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AIS-catcher is free, open-source software that receives and decodes Automatic Identification System (AIS) broadcasts. It needs compatible radio hardware—typically an SDR receiver and a VHF antenna—and can show decoded NMEA data locally or forward it to other applications. It does not transmit AIS and is not approved for navigation or safety-of-life use.
What is AIS-catcher?
AIS-catcher is a dual-channel AIS receiver and decoder that runs on a computer or compatible device. AIS is a VHF radio system through which vessels broadcast information such as identity, position, speed, and course. AIS-catcher listens to those broadcasts and turns them into decoded messages; it is not a standalone radio or a transmitter. The project README describes its supported inputs, output options, and open-source license.
The project provides command-line operation as well as a browser dashboard and setup wizard. Installation routes vary by operating system and deployment, with project materials covering Linux and Raspberry Pi, Windows, macOS, Docker, Android, and building from source. Consult the installation overview and check device dependencies for your chosen setup rather than assuming every receiver works with every platform.
What do you need to receive AIS?
A typical station consists of a computer, a compatible receiver, and a marine VHF antenna. The official Quick Start names a Raspberry Pi, PC, or Mac as possible computers; an RTL-SDR or dAISy-catcher as receiver examples; and an antenna tuned to approximately 162 MHz.
#1 Best Overall
- Turn your computer, phone or tablet into a radio scanner/ham radio receiver that can receive nearly all RF signals! Compatible with Windows, Mac OS, Linux, and Android
- NESDR SMArt RTL-SDR v5 can be used for the reception of broadcast AM radio, broadcast FM radio, shortwave radio, CB radio, public security radio, trunked radio, air traffic control, ACARS (plane-ground communications), ADS-B (plane tracking), AIS (ship tracking), POCSAG (pagers), NOAA and GOES weather satellites (weather images), weather balloons, radiosondes, DAB radio, DVB-T video, Inmarsat, Iridium, and so much more!
- The best-performing low-cost RTL-SDR available anywhere! Compared with RTL-SDR v3, HF SNR is improved by up to 15dB, VHF & UHF SNR is improved by up to 6dB, tuning accuracy is improved by an average of 4x, and the frequency range is expanded all the way down to 100kHz
- v5 has a frequency capability of 100kHz to 1.75GHz and up to 3.2MHz of instantaneous bandwidth. HF reception below 25MHz is accomplished with direct sampling and requires a suitable antenna. We recommend using a Balun One Nine to make a DIY long wire or dipole antenna (sold separately, product ID B08HGSYB7R or B00R09WHT6)
- Though the direct sampling implementation of NESDR SMArt v5 is much better than any other RTL-SDR, we still recommend using an upconverter like the Ham It Up for a more fulfilling HF experience (sold separately, product ID B076CYK8XZ)
- Computer: Choose a device supported by the installation method and receiver drivers or libraries you plan to use.
- Receiver: The project lists RTL-SDR dongles, Airspy, HackRF, SDRplay, and SoapySDR among supported SDR input families. It also supports file and network input sources, including ZMQ, RTL-TCP, and SpyServer. Confirm model-specific and operating-system compatibility in the README.
- Antenna: Use a VHF antenna suitable for AIS frequencies, around 162 MHz. The Quick Start advises placing an outdoor vertical antenna as high as practical with a clear line of sight toward the water. That is setup guidance, not a guaranteed range or comparative performance result.
The project’s setup guide notes that antenna height and location can matter more than the receiver. Actual reception depends on local conditions; the official materials do not establish a particular range, accuracy level, or vessel count.
How do you choose a receiver?
Two common paths are a general-purpose SDR dongle and a purpose-built AIS receiver. The project names the RTL-SDR Blog V4 among compatible RTL-SDR devices, while describing the Wegmatt dAISy-catcher as a plug-and-play alternative. The right choice depends on your hardware preferences and setup, not on a documented reception comparison.
Rank #2
- Turn your computer, phone or tablet into a radio scanner/ham radio receiver that can receive nearly all RF signals! Compatible with Windows, Mac OS, Linux, and Android
- NESDR SMArt RTL-SDR v5 can be used for the reception of broadcast AM radio, broadcast FM radio, shortwave radio, CB radio, public security radio, trunked radio, air traffic control, ACARS (plane-ground communications), ADS-B (plane tracking), AIS (ship tracking), POCSAG (pagers), NOAA and GOES weather satellites (weather images), weather balloons, radiosondes, DAB radio, DVB-T video, Inmarsat, Iridium, and so much more!
- The best-performing low-cost RTL-SDR available anywhere! Compared with RTL-SDR v3, HF SNR is improved by up to 15dB, VHF & UHF SNR is improved by up to 6dB, tuning accuracy is improved by an average of 4x, and the frequency range is expanded all the way down to 100kHz
- v5 has a frequency capability of 100kHz to 1.75GHz and up to 3.2MHz of instantaneous bandwidth. HF reception below 25MHz is accomplished with direct sampling and requires a suitable antenna. We recommend using a Balun One Nine to make a DIY long wire or dipole antenna (sold separately, product ID B08HGSYB7R or B00R09WHT6)
- Though the direct sampling implementation of NESDR SMArt v5 is much better than any other RTL-SDR, we still recommend using an upconverter like the Ham It Up for a more fulfilling HF experience (sold separately, product ID B076CYK8XZ)
| Choice | Connection and setup | Consider it if |
|---|---|---|
| RTL-SDR dongle | USB SDR; install the receiver support required by your operating system and AIS-catcher setup. | You want a general-purpose SDR or value other radio uses in addition to AIS. Verify the exact dongle and driver compatibility before buying or installing. |
| Wegmatt dAISy-catcher | The project describes serial, USB, and Raspberry Pi HAT connection options. | You prefer a dedicated, plug-and-play AIS receiver. See the project’s README for its link to the product information. |
The official sources do not provide a controlled comparison of reception distance, decoding accuracy, or reliability between these options. Neither should be treated as a guaranteed performance upgrade over the other.
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How do you set up AIS-catcher?
- Choose an installation route. Use the installation overview to select instructions for your operating system or deployment method. The project also provides a Getting Started guide.
- Connect your receiver and antenna. Check the receiver’s operating-system dependencies, connect it as required, and attach an AIS-suitable VHF antenna.
- Open the browser setup workflow or use the command line. In the dashboard wizard, select the input device and configure the available options for your installation. The exact screens and choices depend on the platform and input source.
- Choose where decoded messages go. Keep output local for display, or configure a supported feed if another application or service needs the data. Community sharing is optional.
- Check for decoded messages. If none appear, use the troubleshooting checks below and confirm the receiver, antenna connection, selected input, and output configuration.
What can AIS-catcher do with decoded messages?
AIS-catcher produces NMEA messages that can be displayed or forwarded to other software. The README describes UDP, HTTP, and TCP output; the Quick Start’s configuration walkthrough also gives examples including MQTT. Available choices depend on the build and configuration, so use the documentation for the specific installation you are running.
Rank #3
- Includes 1x RTL-SDR Blog brand R860 RTL2832U 1PPM TCXO HF Bias Tee SMA Dongle (V3) (Dongle Only)
- Several improvements over other brands including use of the R860 tuner, improved component tolerances, a 1 PPM temperature compensated oscillator (TCXO), SMA F connector, aluminum shielded case with thermal pad for passive cooling, and an activatable bias tee circuit.
- Can tune from 500 kHz to 1.7 GHz and has up to 3.2 MHz of instantaneous bandwidth (2.4 MHz stable). (HF reception below 24 MHz in direct sampling mode with reduced performance). Please note RTL-SDR dongles are RX only.
- Please follow the quickstart guide linked in the included the manual for installation of the drivers and free software. Please feel free to contact us via Amazon messaging for technical support - we're happy to help
The project also supports optional community data sharing. Its repository explains that contribution requires station registration and a sharing key. Sharing is not required to use AIS-catcher locally; check local rules before publicly redistributing radio data.
“I see no messages — what now?”
Work through the signal path from the antenna to the output rather than changing several settings at once:
Rank #4
- A full, wide-band RF solution for those interested in getting started with software defined radio and with a keen interest in HF bands
- The NESDR SMArt HF Bundle utilizes a well-designed upconverter--the Ham It Up--to receive HF, NOT direct sampling hacks. This results in a vastly different HF experience--much better performance, and no loss of gain controls
- Included is a Ham It Up v1.3 upconverter, installed in a custom black aluminum enclosure; an NESDR SMArt RTL-SDR, 3 antennas, an impedance matching balun for longwire and dipole antennas, and interconnect adapters
- Proudly manufactured by NooElec in the USA and Canada, with a full 2 year product warranty on all bundle components and 24/7 technical support availability. Please contact our support team any time if you have questions!
- Amazon-exclusive bundle! Only available for a limited time
- Confirm the source is selected. Check that the dashboard wizard or command-line configuration points to the receiver or file/network input you intend to use.
- Check device support and dependencies. Confirm that your exact receiver is supported by the installed version and that its required drivers or libraries are available on your operating system.
- Inspect the antenna setup. Check the antenna connection and suitability for AIS around 162 MHz. If practical, improve its height and clear line of sight toward the water.
- Separate reception from forwarding. Confirm whether AIS-catcher is decoding messages locally before troubleshooting a UDP, HTTP, MQTT, or TCP destination. A forwarding destination can fail even when local decoding works.
- Recheck the installation guide. Installation and input configuration differ across platforms and source types; follow the matching instructions in the official documentation.
Is receiving AIS legal, and is AIS-catcher suitable for navigation?
Radio reception and redistribution rules vary by jurisdiction. The Quick Start advises checking local rules, especially before publicly sharing data; the available project guidance does not establish a jurisdiction-specific legal conclusion.
AIS-catcher is a hobby project, and the project says it has not been tested and designed for reliability and correctness. Its official disclaimer states: “DO NOT rely upon this software in any way including for navigation and/or safety of life or property purposes.” Do not use it as a substitute for certified marine navigation or safety equipment.
Quick Recap
Best Value
- Included: Nooelec USB dongle & antenna
- RTL2832U interface IC & R820T tuner IC on USB dongle
- These are custom USB devices tuned for SDR and include much better components than generics
- Full 1-year warranty & installation support available!
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