What You'll Need¶
A complete AIS receiving station needs three pieces of hardware — roughly €60 when starting from nothing, and chances are you already own half of it.
The SDR Receiver¶
An RTL-SDR dongle is the standard choice: inexpensive, well supported and more than capable — a single dongle receives both AIS channels simultaneously. When buying new, pick a current model (RTL-SDR Blog v3 or v4) with a TCXO (temperature-compensated oscillator, ±1 ppm): the very cheapest DVB-T sticks drift with temperature, which costs sensitivity on AIS.
Already have other receiving hardware? AIS-catcher also supports AirSpy, AirSpy HF+, SDRPlay, HackRF and several network sources — see the input options.
The Antenna¶
The antenna — and where you put it — determines what you will receive far more than any other component.
- Starting out: the telescopic antenna included with most SDR bundles, extended to about 44 cm (a quarter wavelength at 162 MHz) and placed at a window facing the water, is enough to see your first ships in a busy area.
- Upgrading: a dedicated AIS or marine VHF antenna mounted outside — as high as you can manage, with a clear view of the water — is the single most effective improvement you can make. Height beats everything: the radio horizon grows with antenna height, not with amplifier gain.
- The cable counts too: coax loss at 162 MHz adds up quickly, so keep the run short and the cable quality high — see Antenna and Cable. Or skip the problem: mount the computer near the antenna and run a network cable instead.
The Computer¶
Almost anything works — AIS decoding is light work:
| Option | Notes |
|---|---|
| Raspberry Pi | The classic choice for a 24/7 station: a Pi Zero 2 W is sufficient, a Pi 3 or newer is comfortable. Draws only 2–3 W. |
| Linux / Windows / macOS | Native packages and builds for all of them. |
| Docker | Ready-made images for containerized setups. |
An internet connection is needed for installation and for sharing your data — the receiving and decoding itself runs entirely locally.
The Location¶
VHF signals travel line of sight: water you can see (or nearly see) is water you can receive.
- Distance to shipping: a station near a harbour, river or shipping lane sees traffic even with modest equipment; far inland, even a perfect setup has nothing to hear.
- Elevation and obstructions: every metre of height extends your radio horizon, and buildings or hills between you and the water block signals. A rooftop or attic facing the water beats a ground-floor window on the wrong side.
- What to expect: a rooftop antenna at 5–10 m typically receives large ships out to 25–30 km (14–16 nmi) — and considerably farther from an elevated site.