The high-altitude balloon flight OH3HAB #7, launched on September 2nd 2023 by amateur radio club OH3AA in Hämeenlinna, Finland, was a special flight with two new technical experiments: a RadSens radiation sensor based on a Geiger tube and an image transmitter using the Wenet modulation. The flight payloads included a Vaisala RS41 radiosonde that was repurposed for amateur radio use and a Raspberry Pi Zero W with a Uputronics LoRa board to transmit photographs. With the transmissions of the position and image data available for anyone to receive easily, tracking of the flight became a true community effort!
Repurposing radiosondes for amateur radio high-altitude balloon tracking was a presentation I gave at VUSHF2022, the 42nd Nordic V/U/SHF meeting held between 26th and 29th of May 2022 at Kristalliranta, Säkylä, Finland. The presentation describes the hardware of Vaisala RS41 radiosondes, discusses why they are useful for amateur radio hobbyists and, finally, gives instructions on how to find your own radiosonde - an STM32 microcontroller board fallen from the sky! The presentation slides are available here for download.