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.

📖 Read the Handbook — installation, configuration, and operation guide.

🔧 Known-Working Configurations — community-tested hardware setups with exact settings. Check here for your device, and submit a PR if yours isn't listed.

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 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.

Performance

Graywolf achieves high decoding performance using inexpensive, off-the-shelf hardware. Its AFSK decoder can decode 1005 packets off track 1 of the WA8LMF CD, identical in performance to Direwolf, from which Graywolf was ported.

Building Direwolf (atest)...
Building Graywolf (demod_bench)...

=== Direwolf (atest) — 1 iterations ===
982 packets decoded in 45.614 seconds.  34.0 x realtime

=== Graywolf (demod_bench) — 1 iterations ===
982 packets decoded in 6.792s.  228.2 x realtime

Features

• Modern Web UI - Configure and monitor your station from your browser, with live packet logs and preset-driven setup for digipeater and iGate

  • Imperial/Metric unit toggle for altitude, distance, and speed

• Live Map - Real-time APRS station map with trails, weather overlays, APRS-IS layer, and station popups with path and heard-via details

• Software Modem - Native Rust DSP, no external sound card tooling required

  • AFSK 1200 baud (Bell 202)
  • 9600 baud G3RUH
  • PSK
  • FX.25 and IL2P forward error correction
  • SDR input support

• Digipeater - Full-featured APRS digipeater

  • WIDEn-N path handling
  • Preset-driven configuration (fill-in, wide-area, etc.)
  • Duplicate suppression
  • Per-path filtering

• iGate - Bidirectional APRS-IS gateway

  • RF → APRS-IS and APRS-IS → RF gating
  • Configurable filters
  • Packet origin tracking in logs

• TNC Interfaces - Speak the protocols other packet software expects

  • KISS TNC (serial and TCP)
  • AGWPE TCP interface

• Beacons and GPS - Position reporting made easy

  • Static and GPS-driven position beacons
  • Status and telemetry beacons
  • Configurable beacon intervals and paths

• Observability

  • Prometheus metrics
  • Packet logging to SQLite
  • Live packet stream in the web UI

• Simple installation - single binary, SQLite config database

  • systemd service unit
  • Debian/Ubuntu (APT), Red Hat (RPM), and Arch (AUR) packages
  • Windows installer (MSI)
  • Runs on x86-64 and ARM (Raspberry Pi)