2023-03-17 - Zero Retries 0090 Omnibus of Zero Retries Interesting Information, Observations on Radio Frequency Interference
Hi Steve, thanks for the mention in the previous issue, and also for stopping by to comment on my 'stack. I'm interested in finding more hams on Substack, both authors and readers. I'm curious if you have any ideas on how to help to encourage engagement on this very nice platform. 73, NT7S.
I hope FreeDV and CODEC2 do well. I gave a presentation to my club on FreeDV 6 .or 7 years ago. I polled the audience about which digital voice mode would be dominant in 5 years. Only one person though CODEC2/FreeDV. He's now SK. One or two members (out of about 100) have played with it, but none uses it in practice. The work on improving modems and speech clarity is great, but more is is needed, like usability and critical mass. It is nice to see embedding part of the project, but how much effort is being devoted to outreach and partnerships with manufacturs? Unless and until the major manufacturers adopt it, it will remain a backwater in the ham radio world, I'm afraid. One path to adoption might be to have something that takes less than 1kHz bandwidth to enable voice communications on 30m ;-) At least that is the case in Canada where modes are not regulated, just bandwidth (despite what WIkipedia says). In the 90s there was a proprietary speech codec (I forget the name) that used a mere 300bps. I remember the VOA using it over the Internet, so it's possible (FLDigi can do 562 bps in 750Hz channel with error correction).
FLdigi, has several OFDM modes. I don't know if it was the first (after VARA, perhaps) to offer that to hams, but it exists. FLdigi has its devotees, especially among those who don't want to use MS-Windows, but it a tiny fraction of the digital mode users in the ham radio population, at least locally. More than FreeDV though :-)
I'd also like to relate some experience with GNU Radio. I've tried it several times and gone through the tutorials. My experience with it on MS-Windows was unpleasant. There are lots of roadblocks to anything except using GRC and the developers are rather blasé about it, being focused on Linux. The custom Anaconda environment is also a PITA for the casual user, interfering with my other Python projects.
Unfortunately GRC can't do some simple things I need, like squelching one channel with another (no control output from the squelch block), or creating timestamped audio files that close when the signal is gone, etc. All that could be done by writing Python blocks, which is not hard, but that requires booting up a Linux system. I tried running my station on Linux, and some things worked well, but it's all the little utilities that come from manufacturers that get you, like the program that controls my antenna tuner, for instance.
From watching the GRCON videos, there's a lot of focus on analysis of digital signals, which is great, but there are also many limitations for doing anything in production, so most of my DSP projects, like my current radio direction finding and transmitter profile investigations, are straight Python/Scipy or C.