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What Hardware Do I Need to Run GopherTrunk?
Four things get you decoding police, fire, and EMS radio with GopherTrunk: a computer, an SDR dongle, an antenna, and a connector or two. GopherTrunk is free, open-source software, so the only money is a bit of hardware — a complete digital-scanning rig costs well under $100 if you already own a computer.
Key takeaways The four essentials: ① a computer (PC/Mac/Linux, or a Raspberry Pi for 24/7), ② an SDR dongle (~$35 RTL-SDR), ③ an antenna (~$25 dipole kit), ④ an SMA adapter/cable. Optional: an LNA or filter for weak signals or overload. Total ~$40–70 + free software. No setup decodes encryption.
The complete checklist
| # | What | Why | Pick | Approx $ |
|---|---|---|---|---|
| 1 | Computer | Runs GopherTrunk | A PC you own, or a Raspberry Pi 5 for 24/7 | $0–80 |
| 2 | SDR dongle | Receives the radio | RTL-SDR Blog V4 or NESDR SMArt v5 | ~$35–40 |
| 3 | Antenna | Actually hears signals | Dipole kit (indoor) or discone (outdoor) | ~$25–40 |
| 4 | Adapter/cable | Connects antenna to dongle | SMA adapter kit | ~$13 |
| + | LNA (optional) | Boosts weak signals | RTL-SDR Blog Wideband LNA | ~$30 |
| + | Filter (optional) | Fixes FM/AM overload | Broadcast notch filter | ~$25 |
| + | USB extension (optional) | Antenna near a window, PC elsewhere | Active shielded USB cable | ~$15 |
1. A computer
GopherTrunk runs on Windows, macOS, and Linux, and on a Raspberry Pi 4 or 5 for always-on monitoring. Decoding one or two control channels is light work — almost any machine from the last decade with a free USB port will do. For a dedicated, low-power box that runs 24/7 next to the antenna, a Raspberry Pi 5 is ideal; see running GopherTrunk on a Raspberry Pi.
2. The SDR dongle
This is the receiver. A good RTL-SDR — the RTL-SDR Blog V4 or a NooElec NESDR SMArt v5 — is the sweet spot at ~$35–40: shielded, temperature-stable, and more than enough to follow P25/DMR/NXDN. Step up to an Airspy only for tough RF or wideband capture. Full comparison: best SDR for GopherTrunk.
RTL-SDR Blog V4 + antenna kit on Amazon →
Buy the bundle. The RTL-SDR Blog V4 with the dipole antenna kit gets you the dongle and a proper antenna in one box — the simplest way to start.
3. An antenna
The antenna matters more than the dongle. The stub that ships with cheap sticks hears strong locals and little else. A telescopic dipole kit (~$25) you can tune to your band is a huge upgrade; a roof-mounted discone covers 25–3000 MHz for serious coverage. Details and mounting: best SDR antenna.
4. Adapters and cables
Most SDRs use an SMA connector. Antennas and coax often end in BNC, N, F (TV-style), or UHF/PL-259. A cheap SMA adapter kit bridges whatever you’ve got, and a pigtail or extension cable lets you place the antenna where the signal is. Full guide: SDR cables and connectors.
Optional upgrades
- LNA (low-noise amplifier) — helps a weak, distant control channel, especially with feedline loss to a rooftop antenna. Powered over the dongle’s bias tee. Don’t overdo gain — it can cause overload.
- Broadcast notch filter — if a strong FM or AM station desensitizes your dongle (common in cities), a notch filter restores weak-signal reception.
- Active USB extension — put the dongle at the window/antenna and the computer wherever’s convenient.
Put it together
- Screw the antenna (via any needed adapter) onto the SDR.
- Plug the SDR into the computer.
- Download GopherTrunk and follow the hardware setup guide (on Windows, bind the driver with Zadig first).
- Enter your system’s control channel — look it up on RadioReference — and start decoding.
New to how any of this works? Start with the RF & SDR learning path and what is trunked radio.
Bottom line
A computer + a ~$35 RTL-SDR + a ~$25 antenna + a few-dollar adapter is the entire shopping list for a GopherTrunk digital scanner — under $100, or the price of the free software plus one bundle. Add an LNA or filter only if your reception needs it. Everything hits the same encryption wall, so buy for the traffic that’s in the clear.
Frequently asked questions
What do I need to run GopherTrunk?
Four things: a computer (any modern PC, Mac, or a Raspberry Pi), an SDR USB dongle (a ~$35 RTL-SDR is ideal), an antenna, and usually an SMA adapter or cable to connect them. GopherTrunk itself is free. That’s a complete digital-scanning setup for well under $100.
How much does a GopherTrunk setup cost?
If you already own a computer, about $40–70 total: ~$35 for a good RTL-SDR, ~$25 for a dipole antenna kit, and a few dollars for adapters. A dedicated Raspberry Pi for 24/7 use adds ~$80. The software is free and open source.
Do I need a special computer?
No. GopherTrunk runs on Windows, macOS, and Linux, and on a Raspberry Pi 4 or 5 for always-on use. Any machine from the last decade with a spare USB port is fine — decoding one or two control channels is light work.
Do I need an antenna, or is the one in the box enough?
The tiny antenna bundled with cheap dongles will hear strong local signals but little else. A ~$25 telescopic dipole kit dramatically improves reception, and an outdoor discone is better still. The antenna matters more than the dongle.
What connects the antenna to the dongle?
Most SDRs use an SMA connector. Coax antennas often use BNC, N, F (TV), or UHF (PL-259). A cheap SMA adapter kit bridges whatever you have. See our cables and connectors guide.
Can I hear encrypted police with this setup?
No. No SDR or scanner can decode AES-encrypted talkgroups — it’s a cryptographic and legal wall. This setup hears everything still transmitted in the clear, which in most areas includes plenty of dispatch and nearly all fire/EMS.