Custom firmware for Vaisala RS41 and Graw DFM-17 radiosondes with support for amateur radio use. Ideal for tracking high-altitude balloons. Supported modes include APRS, Horus 4FSK mode, CATS, morse code (CW) and additional digital modes like WSPR and FT8 via Si5351.
Modifications for DFM17 PWM support for APRS