VE3KCL S-3 WSPR Balloon


On 28-July Dave VE3KCL launched a balloon (in fact two hydrogen-filled foil "party" balloons tied together) carrying a 39g payload. The balloon is currently cruising East across the Atlantic at just over 8,000m.

The electronics payload Dave built has a GPS, battery, solar panels, QRP Labs Si5351A Synthesiser module, and Arduino Nano (for low weight) that runs the QRP Labs Ultimate3S QRSS/WSPR transmitter firmware, but a slightly modified version.

The balloon uses WSPR on 30m (20mW power) but encodes telemetry data onto the WSPR protocol, in three sequential messages. The additional data carries 5th and 6th Maidenhead locator characters, altitude, speed, battery, temperature, GPS status and satellite status. The balloon is also sending JT9 plain text, and CW to the reverse beacon entwork. The WSPR messages logged to the WSPRnet database are decoded automatically and plotted on the map at .

There are more details and photos on

73 Hans G0UPL