I built a software-defined radio transmission platform that runs on a Raspberry Pi Zero W. It spawns its own WiFi hotspot and serves a web UI — connect from any device and you have a portable RF signal generator with 12 transmission modes: FM broadcasting with RDS, FT8, RTTY, FSK, POCSAG paging, Morse code, SSTV image transmission, voice cloning via live mic, spectrum painting, IQ replay, carrier wave, and frequency sweeps.

Everything runs through a browser interface. Upload audio files, type messages, configure frequencies, and transmit. The Pi's GPIO pin does the actual RF generation via rpitx — no external radio hardware needed.

Written in Go with a real-time WebSocket frontend. Includes a preset system, playlist builder, and multi-device support (connect multiple phones/laptops to the AP and share control).

Without an antenna the signal barely reaches 5 meters, which makes it perfect for indoor experimentation and learning about RF protocols without causing interference. All my testing was done indoors with no antenna attached.

Built this because I wanted a single portable tool to experiment with every common RF transmission mode without hauling around expensive SDR equipment.

Pre-built SD card image available if you want to skip the build process.

GitHub: https://github.com/psyb0t/piraterf Blog post: https://ciprian.51k.eu/piraterf-turning-a-20-raspberry-pi-ze...