell… like Open Source software.

FreeDV is indeed breaking into the mainstream of Amateur Radio!

My thanks to Joe Hamelin W7COM (Zero Retries Founding Member 0014) for bringing this development to my attention for inclusion in Zero Retries.

Video - Wake Up, Ham Radio — The Revolution Is Already On The Air

Per the recommendation below, the above link begins at 6:02.

Wes Plouff AC8JF via email:

Dave Owen G3LRC has just recorded a video titled “Wake Up, Ham Radio — The Revolution Is Already On The Air.” Owen advocates not buying a “Big 3” HF transceiver because the “four horsemen of the amateur radio apocalypse” have arrived, namely:

  • Polar modulation (SSB with 80% efficient power amplifiers)

  • Controlled envelope single sideband (CESSB)

  • Adaptive predistortion

  • Meaningful firmware updates

Two rigs that you can buy today, at opposite ends of the price spectrum, are the QRP Labs QMX+ and the Flex Radio Aurora. One costs thousands of dollars, the other less than $200, but they have advanced beyond the fairly conservative designs of Icom, Kenwood and Yaesu products.

The video linked below is a bit disorganized, with a kitschy throwaway first minute and a digression into misuse of the Sherwood receiver tables. Around the 6 minute mark, though, G3LRC gets into the meat of his advocacy. He impresses me as knowing his subject well, and he has produced other videos advocating for these new-ish technologies. Do you want creative ferment in amateur radio? Dave Owen does, too.

I haven’t yet taken the time to watch this video but I’d add a fifth and sixth revolutionary changes in radio technology:

  • Software Defined Radio technology which allows the basic functionality of a radio to be altered entirely in software. The most prominent example of this trend is being able to add the FreeDV RADE digital voice mode into a FlexRadio 8000 / Aurora series radio. Current FlexRadio products are all inherently Software Defined Radio technology.

  • Artificial Intelligence modules that are small enough to be embedded into radios. There was an earlier “intelligent” radio technology - Cognitive Radio, which was “programmed” to find available (unused, at the moment) portions of spectrum to operate in. Cognitive radio never quite “caught on” as a widely used technology3, at least in the US (as far as I’m aware) largely because use of “vacant, at the moment” spectrum, such as unused television broadcast channels in a given area, was vehemently opposed by spectrum incumbents such as television broadcasters and US Government / military.

Video - Drone Harvesting INVISIBLE High Voltage From The Sky

Months of drone flights culminated in what can only be described as a remarkable feat in physics. I managed to successfully siphon energy directly out of the atmosphere.

This video demonstrates sending up a drone with a very light wire, and viscerally demonstrates the voltage differential between the atmosphere and ground.

I’d… hazily… known that this effect existed, but this was the most interesting, engaging way to demonstrate it. Turns out there a lot of YouTube videos about “atmospheric electricity.

Video - Mark Rober’s $60 Million Science Experiment | TED

Mark Rober is a modern day science teaching hero. He calls his techniques to demonstrate (teach) science “hide the vegetables”. This is his presentation at the 2026 TED Conference.

If Rober isn’t already familiar to you, the video will provide you with context before the big reveal:

The world has evolved, and teaching science is long overdue for disruption. I’m happy to report that of the teachers who are assigned to teach the pilot lessons to their students, because of our ability to explain complicated things simply and for our very unique experience in solving the science motivation gap for 15 years, 95 percent of the teachers said that when we’re done, they would want this to be their full science curriculum.

And so the idea is you combine incredible teachers with incredible resources to get this explosive output, sort of like you’d expect to see if you combine this bucket of boiling water with this trash can of freezing-cold liquid nitrogen.

So to all those teachers out there in the trenches, I want you to know reinforcements are on the way.

In fact, a bunch of the videos and lessons are already available right now, and we’ll finish the rest over the next four years, because I know this will be the most important thing I do my whole life.

And even though this is going to cost us $60 million to make, my official declaration tonight is every single lesson plan, every teacher training, every original class demo will cost exactly zero dollars and be 100 percent free for all teachers forever, as we work to ignite those brain fires of curiosity in the next generation of big problem solvers.

There’s nothing radio-related in this video, but if you have an interest / investment in there being more science-literate young people in the coming decades… and every one of you reading this, as part of humanity, you do in fact have such an investment… Rober’s announcement is incredibly good news for humanity.

Seriously… please accept my recommendation to watch this video.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0252.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

Cascade STEAM Spectrum Community Group

I had a great experience earlier this week in Bellingham at the inaugural meeting of Cascade STEAM’s new Spectrum Community Group.

It’s very (very) early days for this group that will be focused on radio technology, and fun, interesting, and relevant ways to learn about it. It feels like this is an ideal way to involve potential NewTechHams from the three colleges in the Bellingham area, and be able to work Zero Retries Interesting aspects of Amateur Radio into the mix of things we’ll be discussing.

One of the biggest advantages of this new group is that it’s just one of a number of Community Groups that are part of Cascade STEAM, which has significant management and organizational depth, and connections with other STE(A)M organizations in Western Washington. Just as one minor example of taking advantage of Cascade STEAM’s infrastructure, they have a mature Code of Conduct, which is an absolute minimum requirement in this era for any group that hopes to attract interest from young folks.

The Spectrum Community Group is a distinct contrast to a group that’s primarily focused on Amateur Radio aspects of radio technology, but rather Amateur Radio as one of many aspects of radio technology. We’re already making plans to do a one-day “teach the Tech test” class, and then a quick (if not the same day) license exam session to get the Spectrum participants licensed to be able to have some Zero Retries Interesting Amateur Radio fun.

We’ve even begun to discuss (again, very early days) the possibilities of building out some SPECTRUM radio infrastructure in this corner of Washington, and perhaps connect with similar efforts in nearby Vancouver, British Columbia.

I’ve agreed to be one of the organizers of Spectrum, and I’m even enthused enough about this to try, again… in my dotage… to get myself on Discord because that’s Cascade Steam’s primary communication channel, and this feels significant enough to justify another attempt at Discord.

Zero Retries - TL;DR

TL;DR is Too Long; Didn’t Read. Statements to that effect were the second4 most heard comment about Zero Retries at the Zero Retries booth at Hamvention 2026. Granted, the sample size was small (< 25 - my best guess) out of 3500+ email subscribers, but it’s visceral to hear that comment repeatedly face to face.

One email commenter who is a marketing professional explained the situation pretty simply to me. Too-lengthy issues of Zero Retries (an average issue) just don’t get read in their entirety. A typical reader reads only so far, stops reading, intending to come back to finish that issue of ZR… and doesn’t. That rings true, because I do the same thing with other lengthy, detailed (text) email newsletters. The email commenter concluded by saying that because much of Zero Retries is unread, that extra work I put into longer issues of Zero Retries is essentially wasted.

What makes it difficult for me is that I’m probably too close to the subject material of Zero Retries. I’m not an impartial Editor “managing” the content to be a certain length, but no longer. Thus it’s hard for me to be objective about what’s appropriate to be included in an average weekly issue of Zero Retries. A problem, for me, is that everything in an average issue of Zero Retries is interesting and relevant to me.

I think part of the problem of too much content in Zero Retries is that I get exposed to that material over the course of a week or two. A Zero Retries reader is getting exposed to all of that content in “a single dose” and at that point the totality of an average issue of Zero Retries can be a bit overwhelming for a reader who just wants an overview of what’s Zero Retries Interesting in a given week. More than that… TL;DR.

That this issue doesn’t have much “long story” content is more of a factor of having traveled for a week around Hamvention 2026 and having to do a lot of catching up afterward.

Zero Retries Magazine?

Zero Retries Magazine prototype cover. Image by Steve Stroh N8GNJ
Zero Retries Magazine (prototype) cover. Image by Steve Stroh N8GNJ

At the Zero Retries / DLARC booth at Hamvention 2026, only a very small handful of people noticed the display, or expressed interest in Zero Retries to the point it was worth showing off a prototype printed Zero Retries Magazine. For Hamvention 2026, I compiled and printed a prototype of all of the April, 2026 issues of Zero Retries newsletters into a “Zero Retries Magazine for April 2026”. It kind-of worked - there were 114 pages worth of content. From a quick check into the economics of printing a Zero Retries Magazine on demand via Lulu.com, it could work, especially if some Zero Retries Interesting manufacturers could be persuaded to advertise in Zero Retries Magazine. The idea of Zero Retries Magazine needs a lot more research, and careful business analysis, but it seems at least feasible.

Of course, there would be a version that’s online / text / PDF. To address an observation Cale Mooth K4HCK, a friend and colleague in free, good Amateur Radio content - Amateur Radio Daily and Amateur Radio Weekly, there would be an online version where the individual stories are individually linkable, probably apart from Substack so there wouldn’t be the “Substack Link Dreck”.

A Zero Retries Magazine might “scratch my itch” for the longer, explanatory articles that I tend to write when explaining something new. Plus it could more easily incorporate presentations that I do, and articles for other venues such as The Communicator, and even excerpts from other sources such as, for example, explanatory articles about PACSAT (Packet Satellite) from the TAPR Packet Status Register (PSR) newsletter, originally published decades ago, but still relevant. As has been the case since Zero Retries began, contributions from other authors would be welcome in Zero Retries Magazine.

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0252.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

Founding Members who generously support Zero Retries financially:
Founding Member 0000 - Steven Davidson K3FZT (Renewed 2025, 3rd year!)
Founding Member 0001 - Randy Smith WU2S (Renewed 2025, 3rd year!)
Founding Member 0002 - Chris Osburn KD7DVD (Renewed 2025, 3rd year!)
Founding Member 0003 - Don Rotolo N2IRZ (Renewed 2025, 3rd year!)
Founding Member 0004 - William Arcand W1WRA (Renewed 2025, 3rd year!)
Founding Member 0005 - Ben Kuhn KU0HN (Renewed 2025, 3rd year!)
Founding Member 0006 - Todd Willey KQ4FID (Renewed 2025, 3rd year!)
Founding Member 0007 and 0010 - Merik Karman VK1DF / VK2MKZ (Renewed 2025 x2, 3rd year!)
Founding Member 0008 - Prefers to Remain Anonymous 08 (Renewed 2025, 3rd year!)
Founding Member 0009 - Prefers to Remain Anonymous 19 (Renewed 2025, 2nd year!)
Founding Member 0011 - Rick Prelinger W6XBE (Renewed 2025, 2nd year!)
Founding Member 0012 - Ryan Tolboom N2BP (Renewed 2025, 2nd year!)
Founding Member 0013 - Newton White N4EWT (Renewed 2026, 2nd year!)
Founding Member 0014 - Joe Hamelin W7COM (Renewed 2026, 2nd year!)
Founding Member 0015 - Rich Stocking N7OP (Renewed 2026, 2nd year!)
Founding Member 0016 - Prefers to Remain Anonymous 77 (New 2025)
Founding Member 0017 - Phil Karn KA9Q (New 2025)
Founding Member 0018 - Prefers to Remain Anonymous 95 (New 2025)
Founding Member 0019 - Prefers to Remain Anonymous 0108 (New 2025)
Founding Member 0020 - Prefers to Remain Anonymous 110 (New 2025)
Founding Member 0021 - Prefers to Remain Anonymous 111 (New 2025)
Founding Member 0022 - Prefers to Remain Anonymous 112 (New 2025)
Founding Member 0023 - Prefers to Remain Anonymous 116 (New 2026)
Founding Member 0024 - Rob Bowser (SPOOLTENNA) (New 2026)
Founding Member 0025 - Dave Stewart K7XST (New 2026)

Numerous Annual and Monthly subscribers who also generously support Zero Retries financially!

You thousands of readers of Zero Retries without which there would be little point in publishing this newsletter.

The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries \ Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0252 was published on 2026-05-29. This issue was 9982 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

While a dedicated book on Modern Aspects of Amateur Radio Packet Radio is on my list of writing projects, it’s down the list quite a bit. Unless some organization could “incentivize” a move up my list of writing projects… just sayin’.

2

When I first got my Starlink Mini and used Standby Mode, it was 400 kbps. But Starlink’s How does pausing service work? page states:
Standby Mode, where available, offers speeds up to 500 Kbps download and upload.

3

Two exceptions of using “vacant” spectrum in the US, that weren’t true Cognitive Radio, was “Television White Space (TVWS) regulations that allowed for Broadband Internet and wireless microphone use of unused television broadcast channels, and Citizens Broadband Radio Service (CBRS) that allowed spectrum from 3.55 - 3.70 GHz allocated to US military use to be used for Broadband Internet (and private, such as interior enterprise, mobile phone use. When originally proposed, both would have used Cognitive Radio techniques, but spectrum incumbents ultimately forced both services to be “advanced permission” systems (I call it “Mother, May I?) techniques.

4

As I mentioned in Zero Retries 0251, the most often heard comment on Zero Retries at Hamvention 2026 from existing Zero Retries readers that stopped by the Zero Retries booth was Thanks for doing Zero Retries. That… was most appreciated!

]]><![CDATA[Zero Retries 0251]]>https://www.zeroretries.org/p/zero-retries-0251https://www.zeroretries.org/p/zero-retries-0251Sat, 23 May 2026 05:39:54 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its fifth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is too big for email clients. Thus, it might be easier to read in a web browser - www.zeroretries.org/p/zero-retries-0251.

It’s easy and free to subscribe for your own copy of Zero Retries every week:

Subscribe now

In This Issue:

I-Frame

Zero Retries Hamvention 2026 Recap

RepeaterBook Project Apollo

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Rich Stocking N7OP for renewing as Founding Member 0015 to Zero Retries in the past two weeks (2nd year)!

My thanks to Dave Stewart K7XST for upgrading from a free subscriber to Zero Retries to Founding Member 0025 in the past two weeks !

Founding members are listed in every issue of Zero Retries!

My thanks to Andrew Herrington KG5JNC for renewing as an Annual Paid Subscriber (three years!) to Zero Retries in the past two weeks!

My thanks to Prefers to Remain Anonymous 27 for renewing as an Annual Paid Subscriber (three years!) to Zero Retries in the past two weeks!

My thanks to Prefers to Remain Anonymous 28 for renewing as an Annual Paid Subscriber (three years!) to Zero Retries in the past two weeks!

My thanks to Ed Wilson N2XDD for upgrading from a free subscriber to Zero Retries to a Paid Subscriber in the past two weeks!

My thanks to Prefers to Remain Anonymous 126 for becoming a Paid Subscriber to Zero Retries in the past two weeks!

PRTA 126 included this nice note:
I think we need to keep up writing to advance the hobby. YouTube is not the answer.

I replied:
I agree that YouTube is not the answer. It certainly has its uses and I’ll be making more use of YouTube in Zero Retries, but Zero Retries will remain mostly text.

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Lots of Photos This Issue

This is the most use of photos I’ve ever done in Zero Retries and I have no idea how well it will work given that this is a newsletter that’s nominally distributed via email. I made no attempt to reduce the file size or resolution of the photos, thus this issue will be big (as in file size). Please let me know (via comments) on how well it worked out for email subscribers.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0251.

Zero Retries Hamvention 2026 Recap

By Steve Stroh N8GNJ

Hamvention 2026 is in the rear view mirror, and I reflect on what I saw from the Zero Retries perspective.

Hamvention Is FUN!

In this article, I do a tiny bit of grousing about the new experience, and minor inconveniences and discomforts of being a first time exhibitor at Hamvention this year. It’s important to disclaim in advance, for this techie being intensely interested in all things involving radio technology, Hamvention is a very fun, involved, full immersion experience in Amateur Radio and radio technology. I had many stimulating conversations at Hamvention, some for the benefit of Zero Retries, and some for the benefit of making connections between others that might not have known about each other. I recommend attending Hamvention at least once, because it’s fun!

Hamvention 2026 is now in the history books. The two big changes for me from previous visits to Hamvention was that I was a first time (co-)exhibitor and for the very first time I didn’t set foot in the flea market area… I just didn’t have the time. Similarly, for the first time, I didn’t have the time to attend any of the forums. A future note to self is to recruit a full time booth staffer so that I can spend some time away from the booth while reasonably representing Zero Retries.

And… N8GNJ / Zero Retries Labs is already full-to-bursting with waiting projects, thus I wasn’t compelled to seek out any new acquisitions and treasures in the flea market. Despite having ample projects in queue, I did pick up a few new treasures which I’ll mention at the end of the article.

Like at Hamvention 2025, within minutes of entering Building 1, my shoulder worn continuous glucose monitor, tethered to my iPhone via Bluetooth, went offline for most of my time inside the five Hamvention buildings. There’s apparently a pretty large buffer in the unit as no data was lost, and within a few minutes of leaving Hamvention buildings, it returned to normal functionality. I attempted to report this behavior to the manufacturer after Hamvention 2025, but they didn’t follow up with me.

Exhibiting is a Different Experience

Friday morning got off to a bit of a rough start with a flat tire on the rental car. We discovered the flat when we stopped for reasonable coffee at Starbucks. As luck would have it, there was a Discount Tire store across the street from Starbucks. When they opened at 08:00 we were the first customer and they handled our flat tire gracefully and efficiently. When they pronounced that the tire was not repairable, the good news was that they had a corporate contract with the rental car company and authorization for a replacement tire and all labor costs were handled with no out of pocket expense on my part. With that delay, we ended up being only thirty minutes late in staffing the booth for Friday morning’s opening. If you live in the Dayton area, I can strongly recommend seeking out Jared S. at the Beavercreek Discount Tire store for all your tire needs.

Steve Stroh N8GNJ and Kay Savetz K6KJN at Hamvention 2026, at the ZR / DLARC booth. Image courtesy of Kay Savetz K6KJN.
Steve Stroh N8GNJ and Kay Savetz K6KJN at Hamvention 2026, at the ZR / DLARC booth. Image courtesy of Kay Savetz K6KJN.

(K6KJN is a better selfie taker than I am.)

The Zero Retries / DLARC booth was a joint effort of wanting to promote Zero Retries and my friend and Amateur Radio colleague Kay Savetz K6KJN to promote Digital Library of Amateur Radio & Communications. I think that DLARC gained significant exposure as we explained to passerby using the pitch Free online Ham Radio library and handed them a DLARC postcard. The postcard format works incredibly well, and that’s a primary lesson learned. One interesting bit was that more than a few passerby were skeptical of the “free” aspect until we explained that DLARC was funded by a grant from ARDC (and pointed to their booth just down the aisle). Many people recognized Internet Archive, so that helped in explaining DLARC.

In contrast, my 4-page 8.5 x 11 inch handout with a ZRDC 2026 flyer stuffed inside… not so much. K6KJN was able to get many hundreds of DLARC postcards into folks hands. I barely managed to give away the slightly less than the one hundred handouts I had made.

In hindsight, I didn’t really have enough “pizazz” (or good signage) to explain, tersely enough, what Zero Retries was about, appropriate for the five second pass-by typical at Hamvention (despite our great location in Building 1 between the Kenwood booth and the DX Engineering section). But I also observed that when someone did stop by, perhaps five percent expressed any interest in digital / data communications. Folks attending Hamvention are, in my observation, mostly interested in “MMA” - microphones, Morse Code keys, and antennas… obviously with some exceptions. There were a number of manufacturers of Morse Code keys exhibiting, and I confess some of those “paddles” felt temptingly comfortable for my very rusty Morse Code skills. Playing with a few units sized and weighted for my large hands and fingers, I can genuinely appreciate the visceral feel of using a Morse Code key to transmit “the original data mode”.

One “note to self” that K6KJN and I agree on is have padded floor mats to ease the burden on feet and knees from so much standing. Another is to bring your own chair if possible as the flimsy plastic chairs provided by Hamvention are wretched. Another “note to self” is that there has to be some physical “hook” at any future Zero Retries booth. Next time I will bring a demo of some Zero Retries Interesting project / product with a sign that “If you know what this is, you’ll be interested in the Zero Retries newsletter”.

Special Thanks to Don Rotolo N2IRZ

Don Rotolo N2IRZ at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.
Don Rotolo N2IRZ at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.

My thanks to Zero Retries Pseudostaffer and Zero Retries Founding Member 0003 Don Rotolo N2IRZ. He helped with the expenses of the Hamvention 2026 booth and helped staff the booth part time, ably assisting and capably representing both Zero Retries and Digital Library of Amateur Radio & Communications to all the passerby that were interested in either. N2IRZ is a fellow author of Zero Retries Interesting content, having written the Digital Connections column that ran for decades in CQ and CQ VHF Magazines. N2IRZ’s articles are now being regularly added to DLARC - Don Rotolo N2IRZ articles.

Zero Retries Readers Said Thanks

I was hoping for a reasonable “bump” of perhaps one hundred new email subscribers to Zero Retries, but as I write this issue, there were perhaps ten. Thus my marketing of Zero Retries at Hamvention 2026 wasn’t that great.

Though I didn’t have many new readers for Zero Retries at Hamvention 2026, the best part of Hamvention for me was face to face conversations with dozens of existing Zero Retries readers, some of whom were casually passing by and saw my Zero Retries material and then suddenly made the connection that the writer and Editor of Zero Retries was standing in front of them. Every one of those ZR readers I met profusely thanked me. Several readers mentioned that their ritual on Saturday mornings was reading the latest Zero Retries with their morning coffee. I hadn’t considered the advantage of publishing Zero Retries late on Fridays, for (presumably, extended) reading on a weekend morning.

At Hamvention 2025 I noted dozens of folks walking around with video gear, engaged in (narrating) recordings or livestreaming. This year, despite seeing dozens of “News Media” badges (distinct color from general attendees), I saw just a handful actually doing video. I haven’t yet taken the time to check out YouTube to see the video coverage of Hamvention 2026, and it will be interesting to compare their impressions with mine.

Another observation is that wearing one’s Hamvention ticket identifying themselves (and as a paid attendee) is apparently now optional. At least a third of folks were not wearing any identification (that I could see).

Four Days In May

A persistent “buzz” that I heard at Hamvention 2026 was references to the Four Days In May (FDIM) Symposium that’s an ancillary event held mostly on the Thursday prior to Hamvention. FDIM is a one-day conference focused on low power (QRP) operation on the HF bands. There is significant emphasis on new hardware, and the event is sponsored by QRP Amateur Radio Club International (QRP ARCI). In addition to the Symposium held on Thursday, as part of FDIM, QRP ARCI holds casual evening events on Thursday, Friday, and Saturday evenings which are open to anyone.

The first of two big “buzzes” I heard from FDIM 2026 was about the LARCSet (video link), web page link, a $29 (apparently $39, per the web page) 5-watt SSB / CW Radio that fits on one PCB and can be built in a weekend. That was a project from the prolific Ashhar Farhan VU2ESE of HF Signals. Given that the LARCSet is entirely analog - no digital in it at all, it would be a fun (for me) dichotomy to operate a data mode like FT8 or JS8Call with a LARCSet, especially with something like a smartphone app.

The second big buzz from FDIM 2026 that I heard was that Pebble HF 20m Radio was shown off to the FDIM attendees to intense interest. I’ve covered the Pebble HF in Zero Retries 0248 - Pebble HF - Under $50 QRP HF Radio Kit.

In future Hamvention visits, I’m going to have to make time to attend FDIM, whether Zero Retries has a booth, or not.

My compliments to QRP ARCI’s video editor - videos from the FDIM 2026 Symposium presentations are already up on YouTube.

I did manage to make at least a couple of passes of all the commercial exhibits in the five buildings and I’ll discuss the Zero Retries Interesting exhibitors and developments below.

Product Announcements

  • Carlson Tower Lift – Model 25
    This was easily the coolest new product I saw at Hamvention 2026. The Carlson Tower Lift is a “shuttle” that rides on the outside of a Rohn 25 tower that conveys the antenna(s) to the top of the tower via a cable and pulley mechanism. When you need to service the antenna (or add one), you lower it to the ground and do the work safely at ground level. This seems much more practical to me than collapsing towers or tilt-over towers. I told one of the reps that this product makes it worth buying a Rohn 25 tower. One minor product gap I noted was that there didn’t seem to be a way to contain the trailing cables - they seem to be left “free” to dangle to the ground and blow (and get abused / chafed) by the wind. But given Carlson’s ingenious mechanical design capabilities, I’m sure this issue will be addressed. Amusingly, at Hamvention 2026, the Carlson booth staff discovered a new customer base for this unit that they weren’t expecting - wives of hams who continue to climb their towers despite their wife’s concern. I overheard one wife saying “look - now you don’t have to climb the tower”. Apparently a Tower Lift - Model 45 is in development for Rohn 45 towers.

  • Software and Services - General Theme
    There were three new software “products” and four new services announced at Hamvention 2026. Thus collectively it’s notable that software and services were most of the Zero Retries Interesting significant products this year, rather than the more usual new hardware.

  • FreeDV RADE in FlexRadio
    It wasn’t mentioned by Flex, and I wasn’t able to check in at the FreeDV booth (which was very busy when I did my passes by their booth) to see if they mentioned this, but I consider it a significant product that FreeDV RADE v1 can now be installed in the radio of FlexRadio’s current units. That’s a Zero Retries Interesting development of 21st century technological innovation for Amateur Radio! Once you do so, FreeDV RADE is just another mode selection such as SSB. None of the other major Amateur Radio HF radio manufacturers have taken such a step. This capability took significant work both by FlexRadio and FreeDV developers, but finally there is “plug and play” of a digital mode that was developed in 21st century by a major Amateur Radio manufacturer. I hope other Amateur Radio developers (such as Mercury) will follow this lead as this “load it into the radio” capability is now available for use in the current (8000 series and Aurora) FlexRadio units, not a special arrangement unique to FreeDV. (Notably, such “user apps” are “sandboxed” in a current FlexRadio unit.)

  • Mercury Modem
    While it wasn’t demonstrated at Hamvention 2026, the formal release of the Mercury open source data communications mode was announced shortly before Hamvention 2026. See Zero Retries 0250 - Rhizomatica Releases Mercury, a Fully Open-source Modem for Digital on HF.

  • Digital Signal Processing Improvements in Elecraft Radios
    I’m only aware of this software improvement in Elecraft radios from an article by Jeff Davis KE9V - Spectral Subtraction Noise Reduction where noise is significantly reduced digitally via software improvements, resulting a much more pleasant experience monitoring HF bands. This seems akin to the same approach as West Mountain Radio’s CLRspkr ClearSpeech® DSP Noise Reduction Speaker, but implemented internally in the Elecraft radios.

  • Sierra Radio Systems iShareRadio Service
    The iShareRadio service was demonstrated at the Sierra Radio Systems booth. I did a big article on iShareRadio in Zero Retries 0248 - iShareRadio Remote Radio Sharing Service. I dragged a few folks, including one ARDC staffer, over to the Sierra Radio Systems booth to see that demo. (ARDC grants have paid for a lot of FlexRadio units for shared use by Amateur Radio clubs). iShareRadio was another collaboration with FlexRadio that created new capabilities in sharing remote FlexRadio units for clubs and individuals. Notably, in user accounts on iShareRadio, granular permissions can be set per each user’s license class, such as Technicians only having unrestricted capabilities on a shared FlexRadio unit on 50-54 MHz (6m).

  • Sierra Radio Systems Project Argus Hardware / RepeaterBook Reporting
    Zero Retries was privileged to get the “scoop” on Project Argus in an article by George Zafiropoulos KJ6VU in Zero Retries 0249 - Announcing Project Argus. “Argus” is a board that’s installed on repeaters. It monitors some parameters of the repeaters such as “start of repeat” and “end of repeat” and then “phones home” to RepeaterBook where that acquired data can be displayed on the repeater’s individual page on RepeaterBook. While “Argus” was developed in conjunction with RepeaterBook, it can be used independently of RepeaterBook.

  • RepeaterBook Project Apollo

    RepeaterBook’s Project Apollo is easily the most Zero Retries Interesting development that I saw at Hamvention 2026. For consistency, I’ll mention RepeaterBook’s Project Apollo here, but it’s such a significant development that I wrote a separate story about it later in this issue. Tersely, Project Apollo is a project to place radio receivers to monitor the activity of repeaters and report that (passively) observed activity on RepeaterBook. You’ll be able to see the level of activity on each repeater on RepeaterBook.

  • ARRL QST Product Review Comparison Tool (website)

    John McAuliffe W1DRF at Hamvention 2026, demonstrating the forthcoming QST Product Review Database website. Image courtesy of Steve Stroh N8GNJ.
    John McAuliffe W1DRF at Hamvention 2026, demonstrating the forthcoming QST Product Review Database website. Image courtesy of Steve Stroh N8GNJ.

    In the ARRL section of Building 2, ARRL Lab Digital RF Engineer John McAuliffe W1DRF demonstrated a new service (available 2026-06-01) that consolidates information from products reviewed in ARRL’s QST magazine for easy reference and comparative (A vs B vs C) evaluations of many aspects of those reviewed products. For example, selecting several HF radios, you can sort by power output or any other feature. As demonstrated, this is a really impressive service and despite the only mention I found of it online by ARRL, some features of this service will be accessible without ARRL membership. It provides objective data on a number of products reviewed in QST by ARRL Lab measurements, and there’s been nothing like it to date (that I’m aware of). This will be a really valuable service to Amateur Radio by ARRL. Per the signage at the booth, when it goes online, its web page will be compare.arrl.org.

  • Icom ID-5200
    Icom displayed the Icom ID-5200 at Hamvention 2026. It has some Zero Retries Interesting features such as a KISS TNC and (future update) APRS capability, and 1200 and 9600 bps modes. While there isn’t a flat audio connection, there is a USB connector on the rear of the radio with the functionality of that to be determined. Notably, it includes Wi-Fi and Bluetooth connectivity, implying there’s a TCP/IP stack in the radio. The ID-5200 is not yet available for purchase.

  • Kenwood TM-D750
    Like all previous in-person displays of the TM-D750, at the Hamvention 2026 Kenwood booth, the TM-D750 unit was kept under a “don’t touch… really… don’t ask” glass cube. Like the ID-5200, the TM-D750 features Bluetooth and Wi-Fi (er, “Wireless LAN”) implying there’s a TCP/IP stack in the radio. The TM-D750 is not yet available for purchase.

  • Yaesu DR-3X Repeater
    The Yaesu DR-3X Repeater(s) provide improved higher power, full duty cycle performance - 85 watts for the 144-148 MHz (2m) unit, and 65 watts for the 420-450 MHz (70cm) unit. Other new features of the DR-3X include “IES - Interference Evasion System” and “ASP - Audio Digital Signal Processor”. My impression is that both of those new features depend on corresponding features in newer Yaesu mobile / base radios. Also, both DR-3X units can receive the other band, but only transmit on the stated band. The DR-3X(s) are not yet available for purchase.

Zero Retries Interesting People At Hamvention

Of course, the ultimate joy of an in-person conference is seeing lots of folks in person. Here are a few “people highlights” for me.

  • Kay Savetz K6KJN
    K6KJN (a Zero Retries Pseudostaffer) is the Program Manager, Special Collections at Internet Archive for Digital Library of Amateur Radio & Communications. K6KJN and I have been friends for years now. I’ve been a contributor in promotion and material to DLARC, and of course K6KJN is a monthly contributor to Zero Retries. Spending this many hours in close proximity allowed us to swap even more interesting stories and observations about Amateur Radio.

  • Don Rotolo N2IRZ
    N2IRZ and I have known each other for decades by now, and we share a common history of the glory days (and promising future) of Amateur Radio Packet Radio. While he was assisting at the booth, N2IRZ suggested several potential articles for Zero Retries, and I eagerly agreed to all of his ideas.

  • Glen Popiel KW5GP

    Glen Popiel KW5GP at Hamvention 2026 autographing my copy of his new book Digital Networking for Ham Radio book. Image courtesy of Steve Stroh N8GNJ.
    Glen Popiel KW5GP at Hamvention 2026 autographing my copy of his new book Digital Networking for Ham Radio book. Image courtesy of Steve Stroh N8GNJ.

    Meeting KW5GP, author of the new ARRL book Digital Networking For Ham Radio was a highlight for me. At a “Meet the Author” session at the ARRL section in Building 2, I bought a new copy of the book specifically to get autographed by KW5GP and that one will go into my autographed books collection. KW5GP and I got to talk a bit more at length when he visited the Zero Retries booth and we talked more about his book and the overall subject matter and all things Amateur Radio networking. KW5GP promised a followup discussion about my impressions of the book from Zero Retries 0240.

  • Steve Davidson K3FZT

    Steve Davidson K3FZT at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.
    Steve Davidson K3FZT at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.

    K3FZT is Zero Retries Founding Member 0000. K3FZT has provided great feedback on Zero Retries and is unfailingly encouraging. He’s always a delight to talk to and catch up with

  • Cale Mooth K4HCK

    ale Mooth K4HCK at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.
    Cale Mooth K4HCK at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.

    K4HCK is a Zero Retries Pseudostaffer and Editor of Amateur Radio Daily and Amateur Radio Weekly. K4HCK and I enjoy comparing notes about our respective publications and projects, but our paths didn’t sync up for very long at Hamvention 2026.

  • Dan Romanchik KB6NU

    Dan Romanchik KB6NU at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.
    Dan Romanchik KB6NU at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.

    KB6NU is another Zero Retries Pseudostaffer and author of the KB6NU’s Ham Radio Blog and the No-Nonsense Study Guides (for Amateur Radio Exams).

  • John McAuliffe W1DRF is the ARRL Labs Digital Engineer and is a fan of Zero Retries. Now that it’s been made public, I reveal that W1DRF gave me an early peek at the ARRL QST Product Review Comparison Tool when I visited ARRL Headquarters earlier this year. Thus I was looking forward to the formal unveiling at Hamvention. It was great reconnecting with W1DRF briefly at Hamvention (he was very busy demonstrating the “Tool” to passerby).

  • Ron Diehl NQ8W

    Ron Diehl NQ8W and Steve Stroh N8GNJ at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.
    Ron Diehl NQ8W and Steve Stroh N8GNJ at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.

    NQ8W is Editor of ARRL’s QEX Magazine. We first connected at HamSCI 2026 earlier this year and we had a fun conversation at Hamvention 2026. He gifted me with an exclusive QEX hat that can’t be purchased, only gifted by him, and he also had one for me to bring back home to Tina KD7WSF.

  • Jim McLaughlin KI6ZUM

    Jim McLaughlin KI6ZUM at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.
    Jim McLaughlin KI6ZUM at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.

    KI6ZUM is proprietor of ZUMRadio and the is one of the principals of the MMDVM Project. We were only able to talk briefly prior to the opening; once the attendees were present, the MMDVM booth was mobbed. At the MMDVM booth, KI6ZUM was showcasing the new MMDVM units that provide full transcoding between digital voice modes (MMDVM-Cross Mode).

  • Drew Glasbrenner KO4MA

    Drew Glasbrenner KO4MA at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.
    Drew Glasbrenner KO4MA at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.

    K04MA is President of AMSAT. We were able to have a good conversation at the AMSAT booth and exchange our respective views about the future AMSAT projects that are Zero Retries Interesting, including PACSAT, an SDR / microwave payload, and especially the (disappointing, to date) progress on an AMSAT Amateur Radio payload (or satellite) at GEO to provide service to North America. I suggested that the PACSAT board would be useful and interesting for terrestrial use, and KO4MA seemed surprised at that suggestion, but had an alternate suggestion that I can’t yet talk about.

  • Mikel Turner W4OPS

    Mikel Turner W4OPS at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.
    Mikel Turner W4OPS at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.

    W4OPS is President and Director of Operations & Logistics of National Amateur Radio Alliance (NARA). It was good to put a face to the name. W4OPS and I have exchanged a number of emails that, in my opinion, NARA would be more interesting to NewTechHams if it acknowledged the growing role of digital / data modes in Amateur Radio.

  • Adam Zimmel W0ZML

    Adam Zimmel W0ZML and a new treasure at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.
    Adam Zimmel W0ZML and a new treasure at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.

    W0ZML is the ARDC Grants & Admin. Associate and the staff lead of the ARDC Grants Communication Team. W0ZML is a classic NewTechHam and is an enthusiastic collector of vintage computer tech. He acquired some interesting, and heavy new computer hardware (DEC Rainbow?) at Hamvention 2026. He also provided a “slideshow” at the ARDC booth on a vintage VT-102 dumb terminal (what he had to do to make the demo work was impressive).

  • Rosy Schechter KJ7RYV

    Rosy Schechter KJ7RYV at Hamvention 2026 at the ARDC booth, with (unknown) in foreground. KJ7RYV really rocks the hats! Image courtesy of Steve Stroh N8GNJ.
    Rosy Schechter KJ7RYV at Hamvention 2026 at the ARDC booth, with (unknown) in foreground. KJ7RYV really rocks the hats! Image courtesy of Steve Stroh N8GNJ.

    KJ7RYV is ARDC’s Executive Director / CEO and is always a delight to catch up with when we’re at the same conference.

  • Jeff Francis N0GQ

    Jeff Francis N0GQ at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.
    Jeff Francis N0GQ at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.

    N0GQ is a long time Zero Retries Interesting friend from the Seattle area, but now lives in Colorado. He has a lot of projects in progress - see his QRZ page.

  • Garrett Dow KD6KPC

    Garrett Dow KD6KPC at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.
    Garrett Dow KD6KPC at Hamvention 2026. Image courtesy of Steve Stroh N8GNJ.

    KD6KPC is the principal of RepeaterBook. Turns out he’s yet another Amateur Radio entrepreneur now located in the greater Portland, Oregon area, and I hope to catch up with him and talk to him at length about future RepeaterBook enhancements that came to mind on a future visit to the Portland, Oregon area.

  • George Zafiropoulos KJ6VU is host of Ham Radio Workbench (HRWB) podcast and the principal of Sierra Radio Systems (SRS). In seeing KJ6VU at least five Amateur Radio conferences, I’ve never seen him not engaged in a conversation with a customer. I made an introduction for a potential guest on HRWB and had to verbally elbow my way in to do the very brief introduction. Life KD6KPC, he’s also located in the greater Portland, Oregon area and now the close collaboration between SRS and RepeaterBook makes a lot more sense. (Alas, no photo…)

  • Amateur Radio Fediverse Meetup

    Amateur Radio Fediverse Meetup at Hamvention 2026 (partial). Pictured L-R are Victoria Yanovich K8VSY, Dan Romanchik KB6NU, Cale Mooth K4HCK, (unknown), Chris Ruvolo K2CR, Terry Schanno NV0O, and (unknown). Image courtesy of Steve Stroh N8GNJ.

    Apologies to the two “unknowns” in the above photo. Please reach out and I’ll update the web version of this photo. Cale Mooth K4HCK and Dan Romanchik KB6NU arranged a meetup of ten or so folks involved with Amateur Radio on the “Fediverse” (generally, the Mastodon social network) at the Zero Retries / DLARC booth on Saturday morning. That was fun meeting folks, including some Zero Retries readers that are active on Mastodon. In researching this item, I discovered fediverse.radio which is a great roundup of Amateur Radio themed Fediverse servers. I particularly enjoyed meeting K8VSY who is a longtime, enthusiastic fan of Zero Retries and is a Paid Subscriber of Zero Retries.

  • Dozens of Zero Retries Readers - Thanks to all of you Zero Retries readers who stopped by the Zero Retries / DLARC booth, many of whom I enjoyed meeting that I didn’t remember to record names and callsigns if they weren’t present from the photos I snapped. I’ll post those photos in a future Photo gallery.

Zero Retries Interesting Commercial (Indoor) Vendors

This is just a quick roundup of Zero Retries Interesting vendors / booths, partially for my own future recall. It’s notable that there were a number of vendors for Meshtastic / MeshCore / LoRa products (indicated in bold).

  • Amateur Radio Digital Communications (ARDC)

  • AMSAT

  • ARISS-USA

  • Carlson Roof Towers

  • Digirig - Not listed as an exhibitor, but they had a table on Saturday.

  • DX Engineering - The array of widgets, accessories, and products was easily the most comprehensive vendor at Hamvention, far eclipsing Ham Radio Outlet.

  • DZKit - This was cool - take a QRP Labs low power radio, and wrap an HF radio around it with a full featured front panel, power amplifier, and power supply, and it’s all a kit.

  • FlexRadio Systems

  • FreeDV

  • Halibut Electronics

  • HF Signals

  • HamSCI

  • Icom America

  • JVC Kenwood USA

  • Japan Amateur Radio League - Rats! Missed that they were at Hamvention.

  • Libre Space Foundation - Double rats! I didn’t get to visit their booth.

  • LowMesh

  • MMDVM

  • National Amateur Radio Alliance

  • QRP Labs

  • Radio Club of America

  • Rockland Tech - Rats! Missed that they were at Hamvention.

  • RT Systems - Provided booth space for RepeaterBook.

  • SPOOLTENNA

  • Seeed Technology - I didn’t get to visit their booth.

  • Sierra Radio Systems / PackTenna / Ham Radio Workbench Podcast

  • SpecFive

  • TAPR (Tucson Amateur Packet Radio)

  • Whistler Group - They now manufacture portable and mobile scanners, at least one of which covers the 222-225 MHz (1.25m) band.

Acquisitions

I bought three items:

  • SPOOLTENNA PARKS - To accompany my HF Signals zBitx for portable HF operation. They sold out of their stock on hand, but sold me one at Hamvention price with free shipping.

  • LowMesh Outdoor PoE Node v1 - I had been looking for a rugged outdoor 902-928 MHz “mount on pole” MeshX unit with an antenna connector and Power Over Ethernet. This unit was the first one I’ve seen that I liked and looked and felt well built. It seems well supported, including LowMesh’s nice looking and well organized website. The antenna connector is a Type N, and thus I can use a better high gain antenna for better range in my suburban / rural county.

  • Quick Strip automatic adjustment wire stripper - By the pressure exerted, it seems to cleanly strip nearly any wire between phone cord and large gauge electrical wire. The demo was impressive, and the demonstrator claimed that $25 was the “special show price” (turns out that’s the same price as the website), so I bought one and look forward to testing it out myself.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0251.

RepeaterBook Project Apollo

By Steve Stroh N8GNJ

RepeaterBook’s Project Apollo was the most impressive new product I saw at Hamvention. This is a badly needed capability for Amateur Radio to really understand what is actually happening with VHF / UHF repeater activity on a regional basis.

It’s notable, and indicative of the overall quality of RepeaterBook that they, of all the vendor announcements and developments from Hamvention 2026, were the only vendor that I saw to provide a dedicated summary of their (thirteen!) announcements from Hamvention 2026. This article focuses on only one of those thirteen announcements - Project Apollo, only one of those thirteen announcements.

Project Apollo

Project Apollo adds listening nodes for repeater activity and verification in the field to strengthen the quality of the information RepeaterBook already receives every day from users, admins, and repeater owners.

Public Apollo scanner-node views are live for Oregon and Idaho, with a UK node coming soon.

See current Apollo nodes

Why it matters: it adds another layer of confidence and helps keep repeater information more accurate and up to date.

…

What we plan to show at the booth.

Project Apollo preview

Booth conversations will also introduce Project Apollo as an automated repeater activity and verification initiative alongside the daily community input RepeaterBook already receives.

…

DAY 2 RECAP

Project Apollo became the hot topic

Project Apollo listens for repeater activity in an area and reports back activity signals that can help hams choose which repeaters to try based on their preferences. Many visitors from across the country volunteered to host nodes for this community-driven effort.

I met up with Garrett Dow KD6KPC at the RepeaterBook (RT Systems) booth at Hamvention 2026 and we had an interesting conversation.

In my opinion, Project Apollo is a badly needed capability for “ground truth” of what Amateur Radio repeaters are actually doing in a given area or region. Or, more importantly, not doing, as in objective observation of repeaters that are little used (quiet) or actually not on the air for extended periods. Personal / individual observations of repeater activity / inactivity suffer from the potential of (accusations of) individual bias, and questions about methodology / accuracy. Example - in reporting a quiet repeater, the repeater owner would likely protest that “You must have a really bad radio or antenna because our repeater is on the air!” (whether it actually is, or not). The independent, objective nature of RepeaterBook with reporting from Project Apollo, coupled with PA’s requirement of a “certified receiver” would considerable reduce accusations of bias and methodology / poor equipment in individual’s observations of repeater activity.

Project Apollo, offered by RepeaterBook, is an independent, impartial methodology of repeater activity and thus is a significant improvement of situational awareness of overall Amateur Radio repeater activity in an area.

This adds the same kind of capability for Amateur Radio repeaters as monitoring local and regional Amateur Radio APRS, Marine AIS, or Aviation ADS-B activity with a (eventual) local, regional, national, and worldwide network of receivers feeding a “dashboard” page via Internet.

KD6KPC had started Project Apollo with scanners, but then moved to (less extensive, but still very capable) Software Defined Receivers with his own software to emulate a scanner, as in sequentially, briefly, monitoring activity on each repeater channel. There is also some software that’s part of Project Apollo for extended situational awareness such as decoding repeater identification using CW (Morse Code) and Continuous Tone-Coded Squelch System (CTCSS) tones used for accessing (analog FM) repeaters. The Project Apollo software will continue to be in active development for the foreseeable future to add as much situational awareness as possible.

I was eager to mention ka9q-radio to KD6KPC as a “receive all channels, simultaneously” capability instead of the sequential scanning paradigm which can’t be as accurate about what’s happening when scanning, for example, the time it takes to sequentially scan 10 MHz from 440-450 MHz. Not only was KD6KPC already aware of ka9q-radio, but Phil Karn KA9Q himself had found the RepeaterBook booth, introduced himself, and suggested that Project Apollo make use of ka9q-radio. If implemented, that would be a big deal for Project Apollo’s capabilities in being able to provide long term, high resolution situational awareness. For example, monitoring a DMR repeater channel full time using ka9q-radio would allow parsing of who is using the repeater (parsing the DMR ID that’s transmitted at the beginning of every transmission), not just that the repeater is active for x amount of time resulting from successive scanning sweeps.

KD6KPC’s original plan to gradually expand Project Apollo’s footprint was deploy a private or “trusted partner” network of receivers, initially in major metro areas, using a “certified” combination of radio, antenna, antenna height, reasonable Internet connectivity, and always-current Project Apollo software. To his surprise, individual Amateur Radio Operators volunteered to use their own equipment to contribute to project Apollo. That change in direction would allow Project Apollo to scale much faster than the original approach of using only private or “trusted partner” network of receivers. Multiple receivers in an area would also allow for redundancy.

Project Apollo monitoring is will expand to cover General Mobile Radio Service (GMRS) repeaters.

It’s an interesting capability that Project Apollo will monitor all portions of Amateur Radio VHF / UHF spectrum that’s allocated for repeaters. Thus activity from repeaters that are “private” or uncoordinated, or intended as “stealthy” will be reported impartially.

I would hope that Project Apollo would eventually be extended from repeaters to other portions of Amateur Radio spectrum, such as the monitoring activity on the ten simplex channels used for packet radio from 144.91 to 145.09 MHz.

It will also be very interesting to view the overall activity of all of the VHF / UHF bands - 10m, 6m, 2m, 1.25m, 70cm, 33cm, and 23cm to see if, for example, it’s worth investing in a 6m radio to participate in local 6m activity. Monitoring 33cm will be a bit tricky given that it’s 100% shared with unlicensed users. For example, it would be useful to understand the overall use of Meshtastic / MeshCore on that band.

I’m also imagining the synergy between RepeaterBook and the KK7NQN Transcriber Service Node to enable realtime transcriptions of (selected) activity on various repeaters, as well as selective alerting based on (audio) callsigns. For example, with the incorporation of Transcriber Service Node into Project Apollo, it might be possible to type in a callsign such as N8GNJ and then see a summary of which repeaters, and when, that callsign has been heard. This is easy on digital voice repeaters with the user transmitting an embedded callsign or DMR user ID. Doing that on FM (analog) repeaters (no embedded callsign or user ID) is tougher, but the Transcriber Service Node capability would bridge that gap.

For the background on this possibility, see Zero Retries 0217 - KK7NQN Transcriber Service Node – Now Open to Any AllStar User and in Zero Retries 0220 (wrap up of Zero Retries Digital Conference 2025) - KK7NQN Transcriber Service Node, and the video of KK7NQN’s presentation at ZRDC 2025, and I’ve provided an introduction between KD6KPC and KK7NQN and I hope that they are able to work something out to blend their respective very cool technological innovations in Amateur Radio.

Just as an example of why the combination would be so useful is a potential, or new Amateur Radio Operator could go to RepeaterBook, select Bellingham, Washington, and query which repeaters have recent conversations about “digital” or “packet radio" or “Hamvention”, and then choose to operate on, or monitor that repeater as having interesting (to me) conversations.

In summary, I think that Project Apollo offers very exciting potential to enhance the appeal of Amateur Radio voice repeaters for greater visibility of repeater activity in a given area. If KD6KPC can work out the particulars of the specifications for “certified” Project Apollo by individual users, Project Apollo could scale very rapidly.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0251.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

ZR > BEACON will be a bit abbreviated this week in deference to timely publication of this issue mostly about Hamvention 2026.

Flipper One — we need your help

Flipper One - Image courtesy of Flipper Devices, Inc.
Flipper One - Image courtesy of Flipper Devices, Inc.

Pavel Zhovner on the Flipper Blog:

We’re finally ready to talk about Flipper One — a project we’ve been grinding on for years and have rebuilt from scratch several times. It’s an incredibly hard project, both financially and technically. So today we’re going public not with a big shiny announcement, but to tell the whole story straight. Honestly? We’re genuinely terrified, and we need your help.

TL;DR With Flipper One, we’re reimagining what a Linux cyberdeck can be — it’s a huge project. We’re opening up the development process and asking the community for help.

With Flipper One, we’ve set ourselves a list of ambitious goals:

  • Build the most open and best-documented ARM computer in the world, with full mainline Linux kernel support.

  • Push vendors to open up their existing closed-source code and ditch binary blobs entirely.

  • Build an unconventional hardware platform based on a co-processor architecture that pairs a microcontroller with a CPU, and port tons of low-level MCU code.

  • Rethink how people use Linux and develop our own GUI framework with wrappers around existing CLI utilities.

Many of these goals come with a lot of uncertainty, which is scary. But we believe this is the only way to make a truly meaningful contribution to the open-source community and to education.

What is Flipper One?

Flipper One isn’t an upgrade to Flipper Zero — it’s a completely different project with its own goals. Flipper One is an open Linux platform you can build almost anything on: from a 5G-enabled IP network analyzer to an SDR-powered radio signal analyzer with local AI. We focused a lot on the hardware expansion system. You can connect high-speed modules to Flipper One over PCI Express, USB 3.0, and SATA interfaces. Add an SDR, a fast SSD, or a cellular modem — just plug in the right module.

Flipper One comes with several network interfaces: 2x Gigabit Ethernet, USB Ethernet (5 Gbps), and Wi-Fi 6E (2.4/5/6 GHz). You can add 5G connectivity by plugging in an M.2 modem. That means you can use Flipper One as a router, a VPN gateway, or a bridge between wired and wireless networks.

“Help” referenced in the title seems to be this section:

Developer Portal – let’s build together

Openness has always been our thing. With Flipper One, we want to go further — not just open-source code, but an open development process. We’re publishing our task trackers, internal discussions, half-finished docs, and architectural debates. All the messy stuff companies usually keep behind closed doors.

Introducing → Flipper One Developer Portal

This is uncomfortable. We’ve never been this open before, and there’s a real instinct to hide the unfinished work, the wrong turns, and the arguments. But we believe the educational value of building openly is worth more than the polish of pretending it was easy.

What is the Developer Portal?

Flipper One Developer Portal is a public wiki with all the development documentation for Flipper One, and anyone can edit it. The portal describes the project’s structure and ways you can participate in development.

Flipper One seems like an ideal Amateur Radio “Cyberdeck” / radio technology multi-tool. It’s an intriguing possibility of an Amateur Radio data communications radio with an M.2 interface and form factor. There’s lots more detail in the article, with a lot of detail on how they’re trying to be accommodating towards radio modules (such as Amateur Radio) that they’re not currently imagining.

I’m going to try to follow the progress of Flipper One and feature regular updates on it in Zero Retries.

AI is killing the cheap smartphone

David Oks:

The global memory crunch and the great repricing of consumer electronics.

One of the most remarkable things about the last few decades is how cheap computers have gotten.

In 1985, if you were a reasonably affluent American, the best computer that you could afford was the IBM PC AT. The PC AT would cost you about $6,000—$19,400 in 2026 dollars—and thus represented about a quarter of the median American’s annual income; and it ran on an Intel 80286 processor, capable of something like 900,000 instructions per second. Today, if you find yourself in a market stall in Nairobi or Lagos, you’ll be able to find a cheap smartphone—like the Tecno Spark Go, manufactured by China’s Transsion—for somewhere between $30 and $120. That phone will run on a processor capable of billions of calculations per second.

In other words: you can buy a computer thousands of times more powerful than the best consumer device from 40 years ago, for something like 0.3 percent of the price. No other good in history has experienced a decline in cost on that scale: poor people can now carry around in their pockets computers many orders of magnitude more powerful than what the richest slice of the world’s population could afford a few decades ago. And that great cheapening of consumer electronics has enabled a diffusion of computing power to the world’s population that is nothing short of miraculous. Hundreds of millions of the world’s poorest people are able to access the internet because of cheap smartphones like the Tecno Spark Go.

That era is now coming to an end.

This article is interesting for the stated subject, but it’s also a cautionary tale for Amateur Radio as well given that we’re now firmly and irrevocably in the Software Defined Radio (SDR) era. For SDR, large amounts of RAM is the second most critical component behind the SDR chips themselves. It’s going to be a rough few years for Amateur Radio as prices for some of our favorite Amateur Radio gadgets will inevitably rise… if not become unobtainium because the increased prices aren’t reasonable for the overall value of the device. One example is of such an embedded device, besides the Flipper One in the previous story, is the really cool SharkRF M1KE Wi-Fi Amateur Radio. Or perhaps Amateur Radio devices will become largely a front end interface to move the SDR processing into commodity devices like our (expensive and capable, but already paid for) Android phones and iPhones.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0251.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

ImaginizeWorld Interview Now Online

Jane McConnell is an accomplished writer, and now an interviewer who runs Imaginize World. She interviews people from widely varied backgrounds about the near term future. McConnell had reached out to a distant acquaintance of mine looking for writers who were making productive use of AI. I replied to her that I was using AI “lightly” in doing research for “my small newsletter, Zero Retries” and my use of Google’s NotebookLM AI tool as essentially a “smart index” of my five years of weekly newsletters. I also mentioned that AI was becoming increasingly useful in Amateur Radio in embedded roles for many different activities. Apparently I was one of the few that contacted her about the use of AI that had an overall positive view of using AI.

McConnell contacted me back and seemed fascinated with Amateur Radio, which she had never heard of. In preparation for the interview we exchanged extensive emails. She did a lot of her own research in reading archival Zero Retries material. Thus she was well-prepared, asked a lot of interesting, informed questions in the interview, and I really enjoyed talking to her. She uses the same model for interviews that I wish I could do - just research, talk, and hand over editing, production, and posting to a capable (human) video / audio / website Editor.

I really appreciated that McConnell goes to the trouble and expense of paying for and posting a full transcript of our conversation for faster absorption of the discussion for those of us who prefer text input.

I hope that McConnell and I talk again at some future point. I’m now a fan of her work and will slowly work through her back catalog of interviews and other material on her website.

Weekends Are For Amateur Radio! Assembling Shed Kits!

A couple of months ago Tina and I bought a small shed “kit” at Costco that was two very large, very heavy flat packs that when assembled would be a nice “garden shed”. It looked neat at the store already assembled and we needed a bit more storage that wasn’t in the shop, or the attached garage, and this seemed like a reasonable solution.

But wow, was it hard to move - very heavy, large, and awkward! It was all we could do to slowly push it out of the back of my pickup truck and stand it up on edge in our attached garage to await a reasonable time after six weeks of various travels, when we could arrange enough time to assemble it, arrange for help from friends, and have reasonable weather. The weather issue was if we put it out too soon, and it got rained on, the cardboard would disintegrate and oh, what a mess it would be to have to move all those pieces separately.

One of our neighbors just happens to have an outdoor forklift! Thus he’s going to bring his forklift up to our attached garage and we’ll “just push out” the two big boxes out of the garage and lay them over onto the forks. He’ll then do the (literal) heavy lifting to place the two boxes several hundred feet away, behind N8GNJ / Zero Retries Labs (our detached shop). He’s a great neighbor - he had a snowplow attachment made for his forklift to keep our private street accessible in the very occasional snowstorms. Two other friends love to help with projects like this. Thus this week, tomorrow (Saturday) won’t be Amateur Radio time, but instead will be devoted to shed assembly with help from these three friends. Tina will supervise (it’s her shed), and Tina will enjoy having an excuse to be an event hostess and feed the crew.

Of course… this detached shed will be a great excuse to “technify” it, with a solar panel, some kind of radio and antenna, and various other electronic and radio gadgets.

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0251.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

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The Usual Administrivia

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Zero Retries 0251 was published on 2026-05-22. This issue was 8686 words.

]]><![CDATA[Zero Retries 0250]]>https://www.zeroretries.org/p/zero-retries-0250https://www.zeroretries.org/p/zero-retries-0250Sat, 09 May 2026 00:31:01 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its fifth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is too big for email clients (especially mobile devices). Thus, it might be easier to read in a web browser - www.zeroretries.org/p/zero-retries-0250.

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In This Issue:

I-Frame

Rhizomatica Releases Mercury, a Fully Open-source Modem for Digital on HF

Networking, Networking, Networking

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Victoria Yanovich K8VSY for three years of being a Paid Subscriber to Zero Retries as of this past week!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

No Zero Retries Next Week

Zero Retries will not be published next Friday 2026-05-15.

The next issue of Zero Retries - 0251 will publish on 2026-05-22 (or shortly after). I will be attending Hamvention 2026 on 2026-05-15 thru 17, and I know from previous experience that the Hamvention experience is “full saturation” and there is no “spare time” to sit down and write Zero Retries. Not to mention that this year, I will be staffing the first ever Zero Retries (shared with DLARC) booth at Hamvention, and I expect that will keep me fully occupied for the length of the entire event. I will also be doing some personal travel the following week.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the hashtag #ZR0250.

Image courtesy of Rhizomatica

Rhizomatica Releases Mercury, a Fully Open-source Modem for Digital on HF

Press release from Rhizomatica:

May 2026 — Rhizomatica is pleased to officially launch Mercury, a completely open-source Digital Radio OFDM protocol for HF broadcast and peer-to-peer ARQ connections with compatible TCP interfaces, built for reliable store-and-forward email and file transfer over HF radio links. Mercury is the newest element of the HERMES software suite, actively developed by Rhizomatica since 2017, with generous funding from ARDC and others.

Mercury is written in C, released under a GPL-3.0 license, and features a modular architecture with per-direction mode selection, hybrid SNR + delivery feedback-based gear-shifting, split control/data channel design, and uses field-proven FreeDV digital data modes, with each mode kept resident in a pool, eliminating codec re-initialization overhead. Pre-built binaries are available for Windows and Debian operating systems and Mercury is suitable for use with most HF transceivers and completely compliant for amateur use.

In early tests, compared to the commercial alternative, Mercury has performed well and is nearly at parity in optimal SNR conditions and outperforms the alternative in poor SNR conditions.

“Not only has Rhizomatica developed a fully open-source software modem, they have done so to empower communities in need of their own communication infrastructure. We are proud to have supported Rhizomatica in this work, and very excited to see it now available to the amateur community and others around the world using HF for critical communication.” — Rosy Schechter (KJ7RYV), Executive Director of ARDC.

“I am very pleased to see Rhizomatica using the FreeDV data modes combined with their own custom ARQ protocol to send data over low SNR HF channels. It is great to see Rhizomatica embracing those waveforms, and spreading the use of open source in HF Data.“ — David Rowe (VK5DGR), inventor of Codec 2 and FreeDV.

More information can be found from the following sources, or by contacting Rhizomatica directly using the Contact information provided below.

MAILING LIST [https://lists.riseup.net/www/info/hermes-general]

SOURCE CODE [https://github.com/Rhizomatica/mercury]

YOUTUBE DEMOS
[https://www.youtube.com/@rhizomatica_communications/playlists]

###

CONTACT

ABOUT

Rhizomatica Communications is a US-based non-profit with the mission to support communities to build and maintain self-governed and owned communication and energy infrastructure. [https://www.rhizomatica.org]

HERMES is an open-source software stack created by Rhizomatica to make it easier to use HF/shortwave radio for digital communications. Since 2017, together with social organizations and remote communities around the world, Rhizomatica has been designing, building and testing HERMES to create reliable, secure, long-range, autonomous voice and digital communications. [https://hermes.radio/]

Editor’s Postscript

For good reasons, Rhizomatica’s press release references “the commercial alternative” as a point of comparison. I’m under no such constraints. “The commercial alternative” is, of course, VARA HF. But it could also apply to the similar capabilities of PACTOR 4 from SCS.

I first saw Mercury demonstrated at Hamvention 2025, and it was impressive then.

In my opinion, this development is a very big deal in the evolution of data communications in Amateur Radio. Mercury now offers a well-engineered data communications system for use on the Amateur Radio HF bands. HF is a “hostile environment” for data communications - it’s noisy (with highly variable types of noise), with fading, distortion, and significant interference (it’s a shared resource, worldwide - every frequency is already in use, somewhere on the planet).

But the real significance of Mercury is that it’s an open source project, and has already been ported to Linux.

Prior to Mercury, open source data communications systems for HF were generally lower performance, and not very robust, such as 300 bps Audio Frequency Shift Keying (AFSK) packet radio.

I applaud the Mercury developers for their savvy choice to implement the Orthogonal Frequency Division Multiplexing (OFDM) subsystem that was developed and proven out by FreeDV. Being able to use the FreeDV OFDM subsystem is one of the many benefits of open source development.

Mercury’s development was made possible by grants from ARDC (2021, 2023, 2025) which enabled the developers to apply significant time and resources to Mercury. The success of Mercury wonderfully illustrates ARDC’s fundamental role in Amateur Radio of the 2020s and beyond - providing financial support that enables the creation of new technologies in Amateur Radio. It’s notable that the OFDM subsystem used in Mercury, originally developed by FreeDV, was also the result of ARDC grants.

I hope… expect… that Mercury will eventually become the primary data communications mode in use on Amateur Radio HF. For a while, FreeDATA seemed promising as an offshoot of FreeDV (it repurposed FreeDV’s OFDM subsystem to transmit and receive data rather than digital voice), but there doesn’t seem to be much development activity on FreeDATA of late. There has also been some continuing development on Amateur Radio Digital Open Protocol (ARDOP).

I also hope that Mercury will eventually become embedded into Amateur Radio HF radios as a mode selection in the same way that RTTY is a mode selection. Such integration is beginning to happen now with FreeDV in with FlexRadio’s current generation products. This seems a reasonable extrapolation - Mercury offers fast, robust data transfers, it’s open source (and thus, free to implement in a wide variety of systems, projects, and products), and the only significant competition on Amateur Radio HF is VARA HF and PACTOR 4; both are commercial, proprietary products.

Like VARA HF and PACTOR 4, Mercury is just the “bit transport” portion of a data communications system, much like Ethernet is just “bit transport”. It’s applications that make such “bit transports” useful. To enable applications to easily use Mercury, I’ve seen references on email lists that Mercury’s developers have provided the same software and network interfaces as VARA HF, thus hopefully enabling Mercury to be used with the same applications that make use of VARA HF.

One of my hoped-for use cases for Mercury is that we will be able to use the very popular and very capable VarAC application with Mercury to do personal email, bulletins, file transfers, text chats, and much more over HF.

Credit Due to EA5HVK for VARA HF and VARA FM

While this story is about Mercury, I think it’s useful and relevant to reference VARA HF and VARA FM for context for why Mercury is such a big deal for Amateur Radio.

Prior to the development of Mercury, and at least part of the inspiration for Mercury, Jose Alberto Nieto Ros EA5HVK deserves credit and kudos as the developer of VARA HF and VARA FM. EA5HVK was the first (that I’m aware of) to provide a modern HF data communications system for Amateur Radio - adaptable, reliable, and fast, implemented in software running on an affordable (Windows, in this case) computer1. It’s especially notable that EA5HVK pioneered the use of “Audio band OFDM” making VARA HF and VARA FM incredibly robust. EA5HVK has chosen to only offer VARA HF and VARA FM as a commercial and proprietary product running on Windows2. VARA HF and VARA FM have become the basis of many successful Amateur Radio systems, such as Winlink, VarAC for personal (and some Emergency Communications), The Packet Radio RF Forwarding Network (TPRFN), and VARAtrack (APRS over HF using VARA HF).

Related - See Zero Retries Guide to Amateur Radio HF Data Communications, which has been updated to incorporate this information.

Related - See ZR > BEACON - varamodem.com - New Website for VARA HF / FM / SAT.

My thanks to Peter Bloom for bringing this development to my attention for inclusion in Zero Retries.

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0250.

Networking, Networking, Networking

By Steve Stroh N8GNJ

We’ve been doing data networking on Amateur Radio spectrum for more than four decades now. We’ve actually gotten pretty good at it. But we haven’t been very consistent about it, being interoperable, or publicizing what we’re doing or how to get in on the fun.

Not consistent about it as in there are islands of good Amateur Radio network connectivity, amidst an ocean of lack of good Amateur Radio network options.

We know how to create good connectivity. We do a great job of providing ubiquitous access to Amateur Radio voice repeaters. But we don’t have the equivalent for of ubiquitous Amateur Radio networking.

I posit that we should have ubiquitous access to Amateur Radio networking at least on par as coverage of voice repeaters.

Many Amateur Radio Network Technologies

We have no shortage of Amateur Radio network technologies to choose from. And choose, we have (from many different network technologies):

  • AREDN in Northern California has a great network operating on 5 GHz. It’s pretty much the ultimate of ideal Amateur Radio networking connectivity - it’s pretty much equivalent to Internet connectivity - 10+ Mbps, any app that works via TCP/IP, etc.

  • I predict there will soon be “AREDN-900” advocates (AREDN operating on the 902-928 MHz band)…

  • There are Amateur Radio Packet Radio advocates, both 1200 bps and 9600 bps…

  • There are Amateur Radio Packet Radio advocates, both 1200 bps and 9600 bps that use FX.25 or IL2P Forward Error Correction (FEC)…

  • There are APRS / APRS messaging advocates…

  • There are Winlink advocates…

  • There are Eastnet advocates…

  • There are TCP/IP over Packet Radio advocates…

  • There are (at least a few) IPv6 over Amateur Radio advocates…

  • There are Meshtastic / MeshCore / MeshCom advocates…

  • There are LoRa advocates (using LoRa other than MeshX) advocates…

  • There are MMDVM Radio Hotspot advocates…

  • There are Amateur Radio Over Internet advocates…

  • There are M17 Data advocates…

  • There are VarAC-as-a-network advocates…

  • There are “cheap Standby tier” Starlink experimenter advocates…

  • There are Net/ROM / TheNET / Kantronics K-Node advocates…

  • There are TARPN advocates…

  • There are fsq (and other fldigi modes) on VHF / UHF FM advocates…

  • There are VARA FM / VarAC advocates…

  • There is one SuperPeater advocate3

  • There are New Packet Radio advocates…

  • There are MeshX / LoRa advocates…

  • There are TPRFN advocates…

  • There are 44Net / 44Net Connect advocates…

  • There are Icom D-Star DD mode advocates…

  • There are QO-100 (generically Amateur Radio GEO satellites) advocates…

  • There are HamWAN advocates…

  • There are “pure Part 15” (unlicensed spectrum) microwave network advocates…

  • There probably will be IP400 advocates…

  • There probably will be Mesh Operations Protocol (MOP) advocates…

  • There were Broadband Hamnet / HSMM-Mesh advocates…

  • There were WA4DSY 56k RF Modem advocates…

  • There were ROSE network advocates…

  • There were TEXNET network advocates…

  • There were PacketCluster network advocates…

You get the point.

All of those different types of networks have (or had) their valid points, advantages, and existing communities.

But in the big picture, Amateur Radio networking is too fragmented.

What makes the Internet work is the consistency of connectivity. Recall that prior to the creation of the Internet (and the ARPANET before that) we had data networking connectivity - but islands of it. We had IBM SNA, DECNET, ARCNET, NETBIOS, and gazillions of others. But they could not interoperate except very painfully, very expensively, and very limited and inflexible. If one detail about a data networking protocol changed, all the built-for-purpose bridges between, say, DECNET and SNA broke until the change was added into the bridges.

Amateur Radio is in roughly in the same situation now. We have lots of successful implementations of data networking connectivity over Amateur Radio. There are good reasons for this situation. Amateur Radio is under no economic or efficiency imperative to consolidate its disparate networks to be more interoperable or efficient. It’s also the case that Amateur Radio Operators (and groups) are encouraged to experiment. And sometimes, an unusual network is just fun to play with.

But none of the current Amateur Radio networks are big enough, successful enough to be considered the data networking solution for Amateur Radio. Thus, Amateur Radio can’t really cite a “success story” for Amateur Radio networking.

Straw Figure Test - What Network System Would You Recommend?

Not convinced? Here’s a simple straw figure test:

Imagine a bright first year high school student - let’s call her Shelly Jones. Shelly is a techie, and curious about radio, and hears about Amateur Radio. She likes the challenge of getting her license and gets her Technician license. She wants to figure out some way to create an Amateur Radio data network in her small town so she can chat with, and experiment with her fellow students via Amateur Radio.

What Amateur Radio data networking system would you recommend to Shelly and her friends?

The easiest system to recommend is Meshtastic / MeshCore / MeshCom. There’s ample enthusiasm, peer support, a wide variety of hardware, and there are options for Amateur Radio 420-450 MHz band and the 902-928 MHz band.

But that’s limited to what can be done with LoRa, and generally low power. MeshCore and MeshCom are reportedly more stable and scalable. But MeshX is limited in what it can do because of the low bandwidth.

AREDN is what first comes to my mind, but it has the dual handicap of requiring at least one high profile node, and the most usable AREDN radio hardware operates at 5 GHz which requires an optical clear line of sight. AREDN-9004 is promising, but there are only a few such units that AREDN has been ported to.

For those that cannot access a node at 5 GHz, there is the option of an Internet tunnel, and that’s been made more feasible with 44Net Connect.

There are tradeoffs for all of the systems listed above. And, there’s the community / local support factor. There’s a strong disincentive for Shelly and her friends to create a new AREDN-900 network if there is an existing VARA FM + VarAC network already in existence in their town.

So… what to do… and again, what to recommend to Shelly and her friends? And in the larger perspective, what can those advocates for Amateur Radio - to prospective Amateur Radio Operators, and regulators, and the general public, point to as a success story for Amateur Radio Networking?

I don’t have the answer for those questions. Perhaps for now, AREDN is a good enough success story, especially if AREDN-900 becomes more widely used. It’s very Internet-like, can run an impressive range of apps and use cases.

AREDN Equivalent for VHF / UHF

But in my opinion, we need an equivalent to AREDN that can operate on VHF / UHF bands. Blending some of the elements from above:

  • Use our “awesome transmit power” levels, like 25 / 50 watt transmit power

  • Use our ability to operate on multiple bands simultaneously, such as 50-54 MHz, 144-148 MHz, 222-225 MHz, and 440-450 MHz.

  • Mesh networking, especially cross-band, such as MOP, IP400, and Net/ROM.

  • Use repeater technology and coverage, such as SuperPeater.

  • Achieve reasonable speeds for narrow channels such as VARA FM, up to 100 kbps such as New Packet Radio.

  • Use TCP/IP (IPv4 initially, and eventually IPv6) to interoperate with AREDN.

  • Universally implement AX.25 Version 2.2.

In suggesting all of the above, it seems to me that Amateur Radio needs at least one coherent, consistent, interoperable “network strategy” in the mid-2020s and beyond.

I’m going to call it ARDNET - Amateur Radio Data Network.

Related - Zero Retries 0249 - The Perceived Irrelevance of Amateur Radio Networking

Please direct comments / feedback about this article to the Zero Retries email list with the hashtag #ZR0250.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

varamodem.com - New Website for VARA HF / FM / SAT

Image courtesy of varamodem.com

This is a new official website for VARA, including downloads of the latest versions of EA5HVK VARA-related software, and a direct link to purchase a VARA license. Official because of the copyright notice:

Copyright © 2026 Jose Alberto Nieto Ros | EA5HVK - VARA Modem

This is a welcome development as this website is streamlined and modern-looking. In my opinion it’s’ much easier to navigate to quickly find what you’re looking for. It’s welcome that this website doesn’t spam you with irrelevant advertisements, and the Downloads section redirects to winlink.org rather than the (slightly spammy) mega.nz website.

Another promising feature of the new website is that a Blog tab is present (currently linking to posts on the previous website), perhaps hinting that EA5HVK will use that for discussing VARA “straight from the source”.

Documentation doesn’t seem to be available on this new website at the moment.

Lastly, it was interesting to see this mention of the non Amateur Radio users of VARA:

In use across many services as Department of Homeland Security SHARES, USCG Auxiliary, TNSG (Tennessee State Guard) , Canadian CFARS, FNRASEC, OEM (Oregon Department of Emergency Management) Austrian Armed Forces (CIS & Cyber Security Centre) and the amateur radio Service.

Lastly, the maximum speeds on this new website for VARA HF and VARA FM WIDE are different than what I’ve seen stated in VARA documentation. (VARA FM NARROW is the same.)

  • VARA HF’s maximum speed, on this new website, is stated as 8489 bps. The speed tier chart in VARA 4.7 quick guide.pdf states the max speed for VARA HF (2300, Standard) as 7050 bps.

  • VARA FM WIDE’s maximum speed, on this new website, is stated as:
    VARA WIDE (Max 19200 bps).
    The speed tier chart in VARA FM 4.0 Features.pdf states the max speed for VARA FM WIDE as 25210 bps.

SafecomLink Hamradio Edition

Link from the VarAC website:

SafecomLink is the only platform that fully meets all hamradio operational and emergency communication (EmComm) needs for HF/V/U base data management. Its comprehensive features deliver unmatched versatility, reliability, and performance for hamradio operators worldwide.

SafecomLink for SCS Pactor Modems

Rediscover your Pactor modem and turn your past investment into a powerful, modern communication tool with SafecomLink.

Supports both legacy and modern SCS Pactor modems:

PTC-II, PTC-IIPro, PTC-IIe, PTC-IIex, PTC-IIusb, PTC-IInet, PTC-IIIusb, DR-7400, DR-7800, DR-9400.

This is an interesting development. SafecomLink is a rebranded version of VarAC. Apparently the VarAC developers decided to make SafecomLink available to Amateur Radio Operators that want to use a Pactor modem rather than VARA HF with VarAC. Pactor 4’s maximum data rate is 10.5 kbps on HF (and 9600 bps on VHF / UHF). One big difference between VarAC and SafecomLink is that VarAC is free for use by Amateur Radio Operators and CB operators. SafecomLink is requires an annual paid subscription, which is understandable given it’s intended for commercial / public safety organizations.

Apparently this is the week for VARA related website updates.

g4klx / MMDVM-IQ Github Repository Now Public

This is the source code of the MMDVM firmware that supports the D-Star, DMR, System Fusion, P25, NXDN, POCSAG, and FM modes.

It is currently used with the SXceiver Pi hat or similar running on a Raspberry Pi. All of the development work is done on a Pi 4 as there are reports of incompatibilities with the Pi 5. It uses the SoapySDR interface that can be found at https://sxceiver.com/

Two subtle things about this development. First, “-IQ” designates that this is a new version of MMDVM that uses hardware that operates using I+Q interfaces. This is significantly more capable than “classic” MMDVM.

Second, for the first time, Frequency Modulation… yes, classic FM, is now supported in MMDVM (using the more capable hardware being developed in conjunction with MMDVM-IQ).

The most significant aspect of this work is that with the new hardware, and software, MMDVM will be able to do on-device, realtime transcoding between digital voice modes, such as D-Star in, DMR out and vice versa.

Some of this will be on display (though working demonstrations may not be displayed), but much information will be available at the MMDVM booth (1609) at Hamvention 2026.

My thanks to Jim Mclaughlin KI6ZUM for bringing this development to my attention for inclusion in Zero Retries.

Island Magic Products Update

Image courtesy of Island Magic

Email update from Island Magic / Georges Auberger WH6AZ (unfortunately, no web page version):

RadioMail

I’ve been working on version 1.6, focusing on bug fixes and quality-of-life improvements. One of the bigger usability win is bulk message editing.

There’s also experimental emoji support. Winlink limits the character set to ISO-8859-1, so emojis can’t be transmitted as-is, but they will display when sending messages from RadioMail to RadioMail. Not exactly standards-compliant, but good enough to have a little fun 🤪.

The most significant addition is a built-in ARDOP modem for HF.

Supported interfaces include:

  • Digirig Lite

  • AIOC (All-In-One Cable)

  • ICOM IC-705 (USB audio + Bluetooth for CAT control)

If you’d like to help test you can download the Beta on TestFlight

RadioMail 2.0

The longer-term goal is still to offer a proper Winlink experience on Mac. Getting there means supporting you across all your devices, which in turn means syncing messages across applications.

The path forward I choose is as follows:

  • Updated UI with a first-class iPad experience (multi-column layout, keyboard support, better use of space)

  • iCloud sync for mailbox content

  • Make iPad version available on Mac

To make this happen, I ended up rewriting the app from scratch. It wasn’t the original plan, but it gives me a much cleaner foundation using modern SwiftUI.

It’s a large effort. I’m fairly far along, but there’s still a lot of surface area to cover. I got a bit distracted by other things and travels. Expect a beta sometime this summer.

VARA On-a-Stick

Some of you might remember my earlier attempts at building a portable, headless “VARA appliance.”

That effort led to varanny, a small command-line daemon that lets RadioMail orchestrate VARA on a remote machine.

That setup relied on a small 12V BeeLink computer, which was compact, but still had a fan. Also the Windows variation was finicky to say the least.

More recently, I’ve been experimenting with stick PCs which provide a much smaller form factor, are fanless and can be powered over USB-C PD.

The key breakthrough was getting everything to run on a minimal Linux distribution without a desktop. It boots quickly and runs comfortably even on a 4GB RAM device.

The experience is simple: power it on, connect from RadioMail, and you’re on the air. Hard to describe how liberating this is.

A set of scripts will install everything and provide support for:

  • VARA FM and VARA HF with Digirig Lite and AIOC audio interfaces

  • Full IC-705 support, including CAT control

  • Built-in WiFi access point for easy pairing in the field

Build your own with: https://github.com/islandmagic/vara-on-a-stick

Possibly the world's smallest VARA FM station

Possibly the world’s smallest portable VARA FM station.

At this point, I no longer want to think about Windows or wrestle with VARA just to reach Winlink gateways. That alone makes it worthwhile.

Note that if you run into issues, you’ll need to troubleshoot on your own. I’m not planning to spend more mental cycles on that stack. And hopefully in the not too distant future, we eventually will get proper protocol documentation, which might open the door to broader interoperability.

Radio Messenger

This is something I’ve been thinking about for a long time and finally started building an app to see if that made sense.

The core idea is simple: messaging over amateur radio works, but it doesn’t feel like modern messaging.

APRS already gives us a global, resilient network. But most software treats messaging as a secondary feature behind maps and tracking.

This project flips that. Messaging is the primary experience and conversations come first.

Of course, radio has real constraints. You’re not always in range, radios are often off and APRS doesn’t store messages you miss.

The approach here is pragmatic. RF delivery is always the priority, but internet delivery can serve as a fallback. If a message doesn’t get through, it can be held briefly and delivered later via push notifications.

The goal isn’t to replace radio with the internet, just to make the experience less brittle.

The app also supports so-called AX.25 UNPROTO messaging, which was a frequent request for Packet Commander. It simply didn’t make sense to build that into a connection-oriented app.

With UNPROTO, there is no acknowledgments, no retries, just packets sent on the air. In practice, this creates a lightweight, shared-frequency chat experience. This opened the door for some early experimentation with message signing (inspired by Chattervox). No encryption, just a way to verify that a message came from who it claims to be.

The app works best with Bluetooth HTs that have built-in packet modems, like the UV-PRO or the Kenwood TH-D75 with the B.B. Link adapter.

If you have these radios and would like to provide feedback, message me and I’ll send you a TestFlight invite.

I’m looking forward to using RadioMail, especially RadioMail 2.0 that will sync on my iPhone, iPad5, and Mac(s) via iCloud sync. We Apple ecosystem users are admittedly spoiled from the overall Apple experience of our info generally staying in sync across devices without us thinking about it. It’s jarring when we don’t have that experience, and kudos to WH6AZ for bringing that experience to Amateur Radio on Apple devices.

APRS messaging as a primary function app is something that I previously discussed in Zero Retries as an unmet need in Amateur Radio. I’m glad WH6AZ, with demonstrated talent in doing IOS apps and good user interfaces, has decided to step up to that challenge with Radio Messenger. I’m looking forward to that experience also.

Other notable Island Magic products are:

I’m just in awe of WH6AZ’s design chops and his skill at spotting unmet needs especially for us IOS / Mac users.

My thanks to Georges Auberger WH6AZ for bringing this development to my attention for inclusion in Zero Retries.

APRS Messaging 36 Miles with Two HTs

Cale Mooth K4HCK on his Midnight Cheese blog:

Open up aprs.fi and most of the traffic you’ll see is position based. I’ve spent many years playing around with that aspect of APRS but recently had an opportunity to play with the messaging side. With the rise of Meshtastic, I’ve become more curious about what APRS messaging is capable of considering availability of greater transmit power and a long established network of Igates and digipeaters. I’ve successfully received messages over RF from an internet connected source such as APRS Graffiti Wall and APRS WX Bot. What I really wanted to see was a true RF to RF message setup.

I run an igate here in Murfreesboro with both receive and transmit capability, so one side of the RF based messaging equation has already been complete for some time. It’s a modest station powered by Direwolf and a lowly Quansheng UV-K5 5 watt HT. But it’s connected to a large dual-band vertical about 20 feet off the ground which provides excellent reception and decent transmission to local digipeaters.

A few months ago I had the chance to set up a temporary APRS station in the Nashville Metro Center area. This station was very similar, a 5 watt Kenwood HT powered by Direwolf, but connected to a j-pole set up on a 4th story balcony practically with line of sight to one of the most powerful digipeaters in the area, W4CAT-1. W4CAT-1 sits at about 1,000 feet atop Music Mountain.

This is an interesting experiment with the too-often-neglected APRS Message capability that’s been a feature of APRS and APRS infrastructure practically since the creation of APRS.

It was fun to discover this article the same week as reading about Island Magic’s upcoming Radio Messenger. The two articles bookend nicely together.

NVIS is an Overlooked Jewel

Chris Warren on Off Grid Ham:

…

Near vertical incidence skywave (NVIS) fills in the gap between local communications and DX and is one of the most under appreciated forms of HF radio.

What is NVIS?

It is probably better to start by talking about what NVIS isn’t. It’s not a specific mode. Any operator can apply the principle to voice, code, or data. You do not need specific equipment. You can use whatever HF radio you’ve already got. As for antennas, a simple wire antenna will do. There is no need for towers, beams, or specialty hardware.

NVIS is simply sending a signal deliberately intended not to “skip” great distances. To send an effective DX signal, one must transmit at low wide angle to the ionosphere. In NVIS, the signal is sent at a very sharp, acute angle, almost ninety degrees. That’s where the “near vertical” part comes from.

Think of it like throwing a ball while inside a large building. In the first attempt, you throw the ball at an angle nearly parallel to the floor, like pitching a baseball. The ball will hit the ground, then bounce off the ceiling, and travel a fairly long distance. For the second attempt, you slam the ball on the ground in front of you at nearly a ninety degree angle. The ball will bounce many times between the floor and the ceiling but not travel very far from where you threw it.

Ever since I read about the use of NVIS techniques by The Packet Radio Forwarding Network (TPRFN) for achieving reliable regional communications via HF, NVIS made complete sense to me as a “middle” between local communications using VHF / UHF and continental and intercontinental communications with typical HF antennas.

My thanks to Amateur Radio Weekly Issue 419 for bringing this development to my attention for inclusion in Zero Retries.

Raspberry Pi in Ham Radio: The Honest Best Practice Guide for 2026

Karl-Heinz Krawczyk DL1GKK on DL1GKK.com:

Let’s not kid ourselves: The Raspberry Pi is a brilliant little machine and pretty much indispensable for our hobby nowadays. But getting the hardware and software to play nice together is rarely plug-and-play. If you’ve ever spent half the night wrestling with error messages, you know exactly what I mean.

That’s why many people grab pre-built images. The catch? They are usually outdated before the download even finishes. And ready-made install scripts? One minor update to a Linux package or the operating system, and boom—the script throws errors and you’re dead in the water.

From the trenches, for the trenches, the real best practice is this: Build your system yourself and compile the software exactly for your specific needs. You’ll find plenty of practical, hands-on examples on my blog at dl1gkk.com.

After countless hours at the keyboard, today, in April 2026, I’m giving you the absolute basics to ensure your Pi actually runs smoothly in the shack.

  1. Hardware: Which Pi should you use?

  2. Operating System & Display Server: The right foundation

  3. Troubleshooting: Your digital co-pilot

  4. Backups: The safety net

  5. On the Air: RF is a beast

Each of those five points contain additional detail of solid, well-considered recommendations. DL1GKK put a lot of thought (and evident experience) into each of them. I almost missed his graphic at the bottom of the post that distills his recommendations:

Image courtesy of Karl-Heinz Krawczyk DL1GKK

Fast Long-Range Communication: Semtech® LR2021 Enables High-Speed Image Transfer Without Compromise

Swaroop Chitturi on the Semtech website:

For many years, wireless communication technology has faced a trade-off between achieving long transmission ranges and supporting high data rates. Semtech’s LR2021, the first radio in the LoRa Plus™ line, incorporates 4th Generation LoRa® IP with an innovative Fast Long-Range Communication (FLRC) modulation, enabling data rates of up to 2.6 Mbps on both sub-GHz and 2.4 GHz frequency bands. This advanced modulation supports diverse applications, including reliable image transfer over extensive distances with strong penetration through materials, all while maintaining the low power requirements necessary for battery-powered devices.

The Range-Speed Trade-off in Wireless Communication

The Technology Behind FLRC

Fast Long-Range Communication (FLRC), featured in the LR2021, offers an enhanced link budget and significantly higher data throughput. By utilizing coherent Minimum-Shift Keying (MSK) modulation, FLRC achieves long-range transmission with notable spectral and energy efficiency. Unlike LoRa, FLRC does not employ spread spectrum methods; consequently, the raw bit rate is equivalent to the channel bandwidth prior to the application of Forward Error Correction (FEC). This direct mapping enables FLRC to deliver higher throughput while maintaining the extended range that long-range applications require.

Key Advantages of FLRC

  • High Data Throughput: Supporting data rates up to 2.6 Mbps, FLRC enables applications requiring significant volumes of data transfer, including images, audio, extensive data logging, Firmware Updates Over-The-Air (FUOTA), and Edge AI model training.

  • Extended Range: FLRC offers 8–10 dB improved sensitivity compared to Bluetooth Low Energy (BLE), effectively doubling operational range at comparable bit rates. While BLE typically reaches 100 meters, FLRC extends this to 200+ meters in outdoor environments. Sub-GHz operation delivers superior material penetration, ideal for deep indoor deployments.

  • Low Power Consumption: Optimized for battery-powered platforms necessitating prolonged runtime. Typical security camera deployments achieve 2+ years of battery life with periodic image transmission.

… enabling data rates of up to 2.6 Mbps on both sub-GHz and 2.4 GHz frequency bands.

I’ve been seeing mentions of MeshX beginning to take advantage of “new LoRa capabilities” for higher speeds, but the mentions I’ve seen only make reference to doing so on the 2.4 GHz bands. But now… this looks interesting for those speed tiers perhaps being able to be used on spectrum below 1 GHz. Yes, but… read on.

To date, using LoRa has been a tradeoff between reliability and range, at the expense of speed (bandwidth). LoRa works great for use cases such as text messaging and position / telemetry (it’s original use case). LoRa is especially useful and relevant in Amateur Radio because there are options for LoRa to operate on 433 MHz (unlicensed in Europe).

After a bit of reading, I noted:

  • “Sub GHz” is restricted to 868 MHz (unlicensed in Europe) or 915 MHz (unlicensed in North America). There doesn’t seem to be an option for FLRC on 433 MHz as there is with “traditional LoRa”.

  • FLRC has little or nothing in common with “traditional LoRa”. FLRC modulation is Minimum-Shift Keying (MSK). “Traditional LoRa” is Chirp Spread Spectrum (CSS). There’s no explanation for not using CSS for FLRC.

  • There’s no mention of the bandwidth used - probably buried in the application notes.

I didn’t understand why “LoRa” was even mentioned on this page until I saw this:

About Semtech LR2021

The LR2021 transceiver integrates LoRa, FLRC and other modulation protocols utilized in low-power wireless designs, offering developers exceptional versatility in communication system engineering.

Aha! This new LR2021 chipset offers a choice of modulations in the same chipset - LoRa, or FLRC, or “other modulation protocols” (not stated). But, again, only for 868 / 915 MHz or 2.4 GHz, not 433 MHz. Bummer!

Lastly, this interesting mention in this article:

FLRC Compared to Other Wireless Technologies

Data Rate: Traditional LoRa - 50 kbps

I’ve never seen LoRa described as having 50 kbps bandwidth. At most, I’ve seen ~20 kbps.

In conclusion, FLRC sounds neat, but we have a lot of other existing options for Amateur Radio data communications and networking for data commutations in 902-928 MHz and 2.4 GHz, with reasonably long range and bandwidth such as Wi-Fi HaLow / 802.11ah. While FLRC doesn’t sound like “LoRa on steroids”, it would be interesting to see how it stacks up for Amateur Radio use on the 902-928 MHz / 33cm band.

As Robert Heinlein said so well, TANSTAAFL6.

Announcing tncd: Keeping Packet Radio Working on Linux

Ben Kuhn KU0HN on ku0hn.radio:

tncd.dev — downloads, packages, and documentation

Linux has a packet radio problem.

When Linux 7.1 ships, the native AX.25 kernel networking stack goes away. The AF_AX25 socket family is being removed. Tools like ldsped that depend on it will stop working. PAT will lose its AX.25 transport. Xastir will go silent. Anyone running a current distribution will eventually face this, and “don’t upgrade your kernel” is not a long-term answer.

I wrote tncd to fix this before it becomes everyone’s problem.

What it does

Most packet software speaks AGWPE — a TCP-based protocol that lets applications talk to a TNC without needing kernel socket support or direct serial access. On Windows, AGWPE itself handles everything. On Linux, the kernel’s AX.25 stack has traditionally done the heavy lifting, with tools like ldsped sitting between the application and the kernel.

KISS TNCs — everything from a classic Kantronics KPC-3 (in KISS mode) to a modern Mobilinkd or BTECH UV-Pro — are dumb modems. They encode and decode packets over the air but do not implement AX.25 Layer 2. The handshake, the sequencing, the acknowledgements have always lived somewhere else. tncd moves that somewhere else into userspace.

[PAT / Xastir / Paracon]
         |
      TCP:8000  (AGWPE protocol)
         |
       [tncd]
         |
   serial / TCP  (KISS protocol)
         |
     [TNC hardware]

tncd handles the full AGWPE protocol surface — version negotiation, port enumeration, callsign registration, UI frames, raw KISS passthrough, and monitoring events — and runs a complete AX.25 v2.0 Layer 2 state machine on the KISS side: SABM/UA handshake, I-frame sequencing with a mod-8 window, RR acknowledgement, duplicate detection, T1 retransmit, flow control, and clean DISC/DM handling. Serial (including USB), TCP, and Bluetooth RFCOMM TNCs are all supported.

A bit more backstory on this project from KU0HN was posted on the Zero Retries email list - AX.25 removal from the kernel, and scratching my own itch.

KU0HN also mentioned in passing two applications I wasn’t familiar with that seem worth an expanded mention:

  • ldsped - “expanded” to the next item.

  • paracon - a packet radio terminal for Linux, Mac and Windows. It is focused on simplicity and ease of use, and incorporates the core functionality that most packet users need without trying to include all of the bells and whistles that few would use.

This is the first of three semi-related stories. I’m in awe of the creativity and energy of Amateur Radio software developers such as KU0HN that work to make Amateur Radio data communications better.

ldsped - Open-source, multi-platform replacement for AGWPE

on7lds.net:

As a radio-amateur, I’m mainly busy experimenting with APRS (when I’ve some time left ...).

I’m a linux-user and a registered user of UI-View. But these two do not communicate the way I’d like to.

Of course, I can use Xastir. But my linux computer was at the time, an old PII@266 MHz, running headless in a closet. Running Xastir (remote) is not what you can use ‘fast’.

The ‘workstations’ are windows PC’s or dual boot (Linux/windows) PCs.

As mentioned, I wanted to use UI-View. You may comment on my project, of course, but do not try to convince me to use any alternative. The project is just about running UI-View.

But what started as a wish to use the TNCs on my linux box from the windows computer(s) running UI-View, became a more and more mature linux daemon acting as an agwpe replacement.

Eventually I even added functions, not present in agwpe !

At this moment, a lot of client programs (windows and linux) can work without problems with ldsped. Among them are UI-View, Xastir, Outpost, Radio Mobile, Paclink, AGW*, UISS, ...

How I came to the result can be found on this site.

Use the menu to check out my pages!

…

ldsped GitHub repository - github.com/ampledata/ldsped

AGWPE is AGW Packet Engine, one of many Amateur Radio Packet Radio o applications by George Rossopoylos SV2AGW. Packet Engine has been a fixture of Amateur Radio Packet Radio for nearly four decades. As I understand it, the older version of Packet Engine (AGWPE) is freeware (for Amateur Radio) but not open source. The newer version - Packet Engine Pro is shareware.

This is the second of three semi-related stories. I’m in awe of the creativity and energy of Amateur Radio software developers such as ON7LDS that work to make Amateur Radio data communications better.

Ethernet and IP over Packet Radio TNCs with tncattach

unsigned.io website:

If you just want the most minimal-effort setup guide on how to run ethernet and IP over packet radio TNCs, skip down to the section: “One to Many, Many to One”.

The Old Ways

Running IP applications over packet radio TNCs and similar hardware has traditionally been possible, albeit in a somewhat limited form, using the Linux AX.25 kernel modules and utilities like kissattach. Recent bugs have prevented this method from working correctly in new versions of Debian (and derivatives), and there is even a discussion about removing kernel AX.25 support altogether.

While the kissattach method of IP networking over packet radio traditionally worked relatively well, it also has the drawback of having to encapsulate everything in AX.25 frames, and thus not supporting standard ethernet, while incurring overhead that is entirely unnecessary for IP networking.

A Cleaner Solution

With all that in mind, I found it was probably time to offer an alternative, so I wrote tncattach. It’s a small program that replaces the functionality from kissattach, and doesn’t require any special kernel modules.

With tncattach you can attach any KISS-compatible TNC as a fully ethernet-compatible network interface in Linux. It also supports more “lightweight” tunnel interfaces, for point-to-point links (where you don’t need the overhead of ethernet). And it of course fully supports both RNode and OpenModem.

After writing tncattach, I optimized the buffering and queues in the device firmwares, so be sure to update your RNode to at least version 1.16, and your OpenModem to version 1.05 or above for the best results.

This isn’t a new development (2022-01-25), but perhaps more relevant with the “recent unpleasantness” of Amateur Radio utilities being removed from the Linux kernel.

This is the third of three semi-related stories. I’m in awe of the creativity and energy of Amateur Radio software developers that work to make Amateur Radio data communications better.

Connect Systems - What Is New In M17

Email from Connect Systems (unfortunately, not available on web):

New Release of M17 Firmware

OpenRTX just released a new version of the M17 firmware. A complete list of the changes are below. However, there are only two significant changes:

  1. Ability to send text messages between two radios

  2. Improved voice quality by oversampling

For those interested, a users manual that shows how to use these features as well as the new firmware for the CS7000 M17 and the CS7000 M17 PLUS can be found by pressing one of the buttons below

Added

  • gfx: support for on-screen QR code generation

  • M17: metadata text transmission and reception

  • M17: packet transmission and reception

  • NVM: driver for STM32 internal flash

  • platform: API for vibration motor control

  • codec2: noise reduction of mic input via oversampling

  • test: use gcovr and catch2 for unit tests

  • ui: increases power level granularity

  • AGENTS.md with project guidelines for AI agents

  • CHANGELOG.rst

Changed

  • core: optimized FIR filter implementation

  • build: rename “build_arm” file to “build_cm4”

  • NVM: reorganized API and data structures

  • M17: optimized CRC calculation routine

  • CS7000 Plus: use VOX input for microphone input level

  • Adopt SPDX-compliant header

Fixed

  • audio: runtime bugs in Linux file_source module

  • audio: clipping in HR_Cx000 “beep” tone generator

  • gpio_stm32: fix OPEN_DRAIN_PU setup mode

  • ui: missing bound checking in repeater offset input

  • ui: wraparound on repeater offset entry

…

Link To Get Firmware For CS7000 M17 PLUS and Users Manual

Link To Get Firmware For CS7000 M17 and Users Manual

opensource.radio Website / Project Now Offline

Open Source in Amateur Radio

Welcome to the Open Source in Amateur Radio wiki! This resource is dedicated to providing information about open-source software and hardware as well as free home-brew projects for amateur radio enthusiasts. The idea of this website or wiki is to give a (future) radio amateur an overview of all available open source projects. The aim is to promote the use of open source software and hardware in amateur radio. Depending on personal requirements, it is now possible to set up an amateur radio station whose main components are open source.

This was an ambitious project, which I hoped to participate in… but I didn’t, so I’m one of the guilty parties this statement refers to:

Help!

This wiki cannot be filled and maintained by one person alone, which is why I call on people to register on the wiki in order to correct errors, add information, translate articles and/or create new content.

Fortunately it was being snapshotted by the Internet Archive Wayback Machine. This seems to be the last snapshot - web.archive.org/web/20250113172443/https://opensource.radio/start

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the hashtag #ZR0250.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

Zero Retries 0250

Despite the title of this issue, the 250th issue of Zero Retries probably passed a couple of months ago as I have occasionally published special issues that weren’t numbered.

That said, each of these significant anniversary and issue number milestones amaze me. When I started Zero Retires, I never imagined that it would continue for more than five years, reach more than 3500 email subscribers, or that there would be enough source material to justify a new issue nearly every week. But Zero Retries is largely a virtuous cycle - the more issues are published, the more readers, the growing exposure all “widen the net” in finding technological innovation in, and adjacent to Amateur Radio, and then trying to report out some of those findings. It’s arguable if I’m just reporting on what’s happening, or that Zero Retries is playing some small part in growing that technological innovation. But, largely, thank you Zero Retries readers. If there wasn’t a substantive reader base, there would be little point in continuing to publish Zero Retries.

Thanks very much to the financial supporters of Zero Retries - the paid subscribers - Founding, Annual, and Monthly. There are significant expenses in publishing Zero Retries, and the financial contributions really, really help keep Zero Retries viable.

Burnout on Open Source Projects

In my research for this issue, I came across this sobering reminder - Carrier Switch, that for all the glories of creating open source hardware, software, documentation (and newsletters, and podcasts, and videos…), while those might be free to us users, creating them comes at a cost. Sometimes significant cost, as “Carrier Switch” explains.

It’s hard to understand why some open source projects seem sustainable, and others spark, burn brightly, and then eventually burn out. I wish someone could do a systemic study of that phenomenon. I certainly don’t have any answers, but I do have some observations.

  • Open source creators really need to maintain significant balance in their lives and be careful not to let their open source projects consume too much of their time and energy. I know - easier said than done. Really, I get that point, and I try to apply it to my life, and Zero Retries. Sometimes there are urgencies that need to be addressed, but long term, an open source project “isn’t your life”.

  • Forming a community seems to be a long term buffer against burnout, especially when you can distribute the load, especially the support load, amongst trusted others supporting the project.

  • If the open source project becomes significant enough that it does seem worth investing a significant portion of your time and energy (equivalent to at least a part time, if not full time job), then consider trying to get a financial grant such as those available from ARDC to “lighten the load” financially.

  • Similar to getting a grant, getting the help of an incubator organization like Crowd Supply lightens the load. Such organizations have much greater scale to expose your project to a wide audience, they can provide fulfillment services (especially critical in this era of complex tariffs, etc.) and they can just generally offer advice and support because they’ve seen many other projects before yours and know where the pitfalls are.

  • Sometimes, you just can’t keep going on a project due to other priorities, or interests, or lack of community support, or other circumstances beyond your control - and you need to be OK with that. I think this advice applies:
    If At First You Don’t Succeed, Try, Try Again. Then Quit. There’s No Use Being a Damn Fool About It.

  • This might seem self serving given how often I mention this it in Zero Retries, but many open source projects “self sabotage” by not publicizing and promoting the project with a public website that supports and promotes the project. It’s not enough for information about your project to be exclusively on Facebook, or Discord, or LinkedIn, or X, or YouTube, or Groups.io (though that has a decent Wiki that can function as a website). A few of my favorite examples of project support / promotion websites are M17 Project, DigiPi, FreeDV, and AREDN.

Hamvention Ho!

1 week until Hamvention 2026
in Xenia, Ohio, USA...
Zero Retries / DLARC booth 1506
in Building 1 / Maxim

Fediverse Meet-up at Hamvention 2026

Cale Mooth K4HCK in Amateur Radio Daily 2026-05-01:

Members of the Fediverse are invited to join fellow users at Hamvention 2026. An informal meet-up will take place Saturday, May 16th at 11:00 AM. We’ll meet in front of booth 1506 in Building 1, aka the Maxim building. Thanks to KB6NU for helping to organize!

(Booth 1506 is home to Zero Retries and DLARC. Thanks to Steve and Kay for allowing the use of their booth as a rendezvous point!)

I’ll be at the meet-up with stickers. Hope to see you there!

What is the Fediverse and how does it relate to ham radio? The Fediverse is a collection of social networking sites that communicate with one another in a decentralized way. It’s an open source alternative to centralized social networks such as Facebook and X. There are several ham radio themed Fediverse instances with thriving communities of radio amateurs:

You can find me on the Fediverse at https://mastodon.radio/@K4HCK.

I’m @n8gnj on mastodon.radio. Mastodon, and especially mastodon.radio7 is the only social media that I attempt Zero Retries to be involved with8. Mastodon has a reasonable number of Zero Retries Interesting techies that share interesting info there. I’ve been a poor participant of late, but I’m going to be working on that, and may try to post brief updates there from Hamvention 2026.

No Demos at Zero Retries / DLARC Booth

I’ve received several suggestions about doing demos of Zero Retries Interesting projects at the Zero Retries / Digital Library of Amateur Radio & Communications booth at Hamvention 2026.

It’s just not feasible to do so, at least this year.

The goal for Hamvention 2026 is to widen the exposure to Zero Retries within the wider Amateur Radio community that otherwise wouldn’t encounter Zero Retries. Another goal I had with the Zero Retries booth was to make half of it available to DLARC for it to have some exposure at Hamvention 2026 (commercial, indoor booths are very hard to get on short notice - there’s a considerable waiting list).

I suspect that I’ll be explaining Zero Retries until my voice is hoarse, and shaking hands to the point of hand cramps (per a friend who’s a veteran of many Hamventions as an exhibitor.

I was gratified to receive personal invitations to meetups on Friday and Saturday evenings from groups that I admire and follow in Zero Retries.

The Adventure Begins in Xenia: Hamvention 2026

Michael Kalter W8CI via Amateur Radio Daily 2026-05-04 had an interesting mention:

Amateur Radio in 2026: A Hobby Transformed

…

The hobby has evolved dramatically in recent years. Digital modes like FT8 rewrote what “weak signal” communication means, allowing operators to make transcontinental contacts with just a few watts of power. Experimental modes like FT2 are already being discussed in labs and forum threads. Software-defined radios (SDRs) have put sophisticated spectrum analysis tools in the hands of anyone with a laptop. Mesh networking on VHF and UHF bands is enabling hams to build their own internet-independent communication infrastructure. Machine-learning-assisted decoders are pushing the boundaries of what the human ear — or any radio — can resolve from noise.

I found this a refreshing, and accurate, if incomplete nod that by Hamvention that Amateur Radio is being transformed in the 2020s with such technologies. I hope those technologies will actually be substantively featured in the exhibitors and forums at Hamvention 2026.

My thanks to Amateur Radio Daily 2026-05-04 for bringing this article to my attention for inclusion in Zero Retries.

Weekends Are For Amateur Radio!

We’re traveling over this weekend, and when we return we will be in frantic preparations for exhibiting at Hamvention 2026. But after my return… N8GNJ / Zero Retries Labs is literally full (almost to burstin’) of deferred projects.

The weather here in Whatcom County, Washington this late Spring is about as perfect as it can be with mild temps and ample sunshine, which means the Labs big shop doors can be open to the fresh air and sunshine.

Three urgent projects are to get systems on the air for MeshCore (thanks again to Steve Monsey N0FPF for the loan of that unit), 1200 bps AX.25 Packet Radio, and VARA FM, as there are now folks on the air in this area to interoperate with on those modes.

A connection to HamWAN, and 44Net Connect are also near term projects. As you read above, Connect Systems just made a new firmware update for my pair of CS7000 M17 PLUS portable radios, so that’s also on the near-term list.

Lastly, I have several review units that have been sent to me that I have not yet taken the time to review.

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the hashtag #ZR0250.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

Founding Members who generously support Zero Retries financially:

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The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries \ Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0250 was published on 2026-05-08. This issue was 9875 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

As opposed to the SCS Pactor 4 modem units.

2

I have no issues with EA5HVK choosing to offer VARA as a product (purchase of a license key for full functionality), not releasing the source code, and only releasing a version for Windows.

3

Singular, as I’m the only known advocate of the SuperPeater concept.

4

My name for AREDN operating on the 902-928 MHz band, based on 802.11ah / Wi-Fi HaLow.

5

I’ve long needed a new iPad. My current “big iPad” that I inherited from my late Mother In Law continues to work great… but it’s now aged beyond Apple’s willingness to provide all but the most critical security updates, so a lot of cool apps cannot be loaded onto it.

6

The version I know best is by author Robert A. Heinlein - There Ain’t No Such Thing As A Free Lunch.

7

Thank you Christopher M0YNG for doing such a great job with mastodon.radio!

8

I’m also on Bluesky, but there’s very little interactivity there, at least for Zero Retries subjects, and I’ll eventually wind that down.

]]><![CDATA[Zero Retries 0249]]>https://www.zeroretries.org/p/zero-retries-0249https://www.zeroretries.org/p/zero-retries-0249Fri, 01 May 2026 22:30:57 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its fifth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is too big for email clients. Thus, it might be easier to read in a web browser - https://www.zeroretries.org/p/zero-retries-0249.

It’s easy and free to subscribe for your own copy of Zero Retries every week:

Subscribe now

In This Issue:

I-Frame

Amateur Radio Drivers Removed From Linux Kernel
Steve Stroh N8GNJ

The Perceived Irrelevance of Amateur Radio Networking
Steve Stroh N8GNJ

Announcing Project Argus
George Zafiropoulos KJ6VU

The Quiet Resurgence of RF Engineering
Anthony Templeton

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Prefers to Remain Anonymous 72 for one year of being a Paid Subscriber to Zero Retries as of this past week!

My thanks to Prefers to Remain Anonymous 125 for becoming a new Annual Paid Subscriber to Zero Retries this past week!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Amateur Radio Drivers Removed From Linux Kernel

By Steve Stroh N8GNJ

Drivers for Amateur Radio Packet Radio and various Amateur Radio Packet Radio hardware (generally no longer used) have been included in the Linux kernel since the early days of Linux. Unfortunately, those drivers have not been maintained, and thus were slated for removal.

That there are multiple perspectives about this situation is yet another example of my humorous explanation to those outside Amateur Radio that three hams could get together to discuss something, and emerge with five different opinions.

See next article for my analysis of the bigger picture of why this happened and a proposed solution for that situation.

Article - Linux Kernel Drops AX.25 and Amateur Radio Subsystem Support

Amateur Radio Daily - April 24, 2026:

Earlier today Linus Torvalds merged a pull request to remove AX.25 and hamradio subsystem support from the Linux kernel. While the headline sounds ominous, most modern AX.25 implementations occur in software at the user level without relying on the kernel level implementation. Direwolf, for example, does not require kernel level AX.25 support. Other software relying on AX.25 may take advantage of dedicated AX.25 Python libraries.

The change comes as a result of AI based bug detection services capable of identifying critical issues among code that may no longer be maintained or utilized by end users. Torvalds stated that the amateur radio related code in the Linux kernel no longer had any active maintainers:

Amateur radio did have occasional users (or so I think) but most users switched to user space implementations since its all super slow stuff. Nobody stepped up to maintain the kernel code.

According to typesense the last Linux kernel commit related to AX.25 was 6 years ago.

Additional code removed includes ISDN support, bus mouse support, and various network drivers including support for old 3Com devices.

Source: Phoronix

Article - Farewell ISDN, Ham Radio & Old Network Drivers: Linus Torvalds Merges 138k L.O.C. Removal

Michael Larabel in Linux Networking on phoronix:

Linus Torvalds did it! He merged the pull request to rid the Linux kernel of the old Integrated Services Digital Network (ISDN) subsystem and various other old network drivers largely for PCMCIA era network adapters. This was the code suggested for removal given the recent influx of AI/LLM-generated bug reports against this dated code that likely has no active upstream users remaining.

It's been a fast-paced week with the patch series to remove old network drivers due to AI-driven bug reports now making these drivers for outdated network hardware a burden. Drivers for old/obsolete hardware has remained in the upstream kernel as long as there are active users and keeping the code around hasn't been a burden on developers or there are developers actively interested in maintaining the code. But now with the large language models and increased code fuzzing finding potential issues with these drivers for obsolete hardware, it's easier to just get rid of these drivers if no one is actively using the hardware from decades ago.

Yesterday the pull request was submitted to remove the old drivers and today Linus Torvalds went ahead and merged it without any fuss.

This merge lightens the kernel by 138,161 lines of code with ISDN gone and numerous old network adapters and also getting rid of legacy ATM device drivers as well as the amateur ham radio support. The main networking drivers removed affect the 3com 3c509 / 3c515 / 3c574 / 3c589, AMD Lance, AMD NMCLAN, SMSC SMC9194 / SMC91C92, Fujitsu FMVJ18X, and 8390 AX88190 / Ultra / WD80X3.

Linux 7.1 also has removed the long-obsolete bus mouse support as well as beginning to phase out Intel 486 CPU support and removing support for Russia’s Baikal CPUs.

In the ARDC community discussion (linked below), this is attributed to Linus Torvalds:

Old code like amateur radio and NFC have long been a burden to core
networking developers. syzbot loves to find bugs in BKL-era code, and
noobs try to fix them.

If we want to have a fighting chance of surviving the LLM-pocalypse
this code needs to find a dedicated owner or get deleted. We've talked
about these deletions multiple times in the past and every time
someone wanted the code to stay. It is never very clear to me how many
of those people actually use the code vs are just nostalgic to see it
go. Amateur radio did have occasional users (or so I think) but most
users switched to user space implementations since its all super slow
stuff. Nobody stepped up to maintain the kernel code.

We were lucky enough to find someone who wants to help with NFC so
we're giving that a chance. Let's try to put the rest of this code
behind us"

Modules Removed

Specific deletions from the merge request (manually parsed by me for recognizable Amateur Radio drivers / hardware / utilities, etc.):

  • Documentation/networking/6pack.rst

  • Documentation/networking/ax25.rst

  • Documentation/networking/device_drivers/hamradio/baycom.rst

  • Documentation/networking/device_drivers/hamradio/index.rst

  • Documentation/networking/device_drivers/hamradio/z8530drv.rst

  • drivers/net/hamradio/6pack.c

  • drivers/net/hamradio/Kconfig

  • drivers/net/hamradio/Makefile

  • drivers/net/hamradio/baycom_epp.c

  • drivers/net/hamradio/baycom_par.c

  • drivers/net/hamradio/baycom_ser_fdx.c

  • drivers/net/hamradio/baycom_ser_hdx.c

  • drivers/net/hamradio/bpqether.c

  • drivers/net/hamradio/hdlcdrv.c

  • drivers/net/hamradio/mkiss.c

  • drivers/net/hamradio/scc.c

  • drivers/net/hamradio/yam.c

  • drivers/net/hamradio/z8530.h

  • include/net/ax25.h

  • include/net/rose.h

  • include/uapi/linux/baycom.h

  • include/uapi/linux/netrom.h

  • include/uapi/linux/rose.h

  • include/uapi/linux/scc.h

  • net/ax25/Kconfig

  • net/ax25/Makefile

  • net/ax25/af_ax25.c

  • net/ax25/ax25_addr.c

  • net/ax25/ax25_dev.c

  • net/ax25/ax25_ds_in.c

  • net/ax25/ax25_ds_subr.c

  • net/ax25/ax25_ds_timer.c

  • net/ax25/ax25_iface.c

  • net/ax25/ax25_in.c

  • net/ax25/ax25_ip.c

  • net/ax25/ax25_out.c

  • net/ax25/ax25_route.c

  • net/ax25/ax25_std_in.c

  • net/ax25/ax25_std_subr.c

  • net/ax25/ax25_std_timer.c

  • net/ax25/ax25_subr.c

  • net/ax25/ax25_timer.c

  • net/ax25/ax25_uid.c

  • net/ax25/sysctl_net_ax25.c

  • net/netrom/Makefile

  • net/netrom/af_netrom.c

  • net/netrom/nr_dev.c

  • net/netrom/nr_in.c

  • net/netrom/nr_loopback.c

  • net/netrom/nr_out.c

  • net/netrom/nr_route.c

  • net/netrom/nr_subr.c

  • net/netrom/nr_timer.c

  • net/netrom/sysctl_net_netrom.c

  • net/rose/Makefile

  • net/rose/af_rose.c

  • net/rose/rose_dev.c

  • net/rose/rose_in.c

  • net/rose/rose_link.c

  • net/rose/rose_loopback.c

  • net/rose/rose_out.c

  • net/rose/rose_route.c

  • net/rose/rose_subr.c

  • net/rose/rose_timer.c

  • net/rose/sysctl_net_rose.c

Amateur Radio Reactions

I’ve seen a number of reactions to this news on various email lists ranging from:

“Without those drivers, x can no longer work”…

to

“No big deal, no one used those drivers anyway”. A similar opinion is “They were useful in the day, but no longer needed.”

The most substantive, insightful discussion thread (that I’ve seen) about this issue seem to be on the ARDC community email list:
Linux Kernel Drops AX.25 and Amateur Radio Subsystem Support

David Ranch KI6ZHD:

The code deletion is probably final but a lot of other elements in that post is just wrong. The primary reason the code was because there wasn't any active maintainer giving guidance and a Q/A blessing and secondarily because many people felt that protocols like this shouldn't have been serviced by the kernel in first place and should have been in userland. That typesense tool is wrong as there have been plenty of patches over the recent years coming from other contributors to deal with clean ups, fix race conditions, etc. It's not about any landslide of AI-based reported bug and there are plenty of in-Linux AX.25 users. What didn't happen in time is anyone with kernel development expertise willing to take on the real maintenance and enhancements to cover this rather premature revocation patch being submitted before there was a real consensus.

The other code that has been ripped out here is at https://github.com/linux-netdev/mod-orphan where you can see what was ripped out in that one commit:

- All ATM network drivers
- All ISDN network drivers

I'm personally very disappointed here as this marks the end for tools like the FBB BBS, the FPAC node with ROSE support, the Linpac terminal program, a Linux native Winlink server and many more. I've been chatting with some people over at the ARDC to see if a new grant could be considered to rewrite the libax25 library to redirect I/O from the kernel and send it to something like an AGW interface but it's very early days there.

Marius Petrescu YO2LOJ:

The good question is if there is a real need for such an effort.

The main reason the ax.25 stack needs to be at kernel level is the fact that it was intended to allow using ax.25 as the L2 transport layer for TCP/IP, while integrating with other L2 protocols.
As we stand now, that specific application has lost its usefulness, since basically nobody uses it for that.
The other use, together with Netrom and Rose, are mainly supported by userspace stacks, like the xNOS packages, with the most outstanding exception of node softwares, like uronode & other similar applications.

Since the decisions related to Linux kernel support are quite unilaterally and tend to be final at the moment of their publication (I have never seen any of them ever reversed), there are not many options available to us in this regard.

We will loose the classical ax, netrom and rose interfaces, and the use of (mostly obsolete), and hardware drivers (like baycom and scc cards, but I don’t think that there are to many of those in use anymore).
But the big problem is the KISS line discipline, which would prevent the creation of virtual ax25 interfaces, even if it would be implemented in userspace.

So IMHO, what needs to be done is a complete rewrite of the ax25 library to allow the same upper level API for the applications, while implementing the whole low level part as a server component, and this is not a trivial effort (I would estimate such an effort at around 1 man-year, with all the needed documentation and testing), without even trying to port the existing hardware drivers to it.

Or, as a second option, we can let go of the kernel support completely, and switch exclusively to NOS for native AX.25 usage.
What should be noted is that the most popular applications using ax.25, more specifically APRS, is not impacted at a significant level, since most implementations can already work in userspace only while also being able to use the original kernel support (direwolf, aprsd & family).

So we need to make a decision here. Support a complete userspace stack implementation, or just let it slide into history.

Decide wisely, since this is a thing that really needs ARDC support to be successful.

Jonathan Naylor G4KLX:

I agree that we don’t need a kernel level AX.25 (or NET/ROM or ROSE) stack these days. When I wrote it back in 1995-97, I wanted to create something akin to BPQ but for Linux. A way to share a KISS TNC with multiple applications without problems, and the sockets interface was chosen. The alternative would have been even more abuse of the ioctl system call.

It worked well in those days, and I’m still rather proud of what I, and others, achieved. You could create some pretty wild system by judicious use of pseudo-ttys and other mechanisms.

If we’d had decent middleware available at the time, something like MQTT, then I would probably have developed it outside of the kernel, and developed a set of libraries to interface to the middleware in a transparent way.

If I were to write it now, I would have the protocol stacks as a separate unit communicating with the chosen middleware, and on one side a library that mimics the socket interface to make porting of open source programs relatively easy. The other side would be another interface that would allow the AX.25 packets to be encapsulated to whichever physical hardware that you have. This would be clean and free of too much legacy code and general bloat.

It’s not rocket science, and would be quite a fun little project. I wouldn’t mind doing it myself…..

and later…

I’m not too worried about my work dying. In its prime, the kernel AX.25 code was used extensively, and the linux-ax25 mailing list was very active indeed. I was happy to be a part of that.

However that was then, and this is now. Looking at the kernel code, I still see a lot that is recognisable from its original development.

I would recommend people who want to run full fat AX.25 and NET/ROM with some great enhancements, then I would point them to LinBPQ which is both open source and fully maintained. You would lose ROSE, but that was always a minority interest compared to the other protocols. If there was enough interest then I am sure it could be added to LinBPQ.

Running in kernel space has the one advantage of making the protocols to numerous user level programs simultaneously, with the downside that even a small bug could cause a spontaneous reboot. I have the mental scars from those days.

So let the kernel code die. I’m not a huge fan of repurposing NOS to replace it, it’s good at what it does for sure, but a user level implementation should be done differently I believe. As for AGW, it’s an abomination of a protocol.

Another discussion thread was on Bpq32 email list was informative (despite misquoting the source1 of the story) - Linux Kernel Drops AX.25 and Amateur Radio Subsystem Support:

David Ranch KI6ZHD:

That one ARDC Linux Packet Radio grant back in 2022 was returned as the person who accepted the grant later rescinded the project and evidently returned the money. The only person I know who was doing any real work on repairing some of the random kernel commits that broke the AX.25/NETROM/ROSE kernel code was Bernard Pidoux F6BVP and some additional assist from Lee Woldanski VE7FET on the libax25/ax25-apps/ax25-tools repos at https://github.com/ve7fet?tab=repositories .

I think it will take a few days for any serious pushback to happen but it's really not clear if that's going to happen. If this is permanent, we're all going to lose the very powerful glue for AX.25 being Linux. :-( NOSes like Linbpq can do a lot of the same things but I'm not familiar enough with it to know if the same level of flexibility is possible.

The ARDC grant in question was Fixing the Linux kernel AX.25:

Date: December 2021
Amount: €179,690

Changes to the Linux kernel over the years have improved and modernized the kernel, but have also made existing AX.25 implementations incompatible and turned preexisting issues into bugs. This can make systems unpredictable or even unusable. Linux kernel development is complex, requiring deep specialized knowledge, and bugs are hard to trace. This may be one of the reasons, why the Linux kernel AX.25 stack is currently in such a bad state.

This ARDC grant funds will allow the Deutscher Amateur Radio Club to hire software developers who can create a stable Linux AX.25 implementation and prevent Linux distributions from dropping pre-compiled AX.25 support. The fixed and functional Kernel-AX.25 stack will improve global amateur radio infrastructure. Professional kernel development can bring Linux AX.25 back to life.

Update

After careful consideration, the Deutscher Amateur Radio Club (DARC) decided to return the total grant amount of $150,445 to ARDC. This decision was made as the project encountered unforeseen difficulties that prevented it from being carried out. However, the club did make some progress on the AX.25 kernel as part of the effort before ultimately concluding that they would not be able to complete the project.

Learn more at https://www.darc.de/home

From the more active software developers of Amateur Radio software I’ve talked to over the past few years is that they made no use of the Linux Amateur Radio utilities. One reason I’ve heard for that is many developers wanted their software to be as cross-platform as possible and so embedded AX.25 functionality into their software. I’ve also heard that the only hardware interface of any importance for Amateur Radio in this era is KISS for TNCs and audio adapters.

Amateur Radio Linux Distributions

This development seems to be the moment to shine for the various distributions of Linux that are optimized for Amateur Radio use such as:

All of which could (re) provide these drivers as standard.

But… Maintenance…

Even if the Amateur Radio distributions were to re-incorporate the Amateur Radio drivers into their distributions… those drivers are apparently not being maintained, and they were (apparently?) designated as a security threat (attack vector) for Linux systems that are connected to the Internet, which is more common than not (in my observations).

In an email discussion with David Ranch KI6ZHD, I asked him about the maintenance issues:

My understanding is that the Amateur Radio utilities were added into Linux very early in the life of Linux, when vetting such additions wasn’t so rigorous… nor were the stakes as high as they are now with Linux sometimes being life safety critical. I think an accurate measure of this situation is whether in the Linux update processes of 2026, would the maintainers be willing to add Amateur Radio utilities into Linux?

My guess is no.

I think if it were to be done properly and securely, I don’t know why they would say no. The biggest issue I see here by moving the stacks out of kernel space is the loss of flexible routing. Linux is VERY powerful and you can basically configure anything you want and if it’s not there, you can code it up yourself if you have the skillset. I know external userland programs like BPQ are quite powerful too but they are their own vertical solution (NOS or Network Operating System) and aren’t Linux.

Any of the big issues have come in over the years have been created by random kernel developers trying to modernize / fix some aspect of the code but they don’t compile it, they don’t test it, yet the code gets committed. It’s been an eye opener to see how some of this open source code is developed. I suppose you can call it “fail fast” but the problem is, some Linux distros might branch their release on a bad kernel and then it takes months or even quarters to get things fixed. It’s really annoying (to be polite).

There are a couple of repositories where there is some work being done:

Another factor is, that as I understand it, the “fix something in the kernel” administrative process is so onerous that few Amateur Radio Operator (as in inexpert) coders are willing to do the rigorous work to get all of the Amateur Radio code fixed. There are those that CAN fix it - they just can’t get their (inexpert) fixes through the kernel vetting process.

I’ve asked and asked different people if there is a place to setup a regression testbed so when commits come in, the code could be tested in an official way. I’ve never heard a single response.

…

I do get that the kernel continues forward and old kernel mechanisms need to be phased out but this isn’t the way to do it.

In a concluding email, KI6ZHD said:

I don’t agree with all of your perspective. For example, to exploit a kernel bug in say the AX.25 could be very convoluted, etc. Maybe the technical risk is present but I personally didn’t think it warranted the outright removal of all this code. I’ve also heard they have ripped out a bunch of PCI nics like the 3Com 3c905, etc. I know that there has been recent efforts to remove 486 code along with these other recent removals of ISA and PCMCIA drivers but I fee removing PCI drivers is going too far.

I understand KI6ZHD’s sentiment, but in my opinion, “Amateur Radio” had ample warning that “it might come to this” (excising Amateur Radio drivers from the Linux kernel) for years now, and no one, no group stepped forward to put in the effort required to maintain these drivers, or to “speak for Amateur Radio” that drivers for the deprecated hardware were no longer useful and could (gracefully) be removed from the Linux kernel.

Another correspondent said:

Well, now it’s done [Amateur Radio drivers removed from the Linux kernel] and there’s no ambiguity or uncertainty about the situation. Now we have the opportunity for a reset and a do-over. If we collectively want Amateur Radio capability back in Linux, we’ll have to do it right. That includes up-to-date, vetted code, including the current AX.25 [Version 2.2] and KISS as you mentioned recently in ZR. Almost certainly we’ll have to have an active maintainer, if not a group. It will be interesting to see who steps up to that challenge, if any.

Conclusion

Now it’s time to see if the collective, worldwide community that’s interested in having standardized support for Amateur Radio networking in Linux steps up and organizes to “fix” this problem and modernize Amateur Radio drivers for potential (re)inclusion into “mainstream” Linux. In my opinion, this effort will fail unless there is a substantial effort to create an organization, even if informal and virtual, to coordinate such work.

I agree with YO2LOJ when they said:

Decide wisely [about whether to start work on modernizing the Amateur Radio kernel drivers], since this is a thing that really needs ARDC support to be successful.

In the thread, Bdale Garbee KB0G (ARDC President) said:

What I think is missing from the discussion so far is an inventory of programs and their user communities actually using these kernel capabilities in 2026, if any.

The best path forward and what role, if any, ARDC can play to “fill the gap” depends a lot on that information.

In this potential involvement of ARDC for this issue, it might be useful to revisit its stated mission (emphasis mine):

Amateur Radio Digital Communications (ARDC) is a California-based foundation with roots in amateur radio and the technology of internet communication. Our mission is to support, promote, and enhance digital communication and broader communication science and technology, to promote amateur radio, scientific research, experimentation, education, development, open access, and innovation in information and communication technology.

Please direct comments / feedback about this article to the Zero Retries email list with the #ZR0249 hashtag.

The Perceived Irrelevance of Amateur Radio Networking

By Steve Stroh N8GNJ

I believe that there’s a bigger picture perspective of the removal of Amateur Radio drivers from the Linux kernel - the widespread lack of knowledge of Amateur Radio networking.

I posit that promotion of Amateur Radio Networking is a reasonable and defensible proxy for the relevance of Amateur Radio in the 21st century. The capacity to build and operate radio-based networks (that are higher capacity, more capable, and more scalable than Meshtastic, MeshCore, MeshCom, etc.) that are independent of other infrastructure is a significant and defensible reason of the relevance of Amateur Radio, and its continuation in the 21st century.

One of the most interesting aspects to this development (see previous article) is how many people rose to the defense of maintaining the Amateur Radio drivers in the Linux kernel, indicating that they are in active use for Amateur Radio networking. For example, several mentions of the Amateur Radio ROSE Network protocol, which I had not heard of any active use in decades.

And that basic issue, writ large, is fundamentally at the heart of this issue…

No organization, no publication is talking about… promoting… evangelizing, in a substantive way about Amateur Radio networks that are in active use in the 2020s. Thus it’s completely understandable that the overwhelming perception is that “no one uses these drivers any more” and thus there’s no reason to continue them in the Linux kernel”.

The Torvalds Statement

The statement by Linus Torvalds explains this situation well:

It is never very clear to me how many of those people actually use the code vs are just nostalgic to see it go. Amateur radio did have occasional users (or so I think) but most users switched to user space implementations since it’s all super slow stuff. Nobody stepped up to maintain the kernel code.

That perspective is completely understandable. In my experience, Torvalds’ perspective is typical of the vast majority of techies in this era. They know that Amateur Radio still exists, that there are some people active in it, but aren’t aware2 about what Amateur Radio is actually doing, especially “modern” networking over Amateur Radio spectrum.

AREDN is the Shining Exception to Lack of Promotion of Amateur Radio Networking

The sole exception to the lack of recognition and promotion of the relevance of Amateur Radio networking in the 21st century is AREDN - Amateur Radio Emergency Data Network. Commendably and consistently, AREDN does a great job of developing (and maintaining) Amateur Radio networking technology that’s relevant in the 21st century.

Techies can look at what AREDN is doing and immediately grasp what AREDN is:

  • Real mesh networking via radio that works

  • Reasonable range - miles

  • Reasonable speeds - 10s of Mbps

  • Minimizes frustrations - manages complexities of IP address assignment

  • Easy to get started

More commendable is AREDN’s consistency at promoting AREDN as relevant and interesting networking via radio. Kudos for this are owed to AREDN Evangelist Orv Beach W6BI, and to one of the AREDN Lead Developers Tim Wilkinson KN6PLV.

Promotion of Amateur Radio Networking in ARRL’s New Book Digital Networking for Ham Radio

This book, released earlier this year, is a a welcome treatment of networking in Amateur Radio in the 2020s. I am a supporter of this book - see Impressions of ARRL’s New Digital Networking for Ham Radio Book in Zero Retries 0240.

But, as I detail in that article, it has some significant omissions, such as no coverage of Amateur Radio Packet Radio. Thus this book doesn’t offer any authoritative reference (that could be quoted to the Linux community) to the importance of Amateur Radio drivers in the Linux kernel. While the book does cover AREDN (and HamWAN), it can be argued that those systems are “Amateur Radio overlays” on top of microwave communication units developed for microwave networking in unlicensed spectrum.

Thus it’s unfortunate that networking systems that are unique to Amateur Radio, such as New Packet Radio, Icom’s D-Star Digital Data (DD), and other network systems unique to Amateur Radio weren’t discussed in the book.

But AREDN and the new ARRL book, laudable though they are, don’t make a substantive enough case for Amateur Radio networking to techies, the general public, or regulators.

The Need for a Substantive Publication, Reference of Record, or Organization to Promote Amateur Radio Networking

There is no substantive publication3, reference of record, or organization that techies can reference to learn about modern Amateur Radio technology, especially Amateur Radio networking. There is no Amateur Radio equivalent of, for example, The Internet Protocol Journal:

The Internet Protocol Journal (IPJ) is a quarterly technical publication containing tutorial articles (“What is…?”), as well as implementation/ operation articles (“How to…”). The journal provides articles about all aspects of Internet technology. IPJ is not intended to promote any specific products or services, but rather is intended to serve as an informational and educational resource for engineering professionals involved in the design, development, and operation of public and private internets and intranets. In addition to feature-length articles, IPJ contains technical updates, book reviews, announcements, opinion columns, and letters to the Editor.

IPJ is supported by the Internet Society and other organizations and individuals around the world dedicated to the design, growth, evolution, and operation of the global Internet and private networks built on the Internet Protocol. Previously published by Cisco Systems from 1998 until 2013, the journal was relaunched in September 2014 with the help of numerous supporters and sponsors.

There used to be…

  • TAPR’s Packet Status Register used to be such a resource, but it no longer serves that role. TAPR has not been substantively involved in Amateur Radio networking for decades.

  • ARRL used to be substantively involved in Amateur Radio networking, including substantive articles in QST and QEX, and a dedicated newsletter - Gateway for the worldwide Amateur Radio Packet Radio community.

  • For a brief period we even had Packet Radio Magazine which did an even better job of covering Amateur Radio Packet Radio and networking in depth than PSR and Gateway combined (and, for a few months, incorporated both of those publications).

But in the 21st century, there’s no organization, no substantive reference, no publication that promotes Amateur Radio networking in a substantive way to the rest of the world.

In my opinion, that is to the ultimate, long term detriment of Amateur Radio as a whole.

Simply, despite the incredible technological innovation (including Amateur Radio networking) that is occurring in Amateur Radio… it’s not being recognized by techies, and it’s especially not being recognized by the general public.

Most dangerously to Amateur Radio, the relevance4 of Amateur Radio in the 21st century is not being recognized by regulators such as the FCC.

One only need ask your techie friends what comes to mind when asked this question - “Have you heard of Meshtastic?”. Universally, the answer is Yes, because it’s being widely, actively, supported and promoted. If you ask the similar question - “Have you heard of Amateur Radio networking?”, the most typical answer will be a blank look, if not a laugh followed with “Is ham radio still a thing?”

What’s my point in raising this issue?

Simply, that kind of organic support and promotion is “good enough” for Meshtastic, etc. because Meshtastic, etc. does not depend on dedicated spectrum and continued support from regulators. Meshtastic operates in portions of spectrum designated for unlicensed devices.

“Organic support and promotion” is not sufficient for Amateur Radio
because it does depend on continued support from regulators.

In the US, there is ARRL, and a part of ARRL’s mission is to promote and defend Amateur Radio and continued access to, and enhanced privileges in, designated portions of spectrum.

Regulatory & Advocacy

Amateur Radio is subject to regulation at the international and national levels with regard to telecommunications and at the state and local levels with respect to land use regulations. ARRL advocates on behalf of Amateur Radio at all of these levels.

But… in the 2020s, ARRL, other than the Digital Networking for Ham Radio book, is not discussing or promoting Amateur Radio networking.

What Amateur Radio Needs to Do Differently, Soon

As I try to make the case in this article, Amateur Radio (writ large), really needs to begin promoting Amateur Radio networking in at least one of these ways:

  • A new organization focused on Amateur Radio networking - Amateur Radio Networking Group (?) that would promote Amateur Radio networking technology, and especially, promote existing Amateur Radio networks.

  • A substantive reference - Amateur Radio Network Reference (?) - An authoritative web page with substantive references to Amateur Radio (specific) network technology, and a directory of existing Amateur Radio networks. A techie, or Amateur Radio Operator, or a regulator should be able to reference this page to “get up to speed” on Amateur Radio networking. I’m not minimizing that organizing such a page would be a huge amount of work. Fortunately, a lot of the references can be pointers to articles, books, etc. that exist in Digital Library of Amateur Radio & Communications.

  • A substantive publication - Amateur Radio needs some kind of reference publication that’s dedicated to Amateur Radio networking, or perhaps just narrowly focused on Amateur Radio technologies relevant in the 21st century. Something on the scale of ARRL’s QEX… but again, focused on networking.

In my opinion, there are two organizations that could be parts of the solution, especially if they combined forces to implement all of the above.

The Potential Organizations for Doing Something Differently, Soon

ARRL

ARRL has a history of convening working groups within Amateur Radio that involve not just individual Amateur Radio Operators and ARRL personnel, but also Amateur Radio industry personnel. One example was the ARRL Future Systems Committee, which tried to look ahead a decade or more about technologies that were relevant to Amateur Radio, such as Spread Spectrum and Digital Signal Processing. Another example was that (if memory serves), ARRL convened the committee which developed the AX.25 protocol. TAPR was involved in later versions of AX.25 (including Version 2.2?).

The most recent example of ARRL convening a working group to tackle a significant issue in Amateur Radio is the ARRL Clean Signal Initiative:

ARRL’s New Program to Improve Amateur Transmissions

The Clean Signal Initiative (CSI) builds on ARRL’s roles in amateur radio education and technology. Key objectives of the CSI are developing specifications and test procedures that will influence equipment design and manufacturing, and educating amateurs regarding signal purity (avoiding and overcoming poor-quality signals).

CSI brings together ARRL Laboratory staff with member-volunteers, manufacturers, and independent technical advisors with extensive amateur radio design and testing expertise. Together, their work will drive improvements to transmitter and amplifier signal purity, and to help educate amateurs on their use.

In addition, ARRL has dedicated editorial staff that could publish an Amateur Radio publication similar to Internet Protocol Journal, but targeted specifically at Amateur Radio networking. Unlike other ARRL publications, an “Amateur Radio Networking Journal”5 should be published outside of the ARRL paywall. See below for the financial aspects of such a publishing model.

Lastly, ARRL has a long term program / role of interaction with the FCC. If there was a dedicated new organization, substantive reference, and a substantive publication, that would be a powerful “tool” with which to engage the FCC about the continuing relevance of Amateur Radio in the 21st century, rather than just “Amateur Radio, when all else fails” that has been the primary justification for Amateur Radio for the past century.

ARDC

Disclaimer: I am a volunteer for ARDC on one small committee, focused solely on one task - see Grants Communications Team. In mentioning ARDC in this section, I’m not “speaking” for ARDC. The discussion below about involving ARDC in this potential project is solely my own perspective.

ARDC also has a history of convening working groups within Amateur Radio that involve individual Amateur Radio Operators and ARDC personnel. This is most notable in the significant evolution of 44Net, and the creation of 44Net Connect over multiple years, guided by ARDC’s Technical Advisory Committee (TAC).

There are multiple potential points of involvement by ARDC on “Doing Something Different, Soon”.

First, ARDC’s entire orientation is right in the organization’s name - Amateur Radio Digital Communications. ARDC’s “DNA” is entirely about Amateur Radio communications created in the 21st century (and late 20th century). The genesis of ARDC was the potential to integrate (then new) Amateur Radio Packet Radio technology and networks with the (then) newly emerging Internet. Thus ARDC’s involvement would bring the perspective of modern Amateur Radio communications, specifically networking, to a partnership to “Do Something Different, Soon”.

ARDC as a grantmaking organization has the ability to financially support a project to “Do Something Different, Soon”, such as:

  • Financially support the publication of an “Amateur Radio Networking Journal” by the editorial staff of ARRL. For example, the editor of QEX is a contract employee specifically for that role.

  • Financially support the expenses of in-person meetings of an Amateur Radio Networking Working Group6 (typically in conjunction with Amateur Radio events such as Hamvention, Hamcation, Pacificon, etc.).

  • Financially and technically support the creation and operation of an independent website reference for Amateur Radio networking.

  • Financially and organizationally support Amateur Radio Networking media relations / outreach that would be independent of both ARRL’s and ARDC’s specific missions.

With ARRL and ARDC jointly supporting an Amateur Radio Networking Working Group, they could jointly invite other Amateur Radio organizations or projects in, such as TAPR, APRS Foundation, Open Research Institute, MMVDM, IP400, New Packet Radio, etc.

Jointly, ARRL and ARDC could publicize, to their respective audiences, including regulatory agencies, that Amateur Radio remains relevant in the 21st century with examples of progress from “Do Something Different, Soon”,

I welcome anyone to contact me to discuss these ideas, including at Hamvention 2026, Zero Retries Digital Conference 2026, and Pacificon 2026.

Please direct comments / feedback about this article to the Zero Retries email list with the #ZR0249 hashtag.

Announcing Project Argus

By George Zafiropoulos KJ6VU

Editor’s Note

I am privileged that KJ6VU offered Zero Retries the opportunity to be the first to publicly discuss Project Argus - a real scoop! This will be a very interesting capability to provide “ground truth” of repeater activity for repeaters.

Image courtesy of Sierra Radio Systems

At Hamvention 2026 in a few weeks, Sierra Radio Systems (SRS), in conjunction with RepeaterBook will unveil a new SRS product and and a new capability for RepeaterBook to display realtime statistics of a particular repeater.

Project Argus is a hardware monitoring solution that you can connect to your repeater or, alternatively a monitoring radio, that observes when the repeater is keyed up. The device sends the keyup date/time stamp and unkey date/time stamp to the RepeaterBook database and the repeater owner can either see the data privately or post the activity on the public RepeaterBook web site.

Why do this?

This will provide a repeater activity metric so when you go to a location you can see on RepeaterBook what repeaters are active.

When a module is installed at a repeater, in addition to the keyup info, a DC voltage and temperature can also be monitored and provided to the repeater owner.

The hardware is like a mini-station controller module. It is also compatible with other SRS Station Controller modules so you can use it for that as well. We will be demonstrating the system and selling the hardware at Hamvention 2026.

image.png
Graphic for display at Hamvention 2026 - courtesy of Sierra Radio Systems

Here is a picture of the board:

image.png

Please visit our demonstration at Hamvention 2026 at Booth 3012 (Sierra Radio Systems / PackTenna / Ham Radio Workbench Podcast) in Building 3 (Marconi).

Garrett Dow KD6KPC from RepeaterBook will be demoing RepeaterBook and Project Argus at RT Systems in Booth 3804-3805 in the same building.

Editor’s Postscript

This is a really unique capability. We’ve had bits and pieces of such a capability since we’ve had microprocessor controlled repeater controllers, but no way to make that info easily, publicly accessible, so kudos to SRS and RepeaterBook for this powerful collaboration.

What makes this possibility really interesting is the possibility of integrating it with a ka9q-radio receiver system that can be configured to receive all channels on a VHF / UHF band simultaneously. That would create the possibility of an “area repeater activity map” such as “222-225 Repeater Activity in Bellingham, Washington”. Such information would be really useful for new Amateur Radio Operators to see, at a glance, where the active repeaters are instead of having to monitor for themselves (and often, with only an inexpensive portable radio with the included (poor) antenna.

I followed up with some questions for KJ6VU:

Q1. Could this capability be also used for a website, like a club’s website, other than RepeaterBook?

A1. Yes. RepeaterBook is developing APIs that could allow an external web site to subscribe to the data that we are gathering from an Argus unit. They could then take that data and display on their own web site. More to follow on this capability in the coming months.

We will be expanding this to supporting other station controller modules as well.

Q2. For remote monitoring, I assume this just makes use of audio output of a speaker? So it would work equally well with digital voice, as long as you have a compatible radio?

A2. The sensor inputs are...

  • Digital input (pull to ground on an optoisolator)

  • DC voltage measurement from 0-60 volts

  • Temperature (digital temp sensor on a cable)

By default when the digital input pulls to ground this is an event that is sent to the RepeaterBook server, and the unkey as well.

For remote monitoring the easiest thing would be to take a radio like just about any Yaesu with a [10] pin MiniDIN and wire the digital input up to the COS output and you are good to go.

On a digital radio as long as you get a pull to ground indication, that will work. It’s possible to configure another input like the voltmeter to also trigger the event which can be useful to measure a high logic state going to a digital radio’s LED or whatever to sense carrier presence.

Q3. It would be cool to provide a “big picture” view of, say, a website like “Bellingham Area Repeater Activity” that uses a ka9q-radio “receive all channels simultaneously”.

A3. Your description is what we hope will happen with RepeaterBook. When you look up Bellingham repeaters, you’ll see the relative activity of all the repeaters listed there (assuming they’re all instrumented with a Argus unit). The difference from your idea is that each repeater will be reporting their activity individually (and independently) instead of with just one ka9q-radio.

In addition to the repeater activity application, the Argus unit can be used to monitor and control just about anything. If more sensors and of different types are needed, the other station controller modules can be used.

We are also developing two energy monitoring modules (not available until later this year) to monitor AC power (voltage, current, kWh, frequency) and DC power (Voltage, current, state of charge for SLA and LiFePo4 batteries).

…

I think Project Argus is a very cool new capability for repeaters, and I look forward to seeing it demonstrated at Hamvention 2026.

Please direct comments / feedback about this article to the Zero Retries email list with the #ZR0249 hashtag.

The Quiet Resurgence of RF Engineering

By Anthony Templeton, as published on Anthony’s Blog

Original article link - atempleton.bearblog.dev/quiet-resurgence-of-rf-engineering/

Editor’s Note

I rarely excerpt an entire article in Zero Retries. I endeavorer to adhere to fair use principles and excerpt only small parts of content from other authors. In such excerpts, I encourage Zero Retries readers to visit the author’s site to read the entire article. In this case, I consider this article to be the rare exception of exceptional relevance to the mission, and the readership, of Zero Retries.

This article, and Templeton’s overall perspective on radio technology careers is a rare example of distilled wisdom on a subject.

In my opinion, Templeton’s observations, and analysis is entirely accurate about the situation about US industry and government’s need for more radio technologists.

The Quiet Resurgence of RF Engineering

14 Apr, 2026

I’ve worked in the aerospace industry for the past 8 years, and for most of that time I felt like I could confidently say that RF engineering felt like it was a quiet, non evolving field. The advice I heard early on, and that I watched a lot of other people follow, was to go into software. Machine learning, cloud infrastructure, web development. That’s where the growth was, that’s where the money was, and honestly, that’s where most new graduates went (myself included at the time). I studied Information Systems in college, not electrical engineering. RF was nowhere on my radar.

But aerospace has a way of pulling you into hardware whether you planned on it or not. I started my career at NASA, building telemetry platforms, ETL pipelines, and spacecraft visualization tools. Pure software work. Then I moved to a private aerospace company. Much smaller than NASA (approx 130 employees at the time I joined), and it required me to wear a ton of hats to work on ground systems. That’s where things shifted. When you’re responsible for ground station services, even when most of it now is software defined you can’t stay in the software lane entirely. I found myself doing link budget analysis, troubleshooting RF anomalies, and developing a working understanding of the RF hardware chain that I never expected to need.

That experience is part of why I’ve been paying attention to what’s happening in RF more broadly. I’ve been feeling a shift over the past several years — more demand, fewer people, and more urgency from the companies I talk to. RF engineering is not only alive, it’s rebounding in a significant way. I wanted to dig into whether my gut feeling here is actually backed by data, or if I’m just seeing what I want to see from inside the aerospace bubble.

What Actually Happened to RF

To be fair to the people who called RF a shrinking field, they weren’t wrong, at least for a stretch. After the dot-com bust in the early 2000s, the telecom industry consolidated hard. Companies merged, manufacturing moved offshore, and a lot of RF design work either disappeared or got absorbed into a handful of large defense contractors. The broader electrical engineering job market stagnated. Electronic Design has documented this trend not just for RF, but across EE as a whole. I feel confident that if the field as a whole is shrinking, then the subfield of RF was also in decline.

And then software exploded. The engineers who might’ve gone into EE or RF design a generation earlier went down the software “FAANG” route instead. University enrollment in RF specific coursework drifted down. Though I’ll be honest, hard numbers on this are annoyingly hard to find so this is more of my gut assumption. What we do know is that today, companies openly describe the difficulty of recruiting RF engineers, pointing to a generation that chose software over EE.

But here’s the thing that gets missed in the narrative: it never actually went away. The defense sector has been keeping it alive this entire time. Raytheon, Lockheed Martin, Northrop Grumman, these companies never stopped hiring people who understand beam patterns, power amplifiers, and antenna design. The majority of RF engineering job postings have historically come from aerospace and defense. RF didn’t die. It just receded from the civilian sector while quietly remaining essential to national security and defense.

So What Changed

The resurgence didn’t come from one place. It’s coming from several industries all hitting the same wall at roughly the same time; a shortage of engineers who can work at the hardware level.

The Space Boom

This is the one I see most directly in my work, and it feels the most dramatic. In 2015, roughly 260 spacecraft were launched into space globally. By 2024, that number hit approximately 2,695. A 10x increase in under a decade. The overwhelming majority of that growth came from commercial constellations, with SpaceX’s Starlink deploying over 1,500 satellites in 2023 alone.

Every single one of those satellites needs RF hardware. Starlink operates in Ku-band for user links and Ka-band for gateways, with V-band planned for Starlink V2. Kuiper and OneWeb follow similar architectures in Ka-band. Each spacecraft carries transceivers, antennas, filters, and amplifiers — and each ground station that talks to them needs the same. The amount of RF hardware per spacecraft adds up fast, and the launch cadence isn’t slowing down.

The money tells the same story. The global space economy hit a record $613 billion in 2024, with commercial making up roughly 78% of that. The space based RF market alone was valued at $18.6 billion and is projected to nearly double by 2033.

And it’s not just commercial. On the defense side, the Space Development Agency is building the Proliferated Warfighter Space Architecture — a LEO constellation targeting 500+ satellites. Only a few dozen are on orbit today, but nearly $35 billion has been committed through 2029. Even with the growing push toward optical links, these spacecraft still carry RF communications hardware and telemetry payloads, and that is unlikely to change anytime soon.

5G Wide Adoption

I think 5G’s impact on RF demand is genuinely understated. A typical 4G base station has 2 or 4 transmit-receive chains. A 5G MIMO radio integrates anywhere from 64 to 256. That’s an 8x to 16x increase in the power amplifiers, low-noise amplifiers, and antenna switches needed per installation. Multiply that across 642 operators and 374 commercial launches, and you start to see why the RF component market is pushing toward $50 billion with no signs of stoppage.

The design challenges make it worse. Millimeter wave frequencies introduce path loss that demands arrays with manufacturing tolerances at the millimeter scale. Additionally, thermal management, ex. dissipating 300+ watts from tower-mounted hardware with passive cooling, isn’t something you can solve reliably in software.

6G Is Already In The Works

It’s early, but 6G isn’t vaporware. 3GPP has been actively working on 6G study items since 2024, with first specifications targeted for late 2028 and commercial deployments expected around 2030. The EU, South Korea, and major telecom players like Ericsson, Nokia, and Samsung are all investing heavily into this research.

The RF challenges are genuinely new territory. Sub-terahertz frequencies and integrated sensing and communication (ISAC), which 3GPP officially scoped into 6G in the middle of last year, push well beyond what current design tools can handle. Worth noting though — the original vision for sub-THz has already been scaled back from outdoor cellular to mostly short-range indoor use cases like data centers and factories. But even with a narrower scope, all of this research eventually has to become hardware, and the people who know how to do that are already stretched thin.

The “Drivers” That Don’t Get Headlines

Space and cellular seem to dominate the conversation, but there are quieter contributors that I think are what make this feeling more durable rather than cyclical.

Automotive radar is a sneaky one. The EU now mandates automatic emergency braking in all new vehicles and, while the regulation is technically sensor-agnostic, most implementations rely on radar. Every new car with adaptive cruise control or collision avoidance has RF hardware running on board. That market alone is projected to hit $7+ billion this year. Then there’s Wi-Fi 7, operating across three bands simultaneously, and the ever expanding IoT landscape with over 21 billion connected devices as of 2025. Anything that communicates wirelessly needs RF work behind it, and that list just keeps growing.

The Talent Shortage

What makes this an interesting pattern, is that the supply side is genuinely broken. IEEE survey data shows 73% of EE employers can’t fill positions within six months, up from 45% five years ago. EE Times has reported specifically on the RF talent gap and its growing demand.

And it’s not just direct competition for RF roles either. RF and semiconductor careers often pull from the same shrinking pool of EE graduates, and right now the semiconductor side is in a hiring frenzy of its own. The CHIPS Act has poured billions into domestic fab expansion, AI chip demand is exploding, and the semiconductor industry is projecting a 67,000 worker shortfall by 2030. All of that competes directly with RF employers for the same talent. When everyone is fighting over the same small group of EE grads, RF companies, which tend to be smaller and less visible than the big chip fabs, often lose out.

Salaries reinforce this. Average RF engineer comp is pushing past $130K, with top-end design positions listing above $200K.

The real signal to me is what companies are doing about it. Mini-Circuits and Keysight are investing directly in university partnerships because they can’t wait for the academic pipeline to refresh itself. Baylor launched a new Graduate Certificate in Microwave/RF Engineering in 2024, one of the few new programs I’ve seen pop up, but I imagine it won’t be the last. When industry starts building its own talent pipeline, that tells me the shortage isn’t a blip.

Looking Forward

I don’t want to oversell this. I don’t think RF is going to become a field with an insane growth pattern. The BLS projects 7% growth for EE broadly, faster than average sure, but not a hockey stick. The demand is real, it’s coming from multiple directions at once, and the supply is genuinely constrained.

My own path is a small version of this story. I came in as a software engineer and had to learn RF on the job because there wasn’t someone else to hand it off to. I say this as someone who made that transition, you absolutely can learn enough RF to be effective in your role, and I’d encourage anyone in aerospace or wireless to do it (honestly it’s a fun niche to get into anyway). But there’s a difference between understanding link budgets and SDR anomalies versus designing a phased array from scratch. The latter takes years of dedicated focus. The underlying physics (electromagnetics, thermodynamics, materials science, manufacturing tolerances) don’t reduce to algorithms. You have to build intuition for it, and that’s not something you can shortcut.

I may one day expand on learning this stuff on the job and on the fly, but I do want to shoutout PySDR. It’s a free resource built exactly for software engineers. It uses Python as the bridge between hardware and software concepts, and starts with no RF knowledge assumptions from the beginning and doesn’t spend a ton of time over explaining the math.

The people who stuck with RF through the lean years are now some of the most sought-after engineers I’ve come across. And for anyone trying to figure out where to focus, either as a primary discipline or as a secondary skill set like it was for me, I think RF is worth a serious look right now.

Who Am I?

Anthony Templeton is a software engineer passionate about high-performance computing and aerospace applications. You can connect with me on LinkedIn or check out more of my work on GitHub.

…

Editor’s Postscript

I think Templeton absolutely nails this subject. I have covered this subject in the past, most notably about the “Spectrum Workforce” in this (compilation) article that first appeared in Zero Retries - Amateur Radio and the Growth of the Spectrum Workforce in the US National Spectrum Strategy.

One small portion of the radio technology industry that I think Templeton missed (though he mentioned Internet of Things) was the embedding of radio technology into things that just weren’t possible even a decade ago. Two examples in my own life is my BiPAP machine has an embedded cellular modem that I don’t pay anything for - the service costs were apparently embedded into the purchase price. Another is the Bluetooth radio that’s embedded into my Continuous Glucose Monitor, which I replace every two weeks (and I’m instructed to throw away). Another is wireless transfer of low power which will eventually allow the embedding of sensors into situations where batteries or external power aren’t practical… such as strain gauges embedded into critical walls to monitor for excessive stress or impending failure, or monitor for water ingress, or air quality in complex ductwork. Lastly… I can’t wait for the radio (RADAR) equivalent of a thermal scanner so a DIY homeowner can finally see what’s inside a wall before cutting into it.

While I agree with the author’s mention of PySDR, I was surprised that he also didn’t mention the GNU Radio framework for learning about Software Defined Radio. If an early or mid career Electrical Engineer wants to get a crash course in SDR, I don’t think you could do better than attending one of the annual GNU Radio Conferences.

This is a slide from a recent presentation I gave at LinuxFest Northwest trying to “evangelize” Amateur Radio to (Linux, in this case) techies:

So… Why Bother With Amateur Radio?

  • It gives you hands on experience with radio technology

  • Radio isn’t magic, and it’s not just an API call or a library

  • Radio is weird, much weirder than wired networks

  • If you understand how radio works at the physical level, you can do a better job with your software and your systems

  • Wi-Fi, Bluetooth, NFC, LoRa, cellular are all black boxes

  • Amateur Radio lets you really learn about radio technology

I think that Amateur Radio could have a substantive role in cultivating interest in young techies about radio technology, potentially leading to a career in engineering, and hopefully radio (RF) engineering. We’re making some progress on that score, but nothing systemic, at scale, yet. Perhaps my proposal in my earlier article will be a start at such systemic promotion, at scale.

Please direct comments / feedback about this article to the Zero Retries email list with the #ZR0249 hashtag.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

The SARC Communicator: May-June 2026

Amateur radio has always been a pursuit of contrasts—venerating the past while racing toward the future. This issue celebrates that duality from cover to cover.

We begin with history: Harry Melville Dowsett, the architect of practical radio, and the curious case of author Zane Grey’s on-air adventures in Tahiti. Then pivot sharply to the present—AI’s creeping influence, TETRA digital tech, California’s controversial Bill AB 1043 that may affect you, and a look at the ARRL’s struggle in the digital age.

Our technical deep dives range from the IC-9700’s capabilities for digital modes to rebuilding the Icom IC-PW1 amplifier to building a vertical HF antenna without radials. For the space-minded, we track LEO satellites, pico balloons, and the mysterious Judica-Cordiglia recordings (fact or fallacy?). And don’t miss the Baker Street walkie-talkie heist or British Columbia’s 2026 QSO Party wrap-up,

Need something lighter? Check page 13’s News You Can Lose, try using a bluetooth speaker IKEA-style, exploring POTACat, or enjoying a classic Spam fritter and mash recipe (yes, really).

Don’t miss the run-up to the FIFA World Cup Special Event Stations and learn how to participate.

I cannot say enough about this (in my opinion, exceptional) issue of The Communicator. There are about ten articles in this issue that I want to read, thoroughly, to learn about Zero Retries Interesting topics. This issue is now queued into my tablet reader for a block of time that I can read, slowly and carefully, to learn more (that I didn’t write) about technological innovation in Amateur Radio.

I wrote this to a correspondent explaining why I think so highly of The Communicator:

Many think “magazines” are something whose time has passed, but The Communicator is an Amateur Radio magazine reimagined for the 21st century - free, easy to read and portable between devices PDF format, and an overall mix of good articles about operating, technical topics. The Communicator imparts an overall sense that Amateur Radio is fun and interesting.

I consider the length, and the content, and the overall quality of The Communicator to be a remarkable achievement. Thus it’s my go-to recommendation when I encounter someone who’s curious about Amateur Radio. I refer them to the Communicator website to download a current issue for them to have a better idea of what Amateur Radio is about.

Each issue of The Communicator seems to get better, and better. Kudos, again, to The Communicator’s stellar and capable Editor John Schouten VE7TI. That said, this issue is exceptionally Zero Retries Interesting (disregarding that I’m one of the contributing columnists).

FreeDV vs Thunderstorm [Atmospheric Noise]

FreeDV blog / web page:

Rick, W7WC, recently emailed me with this impressive example of RADE v SSB during an electrical storm:

I thought you would like to hear a comparison of RADE V1 vs. SSB reception during a recent noisy evening on 80 meters.

We had a line of thunderstorms a few hundred miles long, creating an intense impulse noise environment. Communication is via an NVIS path between my station and a friend about 70km away.

Quite remarkable! Thanks for making all this possible.

I was unable to embed the audio clip, so click the title link for that. The first half of the recording is analog and barely understandable. The second half is FreeDV and it’s slightly robotic, which I attribute to the Forward Error Correction having to be used extensively, but it’s perfectly understandable.

FreeDV RADE is an open source digital voice mode specifically designed for communications via HF and its vagaries - atmospheric noise, fading, etc. RADE is Radio Autoencoder - machine learning techniques applied to digital voice for HF.

I think it’s notable that this is using FreeDV RADE v1, and the FreeDV developers are working on more advanced versions.

I Built an FM Receiver With One FPGA Input Pin

Brian Greenforest on LinkedIn:

Not “one-chip radio.”
Not “a tiny SDR module.”

One input pin receives the RF.
The FPGA threshold turns it into a transition stream.
Four-phase sampling recovers quadrature structure.
XOR logic handles mixing.
A CIC filter downsamples.
A cross-product demodulator recovers FM.
Sigma-delta output produces audio.

What disappears?

No strong external local oscillator spraying around the board.
No conventional analog mixer front end.
No RF/IF amplitude-preserving ADC.
No sine/cosine lookup tables.
No atan2 phase extractor.

The question was not “can I make a toy FM receiver?”
The question was:

How much of radio is actually necessary?

Turns out: less than the inherited stack tells you.

Full writeup in the comments

Talk about digital radio technology…

I met Greenforest after my presentation at LinuxFest Northwest here in Bellingham last Sunday. He told me this story in passing, and I was agog, but now you can be too.

Apparently Greenforest’s LinkedIn post is the only place their accomplishment is written up, so click the title link for more detail.

Amateur Radio to Participate in DoD Armed Forces Day Crossband Test on May 9, 2026

ARRL website 04/25/2026:

Amateur radio operators will participate in the Department of Defense’s Armed Forces Day (AFD) Crossband Test on May 9, 2026. The annual event will not impact any public or private communications.

For more than 50 years, military and amateur stations have participated in this interoperability exercise between the amateur and government radio services. The AFD Crossband Test provides a unique opportunity to conduct two-way communication between military communicators and stations in the Amateur Radio Service (ARS), as authorized in 47 CFR 97.111. These tests present both opportunities and challenges for radio operators to demonstrate individual technical skills in a tightly controlled exercise scenario.

ARRL The National Association for Amateur Radio® hails the Armed Forces Day Crossband Test as an example of the core principles of the US Amateur Radio Service, with its volunteers contributing technical proficiency and readiness in support of public service and national needs.

Military stations will transmit on selected military frequencies and will announce the specific ARS frequencies they are monitoring. All times are ZULU (Z), and all frequencies are upper sideband (USB) unless otherwise noted. An AFD message will be transmitted using the Military Standard (MIL-STD) Serial PSK waveform (M110), followed by MIL-STD Wide Shift FSK (850 Hz RTTY), as described in MIL-STD 188-110A/B. Technical information regarding these waveforms is available at drive.google.com/drive/folders/1pYDj7kQbm-QAyY4RPtx0dOXKohjaEjq9?usp=sharing.

To document your contacts with a QSL, visit: www.usarmymars.org/events-and-announcements and complete the request form.

The US Naval Academy Amateur Radio Club, W3ADO, will activate the historic NSS call sign during the Crossband Test. Several Naval Academy midshipmen and members of the Potomac Valley Radio Club (PVRC), including team leader Frank Donovan, W3LPL, will be operating on the grounds of the former US Navy radio transmitting facility in Annapolis, Maryland. PVRC is an ARRL Affiliated Club.

This annual exercise / test is a unique opportunity to demonstrate that Amateur Radio and US military can interoperate in emergency communication situations.

It’s notable (and Zero Retries Interesting) that the communications between Amateur Radio are apparently data communications rather than legacy CW or analog voice communications.

See the title link for more detailed information.

2025 Bill Orr, W6SAI, Technical Writing Winners Awarded

John E. Ross KD8IDJ, Editor in the 2026-04-30 issue of ARRL Letter:

The ARRL Foundation’s 2025 Bill Orr, W6SAI, Technical Writing Award has been awarded to Dr. Ethan Miller, K8GU, and Dr. Nathaniel A. Frissell, W2NAF, for their August 2025 QST article, “About Traveling Ionospheric Disturbances.”

The editors of QST nominated Miller and Frissell in August 2025, the ARRL Foundation Board approved the awards in January 2026, and the award plaques were distributed to Dr. Miller and Dr. Frissell last week. The award is an annual honor presented by the ARRL Foundation to recognize outstanding technical writing in the amateur radio community.

See the title link for the bios of the two winners.

Zero Retries congrats to K8GU and W2NAF for doing great technical writing (and technological innovation…) in Amateur Radio!

Info on Reporting Interference from AST SpaceMobile on 420-450 MHz (70cm) Band

John E. Ross KD8IDJ, Editor in the 2026-04-30 issue of ARRL Letter article:

FCC Approves Limited Emergency Use of 70 cm Band by AST SpaceMobile Satellites Outside the US

adds some information about what to do to report any interference that’s experienced from AST SpaceMobile in the 420-450 MHz (70cm) Amateur Radio band.

After considering the filed comments, the FCC narrowed the requested authorization to emergency TT&C only and further provided that:

  • Use of these frequencies is permitted only in emergencies when no other spectrum is available

  • Each emergency event is limited to no more than 24 hours

  • Transmissions are restricted to five specific center frequencies (430.5, 432.3, 434.1, 435.9, and 439.5 MHz), each with no more than 50 kHz bandwidth

…

In the US, reports of suspected interference to amateur spectrum can be shared with the ARRL Regulatory Information Manager, email reginfo@arrl.org.

Thus, if there is any use of those frequencies by AST SpaceMobile that are outside those specific frequencies, with a bandwidth greater than 50 kHz, that would be notable to record and report.

It’s solely my impression, but I think it’s a reasonable inference that those limits were imposed because several Amateur Radio Operators in Europe recorded the transmissions of AST SpaceMobile’s test satellites, and made that info public. From that public reveal and that info filed with the FCC, it seemed obvious that AST SpaceMobile wasn’t attempting to minimize interference, and were routinely using the 420-450 MHz band (430-440 MHz in Europe).

Thus that “record” part, if anything outside what they’re authorized to do is observed, is critical to be able to effectively protest against AST SpaceMobile’s unauthorized use of 420-450 MHz.

The GPS III Rollout Is Almost Complete, But What Is It?

Tom Nardi in Hackaday:

…

But in the coming years, that’s finally going to change. Just last week, the tenth GPS III satellite was placed in orbit by a SpaceX Falcon 9 rocket. Once it’s properly configured and operational, it will join its peers to form the first complete “block” of third-generation GPS satellites. Over the next decade, as many as 22 revised GPS III satellites are slated to take their position over the Earth, eventually replacing all of the aging satellites that billions of people currently rely on.

…

While modern GPS receivers are more sensitive than those in the past, there’s simply no getting over the fact that signals coming from a satellite more than 20,000 kilometers away will be by their very nature weak. So not only is it relatively easy for adverse environmental conditions to block or hinder the signal, but it doesn’t take much to override the signal with a local transmitter if somebody is looking to cause trouble.

As such, one of the key goals of the GPS III program was to deliver higher transmission power. This will lead to better reception for all GPS users across the board, but the new satellites also offer some special modes that offer even greater performance.

In addition to the backwards compatible signals transmitted by GPS III satellites, there’s also a new “Safety of Life” signal. This signal is transmitted at a different frequency, 1176 MHz, and at a higher power, so compatible receivers should hear it come in at approximately 3 dB above the “classic” signal. It’s intended primarily for high-performance applications such as aviation, but as compatible receivers get cheaper, it will start to show up in more devices.

…

The new signals being transmitted by GPS III satellites won’t just be louder than their predecessors, they’ll gain some new features as well.

For one thing, GPS III satellites will transmit a standardized signal known as L1C which offers interoperability with other global navigation systems such as Europe’s Galileo, China’s BeiDou, the Indian Regional Navigation Satellite System (IRNSS), and Japan’s Quasi-Zenith Satellite System. In theory a compatible receiver will be able to process signals from any combination of these systems simultaneously, improving overall performance.

The new satellites will also support the L2C signal. While this signal was technically available on earlier generation satellites, it’s still not considered fully operational and its adoption is expected to accelerate as more GPS III satellites come online. Compared with the legacy GPS protocol, L2C offers improved faster acquisition of signal, better error correction, and a more capable packet format.

This is a great article about the enhanced capabilities of GPS III, which will inevitably affect, and eventually improve Amateur Radio such as improved time synchronization and likely eventually embedding GNSS capability into every radio… because it’s so (increasingly) capable and practically free.

This is further justification that the substantial disruption proposed by NextNav’s radical, incredibly disruptive, and proprietary reconfiguration of the 902-928 MHz Band is unwarranted and unnecessary. See Zero Retries 0193 - The Threat to the US 902-928 MHz (33 cm) Band from NextNav. (Disclaimer - it’s very long and very detailed, but there is a detailed “skip to the relevant parts” table of contents.)

RTL-SDR 433: A New Android App For Decoding 433 Mhz Sensors With rtl_433

RTL-SDR blog:

Thank you to Christian Ebner from ebcTech, who has submitted news about his newly released Android app RTL-SDR 433, which lets you run the rtl_433 decoder directly on your phone using an RTL-SDR dongle connected via a USB OTG cable.

The app bundles rtl_433 as a native Android library and supports all 258 device protocols out of the box, including weather stations, TPMS, wireless doorbells, PIR motion sensors, energy meters, door/window contacts, and remote sockets. Decoding runs entirely on-device with no internet connection required, no root, and no special drivers. It uses the standard Android USB Host API together with a libusb Android port.

The UI is built with Jetpack Compose and Material 3, and shows a live list of unique sensors with expandable cards (temperature, pressure, RSSI, raw JSON) plus a full history log. The app is free to try with a decreasing per-session reading limit, and a one-time purchase for a few dollars removes the limit permanently.

We note that the GPL-licensed native layer (rtl_433, rtl-sdr, libusb Android port and EBC’s integration glue) is published openly at github.com/ebc81/rtlsdr433-native-gpl in compliance with GPL-2.0, while the UI layer remains closed-source.

More information about the app is available on the ebcTech page at https://ebctech.eu/rtl-sdr-433-android.

This seems like a cool app, more approachable than some “radio hacking” tools. It would be fun and useful to show off the number of radio-based “radio gadgets in daily life” are in your household, such as car unlock “clickers”7 and all the other devices named in the article. In fact it could be useful for troubleshooting. For example, I have a “garage door opener keypad” that I cannot make work. I’ve changed batteries, I’ve reprogrammed it with the garage door opener, and cannot make it work. It would be useful to see if the unit actually is transmitting. With this you could be a hero to friends and neighbors to be able to do some basic troubleshooting of their household wireless devices. (And, learn what you might disable of your friends and neighbors if you transmit at reasonable power on 433 MHz.)

Also, instead of using a phone for this app, there are low-cost Android tablets that might make using this app easier.

[Husky Satellite Lab - HSL} Newsletter: Spring 2026

“Husky” is the mascot (yes, the dog breed) of the University of Washington.

Cherry blossoms are in full bloom ver in these parts and with them an exciting new chapter for the Husky Satellite Lab (HSL). As campus wakes up for the season, our team is already in motion, pushing forward on some wickedly cool projects and missions.

Before we charge full speed into Spring, we’ve got some major updates to share from our latest endeavors and recent milestones heading into Spring 2026.

From NASA programs to new membership applications, let’s jump right in!

HS-2: Spring Interim Review and F’

No alternative text description for this image
Image of HS-2 Members (from left to right) Arin Kharkar, Henry Adams, David Magidson, and Yaj Jhajhria, at NASA’s Jet Propulsion Laboratory as part of the F’ Workshop.

Though HS-2 finished their PDR review in the fall, the team has not been slowing down! Throughout Spring quarter, HS-2 has been preparing for The Spring Interim Review (SIR), an interim review with our sponsors and mentors at The University Nanosatellite Program. In this presentation, the Payload, Electrical Power System (EPS), and Communications subsystems shared their current progress and received valuable feedback on key questions and areas for improvement.

In addition to these reviews, members of the HS-2 Division (as seen in the image above) had the opportunity to attend the NASA Jet Propulsion Laboratory Flight Software/F´ Development Workshop in Pasadena, California. There, they developed key skills in F´, a software framework designed for the rapid development and deployment of spaceflight, embedded systems, and instrumentation. The HS-2 team has since been sharing this knowledge with subsystem members and has begun implementing the framework across CubeSat software systems.

As Spring continues, much of their hardware is arriving, which means lot more activity in the lab as testing and system design for summer test assemblies.

I’m not so much highlighting the details of the University of Washington (though… they are the “home team” for collegiate Microsats)… as I am highlighting the method / communication methodology of the HuskySat team. They’re making brilliant (effective) use of Substack for communicating with their fanbase / supporters.

That said in my (objective, as I can be), the accomplishments of the HuskySat program have been impressive, in my opinion. Admittedly, I’m a bit biased for the home team.

Go Huskies - In Space!

Building the TinyDX – With a Little Help From AI

Chris Bolton M0KNF via Amateur Radio Daily 2026-04-28:

The TinyDX is a miniature FT8/4 QRP ~1W transceiver designed to be powered and operated via a USB connection to a smartphone/tablet running an FT8 app such as FT8TW for android or IFTX for IOS. It is able to operate on any 2 of the HF “high” bands, 20M, 17M 15M, 12M, 10M which are defined by the builder during the software configuration process. The TinyDx does not have CAT control but uses the transmit audio signal to switch the PA and receiver during the transmit/receive cycle. Band and mode are selected via 2 hardware switches on the main board.

Designer Barbaros (Barb) Asuroglu WB2CBA has shared the design on GitHub with all of the necessary fabrication files for the boards to be built and populated by the PCB manufacturer JLCPCB. The cost of having the boards built by JLCPCB is around £30 per set for an order quantity of 5 sets plus shipping. Choosing this option just leaves the individual to connect the pre-built boards together and load the bootloader and firmware as per the instructions on Barb’s blog.

The use of an AI as the “endlessly patient and knowledgeable Amateur Radio tutor” to figure out the problem with his unit(s) was instructive, and indicative of how useful AI can be.

I think that one of the “killer apps” for Amateur Radio will be a small radio like this that is connected to a “screen device” and powered and communicating via a USB-C cable and allows operation on an Amateur Radio exclusive band like 222-225 MHz (in North America). We have a similar capability with being able to flash AREDN firmware onto small travel routers, but that’s not quite as fun as being able to operate VHF / UHF. I had such a unit for the 420-450 MHz band once upon a time, but it was a prototype project by the manufacturer that wasn’t refined into a product.

My thanks to Amateur Radio Daily for mentioning this for inclusion in Zero Retries.

The ZBitx V2 Migration: Community Fixes For V1 Hardware Owners

G. Selvakumar VU3DXR in DXR Electronics Bits:

The zBitx community is buzzing with the release of the v2 software and hardware update by Ashhar Farhan (VU2ESE).While the new version promises to solve long-standing issues like receiver “chuffing” and the 24 kHz spur, the migration for v1 owners has proven to be a technical challenge. If you are seeing a “white screen” or unresponsive touch controls, you are not alone.

zBitx v2 Migration

Based on the latest discussions from the BITX20 Groups.io forum, here is the comprehensive guide to a successful upgrade.

…

What’s New in zBitx v2?

The v2 update is both a hardware revision and a software overhaul designed to decouple the user interface from the core radio.

  • Wi-Fi Architecture: The Raspberry Pi Zero 2W now acts as an Access Point (SSID:zbitx), and the front-panel Pico W connects via Wi-Fi.This replaces the old$I^2C$ link, eliminating the I2C “hogging” that caused CW keying lags.

  • Hardware Upgrades: The new retail units include a power switch, an in-built EFHW transformer, a passive FET mixer, and high-efficiencyAFT05MS004N LDMOS transistors.

  • 24 kHz Spur Fix: By shifting the clock and adding a center_bin parameter in hw_settings.ini, the BFO is moved outside the crystal filter’s passband.

Click the headline link for all update procedures.

This is a good, comprehensive overview of the process of updating a zBitx V1 to a “V1.5”8. In my opinion, this kind of compilation (kudos to VU3DXR for doing so) is something that HF Signals should be providing on their website (and direct email to [known to HF Signals] zBitx V1 owners that bought direct from HF Signals) rather than forcing zBitx V1 owners to wade through the email list to pick up all the little nuggets that VU3DXR has assembled in this article.

A mild caution about the DXR Electronics Bits website - you might want to turn on “Reader Mode” or some other kind of ad filter because the popup ads can be overwhelming and frustrate you trying to read the content. MacOS Safari’s “Hide Distracting Items” feature worked pretty well for me to create a clean printout of the procedure for tackling my zBitx V1 to “V1.5 upgrade” later this summer.

Earth Venus Earth (EVE) / EME Update and Call for Participation

Michelle Thompson W5NYV on Open Research Institute:

For the upcoming inferior conjunction of Venus and Earth, there is a growing community of amateurs that are bound and determined to get a communications signal bounced off Venus and received here on Earth. This is EVE. The inferior conjunction is when Venus and Earth are the closest together.* This is the right time to attempt this feat, and it happens only once every 18 months or so.

The channel is daunting. So, ORI, SBMS, and others, have put together a link analysis.

Everything can be found at https://github.com/OpenResearchInstitute/EVE

This includes the current link analysis Jupyter Notebook, and all the support files to make it run, and more. Such as, all the documents used to propose observing sessions at the “really big” dishes at Green Bank and Effelsberg.

What can we do now to help make good things happen?

We have a modulation and coding scheme designed especially for this channel.

But we need to test it BEFORE Venus whooshes by in October of 2026. We need to test it now. We’ve tested in simulation, sure, but we all know that’s not good enough.

We need to test it with the Moon. EME is a close enough channel. It doesn’t have the same Doppler spread that Venus has, because the Moon is “locked” to the Earth, but it does wiggle around a bit, and it is a very hard microwave channel.

There was some interesting followup discussion on the DSES (Deep Space Exploration Society) email list.

It makes me proud to be an Amateur Radio Operator that “we” could even contemplate such a challenge as Earth Venus Earth communication.

Hamlib Named Winner of the 2026 Amateur Radio Software Award

Amateur Radio Daily 2026-04-26:

The following is a press release from the Amateur Radio Software Award:

The Amateur Radio Software Award (ARSA) committee is proud to announce that the Hamlib project has been selected as the recipient of the 2026 Amateur Radio Software Award. This year’s award honors the outstanding work of the current core developers: Nate Bargmann (N0NB), George Baltz (N3GB), Daniele Forsi (IU5HKX), and Mikael Nousiainen (OH3BHX).

The annual ARSA award recognizes software projects that enhance amateur radio and promote innovation, freedom, and openness in amateur radio software development. Hamlib was selected for its long‐standing and essential role in enabling software to interface with transceivers and other controllable devices. For more than a quarter century, Hamlib has provided a unified, reliable way to send control commands and read device status. Despite its age, the project remains actively maintained, with new radios and devices added regularly. Hamlib continues to be the go-to library for both established and emerging amateur radio applications.

About Hamlib

Hamlib provides stable, flexible shared libraries that simplify the development of amateur radio equipment control applications. Many modern transceivers include serial (RS‐232, USB, etc.) or Ethernet/Wi‐Fi/Bluetooth interfaces that allow software‐based control. Hamlib abstracts these interfaces, making it significantly easier for application developers to interact with radios, rotators, amplifiers, and other controllable devices. From WSJT‐X and Fldigi to JS8Call, Log4OM, and CQRlog, today’s widely used amateur radio applications are built on Hamlib.

Nate Bargmann (N0NB) notes that “over the lifetime of the project there have been several principal developers. Its founder is Frank Singleton, VK4FCS. Stéphane Fillod, F8CFE, and until about a year ago Mike Black, W9MDB (SK), were successive principal developers.”

Bargmann reports that the current long‐term support branch will receive the 4.7.1 release in the coming weeks, adding support for new radio models and improving existing ones. Work on Hamlib 5 is also underway. The new major version will introduce some backward‐incompatible changes to isolate internal structures and align with modern best practices, including breaking the C ABI. Discussions are ongoing regarding potential API changes, and feedback from client developers is encouraged.

“There is no set date for a release of Hamlib 5.0.0,” Bargmann adds, “but hopefully within the next year seems possible.”

Learn more about Hamlib at https://hamlib.github.io/.

Special Event Station

To celebrate Hamlib’s selection as the 2026 award recipient—and to encourage nominations for the 2027 Amateur Radio Software Award—the ARSA committee will operate the special event station K7A from November 27 through December 7, 2026.

About the Amateur Radio Software Award

The Amateur Radio Software Award is an annual international award recognizing software projects that enhance amateur radio and promote innovation, freedom, and openness in amateur radio software development.

Award Committee

  • Claus Niesen, AE0S (since 2020)

  • Kun Lin, N7DMR (since 2020)

  • Rich Gordon, K0EB (since 2021)

  • Sebastian Delmont, KI2D (since 2026)

For nomination guidelines, event schedules, and information about past winners, visit https://arsaward.com.

When you really look at what Hamlib is, it’s a remarkable accomplishment that is one of the primary technical underpinnings of Amateur Radio, rarely noticed, lurking in the background of software interaction with radios.

Hamlib is a perfect illustration of the XKCD comic Dependency:

Image courtesy of xkcd.com - https://xkcd.com/2347/

With this award, the Hamlib developers have now been publicly thanked.

My thanks to Amateur Radio Daily for mentioning this for inclusion in Zero Retries.

Starlink. Ho-hum.

Eric Grumling K0JEG on his Grand Valley Aviation newsletter / website:

I’ve been watching Starlink build out their satellite constellation over the last few years. I’ve also been hearing plenty of good things about the company and the service. But the hardware price was always a little too much, and the data limits were a little too low. Well, this month that all changed. They dropped the price of the Starlink Mini terminal to $199 and increased the monthly usage limit on the $50 Roam plan to 100GB, a 50% increase. With my life hopefully settling into a little more normal routine compared to the last year (and getting my tax refund) I thought it was time to try them out.

…

I’m Bored.

Satellites used to be the stuff of science fiction (in fact the geosynchronous satellite concept was first proposed by Arthur C Clarke, and because of that the orbit where it takes 24 hours to complete on orbit is called the Clarke Belt). Today we not only take them for granted, we pretty much think they’ve been supplanted by superior, (under)ground based technology like fiber optics. Where the fiber runs it’s great. If you’re at home or work, having fiber is the best communications solution bar none. But if the fiber isn’t available then what? Wireless works but is hard to set up and limited in bandwidth. Starlink works pretty much anywhere with a clear view of the sky.

The fact that anyone who does ‘brainwork’ for a living can work pretty much anywhere on the planet is still a game changing event. The idea of cruising through Glenwood Canyon while downloading lossless music or live-streaming 4K dashcam footage (at the same time) is something that we almost expect but is still a little bit magical to those of us who remember the massive gaps in cell service between cities. Bringing a little piece of “the grid” to places where it wasn’t before will level up the rural access gap, lower prices through competition and open up new ideas that weren’t possible in areas that couldn’t get service without an expensive plant extension.

I made a phone call from one hand to the other, through a network of satellites moving overhead at 17,000 miles per hour. It worked exactly as expected. No drama, no delay, no sense of wonder. Just another day in the life. For fifty years we’ve been solving the same problem—how to make a scarce resource feel abundant. The only difference now is that we don’t notice when the problem’s solved.

This is a great Zero Retries Interesting casual explanation the evolution of satellite communication technology framed in the context of his purchase of a Starlink Mini (now priced at $199 in the US). Like K0JEG, satellites have always been part of my life (though I’m old enough to remember “Live via Telstar” banners on some television programs).

Two additions to K0JEG’s discussion:

  • You can “dial back” your Starlink Mini subscription to Standby service for $5 / month with (unmetered) 400 kbps connectivity and back to full speed on a month to month basis. It’s amazing how useful 400 kbps is.

  • He gives the impression that the Iridium system is outmoded, but that’s not the case any more as the entire satellite constellation was replaced several years ago with vastly more capable satellites, including new data modes and digital voice services.

I concur with K0JEG’s recommendation in the footnotes of the book Eccentric Orbits: The Iridium Story. I couldn’t put it down. It tells the astonishing story of how close Iridium came to being completely killed, and why Motorola pretty desperately wanted to kill it.

Also, see my “Starlink just works” story from 2023 - Meadow Day Experiments.

AMRAD Electronics

Zero Retries Interesting vendor / products - discovered in researching something else.

Leo Bodnar, Rubidium Standards, RF Instrumentation, Software Defined Radio…

Book - The Secret Life of Circuits

Michal Zalewski9 on his newsletter / blog Icamtuf’s thing:

Many of you follow this blog because of the regular features about electronic circuit design. Today, I’m happy to announce that I’ve been working with No Starch Press on The Secret Life of Circuits:

Image courtesy of No Starch Press

I think it’s an exceptional book. It’s the reference I wish I had earlier in my life: an accessible, in-depth exploration of how circuits really work, from the motion of electrons to the dark art of embedded system programming.

The book is meant for the inquiring hobbyist, including those who have tried to learn the craft and hit a brick wall. With 420+ pages and 290+ meticulously-crafted color illustrations, The Secret Life of Circuits focuses on modern problem-solving and emphasizes intuition over cryptic formulas.

It’s a reasonable assumption that this book will be of the same high quality as the author’s blog articles such as Radios, how do they work?.

I think books are still relevant in the 2020s and beyond. A well-written, tightly focused book, written from depth of knowledge of a subject, offers distilled wisdom that lets you get up to speed on a subject10.

Video - K7RAW MagNoodLoop DIY Antenna for 20-10m

I have been in awe of Rudi Wiedemann K7RAW’s encyclopedic knowledge of antenna theory that he shares so freely on his YouTube Channel Antenna Whisperer - K7RAW.

K7RAW came to my attention last October at Pacificon with his innovative Drone Scan 3D project / product. I’ve stayed in touch with K7RAW since then, and this is his latest project. It’s made mostly of PVC, pool noodles (yes, really) and conductive adhesive copper foil tape.

When I realized that the “plunger” at the top of the assembly is the tuning control… I thought that is completely ingenious, and yes, makes for a very inexpensive tunable magnetic loop antenna. (Making a mag loop antenna tunable is the hard, expensive part.) When I discussed this antenna with K7RAW, he revealed that not only is his “plunger” a tunable element, but its action is linearized. I’m looking forward to the next video where he describes how that’s done.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the #ZR0249 hashtag.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

My LinuxFest Northwest 2026 Talk Went Well

My talk last Sunday at LinuxFest Northwest went well, and seemed well received. My goal was to expose the attendees to aspects of Amateur Radio that would be most relevant to them such as Software Defined Radio (being able to transmit in wider portions of spectrum than the unlicensed bands) and that there are many aspects of Amateur Radio that were open source.

There were < 10 attendees that were Amateur Radio Operators, and only five or so Zero Retries subscribers. I’ll post my slide deck here on the Zero Retries website after a bit of reorganizing to create a dedicated page for my presentations.

Hamvention Ho!

2 weeks until Hamvention 2026
in Xenia, Ohio, USA...
Zero Retries / DLARC booth 1506
in Building 1 / Maxim

Weekends Are For Amateur Radio!

Vintage Computer Festival Pacific Northwest (VCF PNW) 2026 is this weekend in Tukwila, Washington (greater Seattle area). I had hoped to exhibit a working Packet Radio system to showcase vintage TNCs (such as TAPR TNC 2s), including radios. But it’s been an intensive couple of weeks and I just haven’t been able to put in the time necessary in N8GNJ / Zero Retries Labs to put together a working system. Thus my exhibit will just show a collection of “vintage” TNCs as a static display.

Post Publication Update - I developed a health bug of some kind on Friday. Out of an abundance of caution that I might be contagious, I decided at the last minute not to attend VCF PNW 2026. Apologies to those who were coming to see the Packet Radio exhibit.

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the #ZR0249 hashtag.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

Founding Members who generously support Zero Retries financially:
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Founding Member 0024 - Rob Bowser (SPOOLTENNA) (New 2026)

Numerous Annual and Monthly subscribers who also generously support Zero Retries financially!

You thousands of readers of Zero Retries without which there would be little point in publishing this newsletter.

The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries \ Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0249 was published on 2026-05-01. This issue was 16,512 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

The quoted article actually appeared in Amateur Radio Daily, April 24, 2026 - Linux Kernel Drops AX.25 and Amateur Radio Subsystem Support

2

“Ignorant of the situation” might be more technically accurate, but that’s a loaded term, and thus I choose not to use it.

3

Realistically, and I’m not being self-deprecating in this statement, Zero Retries, as the product of a single individual with no substantive organization behind it. Thus Zero Retries cannot really be considered an authoritative resource.

4

The relevance of Amateur Radio is what’s in question, as in “what does Amateur Radio do in the 21st century?”. The utility of Amateur Radio, in this era, is largely perceived as the potential for emergency communications. But I consider Amateur Radio’s utility for emergency communications to be increasingly in question - see Zero Retries Perspective on Emergency Communications (EMCOM) Capability in Amateur Radio.

5

“Amateur Radio Networking Journal” is, at the moment, an entirely imaginary title.

6

“Amateur Radio Networking Working Group” is, at the moment, an entirely imaginary name for an entirely imaginary group.

7

I remember that there was one situation where I parked my vehicle and I could not unlock it remotely (which turns off the built-in security system) and I thought that the battery in the “clicker” had died. It turns out that there was a security system in the building that I was parked next to that was swamping the low power signal from the “clicker”. When the vehicle’s security system was alarmed, the ignition was disabled and the horn blared. As soon as I pushed the vehicle away from the building about ten feet, the “clicker” worked again. Kudos to the engineer who designed the security system of the 1997 Dodge Dakota - I’ve never found a way to disable it.

8

It doesn’t seem (reasonably) possible to update a zBitx V1 to a full equivalent of a zBitx V2.

9

I think that the author might be Amateur Radio Operator K7TUF, but cannot verify that.

10

Brief story best offered as a footnote: After I was suddenly thrown into a job to administer a department of more than one hundred users, I was given the task of transitioning them to Windows 3.0 in a matter of months. I was completely out of my depth in administering Windows, and especially the nuances of networking Windows in a server environment. My salvation (and I mean that very literally) to be minimally competent for that project, was the book Windows 3.0 Secrets by Brian Livingston. I spent a two week vacation reading that book cover to cover. I learned the basics of what I had to do to successfully complete the transition of the department to Windows 3.0. Good books by good authors on a very specific subject are distilled wisdom. I still have that book - dog eared, with many Post-It tags, and highlighted portions of pages.

]]><![CDATA[Zero Retries 0248]]>https://www.zeroretries.org/p/zero-retries-0248https://www.zeroretries.org/p/zero-retries-0248Fri, 24 Apr 2026 23:15:12 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its fifth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is too big for email clients. Thus, it might be easier to read in a web browser - https://www.zeroretries.org/p/zero-retries-0248.

It’s easy and free to subscribe for your own copy of Zero Retries every week:

Subscribe now

In This Issue:

I-Frame

Breaking - Major Split in Development of MeshCore
Steve Stroh N8GNJ

Brief Update on The Packet Radio Forwarding Network
Glenn Allison N3MEL

HF Signals zBitx v2 - Inexpensive Open Source HF Software Defined Radio
Steve Stroh N8GNJ

iShareRadio Remote Radio Sharing Service
Steve Stroh N8GNJ

Pebble HF - Under $50 QRP HF Radio Kit
Steve Stroh N8GNJ

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Prefers to Remain Anonymous 69 for renewing as an Annual Paid Subscriber to Zero Retries this past week!

My thanks to Joe Pistritto N3CKF for becoming a new Annual Paid Subscriber to Zero Retries this past week!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Zero Retries Digital Conference 2026

Shown above is our brand new ZRDC 2026 Poster!

This will be a regular reminder that Zero Retries Digital Conference 2026 will be held on Friday October 16, 2026 in San Ramon, California, USA. This is the first day of Pacificon 2026 also in San Ramon. For more information, see www.zeroretries.org/p/conference.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the #ZR0248 hashtag.

Breaking - Major Split in Development of MeshCore

By Steve Stroh N8GNJ

I have no significant expertise to offer on this development in MeshCore, other than this is a regular occurrence in Open Source projects, and also in Amateur Radio.

This philosophical divide - human-generated software versus using artificial intelligence to develop software is now occurring in all elements of software development. There are passionate, well-informed, well-reasoned advocates on both sides. Including, of course, Amateur Radio - see another story about AI assisted software development later in this issue.

Meshcore.io blog - Meshcore.io - Why The Split?

Since inception, the MeshCore development team have been working hard to build MeshCore.

We’ve released more than 85 versions of the MeshCore Companion, Repeater and Room Server firmwares with support for more than 75 hardware variants. All of this has been hand crafted, by humans.

We have always been wary of AI generated code, but felt everyone is free to do what they want and experiment, etc. But, one of our own, Andy Kirby, decided to branch out and extensively use Claude Code, and has decided to aggressively take over all of the components of the MeshCore ecosystem: standalone devices, mobile app, web flasher and web config tools.

And, he’s kept that small detail a secret - that it’s all majority vibe coded.

…

The team didn’t feel it was our place to protest, until we recently discovered that Andy applied for the MeshCore Trademark (on the 29th March, according to filings) and didn’t tell any of us. We have tried discussing this, and what his intentions are, but those broke down and we now have no communication with Andy.

It’s been a stressful few months trying to sort this out, and is now a sad day to bring this out to the public. It’s been a slap in the face to the team that have worked so hard on this project, to have an insider team up with a robot and a lawyer.

“Official” MeshCore

The use of the ‘official’ status is what is currently being contested. Andy is adamant that he owns the brand, and is using the word very heavily with his MeshOS line.

Meanwhile, in reality, the only ‘official’ MeshCore is the github repo. It’s the source of truth in terms of what is MeshCore, and Andy has never contributed to that.

Since the internal split, we launched the meshcore.io site, as Andy controls the meshcore.co.uk site and original discord server. We’ve been left with little other recourse. And, since launching the site, Andy copied the look and feel (again, using Claude) even though we asked him not to.

Project Growth

The MeshCore project has been on an incredible journey.

Having only started in January 2025, we have grown extremely fast!

As of this post, the official MeshCore Map shows 38,000+ nodes around the world, and the official MeshCore App has more than 100,000+ active users across Android and iOS.

It’s pretty epic how we’ve all built such an incredible community in such as a short time!

As the project grows, so does our need for a dedicated space that provides you with official information from the core team.

In recent times, we’ve seen an explosion of growth in MeshCore web sites dedicated to specific countries and mesh communities.

To name a few, we’ve seen:

Andy Kirby did do an amazing job helping to promote the MeshCore project on his personal YouTube, but only promotes his own products now.

Where To From Here?

So, the core team are pushing ahead with the meshcore.io website, the ongoing work of firmware feature development, bug fixes, managing PR’s and developer discussions, etc.

We now release change logs, blog posts and technical documentation for all of our new firmware and app releases here.

You’ll also find some familiar faces on our blog posts, such as:

  • Scott our project founder, lead firmware engineer and developer of the Ripple firmware!

  • Recrof our official MeshCore Map developer and Firmware Flasher guru. He has shared some insights into the early development of the MeshCore Map.

  • Liam Cottle the official MeshCore App developer who will be posting useful guides for getting started with the MeshCore App.

  • FDLamotte who has done epic work on the Python tooling for MeshCore, as well as the STM32 firmware variants.

  • Oltaco (Che Aporeps) who has done amazing work on the new OTA Fix bootloader that makes firmware updates much more reliable.

The Core Team

The MeshCore team, now consisting of Scott, Liam, Recrof, FDLamotte and now Oltaco remain committed to designing and developing high quality, human-written software.

Our New Home

Please update your bookmarks!

This is where we will be hosting all official releases, technical documentation, and community discussions moving forward.

With the new website, we are also starting fresh with a new Discord server!

This is where you can interact directly with the MeshCore developers, get help with your projects, and contribute to the future of MeshCore.

Thanks for being a part of this journey!

The MeshCore Team

This… is going to be a slog.

It seems inevitable that the two MeshCore implementations - the development team, and Andy Kirby / meshcore.co.uk, having different agendas, are going to diverge and it seems inevitable to me that at some point soon they’ll not be interoperable.

Both websites - https://meshcore.io and https://meshcore.co.uk are approachable for newcomers to MeshCore. They’re appealing and engaging, with ample explanations for the various elements of MeshCore - software. hardware, and network. That there is so much in common between both sides, and both using the name MeshCore (and it being claimed as a MESHCORE™ on Kirby’s site), the potential for confusion is huge.

Thus “which MeshCore are you using?” is going to become a frequent question of MeshCore users wanting to be able to communicate with their friends.

My thanks to Franco Venturi K4VZ for mentioning this on the Zero Retries email list for inclusion in Zero Retries.

Please direct comments / feedback about this article to the Zero Retries email list with the #ZR0248 hashtag.

Brief Update on The Packet Radio Forwarding Network

By Glenn Allison N3MEL

Editor’s Note - I pinged N3MEL about an unrelated matter, and he responded with this great update on TPRFN, which he agreed to share with Zero Retries readers.

We are approaching our fourth anniversary and now have 22 full-time stations on the air. We recently added stations in Nevada and Oregon. While they don’t conform to the NVIS configuration to their east, we are seeing reliable West Coast traffic using 20m during the daytime. Establishing this [cross continent] RF path has been a long-term goal for us.

In other TPRFN news:

Winlink-to-Packet Gateway
I developed code allowing Winlink users to send private messages into the packet network. By addressing a message to WLGATE@WINLINK.ORG with the target packet station’s call sign in the subject, users can send ASCII text or TPRFN forms. More details are available here: https://www.tprfn.net/tprfn-gateway-news-1/winlink-to-packet-crossover

Station Lookup
We launched a searchable packet station list with home BBS info: https://www.tprfn.net/us-bbs-search-portal

World Wide Conference Server
I will be sharing the code and setup details for the BPQ to WWnConference Server via AMPRnet to encourage better utilization of this feature.

Packet Forms
We have released Skywarn and NTS Radiogram generators specifically built for packet radio: https://www.tprfn.net/html-to-text-packet-form

Network Utilities
Thanks to Anthony K1JAD and Jay N8FLA, we now have a network health page and live hub stats: https://www.tprfn.net/network-live-connections

You can find more details at http://tprfn.net

Our current needs include:

  1. Network Promotion: Increasing visibility wherever possible.

  2. Hub Stations: Recruiting more full-time stations to fill gaps in the central United States.

  3. Advocacy: Finding ways to return Packet Radio to the mainstream as a viable EmComm digital mode.

Editor’s Note - I clarified that despite “Packet Radio” being embedded into the name of the network, TPRFN is actually using various data modes, including VARA HF.

Please direct comments / feedback about this article to the Zero Retries email list with the #ZR0248 hashtag.

HF Signals zBitx v2 - Inexpensive Open Source HF Software Defined Radio

By Steve Stroh N8GNJ

As longer term Zero Retries readers know, I was enthusiastic about the zBitx low power portable HF radio when it was initially released in early 2025. Apparently too enthusiastic, it turns out as there were several issues with the original zBitx (now called v1) that damped my, and others, enthusiasm for that unit. But the cost of the zBitx v1 was relatively low. Thus I don’t regret my “vote with my wallet” support for HF Signals and the zBitx, and I don’t fault HF Signals for what turned out to be some issues with the initial version. They tried to develop an entry level portable SDR that was open source, and based on a popular microcomputer (rather than a microcontroller).

But small companies like HF signals listen to feedback from their customer base, and can iterate fast. The zBitx v2 is now available for $269 including (international!) shipping.

As with zBitx v1, my enthusiasm for this product is that it is almost entirely a Software Defined Radio driven by a Raspberry Pi Zero 2 W. It’s also open source, with a lot of future improvements to come from active community development. It amuses me that this particular radio is (claimed to be) running 64-bit1 Linux on a $15 microcomputer.

HF Signals zBitx v2 - Image courtesy of HF Signals

From the HF Signals zBitx v2 website:

What’s new in v2

The zBitx v2 brings four major upgrades over the original zBitx:

  • LDMOS-based, efficient 5 watt output.** The new LDMOS final amplifier delivers a clean, efficient 5 watts across all bands with lower current draw, cooler operation and longer battery life in the field.

  • Built-in EFHW transformer.** Connect an End-Fed Half-Wave wire antenna directly to the radio — no external matching unit required. Just throw a wire into a tree and you’re on the air.

  • MOSFET-based reverse polarity protection built into the on/off switch. A MOSFET-based protection circuit is now integrated directly into the power switch, guarding the radio against reversed supply leads with effectively zero voltage drop.

  • Responsive CW operation with macros and logging. The CW path has been reworked for crisp, low-latency keying with editable macros and integrated logging — the v2 is a serious CW machine, whether you’re chasing DX or running a portable activation.

…

Built-in EFHW transformer

The zBitx v2 has an EFHW (End-Fed Half-Wave) transformer built directly into the radio. Connect a resonant half-wave wire to the antenna port and you are on the air — no external tuner, no separate matching box, no extra cables to pack. It’s the ideal companion for pocket-portable, grab-and-go operations.

Reverse polarity protection, done right

A MOSFET-based reverse polarity protection circuit is built into the on/off switch. If you connect your power leads the wrong way around, the radio simply will not power up — and nothing inside gets damaged. Because it uses a MOSFET instead of a series diode, the voltage drop is negligible, so you get full output power and efficiency from every volt of your battery.

Everything is included:

Insert two 18650 LiPo batteries (not supplied) and you are ready to hit the field. At home, plug in a 9V power supply and work it from your monitor/keyboard/mouse. It has a built-in microphone and a high-quality speaker.

Remote into it with just the web-browser on your phone/tablet/laptop.

Specifications

Size: 170mm x 80mm x 45mm (including the battery case)
Weight: 415 grams including two LiPo batteries
Display: 480×320 resistive touch screen display with an independent Raspberry Pico front panel controller.
Software: Fully open sourced and available on https://github.com/afarhan/zbitxv2
Hardware: Hybrid superhet with LDMOS final amplifier, open source circuit with full description
Final Amplifier: LDMOS, efficient 5 watt output
Antenna Matching: Built-in EFHW transformer
Power Protection: MOSFET-based reverse polarity protection integrated into on/off switch
Frequency Coverage: All international ham bands from 80M to 10M
Power: 5 watts on all bands.
Power Supply: 6V to 9V.
Receive Current consumption: 300 mA
Transmit Current consumption: 1.5 to 3A (depending on the Drive settings)
Modes: USB/LSB/AM/CW/CW-Reverse/FT8/Digital modes (with FlDigi)
Preloaded Apps: FreeDV, QSSTV, Fldigi and more are coming

Another point of amusement about the zBitx v2 is that it ships with FreeDV digital voice mode for HF, though it’s undoubtedly an older version of FreeDV which is probably now considered deprecated in favor of the much more capable FreeDV RADE. The only other HF radios I’m aware of that ship with a digital voice mode are Icom HF radios with D-Star digital voice.

One criticism of the zBitx v1 was that some considered that all of the overhead of running the radio (display update, low latency for radio operation, processing voice and digital modes, and especially CW) was a bit too much for the Raspberry Pi Zero 2 W microcomputer, not to mention the “overhead” of running a full Linux stack. I think that this time, we’ll have to wait for the verdict of customers of the zBitx v2 to see if the overall performance / responsiveness has been improved (enough).

I was impressed with two of the improvements that make the zBitx more usable and more forgiving of new user mistakes:

  • Built-in EFHW transformer

  • MOSFET-based reverse polarity protection

Those are the two most common mistakes of new users, especially with batteries / battery holders that allow batteries to be inserted backwards. The reverse battery protection system is elegant and seemingly goof-proof. If you do it wrong, it just doesn’t start up, with no damage done.

The idea of attaching any random wire antenna and the radio just “handles it” with, again, seemingly goof-proof. (Obviously, optimizing the wire length, the better the performance).

Even though the display is a touch screen, you can also:

Remote into it with just the web-browser on your phone/tablet/laptop.

Lastly, for those of us that purchased zBitx v1 units, there is this procedure for updating to v2 software on the BITX20 email list by HF Signals founder Ashhar Farhan VU2ESE:

Upgrading your zbitx (v1) to zbitx v2 software

Note that this process is… apparently not bulletproof, so read the entire thread before attempting.

All in all, I really like the improvements in the zBitx v2 and I’ll likely invest in one later in 2026 after I get a few more projects completed in N8GNJ / Zero Retries Labs.

My thanks to DXR ELECTRONICS BITS blog for mention of this development.

Please direct comments / feedback about this article to the Zero Retries email list with the #ZR0248 hashtag.

iShareRadio Remote Radio Sharing Service

By Steve Stroh N8GNJ

iShareRadio is a new service that allows clubs and other organizations to share remote radios with granular permissions. Apparently it is still in development, but has been mentioned publicly by some of its principals.

I first learned about the iShareRadio service from listening to the Ham Radio Workbench podcast, where it was discussed by host George Zafiropoulos KJ6VU.

The idea of a using a remote radio station / system from anywhere, via Internet, isn’t new. It’s one of the primary benefits of the FlexRadio units, and recently implemented on the newest generation of HF radios from Elecraft, Icom, Kenwood, and Yaesu.

The idea of a “middleware” service to share remote radios amongst multiple users isn’t new either - see Remote Ham Radio (RHR).

But until iShareRadio, there hasn’t been a “middle ground” service suitable for clubs that want more flexibility than systems for individual access such as FlexRadio’s SmartLink, and the approach of Remote Ham Radio of renting a “dream station” as a subscription service. Also a frustration with individual access systems is that they’re unique to the radio manufacturer. To remotely use a FlexRadio requires the use of FlexRadio’s SmartLink, and to remotely use an Icom radio, even at the same station, requires the use of Icom’s remote access software.

Thus a service that’s suitable for clubs to share one or more remote radios is the opportunity that was noticed by iShareRadio. There were several things that were mentioned by KJ6VU that were great features for clubs:

  • Individual accounts, centrally administered. That ability to do centralized administration for a group is highly useful and needed. Didn’t renew your club membership? You lose your access to the club’s remote station.

  • Scheduled access - An individual (club member) can reserve a radio for a specific time slot.

  • Granular access - Features of the radio, or station, are granular enough that, for example, a club member with a Technician license can only use the radio on the bands that are compatible with their license class.

  • Manages multiple types of radios in the same interface / system. If a remote station uses, for example, a FlexRadio FLEX-8400 for HF, and an Icom IC-9700 for VHF / UHF, both can be scheduled and managed by iShareRadio.

Remote Club Stations are More Feasible Than Ever

HF operation has become more problematic for many in the past decade. One primary complaint has been the steadily rising radio noise floor in the HF bands. In my opinion, this is an inevitable, and largely unstoppable result of the use of efficient switch mode power supplies that are used in everything from mobile phone chargers to microinverters on the back of solar panels (and very soon, the rise and inevitable ubiquity of “balcony solar” panels).

Another issue is the constraints of living arrangements of living in, or relocating to housing where external antennas are restricted such as condominiums, apartments, even senior living centers, and dorm rooms. For such situations, having access to a a remote radio is an ideal solution.

A number of club hosted remote radio station situations come readily to mind:

  • A “senior citizen community” that I saw in Florida, where individual Amateur Radio stations at the units were discouraged, but the community center building hosted an Amateur Radio station. Amateur Radio Operators in that community could share (one or more) radios at the club’s Amateur Radio station, and could probably do so using a local microwave network such as AREDN.

  • A college radio station where after hours access to the college Amateur Radio station is prohibited, but members of the club could remotely access the radio systems at the club station.

  • Members of a large urban Amateur Radio club could demonstrate HF operation remotely to, for example, STEM classes, Makerspaces, and other gatherings without the inevitable difficulties of trying to make HF work in meetings.

But one of the most compelling ideas I’ve read about is the idea of finding a remote location where there is little or no electrical interference in the HF band to construct a remote radio station. Conceptually, such a remote radio station is “simple”:

  • 20 foot cargo container,

  • Solar power and battery system (carefully chosen / engineered for low electrical noise, such as not using micro inverter solar panels),

  • Starlink Internet Access

  • Your choice of remotely controlled radios.

The “missing piece” for remote radio systems has been something like iShareRadio that is specifically designed for such situations as a hosted service that manages the complexities of granular sharing of remote radio stations, particularly the complexities of managing radios from different manufacturers.

While HF stations are the most well-known use of remote radio stations, there are many other uses of remote radio stations, especially the flexibility of a “cargo container” remote radio station that could be managed by iShareRadio:

  • Amateur Radio satellite station that integrates the VHF / UHF radio with an automatic antenna tracking system,

  • Earth Moon Earth (EME) station with a large antenna array,

  • Beacon transmitters,

  • Multiple Remote Receivers for multiple bands such as those used for HamSCI experiments,

  • If the area is scenic (such as a long view of mountains), add a high definition video camera for the benefit of club members (some Starlink plans feature uncapped data transfer),

  • If the area doesn’t have any artificial light, add a star camera,

  • Repeater / digipeater

  • Aircraft ADS-B receiver,

The possibilities of such a remote radio station are endless. I imagine possibly locating such a station on some friend’s properties in Montana and Wyoming.

Security Aspects of a Service Like iShareRadio

One issue of individual remote access is that consumer Internet access often is problematic. Sometimes such services require static IP addresses which can be expensive or unavailable from some Internet Service Providers. Sometimes individual TCP/IP ports must be (manually) opened for remote access to function. Other times it’s impossible to “come back in” from the Internet (remote access) to a device that’s connected via Carrier Grade Network Address Translation (CGNAT) such as what Starlink uses for IPv4.

There’s also the administration issue(s) of the potential use of weak passwords, sharing of accounts to unauthorized users… all the headaches of any remote access system. Not to mention the ongoing issues of identifying security issues that need to be patched and distributed, updating application software, etc.

As much as I reflexively want to recommend ARDC’s 44Net Connect free VPN service for Amateur Radio Operators to get access to a free static IPv4 address… 44Net Connect has its issues, such as what it provides you is an unfiltered static IPv4 address. Emphasis on unfiltered. When you use 44Net Connect, there is no firewall or other protection between the device you use with a 44Net Connect IPv4 address and “the rough neighborhood” of Internet bots and other attackers that will rapidly discover your new 44Net IPv4 address and begin probing and attacking it.

Thus a hosted, professionally administered service such as iShareRadio is an attractive option for clubs and even smaller groups such as families or just a few friends that want to share a remote radio station amongst multiple users. The remote radio station “phones home” to a iShareRadio’s known, safe set of IP addresses via a secure connection. Thus “incoming” access is not required - the connections are only outgoing. Thus there’s no need for static IP addresses, or another middle service such as 44Net Connect, and it works with no issues, even with Starlink.

Non Radio System Integration

This nugget from the FAQ was instructive:

What is the Station Controller?

The iShareRadio platform can integrate to a number of products and one of the most exciting is the Station Controller by Sierra Radio Systems. This is a robust, modular and easy to configure solution to manage, control and monitor your radio equipment.

The iShareRadio platform has integrated with the Station Controller as it is perfect solution to managing all the equipment around a radio.

I have also seen references to Node-RED integration… so nearly anything could conceivably be managed within iShareRadio.

I’m looking forward to seeing iShareRadio complete its development and become a fully functional service.

Post Publication Update

Email from KJ6VU:

Thank you so much for covering iShareRadio in Zero Retries! That was a really wonderful surprise. Everything you said in the article was spot on with a few minor comments below.

Radio support

  • The initial release of iShareRadio supports only Flex Radios. We are working on a solution for non-Flex radios but that will come later this year.

  • The Station Controller will work with any radio or equipment today.

Schedule

  • We are in beta now with several users.

  • We will be in full production release and selling subscriptions as of Hamvention this year so in a month.

The pricing model will include...

  • Free for end users to set up an account to access remote stations.

  • Radio station hosts will pay an annual service fee. The price will scale with the number of users, radios, etc.

Marketplace

  • We will be offering a “marketplace” where hosts can advertise their station for rent and users can book time for a fee.

  • Of course, a radio host can offer their radio for free if they choose to do that.

Public / Private

  • A host can offer their station privately or publicly.

  • Private hosting means that only people who the host has invited to use their system by email will know about the station.

  • Public hosting means the host will offer their station for anyone to rent time. The host has the approval of anyone requesting station access.

Please direct comments / feedback about this article to the Zero Retries email list with the #ZR0248 hashtag.

Pebble HF - Under $50 QRP HF Radio Kit

By Steve Stroh N8GNJ

In Zero Retries, I don’t normally mention the many… many… many… low power HF radios that are constantly being developed, especially those that are intended solely or mostly for Morse Code (CW) use. But there’s something different about the Pebble HF.

One attractive aspect of the Pebble HF is that the sponsors offer an engaging backstory. It’s the “product” of a couple of xOTA2 (outdoor casual operation) Amateur Radio Operators - Becky Spiceland N4BKY and Mike Spiceland N4FFF. They have a fun looking YouTube channel - Ham Radio Duo.

Another is that in the video and on the web page, N4BKY and N4FFF don’t shy away from comparisons with other (and in their own words, better) low power HF radio options. They are clearly focused on developing the Pebble HF to be a good enough, and inexpensive low power HF radio kit that is attractive to new, and potential, and budget conscious Amateur Radio Operators that want to “go outside and have fun on the air”.

The development of the Pebble HF was done by two very experienced Amateur Radio Operators - Barb Asuroglu WB2CBA did the hardware, and Guido PE1NNZ did the firmware (with modifications by N4FFF).

Beyond those two elements, this low power HF radio offers a unique confluence of factors that make the Pebble HF Zero Retries Interesting - to me:

  • Hardware design and firmware is open source.

  • The price - “under $50”.

  • The size - comfortably fits in a hand.

  • The simplicity of a single band - 20 meters.

  • Reasonable power - 5 watts with 12 volt input (or the flexibility of 1 watt with USB-C input).

  • Although optimized for CW, it’s usable for (Single Sideband) voice and digital (with an external digital interface). There’s no view of the bottom of the unit where the audio connections are, but it appears to be small jack, hopefully with audio input, audio output, and Push To Talk.

    • But there’s this unclear reference:
      CW, SSB (USB/LSB), and digital mode capable*

      (* an external usb sound card is required for digital modes)

    • So does the “sound card” get connected to the USB-C? Or do you use an external interface such as a Digirig Lite?

  • It’s un-intimidating. It looks like learning to use it is the work of just a few minutes.

  • Lastly… it’s a kit… a reasonable to build kit where the soldering is a total of 14 through hole components, including the coils that you wind.

I can’t quite explain why I find Pebble HF so interesting, more than the many other similar radios and kits. I guess one factor is that I can see showing this off to potential Amateur Radio Operators… and it just seems so approachable and simple - just a few connections. I could also see this being easy to demonstrate - plug in a common USB-C battery pack and a minimal dummy load and transmit across a room between two units.

Keeping to the approachable, un-intimidating paradigm, the “Just OK Mini” 20 meter antenna - 20m band would be a great starter antenna to pair with the Pebble HF.

Please direct comments / feedback about this article to the Zero Retries email list with the #ZR0248 hashtag.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

Breaking News: FCC Grants Frequencies’ Use For Satellite Service

Amateur Radio Newsline Report 2530 for Friday, April 24th, 2026:

JIM/ANCHOR; We begin this week with breaking news. As Newsline prepared to go to production, the US Federal Communications Commission announced that it had authorized AST SpaceMobile’s full, 248-satellite constellation to use requested parts of the radio spectrum, including those that had drawn objections from the amateur radio community.

The agency’s move will permit AST to fulfill its goal of providing services to consumers in so-called “dead zones,” regions without terrestrial networks, especially for emergency services. The successful application on behalf of the low-Earth orbit satellite system was granted on the 21st of April with conditions. The grant for the use of 698 to 960 MHz includes permission to make use of 430 to 440 MHz for emergency control and tracking of the satellites - a move that amateur radio operators feared would cause interference with hams’ operations.

The FCC said that AST emergency telemetry use will be limited to the 430.5MHz, 432.3MHz, 434.1MHz, 435.9MHz, and 439.5MHz frequencies for a duration of less than 24 hours. The FCC has said in the past that interference with ham radio was “unlikely.”

(FCC, PC MAGAZINE AUSTRALIA)

Echo App for iOS Devices

Image courtesy of echosdr.com

Visualize the Spectrum

See the invisible. Stream raw waterfall data directly from KiwiSDR, OpenWebRX, WebSDR, and FM-DX Webservers to explore the radio spectrum in real time on a fluid, hardware-accelerated canvas.

Listen to Anything, From Anywhere

Echo turns your iPhone and iPad into a global radio receiver. Browse 2,000+ KiwiSDR, OpenWebRX, WebSDR, and FM-DX Webservers to hear shortwave, aviation, numbers stations, and distant FM in real time.

This is a really gorgeous iOS application. It’s free to download and use, and in three clicks I had selected a receiver, and a portion of spectrum / station / net to listen to, and it just worked. This is an impressive demonstration of the utility of the global network of radio receivers being made available for use for free via Internet.

I can just imagine how useful this is in testing out one’s station - do a quick test while using this app tuned to a remote receiver. Talk about fast feedback!

We really seem to need a lot more remote receivers here in the Pacific Northwest. I need to get my KiwiSDR online.

My thanks to Conrad Trautmann N2YCH for mentioning this for inclusion in Zero Retries.

Hibbian Installer First Release

Dave “hibby”Hibberd MM0RFN via email:

I‘ve been working on my Linux side projects, and I’ve hit a point where I’m pretty happy with the work done and have things to announce that are probably ZR Interesting!

I’ve finally got weekly builds of a live running & installable Debian for hams available.

It contains the bulk of the amateur radio software we ship in Debian pre-installed, and has the ‘backports’ distribution of more modern software not normally available for Debian stable active, so you can run the recent wsjtx 3.0 out the box, for example, which otherwise won’t ship as Debian Stable until our next major release in 2027ish.

As it’s a ‘live’ distribution, it’ll run straight from a USB stick, bypassing whatever is installed on your computer not touching the existing hard drive, so it makes quickly repurposing a personal computer/laptop for a contest or special event easy too.

There’s also a raspberry pi image built with the same ethos, so your shack pi can be usable out the box without hours spent finding and downloading packages.

From the website:

I’m genuinely thrilled to announce that after years of me working away, one small project at a time, it is now possible to head over to download.hibbian.org and download either a PC or a Raspberry Pi image!

PC Live & Installer Image - Stable

This is an iso compatible with any amd64 computer - this comprises most machines sold in the last 15 years.

That said, I’d recommend at least 4GB RAM, preferably 8GB, and a not too old CPU. If there’s enough demand for a lightweight environment for old machines, I can add this to make life nicer.

The image needs to be written to a USB stick - on Windows I’d recommend Rufus. When the PC boots you will meet a live environment running Debian Stable & KDE Plasma 5 which contains the majority of the Debian Hamradio packages. You may check the list in the latest release notes.

These are the latest versions of the packages available in Debian - either backported by my colleagues in the Debian Hams team or quietly ported to the Hibbian Repo by me to ensure compatibility.

The image contains an installer so you can easily install to your local system if you prefer the conventional approach of running from a hard drive or you can ignore it and use the live image directly as your system disk!

This live distribution capability for Linux Amateur Radio apps is really welcome, especially for Raspberry Pi. This lowers the barrier to entry of using Linux considerably as “if you screw it up, just reboot and try again”. Then exit out and your system is back to normal (Windows, etc.). Speaking for myself, this would be especially welcome for Raspberry Pi as it could be distributed to prospective Amateur Radio users and probably usable enough for the Raspberry Pi 3B+ (only $40).

Kudos to MM0RFN for Hibbian 1.0 (?) and my thanks to him for mentioning this for inclusion in Zero Retries.

Announcing the VARAtrack APRS-over-VARA APRS Tracker

Stephen H. Smith WA8LMF on the aprssig email list:

Several years and 15,000 miles of road-trip drive-testing, using the VARA high-performance HF modem alongside traditional AX.25 HF packet, has shown VARA to be orders of magnitude superior for reliably transmitting APRS position reports on HF.

VARA exists exclusively as a Windows-based sound-card “soft modem” - the only way to do APRS-over-VARA has been to use a mobile laptop or Windows tablet in the vehicle. No simple hardware-only solution analogous to the Byonics TinyTrack for classic packet exists.

Recently, very inexpensive (starting at USD $139) tiny Windows-based ultra-compact computers known as “stick PCs” have become available. These devices are very small fully-functional 64-bit Intel-based quad-core PCs. They include 4 USB-C ports, 1GB Ethernet port, WiFi 5, Bluetooth 5, a Realtek HD sound system, and 4K-capable HDMI video. Further, these devices run directly from 12 VDC, making them ideal for mobile applications!

These devices are widely used to drive the 42” monitors displaying menus over the counter at fast-food places, and in airports for displaying incoming and outgoing flights. I have now one setup one to operate as a stand-alone APRS-over-VARA tracker.

Full details on the VARAtrack setup are on my website at:

<http://WA8LMF.net/VARA>

Scroll down the page and follow the link on that page for “The VARAtrack”. Near the bottom of the VARAtrack page is a link to download a backup image file of my entire setup that can be used to restore the entire setup to another similar stick PC.

I will demonstrating the VARAtrack at the Dayton Hamvention at my radio trailer aka “Studio B” in the Emergency Comms Vehicles Expo.

WA8LMF has been working on testing this solution - APRS over VARA HF for some time. I agree with him that using an inexpensive Windows computer as a “VARA appliance” is the most practical way to use VARA HF (or VARA FM).

Beyond VARA HF, there are other potential solutions for APRS over HF that are more robust than legacy 300 bps AX.25 packet radio, including:

  • NinoTNC (see the section Latest SSB and FM modes - Improved Layer 2 Protocol with supplemental CRC. These are intended to work on SSB sideband channels or with Mic/Speaker connections on FM transceivers.)

  • Mercury Modem

  • Hush

Related - My Zero Retries Guide to Amateur Radio HF Data Communications was recently updated with some related information.

Graywolf - Modern APRS Station

Project by Chris Snell KN6TLO (? Pretty sure.):

Modern APRS station — software modem, digipeater, iGate, and web UI

Graywolf is a complete APRS station that replaces a hardware TNC with a software modem. Plug a radio into a USB sound card, install graywolf, and configure everything from your browser. No external sound card software, no config files to hand-edit — just a single binary and a web UI.

Graywolf dashboard showing station stats, DCD status, audio levels, and live packet feed

The dashboard shows real-time station status and a live packet feed

WHAT YOU CAN DO

Run a digipeater
Set up a fill-in or wide-area digipeater with WIDEn-N path handling, duplicate suppression, and cross-channel routing. Configurable rules let you control exactly what gets repeated.

Run an iGate
Bridge your local RF network to APRS-IS. Receive-only or bidirectional — gate RF packets to the internet and deliver APRS messages from the internet back to RF.

Beacon your position
Fixed station beacons, GPS-driven mobile trackers with SmartBeacon rate adaptation, APRS objects for repeaters or events, and custom status beacons.

Serve as a TNC
Expose KISS and AGWPE interfaces so other packet software (Xastir, YAAC, pinpoint, aprx, APRSdroid) can use graywolf as their modem over TCP, serial, or Bluetooth.

Combine everything
Run a digipeater, iGate, position beacon, and KISS server all at once on the same radio channel — or spread them across multiple channels and radios.

More technological innovation in Amateur Radio! Its interesting / reassuring for the future of Amateur Radio that there are folks like KN6TLO (and many others) who aren’t content with the status quo, same old, same old Amateur Radio paradigms and are willing to reimagine Amateur Radio technologies… even those that seem “static” like APRS.

New SCS PXdragon DR-9400 PACTOR Modem

(Link is to DX Engineering website)

Developed by SCS and distributed by WiMo, the PXdragon DR-9400 supports PACTOR-1/-2/-3 and PACTOR-4, Packet Radio and APRS with 1200 bps AFSK and 9600 bps G3RUH and Robust Packet Radio. Reception modes such as Weather-FAX (RX) and RTTY (RX) and an integrated PACTOR monitor expand the range of applications. Its compact design makes the DR-9400 ideal for stationary and portable operation—perfect for email messaging, file synchronization, telemetry, or APRS beaconing. Modern signal processing, versatile interfaces, and robust protocols make the PXdragon DR-9400 a reliable solution for data-oriented radio operation, even in poor propagation conditions.

…

SPECIFICATIONS SCS PXdragon DR-9400 PACTOR Modems

Supported Operating Modes:

  • PACTOR-1 / -2 / -3 / -4

  • PACTOR Monitor

  • Packet Radio (9k6 G3RUH, 1k2 AFSK)

  • Robust Packet Radio (RPR)

  • APRS (Automatic Beaconing)

  • Weather-FAX (Receive only)

  • RTTY (Receive only)

It’s encouraging that SCS supports Amateur Radio Packet Radio 1200 and 9600 bps in this latest generation of their Pactor modems.

My thanks to Brian O’Connor KA2CGB for mentioning this for inclusion in Zero Retries.

Stix Radio April Update

From Patreon email update and website:

Background:
At its core, the Radio is a handheld, Linux-based (Armbian) radio platform that blends analog VHF/UHF FM voice with LoRa data networking, GNSS and Wi-Fi connectivity. It’s designed to feel like a modern “smart walkie-talkie” — a decent hybrid between a classic handheld transceiver and a connected computing device.

… REV-C board spin. This includes:

  • Cleaning up the power architecture

  • Improving stability across the different voltage rails

  • Making sure everything behaves properly under load (especially RF + display + CPU all running together)

Given how complex this board is — with RF, audio, high-speed digital, and power all interacting — this kind of iteration is honestly expected. It’s much better to catch it now than later. I have always banked on at least 4 to 5 revisions as the bare minimum, so no drama.

This is a project worth following. The graphics (FT8, APRS) give some indication that beyond LoRa, there will be some built-in digital / data functionality on the VHF / UHF FM radio.

Reviving Teletext for Ham Radio > Hack the airwaves with some of the best tech of the 1980s

Stephen Cass KB1WNR in IEEE Spectrum:

Putting Teletext Back on the Air

I wanted to do something a little different. Inspired by how the BBC Micro co-opted teletext for its own purposes, I thought it might make a great radio protocol. In particular I thought it could be a digital counterpart to slow-scan television (SSTV).

SSTV is an analog method of transmitting pictures, typically including banners with ham-radio call signs and other messages. SSTV is fun, but, true to its name, it’s slow—the most popular protocols take a little under 2 minutes to send an image—and it can be tricky to get a complete picture with legible text. For that reason, SSTV images are often broadcast multiple times.

I decided to send the teletext using the AX.25 protocol, which encodes ones and zeros as audible tones. For VHF and UHF transmissions at a rate of 1,200 baud, it would take 11 seconds to send one teletext screen. Over HF bands, AX.25 data is normally sent at 300 baud, which would result in a still-acceptable 44 seconds per screen. When a teletext page is sent repeatedly, any missed or corrupted rows are filled in with new ones. So in a little over 2 minutes, I could send a screen three times over HF, and the receiver would automatically combine the data. I also wanted to build the system in Python for portability, with an editor for creating pages, an AX.25 encoder and decoder, and a monitor for displaying received images.

The reason why I hadn’t done this before was because it requires digesting the details of the AX.25 standard and teletext’s official spec, and then translating them into a suite of software, which I never seemed to have the time to do. So I tried an experiment within an experiment, and turned to vibe coding.

Despite the popularity of vibe coding with developers, I have reservations. Even if concerns about AI slop, the environment, and memory hoarding were not on the table, I would still worry about the reliance on centralized systems that vibe coding brings. The whole point of a DIY project is to, well, do it yourself. A DIY project lets you craft things for your own purposes, not just operate within someone else’s profit margins and policies.

Still, criticizing a technology from afar isn’t ideal, so I directed Anthropic’s Claude toward the AX.25 and teletext specs and told it what I wanted. After about 250,000 to 300,000 tokens and several nights of back and forth about bugs and features, I had the complete system running without writing a single line of code. Being honest with myself, I doubt this system—which I’m calling Spectel—would ever have come about without vibe coding.

But I didn’t learn anything new about how teletext works, and only a little bit more about AX.25. Updates are contingent on my paying Anthropic’s fees. So I remain deeply ambivalent about vibe coding. And one final test remains in any case: trying Spectel out on HF bands. Of course, that means I’ll need willing partners out in the ether. So if you’re a ham who’d like to help out, let me know in the comments below!

I knew of teletext and had even seen it in an expensive hotel room. It was indeed useful to get this stream of information available. I had no idea of the elegance and efficiency of Teletext that KB1WNR describes.

But I think that KB1WNR buries the lede about his experiment in Amateur Radio vibe coding software development… it worked! He started with an idea that he didn’t have the skills or knowledge to tackle entirely on his own. The idea wasn’t so compelling or universally useful that it justified devoting significant time and energy on his part, such as digesting the AX.25 and teletext specifications, or enlisting the help of others. Thus, on “hobby time”, using an AI assistant, he was able to develop a working system… again, from just an idea.

And, I think, writ large, unique new modes like this is going to be increasingly the norm in Amateur Radio. The nature of Amateur Radio encourages such experimentation. As KB1WMR proves out, vibe coding enables a person with some (perhaps minimal) some technical skill to create entirely new digital modes that can then (after being “documented publicly” per FCC Part 97 regulations) be used on Amateur Radio spectrum. While vibe coding might end up being expensive at the moment, surely the rapid evolution of AI technology - more efficient models, more capable hardware will render such hobby projects as unprofessional vibe coding, affordable on a hobby budget.

I was not able to find any public documentation of Spectel beyond this article, and thus I encouraged KB1WMR to do so in the comments section of the article. I also wasn’t able to find any direct contact info for KB1WMR, so apparently the comments section of the article is the only way to “contact” him.

My thanks to Bennett Z. Kobb AK4AV for mentioning this for inclusion in Zero Retries.

IEEE Spectrum’s Modern Amateur Radio Stories Archive

The preceding item is just the latest of a series of great treatments of Amateur Radio in IEEE Spectrum. Stories about Amateur Radio in IEEE Spectrum consistently portray Amateur Radio as relevant and interesting in the 21st century. I particularly appreciate these articles as explaining that Amateur Radio is useful to get hands-on experience with radio technology. These articles are always readable and interesting for IEEE Spectrum’s readership with an assumed technical background.

IEEE Spectrum articles tag: Amateur Radio

IEEE Spectrum articles tag: Ham Radio

Microwave Update 2026 in Rochester, NY is Open for Registrations

Email from Dave Carlson N2OA:

The Microwave Update conference for 2026 in Rochester, NY is open for registrations. We have a great lineup of speakers, a tour of the Antique Wireless Association (AWA) is available https://www.antiquewireless.org/homepage, and we should have some nice prizes. Presentations will be held at L3Harris.

https://microwaveupdate.org/MUD2026

I couldn’t (quickly) find a reference to what the primary activities are at the L3Harris facility near Rochester, New York, but I’m sure there’s ample Zero Retries Interesting activities there. Microwave Update is one of the great technical conferences in Amateur Radio, and definitely recommended if you’re interested in microwave communications in Amateur Radio.

Now mentioned in the latest update of Zero Retries Guide to Zero Retries Interesting Events.

SteppIR Resumes Sales to Amateur Radio

One time popup notification on https://consumer.steppir.com:

This is good news for Amateur Radio! I’m still in awe of SteppIR’s “mechanically tuned antennas”. I wouldn’t have imagined such an approach was viable until SteppIR proved out the concept.

Arcanum: ORI’s New Open Source Antenna Simulation Engine

Michelle Thompson W5NYV on the Open Research Institute web page:

…

The solution to these limitations exists. It is called the Conformal Method of Moments with Exact Kernel (CMoM). This approach replaces NEC-2’s straight-segment approximations with curved segments. The NEC-2 kernel is replaced with the full cylindrical surface integral. This means that we get more accurate modeling for exactly the antenna types that matter most to ORI’s work, such as ground station helices, compact loaded dipoles, loops, and arrays.

There is exactly one production software implementation of CMoM with exact kernel in the world. It is proprietary and the current price is $1599 USD per year for the license.

Until now, that has been the end of the story for anyone who needed high-fidelity curved-wire antenna modeling without a commercial license. We decided to do something about that. Arcanum changes things.

What Arcanum Is

Arcanum is ORI’s new open source CMoM antenna simulation engine. It is, to the best of our knowledge, the first open source implementation of the Conformal Method of Moments with Exact Kernel.

The name is intentional. An arcanum is hidden or secret knowledge. The mathematical techniques underlying CMoM have been in the academic literature for decades. Champagne, Williams, and Wilton described the curved-segment approach in 1992. This reference is listed in the Arcanum bibliography. We assemble these approaches into an accessible, open, community-owned tool. That is what we are building.

…

This is yet another interesting example of technological innovation (adjacent to) Amateur Radio. Given the increased interest within Amateur Radio about space communications, and ORI’s ongoing work in space communications, this ability to model antennas for ground station use more precisely will be highly useful.

The open source aspect of this system gets even more interesting when it can be used with an AI - imagine interactively modeling theoretical antenna designs.

My thanks to Amateur Radio Weekly Issue 417 for mentioning this.

QRX - APRS Missed Message Mailbox

New service for Amateur Radio APRS by Jesse Forkum N0JLF:

Q-code: “Wait / Stand by” — your messages are standing by.

Get started from any APRS radio or client

Send REG to QRX

That’s it. QRX will hold messages you miss while offline.

WHAT IS QRX?

QRX is a passive APRS message safety net. It monitors APRS-IS for messages addressed to your callsign, watches for acknowledgment, and stores any unacknowledged messages for later retrieval.

When you come back online (detected via position beacon), QRX notifies you of missed messages. Think of it as voicemail for APRS.

QRX never ACKs on your behalf, never retransmits messages, and never injects itself into the delivery path. It is purely an observer that catches what falls through the cracks.

HOW IT WORKS

  1. Someone sends you an APRS message while your radio is off

  2. QRX sees the message on APRS-IS, waits 5 minutes for your ACK

  3. No ACK observed — QRX stores the message

  4. You turn your radio on and beacon a position

  5. QRX sees your beacon and sends you a notification

  6. You send R to read messages one by one, like voicemail

There’s an unstated requirement that for QRX to work via radio that there must be an APRS (receive and transmit) Igate in your area.

My thanks to Amateur Radio Weekly Issue 417 for mentioning this.

New 2026 ITU Handbook on Amateur and Amateur-Satellite Services Released

Frank Karnauskas in ANS-109 AMSAT News Service Weekly Bulletins:

The International Telecommunication Union (ITU) has published the 2026 edition of the Handbook on Amateur and Amateur-Satellite Services . The updated reference provides comprehensive information on the amateur and amateur-satellite services, including relevant ITU regulatory texts, technical guidelines, and operational practices.

IARU President Tim Ellam, VE6SH/G4HUA, highlighted the handbook’s release, noting its value to national administrations, regulators, and amateur radio organizations worldwide. The document serves as an essential resource for anyone involved in frequency coordination, licensing, or satellite project planning.

The handbook is available for download free-of-charge at https://www.itu.int/pub/R-HDB-52-2026.

La Plata County Colorado Weather Radar

La Plata County has partnered with the Colorado Department of Local Affairs, the Colorado Water Conservation Board Water, and the Colorado Division of Homeland Security and Emergency Management to acquire, install and operate a permanent weather radar station in southwest Colorado on land adjacent to the Durango-La Plata County Airport. The radar is locally owned by La Plata County.

This game-changer in preparedness for the region came on the heels of the 416 Fire in 2018 and the floods and mudslides that followed during annual monsoons. Relying on radar imagery from stations in Grand Junction, Albuquerque and Flagstaff – the closest radars until now - painted an incomplete picture of what was headed this way. This is because most of the storms that hit La Plata County and its surrounding areas form at or below 28,000 feet, which falls below eyeshot of those other radar stations.

The 416 Fire prompted a solution to this long-recognized gap in coverage, when the Colorado Department of Local Affairs extended a $1.7 million grant to fund a significant portion of the roughly $2.6 million project, with the remainder funded by La Plata County, Colorado Department of Transportation, Colorado Department of Natural Resources and other local partners pitching in for its operation and maintenance.

This is another example of (that I was unaware of), smaller scale weather RADAR systems to monitor weather conditions in local, rural areas not well covered by existing National Weather Service or urban weather RADAR systems.

My thanks to Chuck Kimball N0NHJ for mentioning this for inclusion in Zero Retries.

N0NHJ’s QRZ page is worth a look:

From 1998 through 2018 I completed 18 deployments in the Antarctic as a Satellite and Communications engineer. I worked at all three year round US Research stations…

First Computer Decoded Morse Code in 1975?

This was an interesting discussion I saw in passing about an Amateur Radio Operator’s involvement, including the Amateur Radio National Traffic System, in a US military project to automatically decode Morse Code transmissions via radio.

Jack Haverty on the Internet-history email list:

…

It started in 1963. In high school, I was interested in STEM (acronym not yet in existence though), had joined the school’s Radio Club, gotten a amateur radio (”ham”) license, and somehow gotten involved in something (in the US) called the National Traffic System (NTS - that acronym did exist).

NTS was a network. Actually an Internet. Actually a multi-technology Internet of interconnected networks. It had been evolving since shortly after World War II. Packets (think telegrams or emails) were transported around the world. There were LANs covering cities, Regional nets over the US, and gateways to nets covering other parts of the world. Even a TransContinentalCorps (TCC) that acted as a WAN.

I learned about all sorts of the technical mechanisms that operated inside the network: routing, flow control, addresses, error control, protocols for retransmissions, compression techniques, etc.

NTS typically carried messages such as Birthday Greetings, e.g., from a soldier stationed in Guantanamo Bay (address: “GITMO”) to a family member back home somewhere in the US. Although most of the distance was covered by radio, using Morse Code, the final link might use a different “LAN”, e.g., a telephone call or even simply driving to the house and delivering a piece of paper. NTS still operates today. More details at https://en.wikipedia.org/wiki/National_Traffic_System if you’re curious.

When I was in Lick’s orbit at MIT, that experience made it easy for me to understand the ARPANET. Later also the Internet. Techniques were different but the problems remained the same.

At one point circa 1975, ARPA asked for our help with a critical DoD need. They wanted computers to be able decode hand-sent Morse code. No one ever explained exactly why to us tech grunts, but we knew Morse was being used by both the good and bad guys. The AI technology of the day was “Expert Systems”. We were tasked to use whatever we thought would help solve the problem.

That started a project which lasted several years, and produced a system which did about as well, possibly even better, than a human operator. From my high school experience, I acted as the “Expert”, and we had a series of staff and student projects to make the PDP-10 do the same things I had learned to do while participating in the radio network. ARPA was happy. DoD was happy. No ham operator could afford the millions of dollars to have their own PDP-10 system, but the government didn’t have that constraint.

The project even appeared in a 1990 Mitre report I think of as a compendium of “ARPA’s Greatest Hits”. See Chapter 22 of https://apps.dtic.mil/sti/tr/pdf/ADA239925.pdf (FYI, ARPANET is Chapter 20 of same report).

Some Zero Retries Interesting Forums at Hamvention 2026 - NewTechHams

Spotted in passing browsing the Hamvention website:

Hackers in Amateur Radio
[Friday] Begin: 2:30 PM / End: 3:20 PM
Location: Room 4
Moderator: Jeremy Hong, KD8TUO

Join Jeremy Hong (KD8TUO), Ed Wilson (N2XDD), Arsenio Menendez (KN4OIH), Terry Schanno (NV0O) and Brian Raker (W4WWW) explore the overlap and coexistence of the amateur radio and hacker communities, and how each has influenced the other. We will discuss how modern tools and platforms like Software Defined Radio (SDR) and Meshtastic are enabling new experimentation, rapid prototyping, and open source collaboration in Amateur Radio. We will also highlight how hacker spaces and conferences are becoming major entry points into the hobby. Attendees can expect practical examples, community perspectives, and ideas for welcoming and collaborating across both worlds.

Radio Club of America - Youth Forum

[Saturday] Begin: 9:15 AM / End: 10:50 AM
Location: Room 3
Moderator: Jim Storms, AB8YK

Join Moderator Jim Storms and some impressive young hams. Webelos Scout Adam Grubb (KF8EKW) is currently building a 70cm EME station for his school science project. Carsten Glasbrenner’s (KQ4SJM) main interests are satellites and DIY projects, such as home brew antennas and simple soldering kits. Haley Pendell (KE2EVX) is active operating POTA, contesting with her radio club friends, and participating in nets, serving as net control for her local 2m net on Saturdays, and building DIY antennas. Maggie Dill (KR4FTN) is active in POTA activations and hosting nets on the local repeaters on her own.She has participated in Field Days and state QSO parties as an operator for the local Charlotte club(W4BFB) of which she is a member. She is sharpening her CW skills and can send/receive up to 25 WPM at the moment, and enjoys activating parks in CW.

Teaching a One-Day Tech Class

[Sunday] Begin: 10:25 AM / End: 11:25 AM

Location: Room 3
Moderator: Dan Romanchik, KB6NU

Join Dan Romanchik (KB6NU) of ARROW, and learn why is it important to teach ham radio classes. He will address why it is better to teach a one-day class instead of a traditional multi-session class, where can you hold the class, publicizing the class, possible fees, timing, teaching techniques, and student follow up.

It’s refreshing to see some attention paid to the particular issues in trying to reach out to NewTechHams at a high profile independent conference like Hamvention.

I’m in violent agreement with KB6NU about the value of a one-day class to reach NewTechHams - they often have enough general technical background to understand the basics of Amateur Radio, and can quickly self-educate on any sticking points they encounter.

AMSAT/TAPR Banquet to Feature Ray Roberge, WA1CYB, Update on AMSAT’s SDR Gen2

Also Zero Retries Interesting at Hamvention 2026, Frank Karnauskas in ANS-109 AMSAT News Service Weekly Bulletins:

Ray Roberge, WA1CYB, will be the speaker at the 17th annual AMSAT/TAPR Banquet. Roberge, a member of AMSAT’s Engineering team, will speak about progress on AMSAT’s SDR Gen2 project, including what it does and where it can be used.

AMSAT’s SDR Gen2 is a versatile, programmable GNU Radio transceiver/transponder designed for a 1U CubeSat footprint. The transceiver has 144 MHz – 6 GHz continuous coverage with 10 GHz coverage expected as well. The transceiver will support direct VHF, UHF, L, S, C, and X band operations in all modes – CW, SSB, FT8, NBFM, SSTV, FSTV, etc. and a downlink data rate of up to 1 MBps. This transceiver is being built to fly on GOLF and FoxPlus missions and will be both open source hardware and software.

The 17th annual AMSAT/TAPR Banquet will be held at the Kohler Presidential Banquet Center on Friday, May 15th at 18:30 EDT.

Learning more details about the AMSAT SDR Gen2 might be a reason to attend this event.

Brief Thought Experiment - SuperPeater Transmitter on 50-54 MHz @ 500 Watts

In researching the article on iShareRadio, I checked in on FlexRadio’s website and saw that “Aurora” which debuted at Hamvention 2025 as a prototype, is now a product line, beginning with the Aurora AU-510.

Recall that the signature feature of the Aurora is (up to) 500 watts output, and able to generate that power incredibly efficiently (uses Polar Modulation) from a standard 120 volt 15 amp circuit. 500 watts with no significant strain; the demo prototype at Hamvention 2025 was keyed down continuously and was barely warm to the touch.

One of the modes of the Aurora series is FM.

One of the frequency ranges of the Aurora series is 50-54 MHz.

50-54 MHz propagates really well. Recall that “Low VHF” was the preferred frequency range for wide area two way communications like the early California Highway Patrol.

So… what if an Aurora, operating at 500 watts, FM, on 50-54 MHz was the output of a cross band SuperPeater… Perhaps at 500 watts it’s a MegaPeater.

It might take a bit of persuasion at FlexRadio to create a new mode to transmit a 20 kHz bandwidth (max currently permitted on 50-54 MHz for US users) signal, but imagine that paired with the upcoming “Audio OFDM” modes.

50-54 MHz, especially at 500 watts, would be trivial to receive using a Raspberry Pi and Software Defined Receiver, as I envision in the SuperPeater concept.

Queue a certain iconic movie theme song; but fun food for thought…

Video - Groundbreaking Research Transmits Energy from Space to Earth

It puzzles me why this particular development is so “groundbreaking” as I recall that there have been many such (small scale, low power) demonstrations of microwave transmission of power from satellites to a receiver on Earth.

GuRu Wireless is the commercialization of this particular technology, and apparently it operates at 24 GHz. Power transfer via microwave radio is yet another “eventually critical” radio technology that’s going to need more technologists. It would be interesting to put a power transmitter in your backyard and have a drone staying on station a few hundred feet up, relaying… say, AREDN signals as part of the backchannel of your power beam to the drone. Or, I suppose the 160m fans would enjoy having a full wavelength 160m vertical antenna.

Video - FAST: China’s Radio Telescope Behemoth

Megaprojects YouTube channel:

AI-generated video summary :

Megaprojects explores the engineering ingenuity behind the 500-meter Aperture Spherical Telescope. This film details the decades-long development process, the unique active surface technology that enables precise sky tracking, and the significant social impact of creating a massive radio-quiet zone in Guizhou province.

Whatever the rivalries between China and the US, I’m proud, as a human interested in the furtherance of science and technology for humanity as a whole, especially in space, to celebrate the advances of science and space technology such as China’s Five-Hundred-Meter Aperture Spherical Telescope:

It has a novel design, using an active surface made of 4,500 metal panels which form a moving parabola shape in real time. The cabin containing the feed antenna, suspended on cables above the dish, can move automatically by using winches to steer the instrument to receive signals from different directions. It observes at wavelengths of 10 cm to 4.3 m.

Wow… a mechanically dynamic array antenna (on a massive scale)! I think that's a first (at least, I’ve never read of an equivalent antenna).

In my opinion, it was a tragedy for science and technology for humanity, and incredible short-sightedness (financially, and for scientific research, and for US science capability) that the US National Science Foundation allowed the Arecibo Observatory to deteriorate to the point of failure3. The loss of capabilities of Arecibo is a significant loss for US-based radio astronomy (and the occasional use for Amateur Radio).

But great for humanity and science that China has created this amazing capability! Perhaps China will want to increase interest Amateur Radio (and interest in radio technology, both China and worldwide) by “activating” the Five-Hundred-Meter Aperture Spherical Telescope for occasional Amateur Radio EME events.

Silent Keyboard - Jeff Mein KP3FT

KP3FT’s obituary was the first I’ve ever seen where involvement with Amateur Radio data communications was specifically mentioned:

Jeff was much more than a skilled operator; he was a visionary in his field. As a founding member of TPRFN, his influence is woven into the very fabric of the network. He was the creator of the “TPRFN” acronym-a name that now represents a growing community of operators dedicated to resilient, RF-based communication. His extensive knowledge of Packet Radio and his technical expertise were matched only by his willingness to help others. Throughout Central New York and far beyond, Jeff continually pushed the boundaries of what the hobby could achieve, always eager to mentor and support fellow operators. Jeff was also a member of the PR Digital Operators Group (PR DOG) out of Puerto Rico, where he worked alongside others as part of TPRFN to help ensure the island would never again experience the communication blackout devastation that followed Hurricane Maria. In addition, he was a member of the Eastnet Packet Radio Group.

This was especially poignant:

His “signal” will be greatly missed, but his legacy will continue to live on through every packet sent across the network he helped build.

KP3FT’s QRZ.com page has a lot of additional detail about his involvement, including more detailed mention of the Puerto Rico Digital Operator Group Services:

Member of the PRDOGS Packet Network . Check out their website, they have a large packet network spanning the island with many nodes. They are also part of TPRFN (see below for more info).

Our condolences to KP3FT’s family and his colleagues on TPRFN, Eastnet Packet Network, and PRDOGS.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the #ZR0248 hashtag.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

Updated - Zero Retries Guide to Amateur Radio HF Data Communications

Added mentions of the HF modes in NinoTNC, Hush new data mode, and VARAtrack as a use case.

Zero Retries Index for 2026 Issues

I’ve been intending to do this approximately forever, but there was aways something more pressing, or more usually, interesting to write about. Today I needed a “global” view of articles I’ve written in Zero Retries in 2026, and so I just sat down and got ‘er done.

Zero Retries Index 2026

It was reasonably easy and efficient to do this manually in less than one hour for 2026. For previous years with 50’ish issues each, would be a significant time sink. Now that I have a pattern / template, hopefully I can hand off generation of indexes for previous years over to an AI. Or perhaps it’s a rote task I can do in the evenings watching video entertainment.

Zero Retries Archive on DLARC Updated

The Zero Retries newsletter collection on DLARC is now mostly updated for most issues published in 2026. This is an archive of PDF versions of Zero Retries issues.

It won’t be up-to-the-latest-issue complete except around the end of the month or beginning of the month when I upload a month’s worth of PDF issues to DLARC’s Curator Kay Savetz K6KJN.

Could Be Worse… Could Be Raining

My favorite movie is Young Frankenstein, and one of my favorite quotes in that movie is the above. Click here to get the context. Generally… don’t jinx things like I did on Wednesday evening by considering this issue “complete”. (I’m not griping… just explaining how much interesting new stuff keeps occurring.)

I finished writing and proofreading this issue by the end of the day on Wednesday and queued it up for delivery at 15:30 Pacific on Friday as has always been my goal for publication. I dared hope that, for once in a great while, I was ahead of things and Zero Retries would go out as intended, and I could move on to other overdue writing tasks on the remainder of the week, including my presentation for LinuxFest Northwest on Sunday.

But… could be raining. When I opened my email on Thursday morning, there were no less than six great suggestions of Zero Retries Interesting items for inclusion in Zero Retries. All of them were relevant enough to merit inclusion in this issue, especially the lead story about MeshCore. I had an urgent article to write on Thursday, thus had to add all the new articles on Friday, which, of course, pushed the publication time a little past 15:30.

The word count of this issue on Wednesday evening was 8925. The final word count just prior to publication is 12517.

Weekends Are For Amateur Radio! LinuxFest Northwest 2026

This weekend is LinuxFest Northwest 2026 at Bellingham Technical College. LFNW is the highlight of the Bellingham techie social calendar. There used to be a few other techie events in the Bellingham area, but they’ve all faded out. LinuxFest Northwest also faded out, but it was revived with new energy by a team from Cascade Steam working with Bellingham Technical College to hold this beloved event. I’ve been attending LFNW literally for decades now. Coming to Bellingham every year for LFNW made us familiar with Bellingham and LFNW and the Bellingham techie community was a minor factor in Tina and my decision to relocate to Bellingham from the Seattle area.

I’ll be attending LFNW on Saturday. None of the Saturday presentations leap out at me, but I always manage to pick a few to attend that justify attending LFNW each year. A highlight of every LFNW is hearing John “maddog” Hall speak on… whatever. His topic for LFNW 2026:

Sovereignty

maddog travels around the world. More and more in various countries he hears the word “sovereignty”. Sovereignty, like the word “free” (as in Free Software) is often confusing.

Free Software is not just about the FreeDOM to do what you want with your software, but also about YOU having CONTROL of your software, and not some company or other person.

Today most people think of “Sovereignty” as having your data stored in your own country, under your country’s laws. But Sovereignty also means that YOU are the “sovereign”, YOU are the “king” (or queen) of your computer.

This talk will discuss the issues of sovereignty and how, through Free Software, Open Hardware, Open Data and the Internet you can regain control of your computing, and therefore your business and life.

Saturday, 09:30 - 10:00 in HC 108

It’s always a privilege to hear maddog speak - he’s like the beloved, whacky professor of Linux.

On Sunday, I’m doing a presentation:

Open Source and Linux in Amateur Radio

In many ways, Amateur Radio was the original open source community. Schematics and other aspects of amateur (as in non-professional) projects were shared freely. That open source ethos has continued to the present day, made even more impactful with the development of Software Defined Radio such as GNU Radio. The most impactful project for Amateur Radio at the moment is the Linux Handheld Transceiver (LinHT) which runs Linux and GNU Radio - shell into your portable radio!

Target Audience Techies that are curious about radio technology and want to go beyond using unlicensed spectrum.

Sunday, 11:20 - 11:50 in CC 235

I did a similar talk at LFNW in 2024 and I didn’t think it went well (no converts to Amateur Radio that I could tell). At LFNW 2025 I talked to a Linux fan who attended my 2024 presentation, and I told them I didn’t think it had gone well, so I didn’t submit a request to do a presentation. They said “Your talk was great! You realize that not only did you fill up every seat in the room, but there were people that wanted to attend but weren’t allowed to (overcrowd the room)?” I was humbled by their enthusiasm, so I’m going to do it again.

Hamvention Ho!

3 weeks until Hamvention 2026

2026-05-15 thru 17 in Xenia, Ohio, USA...
Zero Retries / DLARC booth 1506
in Building 1 / Maxim

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the #ZR0248 hashtag.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

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The Usual Administrivia

⬅️⬅️⬅️ Previous Issue of Zero Retries \ Next Issue of Zero Retries ➡️➡️➡️

Zero Retries 0248 was published on 2026-04-24. This issue was 12517 words.

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

I saw at least one reference / plaint that the zBitx software from HF Signals is “still 32 bit”.

2

xOTA - Summits On The Air, Parks on the Air, Whatevers on the Air…

3

There were numerous warning signs of impending failure of the Arecibo radio telescope, which were not acted upon.

]]><![CDATA[Zero Retries 0247]]>https://www.zeroretries.org/p/zero-retries-0247https://www.zeroretries.org/p/zero-retries-0247Sat, 18 Apr 2026 05:07:41 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its fifth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is too big for email clients. Thus, it might be easier to read in a web browser: https://www.zeroretries.org/p/zero-retries-0247.

It’s easy and free to subscribe for your own copy of Zero Retries every week:

Subscribe now

In This Issue:

I-Frame

VARA FM is Not an “Encrypted” Mode and is Legitimate and Legal for Use on Amateur Radio

More Widespread Use of OFDM in Amateur Radio VHF / UHF Data Communications is Imminent

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Prefers to Remain Anonymous 25 for renewing as an Annual Paid Subscriber (3rd year! to Zero Retries this past week!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the #ZR0247 hashtag.

VARA FM is Not an “Encrypted” Mode and is Legitimate and Legal for Use on Amateur Radio

I discuss the significant accomplishment of developing an independent work-alike implementation of VARA FM in the following article.

Billy Penley KN4MKB’s article on his blog TheModernHam - Reverse Engineering VARA FM Part 1 – Connection Request, Legal Disclaimer and Reasoning makes a number of claims against the popular VARA FM data communications mode used on Amateur Radio VHF / UHF bands. Of course, every individual, and every Amateur Radio Operator, is entitled to express their opinion.

Post Publication Update - This article is no longer accessible on TheModernHam website, but it remains online via the Internet Archive - link.

The overall tone of the first few paragraphs of KN4MKB’s article calls into question the “legitimacy” of being able to use VARA FM on Amateur Radio because the information VARA FM’s author has chosen to disclose is not sufficient to create an independent implementation (workalike / interoperable) application of VARA FM for the purpose of passively monitoring VARA FM transmissions.

I disagree with KN4MKB’s assertions that there was not “sufficient” information about VARA FM publicly disclosed by VARA FM’s author.

KN4MKB:

Thousands of amateur radio operators across the United States are using VARA FM, and VARA HF. This issue is that in the United States is that we also have an FCC regulation (FCC Part 97.309(a)(4))

An amateur station transmitting a RTTY or data emission using a digital code specified in this paragraph may use any technique whose technical characteristics have been documented publicly, such as CLOVER, G-TOR, or PacTOR, for the purpose of facilitating communications.

…

At what point between an undocumented frame structure, then XORing the frame bits, 2 different levels of encoding using data tables not viewable from disk(must be dumped from VARA as it is running), and then RNG based constellation mapping that can only be done when you seed the callsigns into a reverse engineered VB6 RNG algorithm do we say this isn’t publicly documented? You are going to keep using something like this, and shake your fist when someone says the word encryption? There is a reason nobody out there up until now has created a decoder for VARA data frames, and it’s not due to lack of trying. The details of this encoding/decoding is not documented anywhere. To me, there’s virtually no difference between that, and encryption itself.

KN4MKB’s assertions are only that - assertions / his interpretation / his personal opinions.

I posit that a reading of the exact wording of § 97.309 RTTY and data emission codes negates KN4MKB’s assertions about VARA FM:

… may use any technique…

… technical characteristics…

… documented publicly…

By the metric of the exact wording…

  • VARA FM’s author has used a technique…

  • With various technical characteristics…

  • That has been documented, publicly.

Whether a particular “data emission code” in use in (US) Amateur Radio is compliant with “documented, publicly”, rests solely with the FCC. Note that in 97.309 (b), if a “data emission code” is not sufficiently “documented, publicly”, there is a specific remedy:

When deemed necessary by a Regional Director to assure compliance with the FCC Rules, a station must:

(1) Cease the transmission using the unspecified digital code;

(2) Restrict transmissions of any digital code to the extent instructed;

(3) Maintain a record, convertible to the original information, of all digital communications transmitted.

§ 97.309 does not offer any specifics as to the degree of detail what must be documented, publicly to use a new “data emission code”.

§ 97.309 also does not offer any specifics about “publicly”. In the 2020s, it’s reasonable to consider “publicly” to be posted on a publicly accessible website. But in earlier eras, prior to the widespread availability of Internet access, “publicly” often meant publication in a magazine. Thus this flexility of “documented” being not specifically defined, and “publicly” not being specifically defined is, in my opinion, a net positive to Amateur Radio.

§ 97.309 is an Amateur Radio Superpower

I posit that being able to develop and use new “data emission codes” in Amateur Radio with the simple requirement to have (some) “documentation”, disclosed in some “public” manner, is effectively an Amateur Radio superpower.

Unlike other radio services that can make use of only those modes, modulations, systems, etc. that are specifically permitted in FCC regulations, Amateur Radio is unique that it can create new modes, modulations, systems, etc.

In the 2020s, this flexibility is going to become highly relevant in Amateur Radio as we begin to see the use of new modes, modulations, systems, etc. that are developed in whole or in part with the use of Artificial Intelligence / Machine Learning. That’s because we humans won’t necessarily know how the AI developed such systems. Especially those of us who aren’t experts in developing new modes, modulations, systems, etc. But there are lots of us who have “ideas” that we’d like to experiment with, and asking an AI to develop such ideas is no different than working with a capable human to develop such systems. What we will be able to “document, publicly” is what AI (especially which version) was used, and what the prompt(s) were to guide the AI to develop the new mode. With the flexibility of “documented, publicly”, Amateur Radio is able to experiment, per…

§ 97.1 Basis and purpose.

The rules and regulations in this part are designed to provide an amateur radio service having a fundamental purpose as expressed in the following principles:

…

b) Continuation and extension of the amateur’s proven ability to contribute to the advancement of the radio art.

(c) Encouragement and improvement of the amateur service through rules which provide for advancing skills in both the communication and technical phases of the art.

…

KN4MKB’s Assertions Are a Slippery Slope

If KN4MKB’s assertions about VARA FM not disclosing sufficient technical detail, what does that say about the use of a number of popular modes, modulations, systems, etc. that also have not disclosed “sufficient technical detail”, such as:

  • Digital voice systems whose core technology is the use of the patented, proprietary, technology-not-publicly-disclosed AMBE vocoder? The AMBE vocoder is used in DMR, D-Star, System Fusion, P25, and other systems in wide use in Amateur Radio.

  • Pactor 4 is widely used in Amateur Radio for HF Winlink. It’s reliable and robust and provides high (for HF) data transfer rates. But the details of Pactor 4 are also proprietary, technology-not-publicly-disclosed.

  • LoRa is becoming widely used in Amateur Radio because it provides a robust, modulation that works amazingly well at low power levels and achieves surprising range at those low power levels. Generically, it is an implementation of Chirp Spread Spectrum (CSS), but the specific technical detail of LoRa is, again, proprietary, technology-not-publicly-disclosed.

Another instructive example of this slippery slope about asserting “not sufficient technical detail” disclosed is that the CLOVER mode, which specifically named in FCC Part § 97.309 has never had “sufficient technical detail” provided. I queried Claude AI for a (simplistic, potentially flawed) reality check:

Are there any “open” implementations of the CLOVER modulation technique for use on HF radio bands? Or, are the technical details of CLOVER considered proprietary, not disclosed publicly?

Claude AI’s response:

CLOVER is largely proprietary and closed, which has significantly limited its adoption and longevity. Here’s the situation:

What CLOVER is

CLOVER was developed by HAL Communications in the early 1990s (Bill Watkins, W5IYV, was the primary inventor)1. It uses a multi-tone PSK/AM hybrid modulation with adaptive rate control — quite sophisticated for its era. HAL sold dedicated hardware modems (the P-38, DSP-4100, etc.).

Proprietary status

The core CLOVER waveform and protocol details were never fully publicly documented in a way that enabled independent implementation. HAL held patents on the technique, and the technical specifications weren’t released as an open standard. This is in stark contrast to, say, PACTOR (where at least the lower modes had some documentation) or the various open modes like VARA, JS8, Winlink/ARDOP, etc.

Open implementations

As far as is publicly known: no open-source implementation of CLOVER exists. There have been no successful clean-room implementations that gained traction. The combination of patent protection (now likely expired, given the age) and lack of published specs meant nobody built one during the window when it was commercially relevant — and by the time patents would have expired, the mode had been eclipsed by newer digital modes.

Current status

HAL Communications appears to have ceased active development and sales of CLOVER hardware. The mode is essentially dead in practice. Most operators who cared about robust HF digital moved to PACTOR III/IV, or more recently to VARA HF (which is semi-open/free but not fully open-source either).

…

If you’re researching this for historical coverage, the ARRL’s QEX magazine had some early 1990s articles on CLOVER that are probably the most detailed public technical documentation available.

And… here we’re presented with a continuation of the slippery slope about what constitutes “disclosed, publicly”. While ARRL provides a reference page for CLOVER2 with some technical detail: https://www.arrl.org/clover, the technical detail that might be sufficient to be able to create an independent implementation of CLOVER is largely in the References articles. Some of the publications listed aren’t accessible at all - CQ Communications is out of business, and access to its magazines are in legal limbo. Does having published once in a magazine (that you can no longer access) count as “disclosed, publicly”? Past issues of QEX are only available to current (paid) members of ARRL. Does access to those issues of QEX by (paid) ARRL members, but not available to those who are not ARRL members count as “disclosed, publicly”?

Over time, Amateur Radio (and the radio technology industry in general) has developed “understanding” of how all of the above “work”… but that’s not the same as having all the technical details publicly disclosed for the purposes of developing independent workalike, interoperable systems to be able to monitor transmissions from these systems.

Want to Monitor? Just Buy a System.

But for anyone that wishes to do so, the simple expedient of buying a compatible system…

  • a DMR, D-Star, System Fusion, P25 radio that incorporates an AMBE vocoder,

  • a Pactor 4 modem,

  • a unit that incorporates a LoRa radio,

  • VARA FM and VARA HF software can be downloaded at no cost3.

provides a reasonable ability to monitor the usage of such systems on Amateur Radio spectrum. Including, if one is really motivated to monitor CLOVER transmissions, going to some trouble, of finding a used HAL Communications P-38 or DSP-4100 on eBay.

Conclusion

In the above, I am not positing that the author of VARA FM has disclosed a lot of technical details about VARA FM sufficient to allow other compatible, interoperable implementations to be created. That is not the case.

I am also not positing that the author of VARA FM didn’t make a number of technical choices in their implementation of VARA FM that are unexplained.

I conclude that that the author of VARA FM has met the letter of FCC § 97.309:

… technical characteristics have been documented publicly, …

because at least some technical characteristics have been documented publicly.

That is all that is required.

An individual Amateur Radio Operator’s opinion (whatever their background) of whether a particular system’s “technical characteristics have been documented publicly” adequately, or not adequately, are irrelevant. That is solely the FCC’s determination.

I further posit that this ambiguity provides a huge advantage to Amateur Radio.

The simple expedient of:

… technical characteristics have been documented publicly, …

allows the development of any new technology, system, modulation, etc. to be used on Amateur Radio spectrum.

Lastly, I offer this a straw man argument… imagine what the FCC would do if it wants to monitor a transmission from an Amateur Radio repeater that uses P25 technology.

Is the FCC going to attempt to create its own independent implementation of a P25 receive capability from “… technical characteristics have been documented publicly…?

Or is it just going to resort to the simpler, more practical expedient of purchasing a P25 radio and begin monitoring?

Please direct comments / feedback about this article to the Zero Retries email list with the #ZR0247 hashtag.

More Widespread Use of OFDM in Amateur Radio VHF / UHF Data Communications is Imminent

By Steve Stroh N8GNJ

Behind the scenes of some popular Amateur Radio modes, OFDM has been quietly emerging as a significant improvement in data communications in Amateur Radio. I predict that in 2026, OFDM will come out from behind the scenes to be more widely used (and recognized). OFDM will create new capabilities… and more capable data modes.

The first (that I’m aware of) and most widely known implementation of “Audio band Orthogonal Frequency Division Multiplexing (OFDM)”4 in Amateur Radio data communications, is VARA FM. With the use of “Audio OFDM”, VARA FM is robust, adaptable to varying conditions on the radio channel, and provides greater data rates than other technologies used on Amateur Radio such as Frequency Shift Keying (FSK).

Very tersely, OFDM divides a communications channel (either an audio channel, or a radio channel) into many subcarriers, and then operates each subcarrier as if it is an independent audio, or radio channel - boosting power for subcarriers that need it, “striping” data across multiple subcarriers with redundancy.

Various Implementations of OFDM in Amateur Radio

As far as I can (very inexpertly) determine, there was nothing unique about the way OFDM was applied in VARA FM. Thus it was possible for others to create audio band, or radio channel modes that incorporated OFDM. For example, the following modes also use OFDM techniques in dividing a channel into subcarriers:

VARA FM implements a number of other techniques besides OFDM to make it so effective as a data mode for VHF / UHF. Examples:

  • Channel sounding

  • Handshake between two stations to determine maximum common capabilities

  • Forward Error Correction (FEC)

  • “Upshift / Downshift” of speeds, modulations, etc. for reliability versus throughput

Thus it’s notable that Billy Penley KN4MKB, in an article on his blog TheModernHam - Reverse Engineering VARA FM Part 1 – Connection Request, Legal Disclaimer and Reasoning claims to have created an independent, interoperable equivalent of VARA FM:

At the point of writing, I have a fully functional modem that can complete a basic connection cycle with VARA FM. It can generate its own compatible frames, and decode the ones sent back from VARA FM as well. It lacks the automatic speed change based on SNR at this time.

A basic requirement of creating a independent, interoperable equivalent of VARA FM is to understand all the elements of VARA FM, and KN4MKB has done an admirable job of describing the basic functionality of VARA FM:

A high level overview of the VARA FM Program.

VARA at its core is a digital modem with Orthogonal Frequency-Division Multiplexing (OFDM) with adaptive modulation, scaling from 4PSK up through 256QAM to achieve data rates from roughly 550 bps to over 25 kbps. VARA operates as a TCP server, listening on one port known as the “Control Port”, and another port known as the “Data Port” (8300, 8301 by default.) The modem handles all modulation, demodulation, error correction, and ARQ protocol internally.

The application seems to have been written in Visual Basic 6 by Jose Alberto Nieto Ros (EA5HVK).

The basic idea, is that an application (like Winlink Express) can simply connect to VARA port 8300, and setup some basic parameters (Listen callsign, connecting callsign, bandwidth mode etc. The application can start and stop connections by sending special commands to this port. Once connected, the application can then send data to the data port on 8301, and also read data from it as well. The great part is that the application doesn’t really need to know much about how the modem itself works. It just sends the connection request, (Or listens for one), and reacts with data meant for the other side.

KN4MKB goes on, at length to describe the inner workings of VARA FM. I hope that KN4MKB follows through in releasing his system. A system that provides equivalent features to VARA FM that is open source and thus can be ported to operate on Linux (especially on Linux systems such as Raspberry Pi 4 and 5) without the need for the “overhead” of operating VARA FM on a typical Windows system, would be welcome and highly useful.

But beyond the news about KN4MKB’s of a “VARA FM equivalent”, there’s other news about the use of OFDM in Amateur Radio.

NinoTNC Implementation of OFDM

Recall this Press Release from Alberta Digital Radio Communications Society (ADRCS):

Calgary, Alberta, January 30th 2026. The Society is pleased to announce that it is collaborating with the Terrestrial Amateur Radio Packet Network group (TARPN) to implement an audio band version of its OFDM technology in their Terminal Node Controller (TNC). “Adding the TNC rounds out the vision of the supernode that we presented at the Zero Retries Digital Conference last September and extends the functionality of the IP400 network to conventional radios on the 2M, 220 and 450 MHz bands, without any modifications”, says Martin Alcock, VE6VH, founder of the IP400 project. “Adding OFDM to our TNC gives us a higher speed mode than previously implemented and practical experience with OFDM”, says Nino Carrillo, KK4HEJ, creator of the TNC. Martin goes on to say “in addition it will give us access to proven KISS mode technology that will greatly enhance the utility of our existing nodes in delivering higher data rates for conventional packet radio applications on existing terrestrial networks”.

Although ADRCS / IP400 is working with KK4HEJ on “Audio OFDM”, their (hardware) implementations are different. IP400 describes their implementation as “Mode B”:

Mode B

Mode B is unique to the IP 400 project, to implement a higher speed data mode that interfaces to conventional radios, by providing a baseband (mic/speaker) connection to the radio. It achieves higher speeds using a technique known as OFDM (Orthogonal Frequency Division Multiplexing), also known to as LTE on the cellular band. This mode can be used with any existing radio or repeater in either the 144, 220, 440 or 902 MHz bands. Existing analog repeaters can be upgraded by adding of a small amount of hardware, and an audio path to existing AllStarLink systems are also supported with a custom audio driver.

The hardware for this mode employs a high end microcontroller and FPGA (Field Programmable Gate Array), all of which are field upgradeable.

(That description, unique to the IP400 project, probably predates the decision to collaborate with KK4HEJ.)

Since then, I haven’t seen any (public) status reports from either IP400 or NinoTNC, but there apparently is considerable progress being made on both “sides”. But recently, there were some public updates on Discord.

I’m not a user of Discord, so I did not see this discussion for myself, but a number of screenshots were shared with me from the ninotnc Discord channel. The text in the screenshots were transcribed by Claude AI, and lightly edited for publication by me.

John N3XKD — Hey Nino, you don’t have any news on the IP400 collab, do you ?

Nino KK4HEJ — Sure do. We have been designing and testing OFDM waveforms that fit in a 3 kHz audio channel, that can be sent and received over an unmodified FM radio through the mic/speaker jacks. The 3kHz audio scheme uses 116 data carriers at about 22.7 symbols per second. Constellation complexities vary from BPSK to QAM256.

John N3XKD — So, What’s that translate to in throughput and what hardware-ish?

Nino KK4HEJ — We hope to realize around 18kbits/sec in an audio channel. Lots more in a wideband channel (like an FM radio with a data port). The IP400 project is building a daughter card that slots into the NinoTNC that carries an FPGA and STM32. But... I am getting more confident that I’ll be able to implement most of the audio channel capability in the dsPIC.

[scatter plot image — IQ constellation]

This is an actual over-the-air test of a QAM64 OFDM constellation that carries around 14kbits/sec. The transmit audio was fed into the mic port of an FTM-3100 and the receive audio was taken from the headphone jack of an IC-2000H. Processing was done on a computer. SNR in that I/Q plot measured at around 25dB, so almost a full-quieting FM signal.

Nino KK4HEJ — The heavy-hitter magic in this mode are the time-domain synchronization approach and the channel equalization scheme. The modem will be performing real-time channel estimation for each packet, which accounts for emphasis mismatch and timing offset errors.

John N3XKD — So, will there be a requirement for time sync ? frequency and phase ? Would you mind if I shared some of your info with the un-official IP400 discord ?

Nino KK4HEJ — Not in an external sense. The transmitter and receiver will be asynchronous. The decoding modem will be doing hard work to search for the sync preamble from the transmitting modem. Once that sync preamble is found, the decoding modem has a fairly large timing window to do the frequency-domain work.

John N3XKD — Ah ok, kinda like T1 timing, how you could time off of one end or the other

Nino KK4HEJ — I don’t mind, this is mostly written into the IP400 spec. I am not the IP400 communication lead, so I’m not sure what they are putting out. There are many modes encompassed in the IP400 project. We were calling this mode OFDM-AB at first (for audio-band), but I think it is called OFDM-B now.

John N3XKD — Yeah, looks like B.

…

John N3XKD — This is going to be essentially a KISS setup right ?

Nino KK4HEJ — There is a KISS mode in the IP400 architecture. The NinoTNC is a KISS device now and it will stay that way in the future. There are other interface methods with their supernode, but that’s outside of my scope.

John N3XKD — Yeah, it’s tough to follow the A and C modes, but this B mode is extremely interesting (edited) It’ll benefit TARPN big time Regular packet, you name it I have a pair of the dev radios and a pair of the Pi Zero hats for the A mode, just haven’t done much with them

Nino KK4HEJ — The B mode is what I care about the most, but we are moving so fast on the B mode that one of the other modes will be a high-speed mimic of it. Can’t remember if it’s A or C. One of those is 4FSK, the other is super-wideband OFDM.

John N3XKD — I ‘think’ A I think the super wide is the C I think the A is the one that’s being targeted to fit into the 70cm rules C is like 900 and up maybe, I ‘think’

Nino KK4HEJ — Ya, it’s a big project. To their credit, they are very focused on actual radio links. I only have enough capacity to keep focused on the B mode. This is the output of one of my python-based ofdm demodulator programs. The input was a wav file of audio recorded from a radio link. Top left you can see the channel magnitude response, bottom left is the phase response of the channel. The equalizer accounts for both, the red dots in the I/Q charts are the output of the equalizer. The grey dots in the I/Q charts are the unequalized samples. This is an early waveform, we have adjusted since, but demonstrates the capability of the equalizer pretty well.

[multi-panel chart image — channel magnitude, phase, and IQ symbol plots]

Tadd KA2DEW — This is incredible!

(I agree with KA2DEW!)

In addition to all of those implementations of OFDM, there is another promising implementation of OFDM in progress - Mesh Operations Protocol (MOP) in development by Stefaan Desmedt KO6IKR:

MODEM - OFDM modulation (4800 bps) / Direwolf / TCP Ether test

All of this development of OFDM is wonderful and welcome. Amateur Radio data communications on VHF / UHF has been hampered by limiting its interoperability to 1200 bps AFSK, and semi-interoperability of 9600 bps FSK, and widely varying implementations of other speeds, and modulation methods.

Yes, we’ve had and have…

  • 25 kbps with VARA FM (proprietary, uses a wideband audio interface and radio with flat audio input / output)

  • 56 kbps with the WA4DSY 56k modem (unique radio + transverter, open source)

  • 128 kbps with the Icom DD mode (unique, proprietary mode, Icom radios only)

  • 100 kbps - 1 Mbps with New Packet Radio (unique radios, open source)

But we’ve had frustratingly little that most people could actually use with their existing radios, other than VARA FM. Apparently in 2026, that will change!

Recounting, these are implementations of OFDM for use for Amateur Radio VHF / UHF intended as a data (file exchange) mode available or in development:

  • MT63

  • Mercury (currently targeted at HF, but not “restricted” to use on HF)

  • Hush (added post publication)

  • VARA FM

  • KN4MKB independent implementation of a “VARA FM Workalike”

  • IP400 “Mode B” by IP400 on IP400 hardware

  • IP400 “Mode B” by Nino Carrillo KK4HEJ for implementation on the NinoTNC

  • Mesh Operations Protocol (MOP)

The energy, creativity, and talent that is being applied to the above is exciting and encouraging. But I can foresee a looming… problem situation emerging.

Another Amateur Radio Tower of Babel - OFDM?

Of the OFDM implementations mentioned,

  • KN4MKB’s project is working to be interoperable with VARA FM.

  • IP400 and NinoTNC are working to be interoperable with each other.

That’s the extent of attempts at interoperability with these new implementations of OFDM in Amateur Radio.

Thus we might be on the cusp of creating a new Tower of Babel situation similar to what has occurred with Digital Voice systems used on Amateur Radio VHF / UHF - not interoperable, despite being very similar from a technical perspective.

It would be a shame if that same situation emerged with OFDM implementations in Amateur Radio such as a NinoTNC operating “Mode B” not being able to interoperate with a MOP node. Similar to the disparate Digital Voice modes, we would have “technical islands” of connectivity that couldn’t interoperate or network via radio.

Given that all of these modes are entirely software-defined, designed to work within the audio bandwidth of a typical Amateur Radio VHF / UHF transceiver, either with microphone / speaker connections or (works better / faster) with flat audio connections, it seems feasible that all of these OFDM implementations could work out interoperability details for the basic modulations. All of the other details about their various modes of operation - protocols, etc. could all be hashed out as “Protocol IDs”.

Yes, it’s going to be possible to “be compatible with any / all modes” with the capabilities of Software Defined Radios such as the LinHT… but there are going to be a lot of existing radios / modems that could be adapted to use these new “Audio OFDM” capabilities. Thus the best-case scenario would be if these Audio OFDM modes could be made interoperable. Or, at very minimum, recognize each other’s transmissions and thus sense an existing transmission in progress and avoid “doubling” with each other. This a real issue with 1200 bps AFSK and 9600 FSK packet radio not being able to share a channel because they cannot detect the other mode’s transmissions.

Perhaps, Some Coordination?

Thus, I suggest, again, the possibility of forming an organization modeled on my idea of the Amateur Radio Standards Organization (ARSO). It doesn’t have to be a formal, dedicated organization - it could be an ad-hoc assemblage of interested parties. I hope that such an organization / activity could be sponsored by an existing “parent” organization. I’ve done some outreach about that possibility… but have not received any encouraging responses.

Or perhaps I’m hopelessly out of date in this approach. Perhaps the necessary technical coordination could be hashed out with the interested parties showing up on the same Discord channel and hash out their respective code on a new Github repository.

I also offer the interested parties involved in the above a forum / presentation slot (panel discussion perhaps?) at Zero Retries Digital Conference 2026.

In any case, whatever the outcomes, 2026 promises to be a very interesting year for Technological Innovation in Amateur Radio.

Please direct comments / feedback about this article to the Zero Retries email list with the #ZR0247 hashtag.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

WSJT-X 3.0 Upgrade Is Significant

Tom Salzer KJ7T in Random Wire 178:

Here’s a rundown of what changed from WSJT-X 2.x to 3.0, released April 8, 2026. (Find WSJT-X on SourceForge.) When you upgrade, it’s good practice to back up your WSJT-X.ini and log — your settings should migrate (mine did), but better safe than sorry.

I had listed WSJT 3.0 as an item for inclusion in this issue’s ZR > BEACON, but when I opened Random Wire 178 Friday morning, candidly… KJ7T did a much better job of explaining the relevance of this upgrade than I was prepared to do in as a short mention in ZR > BEACON. Just click the headline to go directly to that article on Random Wire 178. Or, treat yourself to the entire issue - Random Wire 178.

Two Good Articles on M17 In Random Wire 178

Not to pile on too deep on Random Wire 178 and the KJ7T Admiration Society, but if you’re a fan of M17 and pressed for time, check out these two articles by KJ7T:

Notable: Jim N1ADJ’s M17 Go Tools Project

and

M17 Data Modes: The Sleeping Giant Wakes

I appreciate the excellent job that KJ7T is doing in following developments on M17.

Ham Radio History: How RTTY Became the First Mainstream Digital Data Mode

Mark Haverstock K8MSH on the On All Bands blog:

Radio Teletype (RTTY) became a popular digital mode in amateur radio through a mix of postwar circumstances, technical curiosity, and a group of operators who looked at a 180-pound machine and thought, “This would look cool in my radio room.” Its growth reflects both the experimental spirit of ham radio and the fact that, sometimes, if it makes noise, prints letters, and connects to a transmitter, hams will find a way to make it communicate with the world.

History of RTTY, Part 1

The origins of RTTY can be traced back to the late 19th and early 20th centuries with the invention of teleprinters, also known as teletypewriters. These machines sent typed text over wires using electrical signals encoded in standardized formats, such as the Baudot code. By the 1920s and 1930s, teleprinters were already well established in wireline communications, particularly for news agencies, government operations, and business.

However, early experiments in transmitting teleprinter signals over radio faced several challenges. Noisy radio frequencies were prone to interference, making reliable transmission of digital signals difficult. But soon, engineers discovered that frequency-shift keying (FSK)—a method where two distinct tones represent binary states—was particularly robust against noise. Instead of transmitting simple on/off signals (as in Morse code), RTTY used two tones to represent “mark” and “space,” corresponding to binary 1s and 0s. This made the system far more reliable over long distances and under poor propagation conditions.

This is a really good summation of the history of RTTY on Amateur Radio. One intermediate stage between the mechanical teletypes and personal computers was when microprocessors became widely available, companies like HAL Communications produced microprocessor-based RTTY modems / Terminal Unit (TU) (encoder, decoder). I remember one unit had the innovation of a parallel printer port that you could connect to a common dot matrix line printer which would then print everything received by the TU.

I’m surprised that K8MSH didn’t mention one of the most popular uses for RTTY - RTTY Art. Using the “nuances” of careful selection of characters, one could transmit images via RTTY. Calendars were popular, and some images were… “racy”.

I’ve found that www.rtty.com is a fantastic resource for all things Amateur Radio RTTY. Whenever I’ve done a web lookup for something relating to Amateur Radio RTTY, I seem to get directed to some corner of that site.

My thanks to Amateur Radio Weekly, Issue 416 for the first mention I saw of this article.

Stealth Signals Are Bypassing Iran’s Internet Blackout

Evan Alireza Firoozi in IEEE Spectrum:

…

Thirteen days into the January shutdown, we at NetFreedom Pioneers (NFP) turned to a system we had built for exactly this kind of moment—one that sends files over ordinary satellite TV signals. During the national information vacuum, our technology, called Toosheh, delivered real-time updates into Iran, offering a lifeline to millions starved of trusted information.

…

Satellite TV uses a file system called an MPEG transport stream that allows multiple audio, video, or data layers to be packaged into a single stream file. When you tune in to a satellite channel and select an audio option or closed captions, you’re accessing data stored in different parts of this stream. The NFP team’s insight was that, by piggybacking on one of these layers, Toosheh could send an MPEG stream that included documents, videos, and more.

…

A satellite receiver can’t tell the difference between our data and normal satellite audio and video data since it only “sees” the MPEG streams, not what’s encoded on them. This means the data can be downloaded and read, watched, and saved on local devices such as computers, smartphones, or storage devices. What’s more, the system is entirely private: No one can detect whether someone has received data through Toosheh; there are no traceable logs of user activity.

…

NFP’s solution was to add redundancy, similar in principle to a data-storage technique called RAID (redundant array of independent disks). Instead of sending each piece of data once, we send extra information that allows missing or corrupted packets to be reconstructed. Under normal circumstances, we often use 5 percent of our bandwidth for this redundancy. During periods of active jamming, we increase that to as much as 25 to 30 percent, improving the chances that users can recover complete files despite interference.

This is a fascinating article about this technique of repurposing a bitstream designed for one use case to transfer files. This overall idea, transmitting bulletin files5 is a technology that has been little-used (that I’m aware of). My favorite implementation of this idea is flamp - Amateur Multicast Protocol. flamp (and an earlier implementation of this idea, RadioMirror) divides a collection of files to be transmitted into blocks. All of the blocks are transmitted sequentially with a sequence number and checksum. The flamp receiver is passive - there’s no ARQ (Automatic Retry Request) mechanism. If a block is received with an incorrect checksum, the file isn’t reassembled until a block with the correct checksum is received. I think this system could be made even better with the IL2P Forward Error Correction system that’s now available as open source. When I finally get a test repeater on the air, this will be one of my use cases for the repeater - transmitting bulletin files, using flamp, in the wee hours.

This system is potentially useful for Amateur Radio because of the idea that is periodically floated about “what if Amateur Radio could obtain the use of a transponder on a geostationary satellite”? This system could be used with no changes in the “video” paradigm of the uplink and satellite infrastructure, unlike the unique uplink and receiver hardware that Outernet / Othernet system / service6 required.

Use of a geostationary (GEO) satellite transponder by Amateur Radio isn’t an absurd idea given the increasing irrelevance of the two primary uses of transponders on GEO satellites - broadband Internet access (Starlink has almost entirely killed that business model) and Direct Broadcast Satellite (“cable television via satellite) (also killed by Starlink customers using streaming video). Thus there might be “deals” available for the use of entire transponders or sharing the use of a transponder in the wee hours.

Fixing Baltimore’s Unequal Weather Data Coverage

Rebecca Owen on EOS:

Waugh et al. describe a partnership between universities, state agencies, and Baltimore residents to build the Baltimore Community Weather Network (BCWN) that addresses the missing data coverage around the city. Unlike the patchwork of personal weather stations, community members participating in the BCWN are from underserved areas in the city and are actively involved in data collection and interpretation.

Weather stations are placed in open spaces to avoid obstacles like buildings or trees affecting measurements of temperature, rainfall, or wind. This careful placement is designed to ensure that the data collected are as close as possible to the conditions experienced by actual residents.

BCWN sites are carefully monitored and managed by community members. Baltimore residents are actively involved in data collection, weather station management, and decisionmaking with scientists and local organizations to help promote engagement, education, and community empowerment.

Group Seeks to Close RADAR Gap with Hays Community Radar Project

Cristina Janney in Hays Post:

The Hays Community Radar Project is seeking to raise $360,000 to purchase and install a Furuno dual-polarity Doppler weather radar to cover Hays and the surrounding area.

This initiative aims to eliminate a dangerous blind spot in Kansas weather coverage. Because the nearest National Weather Service radar is in Dodge City, the Earth’s natural curvature creates a beam overshoot problem.

The radar beam from Dodge City travels upward as it moves away from the source. By the time it reaches Hays, the bottom of the beam is at about 6,000 to 7,000 feet.

“Because the NWS beam travels in a straight line, it is over 7,000 feet over our heads in Hays,” said Dr. Kendall Krug, a board member at STEM Harvest and a member of the local amateur radio club.

“Most severe weather events, like developing tornadoes, microbursts and low-level wind shear, typically occur below 7,000, and can go completely undetected,”

I was not aware that purchasing and operating a weather RADAR was even a possibility on the scale of a small community.

Taken together, these two developments are yet more ways in which that radio technology can be used in community settings and operated by technically interested community members. Like community FM radio stations, “professional quality” weather stations, and now apparently weather RADAR can be financed by small communities, and operated by community members. In my previous career, another example of community technology infrastructure was the construction and operation of Wireless Broadband Internet Access systems using unlicensed spectrum. Such systems are even more feasible using Citizens Broadband Radio Service (CBRS) spectrum and systems. Another community infrastructure system could be one or more GMRS repeaters that are used for Skywarn storm spotting.

While none of these systems use Amateur Radio spectrum (and thus supporters are not required to be licensed), participation of Amateur Radio Operators who have hands-on experience with radio technology would be an invaluable contribution to the effective operation of such systems in small communities.

FCC Reviews Growing Space Sector’s Need For Spectrum

Amateur Radio Newsline Report 2528 for Friday, April 10th, 2026:

STEPHEN/ANCHOR: We begin this week in Washington, D.C. An official posting on the website of the Federal Communications Commission refers to potential new spectrum users as - and this is their terminology - “weird space stuff.” Kent Peterson KCØDGY explains what’s going on.

KENT: Expecting that orbital laboratories, inhabitable spacecraft, in-space repairs and many other related uses are going to have a need for greater access to the RF spectrum, the Federal Communications Commission is seeking comment on ways to make that happen. The agency voted last month to address new ways to support tracking, telemetry and command for a variety of on-the-horizon initiatives.

The FCC published the proceeding on its website, referring to the uses as [quote] “weird space stuff.” [endquote] The agency said that the proposed rulemaking is part of a larger effort to modernize policies in support of the quickly growing space sector. It encouraged comments in particular from companies involved in different aspects of lunar missions, satellite-servicing or related operations.

One of the potential frequency ranges referenced in the Notice of Proposed Rulemaking is frequency range 2305 MHz to 2315 MHz, which overlaps part of the amateur radio allocation on 13cm. The proposal is Docket Number 26-54.

This is Kent Peterson KCØDGY.

(FCC)

No joke - the formal title of this FCC posting is Spectrum Abundance for Weird Space Stuff. From the PDF:

FCC FACT SHEET*

Spectrum Abundance for Weird Space Stuff

Notice of Proposed Rulemaking – SB Docket No. 26-54

Background: In this Notice of Proposed Rulemaking (NPRM), the Federal Communications Commission (Commission) looks to bring spectrum abundance for emergent space activities. “Emergent” or “emergent space operations” are those spacecraft or commercial operations in space that use radio spectrum for control of, or communications with, a spacecraft, but which are not communications satellites. Currently there is an acute shortage of usable and readily accessible spectrum for telemetry, tracking and command (TT&C) functions that are essential for operating emergent spacecraft. Accordingly, the NPRM seeks to clarify and expand the Commission’s traditional regulatory classifications so that emergent space operations have more predictable access to spectrum. Additionally, the NPRM proposes to add a secondary allocation for the Space Operation Service (SOS) in spectrum bands that could support emergent space activities, particularly in frequency bands allocated for non-Federal use that may be lightly used in certain geographic areas. The NPRM also proposes to allow existing licensees to lease their spectrum to earth station licensees to provide SOS in connection with emergent spacecraft.

What the Notice of Proposed Rulemaking Would Do:

  • Seek comment on how to provide regulatory clarity and to leverage existing spectrum allocation to support emergent space operations.

  • Seek comment on codifying the use of frequency “piggybacking.”

  • Seek comment on permitting TT&C operations in FSS bands where TT&C may already be provided within the radiocommunication service.

  • Seek comment on a potential interpretation of TT&C definitions.

  • Propose to add an allocation for SOS (Earth-to-space) in the 2320-2345 MHz band and permit a version of de facto spectrum leasing in that band to earth station licensees and ask whether to extend this proposed framework to nearby bands, such as the 2305-2315 MHz and 2350-2360 MHz bands.

  • Seek comment on whether other satellite operators should be authorized by rule to use their FCC-licensed satellites and intersatellite links to provide TT&C and data downlinks to emergent spacecraft.

This constant jockeying for dedicated spectrum allocations for space use reminds me of the era before the consolidation of many disparate portions of spectrum allocations rolled up into national mobile networks. One approach to meet the need for “launch communications” that seems more reasonable to me is the creation of a network of satellites specifically for spaceflight support. “Weird Space Stuff” could use such a satellite network at lower cost and much less effort (and expense, and complexity) than trying to establish unique spectrum, unique network of ground stations, etc.

NASA pioneered this approach with its Tracking and Data Relay Satellites (TDRS) system. More recently, SpaceX has demonstrated the feasibility of this idea with various SpaceX launches downlinking video and telemetry via Starlink satellites. Maybe Amazon with its history of building “sold as a service” infrastructure might consider providing such services with their nascent Leo service that’s currently being built.

Another potential solution to this issue is to begin using “cognitive radios” in such circumstances that can detect moment by moment usage of existing portions of spectrum and “identify, use, and vacate” for each transmission. Honestly, the unique capability of ka9q-radio to “listen to all channels, simultaneously” is an absolute game changer for radio communications. You no longer have to allocate unique portions of spectrum to dedicated tasks “so you know where to listen”. If “Weird Space Stuff Launch 7825” needs to transmit telemetry, it identifies a portion of spectrum that seems clear for a data burst and transmits it. The ground station, being able to “receive every channel” is monitoring every potential portion of spectrum for a telemetry transmission, and thus receives the telemetry transmission of “Weird Space Stuff Launch 7825” with no issue.

ARDC is Hiring: Software Developer (PT Contract)

Editor’s Note - I ran this item several weeks ago and I was asked by ARDC to run it again. I’m happy to oblige!

ARDC seeks a mid-to-senior-level Software Developer to work with our staff on a contract basis. The role will support ongoing development of our 44Net program services, and potentially other related Free Software projects. An ideal candidate will be active in Free and Open technology communities – particularly those related to amateur radio, digital communications science, F/OSS development, and DIY culture.

ARDC is Hiring: Technical Writer (PT Contract):

ARDC seeks a Technical Writer to work with our staff on a contract basis. The role will support ongoing development of our 44Net program, and potentially other technical publishing activities. An ideal candidate will be active in Free and Open technology communities – particularly those related to amateur radio, digital communications science, F/OSS development, and DIY culture.

I’ve been involved previously, and currently, as a volunteer for ARDC. In my experience, they’re good folks to work with, and for, doing important and relevant work in Amateur Radio and adjacent areas such as open source development.

Thus I endorse and recommend these positions and ARDC as a whole.

Tuscon Amateur Packet Radio TNC Radionics Micro Processor RARE!

Ebay listing:

The Tuscon Amateur Radio TNC Radionics Micro Processor is a rare and unique item for ham radio enthusiasts. This micro processor is designed to enhance the performance of ham radio receivers, allowing users to achieve more precise and reliable communication. With its advanced technology and specialized functions, this TNC Radionics Micro Processor is a valuable addition to any amateur radio setup, offering improved signal stability and clarity for a superior listening experience.

Buy it now: $250

This unit is a TAPR Terminal Node Controller (TNC) - later renamed the TNC-1.

Superior listening experience… 😆 Can’t make this stuff up.

Please direct comments / feedback about ZR > BEACON to the Zero Retries email list with the #ZR0247 hashtag.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

Pressures of a Weekly Newsletter

One (of many) limitations of Zero Retries as a weekly newsletter, is that there are weeks that timeliness trumps completeness. In this case, my being a part time writer / Editor (with other things competing for my time during the week), and the desire to get the two stories in this issue published while they’re still timely, conflicts with doing a more complete treatment the subjects of those stories. Ideally I could have (and, arguably, should have) contacted Billy Penley KN4MKB and Nino Carrillo KK4HEJ for their direct perspectives on the stories I wrote in this issue of Zero Retries about their projects.

Thus, sometimes I envy the longer development / editing / production cycle of a magazine format with much longer lead times.

But in the end, I felt that Zero Retries readers were better served by discussing these two developments, in a timely manner, from my perspective. KN4MKB laid out his position very well on his blog, and KK4HEJ has chosen, to date, not to mention anything about his project beyond the brief mention on Discord.

Both of these projects will be much more widely exposed in the months to come so they’ll get ample publicity. Thus I view Zero Retries role, at this stage, is to make more people aware of the exciting potential of these two projects, and the changes they presage in Amateur Radio data communications… and their contributions to Technological Innovation in Amateur Radio.

Focus is the Tradeoff For Keeping Up With Technological Innovation in Amateur Radio

There’s an old (old) joke:

A pedestrian on 57th Street sees a musician getting out of a cab and asks, “How do you get to Carnegie Hall?” Without pause, the artist replies wearily, “Practice.”

So how does one keep up with the amazing, seemingly more, and more interesting, by the month firehose of technological innovation in Amateur Radio?

This Editor replies, wearily, “Focus”.

Really! No one has the bandwidth to keep up with literally hundreds of Amateur Radio (and adjacent fields) innovators that are pushing out technological innovations by the month. I certainly don’t7. It’s not your imagination. The more technological innovation I find and try to feature here in Zero Retries … the more I find. The discovery of one technological innovation leads to another. It never ends. It’s a (joyful, and endlessly fascinating) positive feedback loop.

The only way I know of to truly keep up with technological innovation in Amateur Radio is to restrict one’s focus to what you’re most interested in and what you’re most passionate about.

My favorite example of such focus is the (Digital) Amateur Television folks. Despite that their preferred mode is fundamentally a steam of digital bits, to them, DATV is about realtime image communications. The digital / data aspect of Digital Amateur Television (DATV) is entirely secondary to them having fun with building equipment for and communicating with their buddies with realtime image communications via Amateur Radio. That they could be accomplishing the same thing, perhaps more flexibly, perhaps in a more modern context, by videoconferencing over a data network via Amateur Radio (like AREDN) isn’t of interest to them. They like DATV, not data communications. Thus to keep having fun, the DATV folks exercise an admirable focus on their preferred mode, paying attention to the innovations that occur in relation to DATV - new equipment, new techniques, etc.

If you’re interested in Amateur Television, the best way to keep up to date is to request to be added to the great Amateur Television Journal newsletter edited by Jim Andrews KH6HTV: https://kh6htv.com/newsletter/. You might think that it’s a “local” newsletter, and it covers the activity in the Boulder, Colorado area well, but it also reports on many other areas, including some international activity. Highly recommended!

That… and if there’s something interesting happening that you’re a fan of, like DATV, and there’s a group doing the fun things like DATV that you enjoy hearing about and want to enjoy too, find a way to help support them with participation, encouragement, spreading the word, and perhaps financial support.

Hamvention Ho!

4 weeks until Hamvention 2026
in Xenia, Ohio, USA...
Zero Retries / DLARC booth 1506
in Building 1 / Maxim

Weekends Are For Amateur Radio!

The priority this weekend for me is to dust off some vintage TNCs out of the collection(s) of N8GNJ / Zero Retries Labs for a promised demonstration of vintage (but recent memory, to me) Amateur Radio Packet Radio data communications.

And I really have to get that MeshCore node on the air!

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please direct comments / feedback about Request To Send to the Zero Retries email list with the #ZR0247 hashtag.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

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⬅️⬅️⬅️ Previous Issue of Zero Retries \ Next Issue of Zero Retries ➡️➡️➡️

This issue, Zero Retries 0247, was published on 2026-04-17. This issue was 9296 words.

(end)

Footnotes For This Issue

To see the relevant sentence for the footnote, just click the footnote number.

1

This reference isn’t correct. I met Ray Petit W7GHM who stated that he was the inventor of CLOVER. Additional reference.

2

No explanation provided for the context of this page (or that section, listing a very incomplete list of data modes used on Amateur Radio spectrum).

3

VARA FM and VARA HF require license key (fee is $69) which provides full functionality (full speed tiers).

4

Audio OFDM is OFDM technology applied to the audio bandwidth of a conventional radio.

5

In Amateur Radio, broadcasting is prohibited, but transmission of “bulletins” is encouraged. Thus we try not to say the “B” word.

6

Apparently Othernet is now out of business. Bummer.

7

One of the sadder realizations with Zero Retries is that I can’t do it all. I can’t keep writing Zero Retries on a weekly basis, at a level of quality and quantity that I can feel proud of… and be able to spend entire weekends and evenings noodling around in N8GNJ / Zero Retries Labs. Something has to give, and for the moment, that’s the latter in favor of the former. That’s a conscious choice.

]]><![CDATA[Zero Retries 0246]]>https://www.zeroretries.org/p/zero-retries-0246https://www.zeroretries.org/p/zero-retries-0246Sat, 11 Apr 2026 03:37:14 GMTZero Retries is an independent newsletter promoting technological innovation in and adjacent to Amateur Radio, and Amateur Radio as (literally) a license to experiment with and learn about radio technology. Radios are computers - with antennas! Now in its fifth year of publication, with 3500+ subscribers.

Steve Stroh N8GNJ, Editor

editor@zeroretries.net

Tina Stroh KD7WSF, Business / Conference Manager

tina@zeroretries.net

Substack says this issue is too big for email apps.Thus, it might be easier to read in a web browser - https://www.zeroretries.org/p/zero-retries-0246

It’s easy and free to subscribe for your own copy of Zero Retries every week:

Subscribe now

In This Issue:

I-Frame

What’s New at Digital Library of Amateur Radio & Communications - April 2026
By Kay Savetz K6KJN

ZR > BEACON

Request To Send

Closing Thanks

The Usual Administrivia

Footnotes for This Issue

I-Frame

By Steve Stroh N8GNJ

Brief notes about this issue of Zero Retries.

Paid Subscribers / Founding Members Update

My thanks to Tom Nolan W3EX for renewing as an Annual Paid Subscriber to Zero Retries this past week!

My thanks to Prefers to Remain Anonymous 67 for renewing as an Annual Paid Subscriber to Zero Retries this past week!

My thanks to Jake Steijn KK7HAQ for upgrading from a free subscriber to Zero Retries to an Annual Paid Subscriber this past week!

KK7HAQ included this nice note:
I’ve been reading you for a couple of years, if I recall right. Good stuff and you deserve at least a little support.

My thanks to Prefers to Remain Anonymous 124 for becoming a new Annual Paid Subscriber to Zero Retries this past week!

Financial support from Zero Retries readers is a significant vote of support for the continued publication of Zero Retries.

MoonRF Quad Likely Priced at $399, Not $2k

In Zero Retries 0245, open.space - Moon Launch Update! I speculated that the cost of a MoonRF Quad tile (4 units) could be priced at $2,000. I don’t remember why I offered that (totally unfounded) guess of that price point. Turns out I was way off (5x too high). I added this to the article:

Post Publication Update: Email from Martin McCormick K1MCC:

The QuadRF [kit] is likely to be $399, not $2000.

Wow. Just… Wow. That’s an incredibly reasonable price point.

I’m really looking forward to MoonRF’s crowdfunding campaign, not so much for being able to put a phased array 5 GHz antenna to immediate use… but I really want to vote with my wallet to help encourage the emergence of this technology into Amateur Radio.

Please direct comments / feedback about I-Frame to the Zero Retries email list with the #ZR0246 hashtag.

What’s New at Digital Library of Amateur Radio & Communications - April 2026

By Kay Savetz K6KJN

Greetings from DLARC World Headquarters in sunny Oregon, where I am thrilled to announce that the DLARC free online ham radio library now has a selection of the “big three” American amateur radio magazines: CQ, QST, and 73.

Here’s the TL;DR: we have every issue of 73 Amateur Radio (516 issues published from 1960-2003), 530 issues of QST from its founding in 1915 through 1961, and now 199 issues of CQ Magazine published from 1946 through 1963! The “big three” U.S. amateur radio magazines.

The non-TL;DR “give me more information!” version is that DLARC is now home to those 199 issues of CQ Amateur Radio Magazine, published from 1946 through the end of 1963. The pre-1964 issues have fallen into the public domain, so they’re available for us all to read and use.

CQ’s final issue was published in October 2023, and publisher Dick Ross (K2MGA) died a few months later. The legal status of CQ Magazine is in flux. I’m not sure anyone knows yet what will happen to the material published from 1964 through 2023 — but having access to the first nearly two decades of the magazine is huge news. Many of the issues came to DLARC via the SPARK Museum of Electrical Invention, and some scans came from the University of Illinois Chicago.

But there’s still work to be done: CQ magazine launched in 1945. DLARC doesn’t yet have January 1945 (volume 1 number 1) through March 1946 (volume 2 number 3), most of volume 3, and a smattering of issues in volumes 4, 11, and 12. Those are now in the DLARC Wantlist.

I’ve told the story of 73 here a few times: before Wayne Green (publisher of 73) died, he contributed a complete set of the magazine to Internet Archive and asked that they be made freely available. That collection was just about the first thing I added to DLARC when the project launched.

The last of the big three, arguably the best known, is QST, which has been published by the ARRL since 1915. The ARRL is a member organization, and they work hard to create great information exclusively for their members, which is 1000% their right and privilege. Like CQ, the oldest issues are old enough to be in the public domain, which means the 530 issues published before 1962 are here to enjoy. (When you click the link, you’ll see something like 609 results. Some of those are indexes, not issues. Indexes are available all the way through 2001.)

There’s more in the works (soon!) for DLARC. I’m preparing a post for the Internet Archive blog for World Amateur Radio Day, April 18, that will announce the other new stuff. In the meantime, there are plenty of ham radio magazines to keep you busy.

Digital Library of Amateur Radio & Communications is funded by a generous grant from Amateur Radio Digital Communications (ARDC) to create a free digital library for the radio community, researchers, educators, and students. If you have questions about the project or material to contribute, contact me at kay@archive.org.

…

Editor’s Note - Just a reminder that K6KJN will be representing DLARC at Hamvention 2026 in Xenia, Ohio - 2026-05-15 thru 17. Stop by at booth 1506 in Building 1 / Maxim to say Hi.

Post Publication Update - My article published in ZR 246 just yesterday is already obsolete. Thanks to Daniel Bateman at hamcall.net who filled in the gaps in our collection, DLARC now has a complete set of CQ Magazine from its launch in 1945 through the end of 1963.

https://archive.org/details/cq-amateur-radio?sort=date

Please direct comments / feedback about this article to the Zero Retries email list with the #ZR0246 hashtag.

ZR > BEACON

By Steve Stroh N8GNJ

Short mentions of Zero Retries Interesting items.

MOP - It’s (Web Page) is Back!

In Zero Retries 0239, I wrote (admittedly a bit gushingly) about Mesh Operations Protocol (MOP):

I could try to explain this, but the web page linked in the title is an absolute marvel of self-explanation. It’s really amazing! Scroll down to see the sections Live Network Simulation, Cross-Country Delivery, and MOP vs. The Rest. Read those, and you’re up to speed on the ideas of MOP.

But MOP’s developer, Stefaan Desmet KO6IKR, wasn’t (then) quite ready for MOP to be publicly known (he deliberately had not publicized it). My mention of the website in Zero Retries 0239 resulted in a rush of questions he wasn’t quite ready for, and K06IKR took the MOP website offline. I wasn’t smart enough (then) to have “snapshotted it” to Internet Archive Wayback Machine. I was bummed! But after some encouragement, K06IKR has put the MOP website - https://smasher.be/mop/ back online. And, yes, with a snapshot of it into the Wayback Machine for posterity.

Although it was then, and currently is, a concept / project in development by KO6IKR, it represents one of the best scoped set of ideas / concept / plans of a mesh network for operation on VHF / UHF bands.

A decentralized mesh network for amateur radio.

No sessions. No hubs. No closed-source software.

Just datagrams and beacons — short, efficient bursts.

…

VALIDATE

Integrity & Origin ID (Open)

Each message includes an open, non-obscuring integrity tag that lets receivers verify origin and detect tampering or corruption. Message contents remain readable to any receiving station in compliance with FCC Part 97.

ROUTE

Beacon-Driven Discovery

Gateways beacon every 10 min, relays every 15 min. Route knowledge ripples outward through re-broadcasts. No central directory — your routing table builds itself from what you hear.

ACCESS

CSMA/CA with Exponential Backoff

Listen before talk. If channel is busy, defer. Random backoff avoids collisions between stations that were both waiting. Directed frames get retried with exponential backoff.

MODULATE

OFDM at 4800 bps

First working version of a custom OFDM modem — early tests are very promising. Built in Python with numpy + sounddevice. Beacons use 1200 baud AFSK for APRS visibility.

TRANSMIT

Standard FM Voice Channel

3 kHz audio bandwidth. PTT via CAT command (Yaesu), VOX, or GPIO. No special hardware — any radio with a soundcard interface.

I think KO6IKR made a lot of good decisions in his scoping of MOP. He’s right - short bursts are the way to go, especially in urban areas (he’s located in the Los Angeles, California area). The use of OFDM is another excellent technical choice, and he’s one of a number of folks1 that have chosen to implement OFDM in the audio domain to allow use of existing VHF / UHF “data” radios (at 10 / 25 / 50 watt power levels).

KO6IKR states that MOP will be open source. When he completes his development work sufficiently to the point where he’s comfortable opening it up for collaboration and initial testing, I hope that he gets an enthusiastic response. I think he will get an enthusiastic response. I will jump at the chance to implement a test MOP system in N8GNJ / Zero Retries Labs.

An Old Concept That Could Be Resurrected

Jonathan Naylor G4KLX on the OpenDV email list:

For the last few months I have been working with the SX1255 RF I/Q device in various hardware configurations. We are not alone in working with this chip and there is already a lot of information and code available to help me. I am currently working on porting the MMDVM firmware over to using the device, but unlike the ADF7021 based hotspots, this hardware will support all modes, and potentially any new ones that appear.

Before I explain the reason for this post, let me tell you a short story. At Ham Radio in 2019 (in the “before” times), I was approached by Torsten DG1HT, of DMR+ fame, and he suggested that by using suitable SDR technology it would be possible to build a repeater that would offer a different DV mode on adjacent duplex channels. Technically this was easily achievable, my issue with that idea was to do with licensing. It’s probably true to say that in most European countries, and elsewhere, there just isn’t enough free spectrum to do that, and any such application to try it would be refused at the first hurdle. So apart from the thought experiment associated with it, I didn’t pursue it any further. It didn’t help that we didn’t have any suitable hardware available to try it with. However for low power personal hotspots, such problems don’t exist to any extent as long as you don’t connect it to a large antenna and/or use a power amplifier with it.

News has now reached me that the TETRA guys behind the SXceiver, which I am also using for development, are talking of using that hardware with two sets of channels, one for TETRA and one for DMR. Obviously the output power would be split in half for each carrier, but it is perfectly achievable. It also gets around the problem of integrating TETRA with the operation of the MMDVM in our particular case.

However it also got me thinking about taking this concept to its logical conclusion. How about being able to run multiple MMDVM instances, maybe each one locked to a specific mode, or maybe a couple of modes, connected to a separate program that interfaces to the SX1255 and makes suitable I/Q data available to each MMDVM based on a configuration file. Each MMDVM being unaware of the others. Each I/Q stream would be from a particular offset from the hardware centre frequency and within the configured bandwidth of the chip, and suitably frequency shifted and filtered, with the reverse being true on transmit. For obvious reasons this would have to be done in duplex mode. That would allow for some truly interesting configurations. The people that I would feel sorry for would be those creating dashboards to display it all!

For the DVM project, it would be possible for them to use one device to handle both the control and traffic channels in their P25 phase 1 trunking system instead of multiple duplex hotspots. The same hardware would be able to handle P25 phase 2 when they eventually implement it. Maybe even running it side-by-side with the phase 1 RF.

Any effort to amplify such a system would require very linear amplifiers, probably in class A, in order to ensure that there was no intermodulation between the different carriers. This would be easy for low powers, but would get difficult at higher power levels. There are also question marks about the overall spectral cleanliness of the SX1255 that need to be investigated.

I understand where G4KLX is coming from in this proposal, within the paradigm of making digital voice repeaters more utilitarian in accommodating multiple standards.

But…

My perspective is that Amateur Radio is about at the limit of accommodating digital multiple standards.

Post-publication Update - That paragraph should have read:

My perspective is that Amateur Radio repeater operations is about at the limit of accommodating digital multiple standards.

That omission was unfortunate and widened the scope of my statement beyond what I intended to say.

…

We’re beginning to experience diminishing returns for putting up ever more DMR repeaters, and System Fusion repeaters, and DMR repeaters, and D-Star repeaters, and M17 repeaters, and perhaps even future BBFM repeaters. New Amateur Radio Operators are justifiably confused and can suffer from the “paralysis of analysis” in trying to figure out if they want to invest in a DMR radio, or a D-Star radio, or a System Fusion radio, or a P25 radio, or a TETRA radio. All of those systems have their good points and bad points, and it’s common that there are repeaters using each of those in a given (usually metro) area.

This Amateur Radio “Tower of DV Babel” is resulting in absurd situations like here in Western Washington, USA, the Western Washington Amateur Relay Association (WWARA)2 is effectively mandating a policy that future repeaters (and, eventually existing repeaters) to be “narrowbanded” when, objectively monitored, there’s ample channel airtime to accommodate multiples of the existing number of repeaters that are coordinated by WWARA… just not enough “pairs” for each repeater to have “it’s own channel”.

Being able to operate on multiple digital voice systems using the same radio is on the cusp of being a non-issue3 by the LinHT and successors. And the “capacity” issue of only so many repeater pairs being available might well be solved with the application of Single Channel Time Division Multiple Access technology. But neither of those potential solutions, nor (in my opinion) G4KLX’s proposed system, address the “Tower of Babel” mess that is multiple modulation technologies being proliferated on repeater systems.

Thus, Joe Hamelin W7COM said it well in forwarding this item to me for Zero Retries (which I had not spotted before his mention):

And we could call it a Superpeater!

I understand the desire for accommodating (not obsoleting) the radios that individuals have invested in, and Amateur Radio being under no constraints to consolidate on a particular (digital) voice (or data) technology.

My SuperPeater concept accommodates whatever radio a user wants to use (or has) by setting up virtual receivers (using ka9q-radio) for each mode. Purely for example, here’s an imagined “receiver map” for an imagined SuperPeater:

  • 440.000 is monitored on the SuperPeater receiver for FM transmissions,

  • 440.010 is monitored on the SuperPeater receiver for M17 transmissions,

  • 440.020 is monitored on the SuperPeater receiver for DMR transmissions,

  • 440.030 is monitored on the SuperPeater receiver for D-Star transmissions,

  • 440.040 is monitored on the SuperPeater receiver for System Fusion transmissions,

  • 440.050 is monitored on the SuperPeater receiver for P25 transmissions,

  • 440.060 is monitored on the SuperPeater receiver for NXDN transmissions,

  • 440.070 is monitored on the SuperPeater receiver for TETRA transmissions,

  • 440.080 is monitored on the SuperPeater receiver for DPMR transmissions.

  • 440.090 is monitored on the SuperPeater receiver for POCSAG transmissions.

Similarly, for data…

  • 440.110 is monitored on the SuperPeater receiver for 1200 bps AX.25 transmissions,

  • 440.120 is monitored on the SuperPeater receiver for 1200 bps AX.25 with IL2P transmissions,

  • 440.130 is monitored on the SuperPeater receiver for 1200 bps AX.25 with FX.25 transmissions,

  • 440.140 is monitored on the SuperPeater receiver for 2400 bps AX.25 with IL2P transmissions,

  • 440.150 is monitored on the SuperPeater receiver for 3600 bps AX.25 with IL2P transmissions,

  • 440.160 is monitored on the SuperPeater receiver for 4800 bps AX.25 with IL2P transmissions,

  • 440.170 is monitored on the SuperPeater receiver for 9600 bps AX.25 transmissions,

  • 440.180 is monitored on the SuperPeater receiver for 9600 bps AX.25 with IL2P transmissions,

  • 440.190 is monitored on the SuperPeater receiver for 19200 bps AX.25 with IL2P transmissions.

  • Any “hardware radio format” could be accommodated (it’s “just software”), such as a radio transmitting SSB.

What changes the game, and addresses G4KLX’s concern about spectrum is that the a SuperPeater would output a (unique, as yet undefined) wideband data stream, perhaps 100 kHz wide.

All of the above inputs (and as many more as required) would be translated into a “subsidiary” data stream. The receiver of a SuperPeater is (conceptually) simple and inexpensive:

  • Raspberry Pi computer

  • Software Defined Receiver - perhaps as simple as an RTL-SDR, or perhaps more capable such as a HydraSDR RFOne.

  • Unique software to receive the data stream and parse out each component as necessary (or interested in receiving) and route it into other applications using TCP/IP sockets.

With this concept, you transmit with “whatever radio” to the SuperPeater, and you receive with the SuperPeater receiver. This also accommodates the situation of Operator A using DMR wanting to converse with Operator B using D-Star, on the same repeater.

With some months of perspective, I think the SuperPeater concept has significant potential, especially in this era of quiet repeaters. It needs additional refinement and development of a reasonable specification. And, who knows… with perhaps a few more months of evolution in the capabilities of ClaudeAI, with a reasonable specification, perhaps I could end up doing the software development.

Transceive 1.4 Beta Testers Wanted

Georges Auberger WH6AZ via email (to the Transceive app email list)

Aloha,

I’m getting close to releasing a new update of Transceive. This version includes some significant plumbing changes, and I’m looking for people to help test it and make sure nothing broke.

Here’s what’s changed:

  • Universal binary (Apple Silicon + Intel)

  • Fix for DNS lookup when nodes use non-standard ports

  • Updated authentication for AllStar public auth

  • More robust node reachability (green/red status is more reliable, with less need to hit Cmd-R)

  • New: reorder nodes with simple drag and drop

  • New: add a memo to a node entry

I’m especially interested in people who can test against both public and private nodes. Also, I no longer have access to Intel hardware, so it would be great to have some Intel-based Mac users in the mix.

If you’re interested, head over to this link to join the beta on TestFlight:

https://testflight.apple.com/join/rbWKPna5

Thanks in advance for the help.

Transceive (link to App Store entry)is a $20 MacOS app for connecting to AllStarLink4:

Radio for AllStarLink nodes

Transceive allows amateur radio operators to connect to their AllStar node from anywhere in the world. Operators can administer linked nodes, monitor traffic, and transmit audio, all from the comfort of their Mac. You will either need an account on the node you are connecting to or register for an AllStar account and use it to connect to public nodes.

ALLSTAR PUBLIC AUTHENTICATION

  • Connect directly to public nodes with your AllStar account. Experience the AllStarLink network without the complexity of setting up your own node. A callsign is required to sign up for an AllStar account.

NODE CONNECTIONS

  • Account information is stored for every node you manage. Passwords are securely stored in the macOS keychain.

  • Hostname and port for public nodes are automatically looked up via DNS so you don’t have to remember specific IP addresses.

  • Node indicators let you know if your node becomes unreachable due to change in network conditions, for example when connecting to a new WiFi.

  • Connect to up to 8 nodes at the same time.

  • Nodes can be set to automatically connect when the application opens.

AUTOMATIC IDENTIFICATION

  • Node attributes and location are displayed for each node.

  • Callsign details such as name, license type and country are looked up automatically. (Availability varies by country of callsign issuance.)

  • Node locations can be visualized on a map by clicking on the pin icon.

STELLAR AUDIO

  • Experience high quality audio from any sources connected to your Mac.

  • Monitor and adjust audio levels with the help of a calibrated audio monitor panel.

  • Full duplex support.

RADIO LIKE

  • Transmission is activated by holding down the PTT button or the SPACE bar.

  • When transmitting, a timeout timer is displayed to help you avoid timing out a repeater.

  • Latching PTT option provides a hands-free experience.

LINKED NODES MANAGEMENT

  • Quickly link your node to other nodes on the network.

  • Identify keyed nodes as they transmit.

  • A history of previously linked nodes is preserved for easy access in the future.

  • Automatic unlinking prevents you from inadvertently linking multiple nodes together. This feature can be turned off when necessary, for example when managing a hub.

CUSTOMIZATION

  • Modify built-in DTMF commands to match your specific node configuration.

  • Define your own DTMF sequence presets for quick access to frequent operations.

KEYPAD

  • A keypad allows you to enter arbitrary DTMF commands for your node.

Transceive is independently developed and not affiliated with AllStarLink or its developers.

I haven’t yet seen one, but a handheld Push To Talk microphone with a USB-C interface, similar in size, weight, and feel to a Motorola or a Kenwood mobile radio microphone would, in my opinion, sell very well for use with voice applications like Transceive. Yes, there are adapters for the “real” microphones, but they’re clunky in comparison to handheld microphone with native, integrated USB-C. Having a native USB-C interface (hopefully properly, uniquely “signed”), they could be supported by apps like Transceive.

Image courtesy of Juma Communications

The Juma Communications USB-C Speaker Microphone (finally… someone got this concept) is designed for portable speaker / microphone / lapel use, and what I’m hoping for is a larger, heavier, mobile handheld microphone. (Admittedly I have big hands and such microphones just… feel good in my hand.) I think it would be fun to participating on a net via AllStarLink while sitting in a coffee shop, picking up the microphone to speak. That would be a conversation starter!

Significant Potential for Interference in Amateur Radio 420-450 MHz (70cm) Band in California

A Zero Retries reader alerted me to these FCC Special Temporary Authority grants for testing in California of high power operation in the 420-450 MHz band:

Typical verbiage (location changed with each STA):

Please explain in the area below why an STA is necessary:

To authorize the applicant’s operation on the requested frequencies at Hawthorne, California, in order to perform near term testing and system integration that both prepares for an upcoming technology demonstration at the U.S. Army Yuma Proving Ground and enables the applicant to meet requirements under active and pending U.S. Government contracts.

Please explain the purpose of operation: Operations under the STA will consist of performance testing, system integration, and related development activities conducted to ready the equipment for an upcoming technology demonstration and capability evaluation at the U.S. Army Yuma Proving Ground and to demonstrate and verify performance needed to meet requirements under active and pending U.S. Government contracts.

…

Frequency: 420.00000000-450.00000000 MHz

Output Power/ERP: 3.000000 kW

Mean Peak: 11.020000 kW

Before you fire up your computers to protest to the FCC, recall that in the US, the US Government is the Primary user of 420-450 MHz (various agencies are allocated various segments). Amateur Radio use of 420-450 MHz is secondary. Unlike the earlier use of 420-450 MHz by AST Space Mobile - a private company, use of 420-450 MHz for a demonstration for a US Government project is, yes, a legitimate use of 420-450 MHz, and interference to Amateur Radio is… secondary.

Those of us not in California - enjoy (and use, hopefully productively, and publicly and innovatively) our use of 420-450 MHz! (Or for those of us above Line A, and Canada - 430-450 MHz.)

New AX.25 library for ESP32 Microcontrollers

Robert Ambrose N7GET in the Ninotnc email list:

I’ve been working on a component library for AX.25 on an ESP32 microcontroller. This library is specifically designed to be used to build (or generate) applications rather than an application in and of itself.

The first application I’ve created (generated) is a something I’m calling ‘ESP-TNC’. It is at its core an AX.25 router that connects to a KISS TNC+radio station using a UART or RS-232 interface. It can connect to an existing WiFi network as a station or act as an Access Point. It allows multiple operators to connect to it using KISS or AGWPE over TCP/IP. As an example I’ve tested it with RMS Packet, RMS Express and Easyterm all connected to it at the same time. It also has a BBS, digipeater and a beacon capability.

I’ve paired this with a NinoTNC connected directly to the UART bypassing the USB interface and I think it works great.

This is alpha software. If there’s anyone out there who is comfortable with working with microcontrollers and is interested in this kind of thing, I’m looking for to move this project to the next stage of a controlled release. I will be releasing this as open source under GPL3.

The energy and creativity that’s going into the invention of new generations of TNCs are just amazing.

Introducing Radio Terminal

Andy O’Brien K3UK on the digitalradio email list:

I have set up a sub-group here called Radio Terminal , it is experimental digital mode software developed by a ham well-known to this group, Steinar LA5VA. If you are interested in contributing to the development of this software and its experimental modes , please apply to join
https://digitalradio.groups.io/g/RadioTerminal/topic/radioterminal/118693127 .

Please check your national rules to ensure the modes are permitted by your country .

Andy K3UK

What is RadioTerminal?

RadioTerminal is an open-source digital modem/terminal program written in Python. I have also made a Windows .exe version using PyInstaller. The program is still under development, but at the moment it includes these main parts:

1) Olivia (including an extended/experimental version)
With selectable FEC options, including: Walsh (8 tones, 250 Hz, compatible with fldigi), Golay, LDPC, Polar, Reed-Solomon, Turbo, Viterbi, BCH, and a combined Viterbi + Reed-Solomon mode that I call “Deep.”

2) Olivia ARQ (experimental code)
Based on Olivia, but this is my own MFSK variant: 8 tones and about 250 Hz bandwidth. It uses Reed-Solomon as its core and has a custom ARQ mechanism.

3) SCAMP / Sgump (ported from FLDigi)
A direct port from the FLDigi code base, done with help from an AI tool. I have not changed the algorithm — only ported it to Python.

4) HFCSS

5) FHSS –

6) IFKP – Incremental Frequency Keyed

Sounds like an interesting project. Scamp is an interesting new mode, and of course I’m a long time fan of FHSS (Frequency Hopping Spread Spectrum).

CascadiaMesh

CascadiaMesh is an expanding community built mesh network primarily made up of solar-powered MeshCore radios across the coastal Pacific Northwest. Currently it covers British Columbia, Western Washington, and Western Oregon. The vibe is simple: a region-wide text messaging system that lets anyone message publicly or privately with anyone on the network. We proudly became the first large MeshCore network in North America and are still the largest by both geographic scale and daily active usage in North America.

The best part? It doesn’t depend on outside infrastructure at all! No electrical grid power, no cell coverage, no internet. If the lights go out, the mesh can keep talking.

The choice of MeshCore, rather than Meshtastic, in CascadiaMesh goes a long way in fixing the worst of the issues of scaling LoRa based mesh networks on unlicensed bands.

First, I have to reflexively have to reset myself from framing mesh networks like this operating on unlicensed spectrum “versus” mesh networks operating on Amateur Radio spectrum (used by Amateur Radio Operators). All independent radio experimentation that provides hands-on experience with radio technology is a good thing.

Second, impressive as CascadiaMesh is, I’m not mentioning it as a unique achievement of the Pacific Coast of the United States (despite their claims). I’ve seen mentions of similar regional mesh networks developing all over the US, and of course, also in Europe, and probably in every other region - South America, Asia, Africa… wherever there is access to unlicensed spectrum and curious techies.

That said, Amateur Radio is “losing mindshare” to projects / networks / communities like this. While Amateur Radio has the potential to be able to do the equivalent of CascadiaMesh (and Mesh America), and considerably more, Amateur Radio hasn’t made a significant enough investment in organizing such a program, or motivating manufacturers to develop mesh equipment for the unique capabilities of the Amateur Radio market, such as a LoRa radio operating at 25 or 50 watts on the Amateur Radio 420-450 MHz band (or the 222-225 MHz band).

Thus there may come a point where there will be, and more interesting, people to communicate and collaborate with, on unlicensed mesh networking. That might precipitate a tipping point where the default for a potential NewTechHam is to briefly consider Amateur Radio, but then decide to “just go have fun”; without the complication of getting an Amateur Radio license, arcane rules (no encryption, bandwidth / symbol rate limits) and just join in on the fun of networks and communities like CascadiaMesh. Or, arguably, we’re past that point (I’m not sure).

I confess that despite being alerted to the existence of CascadiaMesh by my friend Michael Gan several weeks ago, I haven’t taken the time to really learn about what CascadiaMesh is doing and the infrastructure it’s developed.

My thanks to Zero Retries Pseudostaffer Steve Monsey N0FPF who reminded me of CascadiaMesh with this email:

Watch the packets fly!

https://cascadiamesh.org/map/

HAM / Amateur Radio - Integrating the Linux and Radio Worlds Together

This page is my attempt to capture my journey in the Amateur Radio (HAM) hobby where I’ve both learned and try to teach my learnings to my fellow HAMs. Hardware is always what people think about when it comes to this hobby but there lot more of powerful software available to complete the job. My primary focus on these pages is how to do that software on Linux even though there is a lot more options on Microsoft Windows. I’m doing my working on fixing that over time but the following documents will hopefully help other Linux-savvy HAMs!

Interesting reference page by David Ranch KI6ZHD with lots of detail and links about operating packet radio on Linux, including Raspberry Pi.

My thanks to Joe Hamelin W7COM for mentioning this for inclusion in Zero Retries.

The mkiss Module Update is Actually a Pretty Big Deal

Ben Kuhn KU0HN on the Zeroretries email list; reference Zero Retries 0245 - Updating the Linux MKISS Driver in Linux:

I was pretty excited to hear the news that someone is taking over maintainership of the mkiss module. Rumors have been going around for a few years now that the Linux AX25 stack may be dropped from the kernel completely due to some bugs and lack of maintainers. The article referenced the mkiss userland utility, but the mkiss kernel module (driver) is for KISS itself, including multidrop KISS.

From the source of the driver itself (https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/net/hamradio/mkiss.c?h=v6.19.11)

MODULE_AUTHOR(”Ralf Baechle DL5RB <ralf@...>”);
MODULE_DESCRIPTION(”KISS driver for AX.25 over TTYs”);

There are other modules for 6PACK BPQEther, YAM, Baycom, and others; but the mkiss driver is what’s used most these days. It’s still *extremely* relevant for us Linux users as it’s how the built-in AX25 stack is able to interact with legacy serial TNCs, Bluetooth TNCs like mobilinkd or those built in to newer radios, as well as software/sound card TNCs like Direwolf. The kernel’s AX25 stack allows for native TCP/IP networking as well as access from applications that support it (PAT, Xastir, etc...). The vast majority of AX.25 software on Linux expects the Kernel/OS to handle these interfaces like it does any other hardware.

AGWPE is great for directly connecting a client to a modem, but KISS support built in to the OS makes more advanced things like IP networking much more seamless.

Thanks for that additional context, KU0HN!

Video - Best Radio for Decoding APRS/Packet Data?

Craig Lamparter KM6LYW:

Let’s look at the internal modems built into many modern APRS-enabled radio and compare their reception and decode rates. Does Kenwood decode more packets than Yaesu? VGC/Vero? Finally, let’s compare to a baseline SDR setup with a software modem to see the best-case scenario.

I’m looking forward to watching this entire video.

Please offer comments / feedback about ZR > BEACON on the Zero Retries email list with the #ZR0246 hashtag.

Request To Send

By Steve Stroh N8GNJ

Editorial, Commentary, and Occasional Digressions

Substack Can Post Without Emailing

I was dreading the process of “backposting” issues of Zero Retries from www.zeroretries.radio to www.zeroretries.org (see below) because I expected there to be much confusion from Zero Retries email subscribers when they received those past issues via email (again - having received a “heads up” email from Substack and the issue from Ghost). But I’d apparently overlooked the option in Substack to publish only to the web, and not via email. (When you do so, Substack puts up a warning that only a small minority of readers will see a web-only post. Substack is really email-centric). That was a great capability, and ideal for this situation.

That capability will also come in handy for some content that could be in the “date flow” of postings, something like a blog, instead of just creating “pages” which aren’t visible except via the top menu bar (such as Zero Retries Guides).

Zero Retries 0241 - 0244 backposted to Substack / www.zeroretries.org

I’ve “backposted” Zero Retries 0241, Zero Retries 0242, Zero Retries 0243, and Zero Retries 0244 on Substack / www.zeroretries.org (formerly published on Ghost / www.zeroretries.radio.

This is in service to consolidate all Zero Retries content to Substack / www.zeroretries.org. I’m not done yet - still to be backposted are ZR 0235 - ZR 0240. Doing so is a high priority so I can just get back to writing Zero Retries instead of this administrivia. I also have to move any articles that were created on www.zeroretries.radio. I’ve moved some of those, but not all.

DLARC is Such an Incredible Resource

It was so cool reading this month’s What’s New at DLARC column describing how there are now issues of not only the complete collection of 73 Magazine, but also the issues of CQ and QST that are public domain (out of copyright). At one point, I’ve been a subscriber of all of those magazines and it’s amazing to think that the issues that are in DLARC can be downloaded and read. You can easily scan through a year’s worth of issues in an evening.

One of the reasons I’m such a fan, and think that DLARC is such an incredible resource is that “Amateur Radio” magazines often cover developments outside of Amateur Radio, discussing fundamental radio technology. For example, the creation of artificial satellites is entirely within living memory (Sputnik 1 was launched 1957-10-04), and I’m sure the progress of various breakthroughs (such as the development of Geosynchronous Earth Orbit - GEO) satellites was discussed as an exciting new development in Amateur Radio magazines. I hope that perhaps the CQ archives could, somehow, be added to DLARC.

Another reason I love DLARC is that there have been so many times that Amateur Radio has attempted projects that weren’t quite feasible or sustainable with the technology or other resources of the era in which they were attempted. For example, Amateur Radio accomplished some amazing things with Amateur Radio satellites such as Packet Radio Satellites (PACSATs) that were expensive to create in the 1980s / 1990s. Now such capability is absolutely routine / easy / cheap. Other times, technological innovations were reported, but not formalized in enduring standards that are easy to reference.

Another was that, for a time, the US (and many countries) had reasonable local, regional, and national (and international) packet radio networks. Packet Radio in that era had a lot of technical issues - 1200 bps, no Forward Error Correction, multiple networking systems (TEXNET, Net/ROM, ROSE, etc.), the TNCs of the era weren’t very capable compared to modern embedded computers such as Raspberry Pi. But, for a while, it worked. We have better technology now, and arguably it’s easier and cheaper to recreate such networks.

My Presentation at SARC

Tina and I very much enjoyed our brief trip to Surrey (Vancouver) British Columbia, Canada for me to give a presentation at Surrey Amateur Radio Communications Society.

Given the activity level of SARC and especially SARC’s worldwide outreach via its stellar newsletterzine The Communicator, as I was developing the presentation, the majority of the presentation morphed into the most comprehensive explanation I’ve done to date of NewTechHams. I plan to clean up and post that portion of the presentation, and expand it into the long promised detailed page on NewTechHams.

But one of the biggest draws of attending SARC’s first in-person meeting of 2026 was meeting John Schouten VE7TI, Editor of The Communicator:

John Schouten VE7TI and Steve Stroh N8GNJ 2026-04-08; photo by Steve Stroh N8GNJ

I’m in awe of the stellar job VE7TI does in producing The Communicator and I gave him a number of appropriate kudos during my presentation. Appropriate because in being free for anyone to access, with great content that represents Amateur Radio very well, The Communicator is a significant resource in attracting and educating NewTechHams and potential NewTechHams.

And yes, boss 😁, I’m mindful that “deadline approacheth” for the next issue of The Communicator, and I’ll get my column in on time.

GMRS in Canada Doesn’t Require a License

I learned something New from Claude AI. I was fact checking what I thought I knew about various unlicensed radio services in the US and Europe (FRS versus DPMR, if memory serves), and I had the random thought to ask if GMRS was the same in Canada as it is in the US? ClaudeAI’s response:

Yes, but with differences from the US:

GMRS is legal in Canada and uses the same frequencies as the US

No license required in Canada — this is the key difference from the US, where a $35 FCC license is required

US GMRS radios work in Canada without modification

So ironically it’s simpler to operate GMRS in Canada than in the US. Cross-border interoperability works fine since the frequencies are the same.

That mention of “cross border interoperability” probably needs a further fact check as us uptight Americans might be kerfluffled at a Canadian, with no license, communicating with a US GMRS user, or using a GMRS repeater.

Or, maybe not. I have no idea - I’ll have to ask around as I’m sure that has come up here in the US / Canada Northwestern borderlands.

Hamvention 2026 Ho!

5 weeks until Hamvention 2026
in Xenia, Ohio, USA...
Zero Retries / DLARC booth 1506
in Building 1 / Maxim

The Technological Innovation In Amateur Radio Firehose Continues

This is yet another issue of Zero Retries that offers a smorgasbord of developments that are occurring, now, in Amateur Radio that you’re probably not hearing about from other Amateur Radio media. I’m not afraid to candidly admit that I can’t keep up with how much is going on, and, again, I drop stuff constantly that I’d love to mention.

In my wilder fantasies (yeah, I lead a pretty tame life), Zero Retries would be a magazine, perhaps monthly. I assign a promising subject for a story to one of a number of capable staff writers. When it comes back. I lightly proofread and edit it, and assemble it into a “73 Magazine” length magazine (online, of course, and free like The Communicator).

And maybe (again, fantasizing here) I can get organized enough, and the AI helpers get good enough, that I can actually accomplish at least something like Zero Retries Magazine. NotebookLM is a stellar research assistant. For general answers, I’m getting increasingly respectful of ClaudeAI.

We need a Packet Radio Appliance

That idea was going to be an article in this issue as a spinout of a email conversation I had this week, but once again, there were too many interesting things to bring to you in this issue. I really want to publish on Friday, and that article would take another few hours, so it’s deferred for now.

Very generally… Amateur Radio needs a packaged solution for using more advanced capabilities that have emerged in Amateur Radio Packet Radio in the last couple of decades. All of this is available, it’s just not integrated / packaged. One example is KM6LYW’s mention of the integrated TNCs in some new portable radios… but those implementations are old, tired, and slow (but works fine for the use case - APRS). We need a “black box” that does:

  • 3600 / 4800 / 9600 bps

  • Both (simultaneous) FX.25 and IL2P Forward Error Correction

  • Net/ROM automatic / auto discovery mesh networking

  • Easy to create routers / gateways that would allow more than one radio / band to be used.

  • Integrated BBS so that you can read BBS messages, bulletins, see files that were transferred to your BBS in the background

  • Good chat system, at least equivalent to Raven in AREDN and Meshtastic / MeshCore.

  • Interface is a web browser, similar to the way DigiPi works.

  • Designed for a (reasonably priced) Raspberry Pi 3B+ - it’s an appliance that connects to the radio.

  • Integration of 44Net Connect for easy access to your station.

“Packaged” similar to TARPN, but more generic than TARPN’s perspective of how to build a Packet Radio network. DigiPi is another great example of packaging, but DigiPi has many more modes than Amateur Radio Packet Radio, and is tightly optimized for use with the Raspberry Pi Zero 2W. I think the greater capabilities of the Raspberry Pi 3B+ is a better platform for what I’m imagining.

My correspondent said that my idea as I pitched it was a bit scattershot, and they were right, so this deserves not just an article but a full treatment as a specification.

Upcoming Events

It’s getting to be the busy season. I created the Zero Retries Guide to Zero Retries Interesting Events page as much for myself and my reference as for public usage.

Comcast - Grrr…

The house I’m staying at this weekend has Comcast Internet. Which mostly works fine (reasonably fast)… but of as I’ve described previously, Comcast customers, including me this weekend, cannot access www.zeroretries.radio.

I can just barely respect the “choice” of Comcast to consider www.zeroretries.radio as a potential phishing site. But, the way that they implement that decision is to simply break the connectivity and leave it for the customer to figure it out. Comcast could put up a redirect page with an explanation like “We consider this page to be potentially harmful so we’re not going to let you see it”. But no, they just break the connectivity with no hint of an explanation.

Thus I hope there’s a special circle in Heck reserved for the network engineers at Comcast who decided to implement that particular method of “protecting” Comcast customers.

As always, I am unreasonably happy to no longe be a paying hostage “customer” of Comcast.

Weekends Are For Amateur Radio!

I’m traveling this weekend, and I’m still not caught up on the conversion of pages and previous issues of ZR from www.zeroretries.radio to www.zeroretries.org. But I did bring my loaned MeshCore node, and with the article about CascadiaMesh, my interest is piqued.

Have a great weekend, all of you co-conspirators in Zero Retries Interesting Amateur Radio activities!

Please offer comments / feedback about Request To Send on the Zero Retries email list with the #ZR0246 hashtag.

73,

Steve N8GNJ

Closing Thanks

My ongoing Thanks to:
Tina Stroh KD7WSF for, well, everything!
Jack Stroh, Late Night Assistant Editor Emeritus
Fiona and Shreky Stroh, Late Night Assistant Editors In Training

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Zero Retries 0246 was published on 2026-04-10. This issue was 7994 words.

Footnotes For This Issue

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1

Two other implementations of “audio” OFDM for VHF / UHF that come readily to mind is VARA FM and more recently, the IP400 Project.

2

In Western Washington, WWARA is the entity that coordinates the use of “repeater pairs” on the VHF / UHF bands and “prioritizes” the usage of particular repeater pairs by particular repeaters.

3

The LinHT will make the multiple digital voice standards a non-issue from the perspective that being a fully Software Defined Radio, you won’t need a separate“DMR radio” to access a DMR repeater, and a separate “D-Star radio” to access a D-Star repeater”. You’ll just use the “DMR” module or the “D-Star” module on the LinHT to access a DMR repeater or a D-Star repeater.

4

This took some time and work to include. The Apple App Store “discourages” copying of text, but a consultation with ClaudeAI resulted in two effective workarounds.

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