2024-08-16 — 2000 Subscribers!, Playing for “Those Five”, Microcomputers in 1976, Linux… and the M17 Project, Followup to The LEO Satellite Industry Needs More Engineers, What’s New at DLARC - 8/2024
1. You can listen to Store and Forward (or watch it) from your web browser - there's a mini-player embedded in the page for each episode. Alternatively you can watch us talk (with the occasional photos) on the video version hosted on Internet Archive / Digital Library of Amateur Radio & Communications.
2. We haven't quite gotten to the point of "pushing" our podcast into the big podcast distribution networks (Apple) so you can't browse for it like you can with most podcasts. That's on Kay's (the brains of the outfit) to do list, and I'll mention when that is completed in Zero Retries.
3. The Apple podcast app does have the ability to add a direct entry (Add URL) but for some reason it doesn't like the URL for Store and Forward.
4. I prefer the Overcast podcast app (https://overcast.fm/) and Overcast had no problem adding Store and Forward by typing in the URL.
VARA HF “Tactical, Level 17” can transfer up to 8489 bps: That is the maximum physical-level transfer rate. Expect no more than perhaps 25% of that on the logical level and definitely not with somehow standard ham radio means!
Using the VarAC data transfer mechanism I have seen peaks of around 1000 bps. OK, VarAC uses VARA with 500 Hz of bandwidth. But transferring 5 kB lasts several minutes due to phases with much lower transfer rates, repetition etc.
You also cannot do this with standard ham radio equipment because of the crest factor of digital transmissions: Within minutes your TX and possibly power supply overheats! When chatting with VarAC my PA heats to perhaps 15 K above surrounding air temperature. But If I try to transmit two sentences in JS8, my PA turns off within 3 min at 60°C. For the next sentence my PA needs 5 min to cool down.
For my purposes, a better fan might suffice. But transferring 1 MB over shortwave needs lots of radiated power and a lot less CMEs than we presently have - another limitation of any shortwave application.
Another analogy for the M17 project, one that's a little more recent, is Ardupilot (https://ardupilot.org) and the more "commercial" fork called Dronecode (https://dronecode.org). I haven't seen too many surveys, but from what I can tell the largest drone manufacturer in the world is DJI, with ~75% marketshare. Then probably all the Ardupilot/Dronecode manufacturers. DJI has fallen out of favor with the US government due to their association with the CCP (either real or imagined... that's a debate for another blog), opening up opportunities for other manufacturers, many of which are running Dronecode.
I have DJI drones, and I have built two Ardupilot drones. The DJI drones are still superior in most aspects, but the Ardupilot builds I've done have the basics of flight down solid. I'm hardly an aerospace engineer. One reason for my success is the extremely active community willing to help newbies troubleshoot their builds, and the extensive data logging that takes place on the autopilots. I haven't needed direct assistance with sorting out issues, but by scouring the community forums I've been able to sort out most issues right away and keep flying. While I don't believe M17 will require the same amount of effort onboarding users I think there's a real need for getting people up to speed. Too often the builders don't put themselves in the shoes of the end users (one thing that might help is making it easy to update firmware through application software via the USB interface instead of a TTL UART adapter hint hint), who run the gamut of ability and interest. For many digital users, the goal was to get on the the DMR network with hardened part-90 radios, or to just talk their buddy who loaded up their code plug, not to explore the bleeding edge. And I imagine the ham community follows the Pareto Principle just as much as any other.
So thanks for funding the M17 Groups.io board Steve. As I learn more about how it works I'll do my best to help onboarding users.
Ready - I appreciate you and a few others that explain the intellectual crossover between Amateur Radio and drone users and drone industry. Drones are fascinating technology and, like 3D printing, I've been tempted to get involved until I think about the backlog of near-term Amateur Radio projects that are in my queue, just waiting for some time to be applied to them.
"Getting up to speed with M17" is exactly the intent of the m17-users email list. While there is also the Discord and Matrix options, an email list is a bit more my (and apparently others) speed for requesting and providing support on M17.
Congratulations on the 2000 subscriber milestone. You do great work in the name of amateur radio and I'm sure many many more will come to find your words, information and inspiration!
Please disregard this ‘no’ —I have no idea how it was generated
The 'Store & Forward' link is broken. How do I listen? Can I use my Apple podcast app? -de NI)K
John - I fixed the link which should have been https://www.storeandforwardradio.org/.
1. You can listen to Store and Forward (or watch it) from your web browser - there's a mini-player embedded in the page for each episode. Alternatively you can watch us talk (with the occasional photos) on the video version hosted on Internet Archive / Digital Library of Amateur Radio & Communications.
2. We haven't quite gotten to the point of "pushing" our podcast into the big podcast distribution networks (Apple) so you can't browse for it like you can with most podcasts. That's on Kay's (the brains of the outfit) to do list, and I'll mention when that is completed in Zero Retries.
3. The Apple podcast app does have the ability to add a direct entry (Add URL) but for some reason it doesn't like the URL for Store and Forward.
4. I prefer the Overcast podcast app (https://overcast.fm/) and Overcast had no problem adding Store and Forward by typing in the URL.
Hope that helps!
John - Breaking update 2024-08-17 09:45 Pacific - Store and Forward can now be found in your normal podcast feed - just look for
Store and Forward - we're the one with the cool yellow logo.
VARA HF “Tactical, Level 17” can transfer up to 8489 bps: That is the maximum physical-level transfer rate. Expect no more than perhaps 25% of that on the logical level and definitely not with somehow standard ham radio means!
Using the VarAC data transfer mechanism I have seen peaks of around 1000 bps. OK, VarAC uses VARA with 500 Hz of bandwidth. But transferring 5 kB lasts several minutes due to phases with much lower transfer rates, repetition etc.
You also cannot do this with standard ham radio equipment because of the crest factor of digital transmissions: Within minutes your TX and possibly power supply overheats! When chatting with VarAC my PA heats to perhaps 15 K above surrounding air temperature. But If I try to transmit two sentences in JS8, my PA turns off within 3 min at 60°C. For the next sentence my PA needs 5 min to cool down.
For my purposes, a better fan might suffice. But transferring 1 MB over shortwave needs lots of radiated power and a lot less CMEs than we presently have - another limitation of any shortwave application.
Alexander - I'll defer to your hands-on experience. It did sound a bit too good to be true... but it was a fun thought experiment.
Another analogy for the M17 project, one that's a little more recent, is Ardupilot (https://ardupilot.org) and the more "commercial" fork called Dronecode (https://dronecode.org). I haven't seen too many surveys, but from what I can tell the largest drone manufacturer in the world is DJI, with ~75% marketshare. Then probably all the Ardupilot/Dronecode manufacturers. DJI has fallen out of favor with the US government due to their association with the CCP (either real or imagined... that's a debate for another blog), opening up opportunities for other manufacturers, many of which are running Dronecode.
I have DJI drones, and I have built two Ardupilot drones. The DJI drones are still superior in most aspects, but the Ardupilot builds I've done have the basics of flight down solid. I'm hardly an aerospace engineer. One reason for my success is the extremely active community willing to help newbies troubleshoot their builds, and the extensive data logging that takes place on the autopilots. I haven't needed direct assistance with sorting out issues, but by scouring the community forums I've been able to sort out most issues right away and keep flying. While I don't believe M17 will require the same amount of effort onboarding users I think there's a real need for getting people up to speed. Too often the builders don't put themselves in the shoes of the end users (one thing that might help is making it easy to update firmware through application software via the USB interface instead of a TTL UART adapter hint hint), who run the gamut of ability and interest. For many digital users, the goal was to get on the the DMR network with hardened part-90 radios, or to just talk their buddy who loaded up their code plug, not to explore the bleeding edge. And I imagine the ham community follows the Pareto Principle just as much as any other.
So thanks for funding the M17 Groups.io board Steve. As I learn more about how it works I'll do my best to help onboarding users.
Ready - I appreciate you and a few others that explain the intellectual crossover between Amateur Radio and drone users and drone industry. Drones are fascinating technology and, like 3D printing, I've been tempted to get involved until I think about the backlog of near-term Amateur Radio projects that are in my queue, just waiting for some time to be applied to them.
"Getting up to speed with M17" is exactly the intent of the m17-users email list. While there is also the Discord and Matrix options, an email list is a bit more my (and apparently others) speed for requesting and providing support on M17.
Congratulations on the 2000 subscriber milestone. You do great work in the name of amateur radio and I'm sure many many more will come to find your words, information and inspiration!