Looks to me like APRS over HF. I used to dabble quite a bit in TCP/IP over HF back in the day, we even had a working email system between our ships before Sat C made it redundant. Codan used to make really nice HF modems, don't know if they still do, but you don't really need much gear to get started these days.
Discussion
Much appreciated! I’m really intrigued by that kind of thing. I’ve done some reading into LORA which sounds like it might be the same kind of idea? Long range mesh communication would be my jam if I had more time and understanding.
Very similar use cases, with very different implementations. I have a 24 acre farm and I've looked into LORA for setting up sensors but it's all very proprietary. A radio link protocol like APRS being used to exchange NOSTR messages using commodity hardware and open source software could work well for long range IoT networks