Store and Forward episode 9 — SuperPeater

Store and Forward

The video version of this episode is at: https://youtu.be/fpmh9S49Fis

Digital Library of Amateur Radio & Communications (a project of the Internet Archive): https://archive.org/details/dlarc

Zero Retries Newsletter: https://www.zeroretries.org

Kay discussed the recent security issues at the Internet Archive, which is now 95% back to normal.

Steve said that it’s been fun to see new material flowing into DLARC, which he sees from DLARC’s RSS feed: http://archive.org/services/collection-rss.php?collection=dlarc

Kay discussed two of the most recent collections added to DLARC from Japan and Russia: a recent project of archiving 600 episodes of a Japanese ham radio show called Ham’s Radio:

https://archive.org/details/hams-radio-japan

With no Japanese language skills, this particular archive was a challenge for Kay. Fortunately there was a related blog for the show, but it wasn’t a 1:1 blog entry for each episode, so Kay had to employ advanced “script ninja” skills to parse out just the blog posts related to episodes. WIth just the episode blog posts, Kay could then use Google Translate and other tools to understand the content. Kay also used ChatGPT’s API to translate the show notes into English.

Steve expressed his excitement about the potential for real-time translation of Amateur Radio voice communications in the future, and mentioned the Radio Autoencoder project within the FreeDV project:

https://freedv.org/radio-autoencoder

Kay discussed the discovery of a vast body of work by a dedicated individual, Dexter Anderson, who had been translating Russian publications into English for decades.

Translations of Russian Amateur Radio Publications 1981-2000:

http://archive.org/details/russian-amateur-radio

Dexter’s translations were not word-for-word but provided a summary of the articles. The conversation also touched on the broader meaning of the term “radio amateur” in the Soviet Union, with a significant portion of radio enthusiasts being passive listeners rather than active transmitters, as explained in the item Summary Translation of the Soviet Amateur Magazine “Radio” 1989-08: https://archive.org/details/summarytranslati00uns_84d/mode/1up

Steve explained that similar to the “not just those who transmit” perspective of the Russian radio publications, he writes Zero Retries not just for those that are licensed Amateur Radio Operators, but also for those that are active in “Amateur Radio Adjacent” activities such as using unlicensed spectrum for experimentation.

One such “Amateur Radio Adjacent” activity that Steve admires is SatNOGS:

https://satnogs.org SatNOGS is Satellite Networked Open Source Ground Station and is a worldwide network of receive-only stations dedicated to receiving telemetry and other data from small low orbit, low powered, research satellites such as those that are conceived and constructed by university students. Such satellite builders have trouble actually conducting the research because their connectivity with their satellites from their location is only minutes per day at best. But SatNOGS stations around the world can also receive the transmissions from research satellites and relay what is received back to the satellite builders.

A SatNOGS station can be as simple as a special antenna called an “Eggbeater” (omnidirectional, but focused towards the sky rather than the horizon), an inexpensive software defined receiver, an embedded computer such as a Raspberry Pi, custom software, and an Internet connection. Building a SatNOGS station makes a great STEM, Maker, or hacker project, especially if you live in a rural area and have a good Internet connection.

Steve then segued mention of archival material in DLARC into a multi-issue project he’s working on in Zero Retries that will culminate in a concept he’s been working on that he’s calling a “SuperPeater”.

In an article Steve wrote for the Internet Archive blog:

https://blog.archive.org/2024/07/10/using-dlarc-amateur-radio-operators-are-resurrecting-technical-ideas-from-the-past-using-21st-century-tech/ … he mentioned one interesting project from past decades called a PACSAT (Packet Satellite). PACSAT’s can be thought of as “Flying Bulletin Board Systems” where a message or bulletin can be uploaded to a PACSAT in one part of its orbit, and downloaded on another part of its orbit. Several PACSATs were flown, and they worked pretty well.

The key concept that unlike a typical Amateur Radio repeater (including data repeaters), a PACSAT featured multiple uplink channels and in the case of multiple simultaneous transmissions received on multiple inputs, a queuing system was used. There were many other innovative features of the PACSATs, including robust modulation methods.

The connection between DLARC and Zero Retries is that all the archival information about PACSATs is in DLARC:

https://archive.org/details/dlarc?tab=collection&query=pacsat

• 11 formal research / presentation papers presented at the Digital Communication Conferences

• 9 newsletter articles in the TAPR Packet Status Register newsletter
• Even a book – The PACSAT Beginner’s Guide

What’s amazing to consider about PACSAT technology in the 2020s is that the PACSAT developers and engineers solved all the hard parts, and made it work, and proved it all out by flying multiple PACSATs. But, back then, they had to invent the technology, build custom hardware, build custom software, invent new algorithms and access protocols, etc.

Now, all of that technology is easy, inexpensive, and off the shelf – mostly software running on existing hardware:

• Different modulation techniques that were tough in 1983, not so much now
• Multiple uplink channels, again tough in 1983, not so much now (ka9q-radio)
• Multiple inputs received – queueing (we have lots of RAM to buffer multiple inputs received simultaneously; 8 GB on a Raspberry Pi 5)
• Dedicated fast computers such as Raspberry Pi for running the dedicated digital processing software
• Multitasking operating systems (including, recently, realtime versions of Linux)
• And, in general, Software Defined Radios hardware

Thus, imagine a terrestrial “SuperPeater” data repeater with its output on 222-225 MHz that transmits at perhaps as fast as 38400 bps in a standard repeater channel. Receiving that data stream can be received with an inexpensive Software Defined Receiver and modem software. There could be multiple input channels to the SuperPeater including on 144-148 MHz and 440-450 MHz, with various data speeds / modem types on multiple channels. The SuperPeater can queue what it receives on each channel and output it all, queued, on the high speed output channel.

As Steve envisions a SuperPeater, it’s mostly a “simple matter of software” 😀

Read the December 2024 issue of Zero Retries for more detail about Steve’s SuperPeater concept.