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GopherTrunk Raspberry Pi / SBC Build
A Raspberry Pi 5 plus a good dongle is the ideal always-on GopherTrunk scanner — silent, low-power, headless, and reachable from any browser through GopherTrunk’s web console. This is the complete parts list for a dedicated box that logs every call 24/7 next to the antenna. The software is free; the build runs about $180–220.
Key takeaways Host: Raspberry Pi 5, 8GB (~$80). Receiver: any good RTL-SDR (~$35) on an antenna. Pi essentials: quality microSD, official USB-C PSU, active cooler, case (~$45 together). Connect the dongle through an active USB extension (~$15). Control it from any browser via the web console. Total ~$180–220. No build decodes encryption.
The complete parts list
| # | Item | Why | Pick | Approx $ |
|---|---|---|---|---|
| 1 | Raspberry Pi 5 (8GB) | The always-on host | Raspberry Pi 5, 8GB | ~$80 |
| 2 | SDR dongle | Receives the radio | RTL-SDR Blog V4 / NESDR | ~$35 |
| 3 | Antenna + adapter | Actually hears signals | Dipole / discone + SMA kit | ~$30 |
| 4 | Official 27W USB-C PSU | Stable power = reliability | Raspberry Pi 5 power supply | ~$12 |
| 5 | microSD card (32–64GB, A2) | OS + call recordings | SanDisk Extreme A2 card | ~$12 |
| 6 | Active cooler | No throttling under 24/7 load | Official Pi 5 active cooler | ~$8 |
| 7 | Case | Protects the board | Raspberry Pi 5 case | ~$12 |
| 8 | Active USB extension | Clean power, moves warm dongle away | Shielded active cable | ~$15 |
Running total: ~$204. Already own a Pi or an antenna? Subtract those lines. This complements the how-to at running GopherTrunk 24/7 on a Raspberry Pi — that page walks the setup; this page is the shopping list.
The picks
Raspberry Pi 5 (8GB)
around $80
Faster cores that decode one or more P25/DMR/NXDN control channels plus voice around the clock — with headroom to channelize a wideband capture. The best-supported SBC for GopherTrunk.
Pi 5 8GB on Amazon →Active USB extension cable
around $15
Gives the warm, power-hungry dongle a cleaner power path so the Pi does not brown out, and moves it off the board and away from RF-noisy USB 3 ports. The cheapest reliability win on a Pi build.
Active cable on Amazon →RTL-SDR Blog V4
around $35
1 ppm TCXO, built-in HF, front-end filtering, switchable bias tee to power a mast LNA up the coax. Rock-steady lock for a scanner that has to hold a control channel for weeks.
V4 on Amazon →Why a Pi for always-on scanning
A desktop PC works, but it is overkill for a job that runs forever. A Raspberry Pi 5 is the natural home for a permanent GopherTrunk decoder because it is low-power and silent (a few watts, cheap to leave on), headless by design (a single Go binary driven entirely through the web console — no monitor needed), small enough to live at the antenna (mount it in a closet or attic where the feedline comes in, minimizing coax loss), and plenty capable (its cores decode multiple channels with headroom). Full context: running GopherTrunk on a Raspberry Pi.
Power, cooling, and the SD card — the reliability parts
Almost every “my Pi scanner randomly drops out” story comes down to power, cooling, or the SD card, not software.
Feed the Pi properly. Use the official 27W USB-C supply. A Pi 5 driving a warm, power-hungry RTL-SDR on a marginal charger will brown out and throw USB errors. Adequate, stable power is the single biggest reliability factor. The active USB extension helps here too by giving the dongle its own clean power path.
- Cool it. Under continuous decode load a Pi 5 runs hot and throttles without cooling. The official active cooler clips on and keeps it quiet — the safe choice for 24/7 duty. See the best SBC for GopherTrunk guide.
- Use a quality microSD. A good A2-rated card (SanDisk Extreme or similar, 32–64GB) handles the OS and call recordings without the corruption cheap cards suffer under constant writes. This is not the place to save $4.
Antenna and the rest of the chain
The Pi build shares the same RF chain as any other: a dipole indoors to start, upgrading to a roof-mounted discone or a full outdoor base build for real range, joined with an SMA adapter kit. Because the Pi is small enough to sit right at the antenna, you can keep the coax run short and send the network the long way — the right way to fight feedline loss.
Setup in brief
- Flash 64-bit Raspberry Pi OS to the microSD and boot headless (enable SSH, join the network).
- Download the GopherTrunk binary for ARM64 and follow the hardware setup guide.
- Plug the dongle in through the active extension; attach the antenna.
- Enter your control channel from RadioReference, start GopherTrunk, and open the web console from another device.
- Set it to start on boot so it recovers after any power blip.
Where to buy
Start the build with the Raspberry Pi 5, 8GB (~$80) and the active USB extension (~$15), then add a dongle, antenna, PSU, microSD, cooler, and case per the list.
As an Amazon Associate, GopherTrunk earns from qualifying purchases — at no extra cost to you. It never changes what we recommend.
Bottom line
For a scanner that just runs, a Pi 5 + a dongle + an active USB extension, fed by a real power supply and cooled properly, is the sweet spot: cheap, silent, always on, and controlled entirely through the web console — about $180–220 all-in. Follow the Raspberry Pi how-to to set it up, and remember nothing here beats encryption. Compare the other setups on the build-lists hub.
Frequently asked questions
What do I need to build an always-on GopherTrunk Pi scanner?
A Raspberry Pi 5 (8GB), a good SDR dongle, an antenna and adapter, plus the Pi essentials: a quality microSD card, the official USB-C power supply, active cooling, and a case. An active USB extension for the dongle rounds it out. Budget about $180–220 all-in; the software is free.
Which Raspberry Pi should I use for GopherTrunk?
A Raspberry Pi 5 with 8GB of RAM is the recommended pick — its faster cores comfortably decode one or more control channels plus voice around the clock, and can even channelize a wideband capture. A Pi 4 works for a single site if you already own one.
Do I need active cooling on a Pi 5 scanner?
For 24/7 duty, yes. A Pi 5 under continuous decode load runs warm and will throttle without a heatsink or fan. The official active cooler clips on and keeps it quiet and cool. Passive cooling can work in a cool room but active is the safe choice for always-on.
Why an active USB extension for the dongle?
Two reasons: it gives the warm, power-hungry dongle a cleaner power path so the Pi does not brown out, and it moves the dongle away from the board and the RF-noisy USB 3 ports. It is the single cheapest reliability upgrade on a Pi build.
Can I use an SBC other than a Raspberry Pi?
Yes — any ARM64 or x86 single-board computer that runs 64-bit Linux can run the GopherTrunk binary. The Pi 5 is the best-supported and easiest pick, but Orange Pi, Radxa Rock, and mini-PCs all work. Give any of them solid power and cooling for 24/7 use.
How do I control a headless Pi scanner with no monitor?
Through GopherTrunk’s built-in web console. Point any browser on your network at the Pi’s address and you get live spectrum, call logs, and controls — no screen, keyboard, or mouse on the Pi itself. That is what makes an always-on Pi so convenient.
Will a Pi build decode encrypted talkgroups?
No. No SDR or scanner can decode AES-encrypted talkgroups, on a Pi or anything else. An always-on Pi build logs every call transmitted in the clear around the clock — usually plenty of dispatch and nearly all fire and EMS.