VE3KCL / QRP Labs WSPR balloon completed world trip!

Hi all

After 20 days flight, Dave VE3KCL's QRP Labs Balloon S11 has completed a circumnavigation. See tracking at

This balloon uses a version of the QRP Labs Ultimate3S firmware (see installed on an Arduino Nano board to reduce the weight. The balloon transmits on 30m and 20m with about 20mW power output to a dipole handing vertically from the balloon. The balloon is two mylar foil party balloons filled with hydrogen. The transmitter sends one standard WSPR message with callsign VE3KCL followed by one special WSPR message in which the some of the callsign, locator and power fields have been re-purposed to send additional telemetry. The telemetry contains 5th and 6th Maidenhead locator characters (for finer position resolution), altitude, ground speed, battery voltage, temperature, GPS status and Satellite status. The balloon altitude is a little over 10,000m. More details are on the page.

The GPS used on this flight has a problem - it stops reporting when the altitude exceeds 10,000m. This is contrary to the manufacturer's specification. Due to this problem, we have only intermittent reports from the balloon, when it sometimes falls just below 10,000m in the early morning. Despite this problem it has been possible to track the balloon around the world and it has been a great flight so far!

Dave VE3KCL also launched his S13 balloon yesterday (4th July), using the same GPS but with a manufacturer firmware update on the GPS so it should be working above 10,000m. This balloon is using Dave's other callsign "VE3OCL". It transmits location on a 12 minute cycle during the day (at night it shuts down as the battery cannot power it through the night). See details and tracking at

73 Hans G0UPL