High Altitude Balloon WSPR transmitter
- Parallax Propeller Multi-core microprocessor
- Spin language
- GPS used for time and postition information
- WSPR transmitter testing has received reports from as far as 7100kM (4400 miles) using 1mW of RF power
High Altitude Balloon Tracking
Weak Signal Propagation Reporter, WSPR
Parallax Propeller
Amateur Radio Relay League, ARRL