Graywolf is a modern APRS station with a software modem, digipeater, iGate, and web UI. It bundles everything you need to put an APRS station on the air — from raw audio demodulation to APRS-IS gating — and makes it easy with a browser-based configuration interface.
Download the Latest Release — prebuilt for Linux (Debian/Ubuntu and Fedora/RHEL), macOS, and Windows.
Read the Handbook — installation, configuration, operation guide, and REST API reference.
Known-Working Configurations — community-tested hardware setups with exact settings. Check here for your device, and submit a PR if yours isn't listed.
Graywolf APRS Discord — community chat for help, discussion, and development.
Graywolf is used all around the world! See a map of currently active stations
Written by Chris Snell, NW5W.
The modem is written in Rust and includes a port of the AFSK demodulator from Dire Wolf by WB2OSZ. The decision-feedback AGC and hard-limiter correlator techniques are credited to Ion Todirel (W7ION), from his libmodem.
The AX.25 decoding, APRS operatations (beacons, digipeater, and iGate), and the web API is handled by a service written in the Go programming language.
The web frontend was built in Svelte.
Graywolf's AFSK demodulator beats Direwolf's best mode (-P AD+) on every track of the WA8LMF TNC test CD, at about 5% of a Raspberry Pi 5.
| WA8LMF Track | Direwolf | Graywolf |
|---|---|---|
| 01 — 40-min traffic | 1020 | 1026 |
| 02 — DE-emphasized Mic-E | 1000 | 1000 |
| 03 — flat Mic-E (100 reps) | 100 | 100 |
| 04 — drive test | 107 | 108 |
Reproduce with ./bench.sh.
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Modern Web UI - GW is managed via the browser, with a responsive interface that works well on desktops and smartphones.
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Software Modem - High performance DSP written in Rust that's slightly more effective than Direwolf and much better than most hardware TNCs. Efficeint: uses about 19% of a single CPU core on a Raspberry Pi 5.
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Live Map - Like having a private aprs.fi for your station. Real-time APRS map with trails, digipeater paths, weather overlays, etc., rendered on our private vector basemap. You can download maps for your state/province/country for offline use!
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Messages - SMS-style APRS messaging with delivery status and unread badges
- Direct messages with auto-ACK and retry
- Tactical callsigns (e.g.
GRAYWOLF,AMIGOS) for group nets - RF-first delivery with APRS-IS fallback
- Long messages up to 200 characters
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Actions - Trigger scripts remotely with specially-crafted APRS messages
- Can trigger via shell script, Powershell script, or webhook
- Can be secured with one-time passwords a la Google Authenticator or 1Password
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Push-to-Talk - Multiple PTT methods for any setup
- Serial RTS/DTR (Digirig, USB-serial adapters)
- CM108 USB HID GPIO (AIOC, homebrew sound card adapters)
- Linux GPIO (Raspberry Pi, BeagleBone)
- Hamlib rigctld (CAT control)
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Digipeater - Full-featured APRS digipeater
- WIDEn-N path handling
- Preset-driven configuration (fill-in, wide-area, etc.)
- Duplicate suppression
- Per-path filtering
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iGate - Bidirectional APRS-IS gateway
- RF → APRS-IS and APRS-IS → RF gating
- Configurable filters
- Packet origin tracking in logs
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TNC Interfaces - Speak the protocols other packet software expects
- KISS TNC (TCP built in; serial via tnc-server)
- AGWPE TCP interface
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Beacons and GPS - Position reporting made easy
- Static and GPS-driven position beacons
- Status and telemetry beacons
- Configurable beacon intervals and paths
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Observability
- Prometheus metrics
- Packet logging to SQLite database, with search ability
- Live packet stream in the web UI
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Simple installation - single binary, SQLite config database
- systemd service unit
- Debian/Ubuntu (APT), Red Hat (RPM), and Arch (AUR) packages
- Windows installer
- macOS binaries
- Runs on x86-64 and ARM (Raspberry Pi)