This is a Micro APRS from this site ( http://unsigned.io/microaprs/ ). I just get a few common parts and put everything together on top of a ProtoShield.
|Arduino AFSK modem/TNC|
Once it was working, I made another one so that it can talk to each other over RF. The picture below are two Arduino UNO connected directly to test the Tx and Rx encoding/decoding.
Decoding APRS packets off the air on 144.390 Mhz.
The Arduino modem / TNC working and connected to my Wouxun handy.