27 km altitude
A user at Stockholm University attached Windsond to a high-altitude balloon with special scientific instrumentation. The balloon rose to 27 km MSL before bursting. Windsond served as backup tracking system. The crew maintained contact with Windsond up to 10 km altitude using the regular whip receiver antenna. When the package was returning to earth suspended from the parachute, the crew got contact again and Windsond helped them to find and recover the package.
Here’s the long video showing the whole flight:
The firmware wasn’t adapted to these high altitudes and got confused. The beeping of Windsond can be heard throughout the whole flight — meaning Windsond was still active at 27 km altitude.
The crew is now planning more launches that will include Windsond and we’re discussing special adaptations for this kind of mission. A detailed report from a previous trial, that didn’t include Windsond, is available in Swedish here.