Project Greyline: Emergency Server Control Over Radio/Shortwave

[skullmeat]

Off and on I have been doing some research on AFSK as a method to administer mission critical servers in an emergency scenario when other methods of communication have failed. Much like some SCADA systems use to remotely monitor and control industrial equipment, it should be possible to get a linux command line over radio (shortwave being the most likely method) using AFSK. It would not be quick, around 1200 baud under perfect conditions, but that should be enough to get a basic command line through in an emergency. Anyone have experience in this kind of thing? Data modulation is like black magic to me.

What I have right now: x2 RTL-SDRs, a linux pc, and a USB soundcard.
If I understand correctly, for proof of concept, I should be able to pipe the RTL-SDR output into minimodem? Then a simple FM transmitter could be used to transmit. One RTL-SDR and FM Transmitter on each end for TX and RX.

[Grafo]

I don't know anything about this but it sound so cool and straightup cyberpunk. Really want to see how this evolves.
The idea also remind me a bit on how some software was transmited on the Commodore 64 era

[bumbervevo]

Pretty cool stuff. I had seen this topic two or three days ago and kept frantically searching for this: https://meshtastic.org/

Same idea of sending messages in an emergency situation where communications go offline. Doing it with a shortwave radio sounds pretty cool...and complicated. Radio and phone mechanics go waaaay over my head.

[skullmeat]

Still on the prep work for the proof of concept. Need to buy some supplies but im low on cash. Will share what I have soon. In theory this should work, but in practice noise and latency are going to be the real issue.

[skullmeat]

Pretty cool stuff. I had seen this topic two or three days ago and kept frantically searching for this: https://meshtastic.org/

Same idea of sending messages in an emergency situation where communications go offline. Doing it with a shortwave radio sounds pretty cool...and complicated. Radio and phone mechanics go waaaay over my head.

Its not as complex as it sounds. Minimodem is capable of AFSK (Audio Frequency Shift Key). Its just data being sent over radio or an audio cable. There's plenty of real world applications of transmitting data over radio. If you are wondering what an AFSK data burst sounds like: https://en.wikipedia.org/wiki/File:AFSK_1200_baud.ogg (Warning, loud.)

[ravanal]

Pretty cool stuff. I had seen this topic two or three days ago and kept frantically searching for this: https://meshtastic.org/

Same idea of sending messages in an emergency situation where communications go offline. Doing it with a shortwave radio sounds pretty cool...and complicated. Radio and phone mechanics go waaaay over my head.

I thought about Meshtastic when i saw the title, but i think i feel Skullmeat's post is about something else-
But if it is related, i do have my little meshtastic setup here. It's as basic as it, i literally used the package box as the support for the antenna, but it works well for off-grid communication. The only thing i upgraded was the antenna itself, and works pretty well. I learned PA has a big mesh community after seeing all the connections i got. Hell, somehow i got connections all the way to Texas.