I recently did a presentation on “Advanced Data Modes for Amateur Radio” (YouTube - skip to 34:00) for the San Juan County Amateur Radio Society. It was intended as a very cursory introduction of some of the things I’m covering in Zero Retries and why they’re relevant. From feedback after the presentation, I seem to have achieved that.
Here is the text from the my slides (no graphics; I’m kind of minimalist that way).
Advanced Data Modes for Amateur Radio
Presentation to San Juan County Amateur Radio Society, Friday Harbor, WA, USA
Via Zoom
SJCARS Meeting Presentation
2021-07-09, 11:30 PDT
Steve Stroh N8GNJ
Slide 2
Since I first got into Amateur Radio in 1985, it’s rare that any of my radios have a microphone attached to them. Most of my radios had TNCs attached to them. Lately, it’s a sound card / modem attached to a computer like a Raspberry Pi. I was into packet radio when I moved to the Seattle area in 1987 and almost immediately fell in with a bad crowd that did radical things like build repeaters that only passed 9600 bps data and use TCP/IP over the air. Eventually I began writing about packet radio, which somehow transitioned into a minor career writing about Broadband Internet Access using wireless technology (back when consumer access to the Internet was a new thing, and using wireless to do so was a radical concept).My other very part-time activity is being a volunteer member of the Grants Advisory Committee for Amateur Radio Digital Communications (ARDC) that I’ve previously spoken about to SJCARC. ARDC is a philanthropic organization providing grants to Amateur Radio projects large and small.I live in Bellingham, and like a few other “mainlanders” I enjoy coming up to Friday Harbor to attend the meetings and see some of my friends who now live in the San Juans.
Slide 3
There are a number of new data modes that are worth knowing about. I’ll be talking about five of the most interesting:
Amateur Radio Emergency Data Network (AREDN)
VARA FM
New Packet Radio
M17 Project
GNU Radio
Slide 4
Amateur Radio Emergency Data Network (AREDN)
- Uses firmware reload on Wi-Fi and Wireless ISP units. New capabilities of the AREDN firmware include auto-forming mesh networks and uses Amateur Radio dedicated spectrum below the 2.4 GHz band (normal Wi-Fi).
- Works similar to HamWAN, but operates on 2.3 GHz rather than 5.9 GHz and automatically forms networks if a connection to another unit can be established.
- High speed TCP/IP like a local area network - usable for video, voice, websites, email, etc. I think AREDN’s highest utility is that every ham that has a Go Kit should include an AREDN system for linking up Go Kits at the same event.
- HamWAN and AREDN networks can be (carefully...) combined, such as what’s being done in Whatcom County.
- More information: https://www.arednmesh.org
Slide 5
VARA FM
- New “software modem” mode for VHF and UHF is highly adaptive to radio conditions and can exchange data at speeds up to 25 kbps.
- Not packet radio - it’s its own system; can only interoperate with other VARA FM stations.
- Requires Windows PC, a “high fidelity” audio interface, a radio with “flat audio” input / output, and for high speed operation, a paid license from the author ($69).
- Very robust - uses Orthogonal Frequency Division Multiplexing (OFDM) techniques, speeds up and slows down depending on conditions, handshakes with other stations, incorporates forward error correction. Can probably operate well over FM voice repeaters.
- More information: https://rosmodem.wordpress.com
Slide 6
New Packet Radio
- Clean sheet of paper rethinking of the radios, software and networking used in Amateur Radio Packet Radio / data communications.
- Designed by a French Amateur Radio Operator for Europe’s more liberal rules on 440-450 MHz, can do up to 500 Kbps. For US antiquated rules that specify “56 kbps maximum” it can be throttled to ~65 kbps.
- Despite the name, has nothing in common with classic packet radio (no interoperation). NPR does not use AX.25. It’s a real data radio using Ethernet and TCP/IP as its interface.
- Open source project, build the radio yourself out of parts, or order a kit of parts. Low power output, but an amplifier (intended for DMR) works reasonably well for ~20 watts output.
- More information:
https://hackaday.io/project/164092-npr-new-packet-radio and
https://spectrum.ieee.org/geek-life/hands-on/build-a-longdistance-data-network-using-ham-radio
Slide 7
M17 Project
- Another clean sheet of paper project to create a digital voice system similar to D-Star, DMR, Yaesu System Fusion, or APCO P25. Started by a team in Poland, but now has contributors worldwide. Entire project is open source.
- No dependencies on the proprietary DVSI codec that most systems use; the codec they will use for voice is the open source Codec 2.
- Their goal is create an entirely open source “stack” - protocols, radios, hardware, software, repeaters, etc. Will have voice, data, and messaging capability.
- Recently received a $250,000 grant from ARDC (via Open Research Institute) to speed development.
- More information: https://m17project.org
Slide 8
GNU Radio
- The ultimate method of experimentation with Software Defined Radio (SDR) is the open source software “toolkit” called GNU Radio.
- You want to experiment with Software Defined Radio? Anything you want to do is probably already available in GNU Radio. Ideal for students and experimenters.
- Hardware supported by GNU Radio ranges from $25 receive only units (RTL-SDR dongles) to very capable but expensive transceivers (Ettus Research). Several capable, (but low transmit power) transceivers available for < $500.
- For those of us who are “code challenged” there’s a training wheels add-on called GNU Radio Companion graphical user interface. Drag blocks (function modules, like FM receiver) around, draw connections (lines) between them, and “compile”. Fiddle around until it works.
- More information: https://www.gnuradio.org
Slide 9
I’ll be experimenting with all of these this coming summer from my shop in Bellingham.
If you’d like to follow along with my adventures and perspectives, I now publish a newsletter called Zero Retries. You can subscribe to it at https://zeroretries.substack.com.
I also blog at https://www.n8gnj.org (my personal Amateur Radio activities) and https://www.superpacket.org (my “big picture” perspectives on Amateur Radio).
Contact:
Steve Stroh N8GNJ
(redacted)
Questions?