SDR--
A software-defined radio application for listening, decoding, and recording. Connect radios, channels, and displays in Patch view, then pin your everyday controls to Rack view.
Run the desktop app with a local SDR, or place the server near your antenna and connect through a browser. Both use the same receiver engine and interface.
Read the docs. Questions or ideas? Join the Discord.
Install
Download a desktop installer or portable server from GitHub Releases, or build it yourself. The installation guide covers macOS, Windows, Linux, Homebrew, APT, DNF, Nix, and Docker.
Start with an RTL-SDR
- Plug in the RTL-SDR and pick it on the Device node. Set the rate to 2.4 MS/s.
- Add a WFM channel from + Node and set it to a local FM station.
- Wire Device
iqto WFMiq, and WFMaudioto the Speaker. - Start the Speaker. Press
pon a node to pin it to the Rack.
Your first receiver walks through it. Radios covers other hardware.
What it supports
- Listening: AM, NFM, WFM with stereo and RDS, SSB, digital voice (DMR, P25, NXDN, D-STAR, FreeDV, M17), and noise reduction.
- Decoding: aircraft, ships, pagers, amateur modes, weather satellites, radiosondes, DAB, DRM, and DVB.
- Displays: spectrum, waterfalls, maps, decoded messages, and video.
- Recording: device IQ, channel baseband, audio, and each call, with a time machine and SigMF playback.
- Finding signals: scanning, signal identification, band monitoring, and transmitter hunting.
- Arrays: coherent arrays, direction finding, and passive radar.
- Location: GPS, satellite tracking, and a propagation map.
- Phones: iPhone and Android remote with CarPlay and Android Auto.
- Tools: antenna calculator, NanoVNA, and radio programmer.
- Automation: REST, WebSocket, and MCP, plus network IQ, webhooks, MQTT, and databases.
Screenshots
| Spectrum and waterfall | Rack view |
|---|---|
 |  |
| FT8 decoding | Signal identification |
 |  |
| Aircraft positions | Ship positions |
 |  |
| Slow-scan television | Amateur television |
 |  |
| Pager messages | Broadcast FM |
 |  |
Thanks
KrakenRF, Airspy, AntSDR, FUNcube Dongle and Aaronia provided hardware for development and testing.
Making a radio? Write to hi@jhaag.me to get it supported and tested.
License
Copyright (C) 2026 Julian Haag.
Licensed under the GNU Affero General Public License, version 3 or later. Need a commercial license or custom work? Write to hi@jhaag.me. Third-party notices and license texts are also available in the app's About panel.