This is a small PIC-based APRS tracker that supports the OpenTracker firmware. It has a small integrated 300mW transmitter on-board, and a pin header to connect a GPS module.
The tracker is controller by a PIC 16F648A microcontroller. The PCB is designed in Eagle CAD and uses 1206 SMD components to keep the board small, while still being manageable to populate and solder by hand.
The back side of the PCB is home to the HX1-144.800-3 narrow-band FM transmitter. This little module puts out 300mW, which gives plenty of range to reach the nearest APRS repeater, even on the quarter wave wire antenna I am using for testing. Especially on a high altitude balloon, for which this tracker was developed, the range is very good due to the wide line-of-sight area.
The hardware is fully compatible with the standard APRS firmware.