I made an APRS transmitter. It uses the internal radio.
The code is up on GitHub now, along with a released .fap: https://github.com/yo3gnd/flipper-zero-aprs-tx
I read in quite a few places that the Flipper cannot really do APRS over Sub-GHz. It may yet be coaxed into receiving, but transmitting does work now. The app can store several packet types, keep a small callbook, and expose a few settings to help whatever is on the other end decode more reliably.
It is, however, a fairly dirty hack: FSK being pushed into doing FM's job. Deviation matters quite a bit. Too low and the signal may not even wake the squelch; too hot and it starts clipping. It works, but in a manner that is more stubborn than elegant.
u/yo3gnd — 1 day ago