@spitfire @pinpox granted, #AFSK can be done on any medium with bandwith to do audio and #SSTV decoder & -encoder #Apps are quite common...

- Similarly #RadioFax can be implemented...

https://en.wikipedia.org/wiki/Slow-scan_television
https://en.wikipedia.org/wiki/Radiofax

@JustinDerrick @triptych @BNetzA @toychicken #LoRa AFAICT is midband, uses spread-spectrum and wider channels, so it's not compatible with like #CEPT standardized #CB radio in 27MHz...

One could do #AFSK modulated Packet Radio, but most juristictions, like Germany, do not allow DIY of Transmitters but necessitate a certified radio to be used...

DIY-ing a compliant transciever is extremely costly due to certification req..
https://en.wikipedia.org/wiki/Citizens_band_radio#Frequency_allocations
https://en.wikipedia.org/wiki/ISM_radio_band#Frequency_allocations
https://de.wikipedia.org/wiki/CB-Funk#CEPT-konforme_CB-Kan%C3%A4le_und_Mittenfrequenzen

@pinpox so basically a two-way #pager?

- Consider #LoRa / #Meshtastic or your combo of #RTLSDR & #CB portable radio with #AFSK on FM for truly low tech!

@nix Ever heard of #CellBroadcast ?
https://en.wikipedia.org/wiki/Cell_Broadcast#Emergency_communication_system

And yes, I know #PTY31 from #RDS...
https://en.wikipedia.org/wiki/Radio_Data_System#Content_and_implementation

Also there's stuff like https://ntfy.sh ...

Personally, I think the next best thing would be #AFSK'ing #PocketCrypto over #CB Radio...
https://github.com/KBtechnologies/PocketCrypto
https://en.wikipedia.org/wiki/Citizens_band_radio#Standard_channels