This Digital Radio Gets Messages to the World’s Remotest Locations

I would expect this system to ultimately be used under a commercial HF license rather than an amateur license, given the feature set and that it seems to have much more in common with military systems like ALE than amateur practice. That said, because of the scarce supply of HF bandwidth, commercial HF licenses are quite restrictive in the US. For the most part, you are only allowed to apply for one if you are an infrastructure operator that needs a contingency communications capability for disaster response. That said, the FCC has permitted experimental licenses for some commercial applications like high frequency trading, so perhaps the situation will become less restrictive over time.

That said, commercial licenses are not per-operator like amateur licenses, so you would potentially only need one to cover the entire network. Some of this is ultimately negotiated.

The licence is not a hurdle. HF licencing in Canada is simple. You get the transmitter certified ($500) and then you rent the spectrum licence. Since there is actually not much demand for HF spectrum it's quite cheap. If you plan to use it domestically it's the same process as like licensing a single 25 kHz VHF channel for a walkie-talkie. And on licensed channel you can encrypt if you want.

But putting a useful transmission on air is expensive. Commercial long-distance shortwave transmitters are megawatt-class. That seems to be the biggest barrier. It turns out to be much cheaper and easier to provide an unreliable 10 kHz channel between A and B through almost any other means.

That said: it's clear there's an uptick in data transmission on shortwave over the last ~decade or so. Get a broadband SDR receiver and look at the spectrum waterfall. Here's a capture live from an SDR in New Zealand: https://i.imgur.com/NfFBO34.png

Between 8250 and 8300 kHz and slightly more faintly centred at 8200, and also at 8150 see the 50 kHz wide spectrum bands of /// rising diagonal lines?

That is a 50 kHz wide channel. Which is broadband in the context of HF when voice band is 3 kHz. It's some kind of spread-spectrum chirp modulation. I've seen broadband OFDM on air as well at extremely low baud like 1 baud but presumably many channels and possible frequencies.

Throughput depends entirely on the levels of error correction etc. but the Shannon limit for a 50 kHz channel at low noise is like ~200 kbps. Well beyond sending some weather reports and teletype data.

Who? Probably military. Spread spectrum techniques are illegal in Canada and the US at least, on HF, for both amateur and commercial users.

Going to be super pedantic here - in ham radio you don't broadcast, you transmit.

Correct. Encryption (or more specifically, obscuring the meaning of a message) is generally not allowed for amateur radio stations except in very narrow circumstances. So any hams using this would have to turn the encryption off.

However, it looks like this stack has encryption available as an option for stations who are transmitting sensitive data and are NOT operating under an amateur license. (Probably government-sanctioned communications or emergency humanitarian efforts.)

These are essential for remote solo hiking.

If you have local stt and tts voice stack on the phone, this would be very useful as the interface to talk to your agent back at home. All inference happens on your local machine while the actual information is sent via text. said text is then processed by your phone via tts as output, same for your voice as input (asr). this project is actually something ive considered doing myself as my voice agent is almost done and ive wanted to take a look and see if i could have acess to him from anywhere in the world..

If you want to have internet everywhere there is Starlink. Competing against it as hobbyist is a waste of time.

But having a small, low-power, lightweight messenger that uses an extremely robust (and thereby slow) mode to send and receive messages is an interesting niche. For VHF/UHF/SHF you can use LoRa.

I haven't used this radio, but I have definitely used a 2.4-kilobit-per-second internet connection productively. Raw TCP/IP with SLIP or PPP will work, and with VJ header compression it works reasonably well. What won't work well is loading a web page with a bunch of images and a megabyte of JavaScript.

I did not yet watch the full video, but Data Slayer on Youtube made a video about this, I guess. It's at https://www.youtube.com/watch?v=5vbl5FL-nsI

Ham radio also has the FT8 protocol which is optimized for bad signal to noise environments, but has low bandwidth. However, using this protocol a 10Watt radio has global reach under the right conditions, which is pretty mind boggling.

About encryption, the US rules are that you can use digital protocols but you must publish the specs so anyone can, in principle, decode the signal.

AX.25 runs at 300 bps over HF while Mercury is 10x faster.

HAM radio isn't allowed to have encryption. (Someone can write a longer comment on why thats wrong.)