What is GopherTrunk?

GopherTrunk is a software-defined-radio (SDR) scanner that follows digital trunked-radio voice calls and decodes them to audio. It is written in pure Go with zero CGO — no librtlsdr, libhackrf, libusb, libasound2, or libmp3lame at build or runtime — and ships as a single ~10 MB static binary for Linux, macOS, and Windows. Drop the binary on a box with a dongle, point a YAML file at a control channel, and it starts recording calls.

This page is the conceptual map: what GopherTrunk decodes, the interfaces you drive it with, and how the parts fit together. When you’re ready to run it, jump to Get started.

Supported hardware

GopherTrunk drives a pool of SDR dongles — one engine, many radios:

  • RTL-SDR — every osmocom-compatible tuner (the cheapest way to start).
  • HackRF — One / Jawbreaker / Rad1o.
  • Airspy — R2 / Mini, and Airspy HF+.
  • Remote backends — rtl_tcp and SoapyRemote, so the radio can live on another host.

Full device matrix, antenna notes, and gain tips are in the Hardware guide.

What it decodes

  • Trunked voice — P25 Phase 1 + Phase 2, DMR Tier II + Tier III, NXDN, Motorola Type II / SmartZone, EDACS / GE-Marc, LTR, MPT 1327, dPMR Mode 3, TETRA TMO; amateur D-STAR and Yaesu System Fusion.
  • Paging & signaling — POCSAG + FLEX paging, MDC1200.
  • Position & safety — APRS / AX.25 packet, AIS marine, ADS-B aircraft, DSC marine distress.

A live shipping-vs-pending checklist per protocol lives in Status.

The interfaces (the parts you drive)

GopherTrunk is one binary and one config file. The daemon is the engine; everything else is a view onto the same running daemon.

Part What it is Reach it with
Headless daemon The engine — owns the SDR pool, decoders, recorder, and APIs. Runs silent (systemd, Docker, Windows service). gophertrunk -headless
TUI cockpit In-process Bubbletea terminal console with 12 panels (dashboard, active calls, scanner, history, …). gophertrunk -tui
Web console Bundled browser SPA served by the daemon — the same panels in a browser. gophertrunk -web
Interactive launcher What plain gophertrunk shows on a TTY: pick [1] TUI, [2] Web, or [3] Headless. gophertrunk
Config Builder Standalone guided editor for config.yaml — add systems, talkgroups, and feeds without hand-writing YAML. Comes as both a terminal app and a browser app. gophertrunk config / config serve
SigLab Standalone signal workbench for offline captures — replay, analyze, identify, and grade decodes. Also a terminal app and a browser console. gophertrunk siglab / siglab serve

The first four surfaces are views onto a running daemon: quitting the TUI or closing the browser does not stop the daemon — it keeps running in the same process until you send Ctrl-C / SIGTERM (see the Launcher). Config Builder and SigLab are standalone — they run on their own, without a live daemon, each available as a terminal interface and a browser interface.

APIs & integrations

  • HTTP REST + SSE + WebSocket on 127.0.0.1:8080 (configurable) — drives the web console and any custom tooling.
  • gRPC on 127.0.0.1:50051 for typed clients.
  • Prometheus /metrics for scraping.
  • Hamlib rigctld wire protocol for amateur-radio tooling — see rigctld integration.
  • Outbound call streaming to Broadcastify Calls, RdioScanner, OpenMHz, and live Icecast / ShoutCast mountpoints, out of the box.

Offline & analysis tooling

Beyond the live daemon, the same binary carries a workbench of subcommands for captures and discovery:

  • gophertrunk capture — record live SDR IQ to a file.
  • gophertrunk replay / analyze / identify — decode and inspect a capture offline, auto-detect its protocol, export JSON/YAML/CSV.
  • gophertrunk hunt — discover and map an unknown trunked system (Hunt).
  • gophertrunk import-pdf — pull a RadioReference PDF straight into your config (Import).

The SigLab and Config Builder interfaces above wrap this workbench in terminal and browser front-ends.

How the parts fit together

One daemon owns the radios and the decoders. The TUI, the web console, and the REST/gRPC APIs are all just views and controls over that one running daemon — which is why you can start headless and attach a UI later, or run the TUI locally while a browser on your phone watches the same calls. Edits made in a UI flow back to config.yaml and many apply without a restart (Live edits).

For the full design — the multi-consumer IQ fan-out, the DSP chain, the voice pipeline — read the Architecture reference.

Ready to run it? → Get started

Once it’s running, the guides continue the tour from your first call all the way to the APIs: Basics → Intermediate → Advanced.