Very small tracker with GPS and 430MHz CW/RTTY radio beacon designed for High Altitude Baloons. Based on ATMega328 @4MHz and powered from single AA Lithium 1.5 V cell
Radio is RFM22 for 430 MHz. PCB is designed for both versions.
GPS is uBLOX MAX-6G or MAX-M8C Module from [HAB supplies] (http://ava.upuaut.net/store/index.php?route=product/product&path=59_64&product_id=71) Tracker send CW an RTTY messages. You can find source code under sw directory.
We can offer bare PCB or KIT without GPS and antenna. http://hamshop.cz/hab-a-aprs-c34/
Be careful, voltage over 1.8 V can damage MAX-6G GPS module. Install power supply first, and measure voltage at output.