direwolf VS minimodem

144.800 is the APRS frequency in Europe. That's part of the 2m amateur band, and you can use tools like Direwolf to decode the packets. See https://aprs.fi/ for a display of the packets that make it to the internet.

Yes, recommended. https://github.com/wb2osz/direwolf

Since you're trying to save money, I'll second the direwolf software TNC. There's packet-radio.net with info about setting up direwolf.

By default it should be printing any successfully decoded packets to the terminal window. Did you follow https://github.com/wb2osz/direwolf/blob/master/doc/Raspberry-Pi-SDR-IGate.pdf or similar?

I use Direwolf with a Pi Zero and I believe there is a way to get the packet data out or passed to a script. I was going to look into this myself as some point as I wanted to just have a small screen on the Pi just to see traffic passing though my iGate on occasion.

Hardware TNC's were a thing in the 90s but nowadays software TNC'S such as Direwolf are far more efficient

On this topic, has anyone here used direwolf (https://github.com/wb2osz/direwolf) to communicate between two computers without radios?

Wheel successfully reinvented :)

Nothing stopping you setting up a whole AX.25 network between multiple machines using Dire Wolf [1] and the built-in AX.25 [2] (a derivation of X.25) support still in the Linux kernel. You get a proper network interface that shows up alongside eth0. Nice short instructions at [3]. Just don't hook it up to radios unless you're appropriately licensed. Speakers and mics only.

[1] https://github.com/wb2osz/direwolf

[2] https://en.wikipedia.org/wiki/AX.25

[3] https://g7vrd.co.uk/ax25-direwolf-linux

https://github.com/wb2osz/direwolf has the current and best instructions.

This will get you started:

Tony Fisher wrote V.32 soft modem stack for SGI Indy back in 1996. York University couldnt handle hosting whole 8 megabytes of his stuff https://www.cs.york.ac.uk/news/fisher/home-page but at least they had the decency to upload it to github instead of just deleting https://github.com/university-of-york/cs-www-users-fisher/tr... Randy Rossi rewrote this project and got working V.21/23 https://github.com/randyrossi/fisher-modem

Fabrice Bellard, because of course he did :), implemented his own version all the way to V.34 with parts of V.90 https://bellard.org/linmodem/

V.21 modem implemented in Gnu Radio https://web.archive.org/web/20170627151353/http://aaronscher...

amodem - good source of ready made modulation implementations https://github.com/romanz/amodem

minimodem- simple radio link FSK modem https://github.com/kamalmostafa/minimodem

audsl - leased line project, not compatible with standard modems https://www.araneus.fi/audsl/ but might give some ideas.

Try downloading it from the tags section instead of cloning the repo. https://github.com/kamalmostafa/minimodem/tags

there's a tool called minimodem http://www.whence.com/minimodem/ it uses audio cards to replicate ancient modem standards - I was watching videos of old modems and was able to use minimodem to simultaneously reconstruct the terminal session locally. It was amusing to do so.

“What do you do when you cannot copy text between computers due to lack of internet connectivity? “

Literally what Minimodem was created for :)

http://www.whence.com/minimodem/