4fsk

Easy-to-use custom firmware for Vaisala RS41 and Graw DFM-17 radiosondes with support for amateur radio use. Ideal for tracking high-altitude balloons. Configure and flash the firmware using a web browser (WebUSB). Supported modes include APRS, Horus 4FSK mode, CATS, morse code (CW) and additional digital modes like WSPR and FT8 via Si5351.

• Updated Jul 8, 2026
• C

Versatile, feature-rich firmware for ALL revisions of Vaisala RS41 radiosondes, supporting factory-calibrated sensors (silver boom and pressure board), excellent GPS performance, Horus/APRS/Morse/RTTY/Pip/Fox radio modes and more! Project usage is straightforward, with web flasher and guided configurator.

• Updated Jul 24, 2026
• HTML

Arduino sketch for a High Altitude Balloon tracker for ESP32 and sx127x, sx126x, RF69, LLCC68 or RFM9x. Supports LoRa, LoRa-APRS and APRS, RTTY, Horus V1 4FSK, Horus V2 4FSK, Horus V3 4FSK and SSDV. Supports LoRa uplink.

• Updated Apr 10, 2026
• C

4FSK HorusBinary V1 and V2 compatible HAB tracker for SX127x and Arduino Pro mini

• Updated Dec 8, 2023
• C++

声语信使:基于 STM32F411 的三模式 4-FSK 声学短信息通信系统

• Updated Jul 19, 2026
• C

The first easy to use Internet of sounds. Audio-communication-network html modem. Turn your sound card into a network adapter. Analog packet radio acoustic internet build for off-grid telecomunication. Cyrinx+TTY+4FSK+2FSK+SSTV PD290+ggwave and revolutionary helscreiber video stream all in one html ready to deploy. (Encryption is optional)

• Updated Sep 6, 2026
• HTML

GNU Radio out-of-tree (OOT) module for QRadioLink blocks.

• Updated Jun 5, 2026
• C++