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.

Download a desktop installer or portable server from GitHub Releases. The installation guide covers macOS, Windows, Linux, Homebrew, WinGet, APT, DNF, AUR, Nix, and Docker.

On macOS:

brew tap newspicel/tap
brew install --cask sdrminusminus

For a headless server on macOS or Linux, install sdrmm from the same tap:

brew install sdrmm
brew services start sdrmm

Open http://localhost:8080. For remote access, configure authentication and HTTPS.

1. Plug in the RTL-SDR and pick it on the Device node. Set the rate to 2.4 MS/s.
2. Add a WFM channel from + Node and set it to a local FM station.
3. Wire Device iq to WFM iq, and WFM audio to the Speaker.
4. Start the Speaker. Press p on a node to pin it to the Rack.

Your first receiver walks through it. Radios covers other hardware.

• Listening: AM, NFM, broadcast FM with stereo and RDS, SSB, and digital voice.
• Decoding: aircraft, ships, amateur radio, pagers, sensors, images, and more.
• Displays: spectrum, waterfalls, maps, decoded messages, and video.
• Recording: device IQ, channel baseband, and audio, with SigMF playback.
• Radio tools: scanning, signal identification, coherent arrays, direction finding, and passive radar.
• Automation: REST, WebSocket, MCP, network IQ export, and event forwarding.

SDR-- is under active development. The decoder catalog shows how well each mode is tested.

These captures use debug-build signal sources and repository IQ fixtures. Regenerate them with cargo xtask screenshots.

Spectrum and waterfall	Rack view

FT8 decoding	Signal identification

Aircraft positions	Ship positions

Slow-scan television	Amateur television

Pager messages	Broadcast FM

git clone https://github.com/Newspicel/sdrminusminus.git
cd sdrminusminus
python3 scripts/build-media.py
export FFMPEG_DIR="$(python3 scripts/build-media.py --print-prefix)"
pnpm --dir web install --frozen-lockfile
pnpm --dir web build
cargo run -p sdrmm

Open http://localhost:8080, or run cargo xtask dev --watch and open http://localhost:5173 for hot reload. cargo xtask check and cargo xtask test are the main gates.

The build guide lists prerequisites and every check. Read Contributing and the architecture before a pull request.

• User and developer guide
• Swagger UI: /api/docs on a running server
• OpenAPI: /api/openapi.json or openapi.json

Copyright (C) 2026 Julian Haag.

Licensed under the GNU General Public License, version 3 or later. Third-party notices and license texts are also available in the app's About panel.