What is involved in installing an AIS Receiver?

Installing an AIS receiver is generally straightforward. At its simplest, an AIS receiver needs a suitable VHF antenna, a power source and a connection to the device or network where you want to view or process the AIS data.

The exact installation will depend on whether the AIS receiver is being used on board a vessel with a chartplotter, PC or mobile device, or as part of a shore-based AIS monitoring system for a port, harbour, vessel tracking network or other commercial application.

What do you need to install an AIS receiver?

A typical AIS receiver installation requires:

• An AIS receiver
• A suitable VHF/AIS antenna
• An appropriate power supply
• A method of connecting the receiver to a chartplotter, PC, mobile device or network
• Suitable antenna, power and data cabling

Some installations may also require a dedicated GNSS/GPS antenna or network connection, depending on the receiver and application.

Does an AIS receiver need an antenna?

Yes. AIS operates on marine VHF frequencies, so an AIS receiver requires a suitable VHF antenna to receive transmissions from nearby AIS-equipped vessels, Aids to Navigation (AtoNs), AIS SARTs and other AIS devices.

For best performance, the antenna should have a clear position with minimal obstruction. As VHF communication is largely line-of-sight, antenna position and height can have a significant effect on the AIS reception range.

Comar Systems offers a range of AIS and VHF antennas for both vessel and shore-based installations.

Can an AIS receiver use my existing VHF antenna?

It is possible for AIS equipment and a VHF radio to share an antenna when a suitable AIS/VHF antenna splitter is installed.

For installations requiring a shared antenna, the Comar Systems AS350 AIS/VHF Antenna Splitter allows an AIS receiver or compatible AIS Class B transponder to share the vessel’s main VHF antenna with the onboard VHF radio.

This can be particularly useful where installing a second antenna is difficult or undesirable.

How do I connect an AIS receiver to a chartplotter?

For marine installations, AIS data can typically be sent to a compatible chartplotter or navigation system using a marine data interface such as NMEA 0183.

Once connected and correctly configured, received AIS targets can be displayed alongside chart information, allowing the navigator to see information transmitted by surrounding AIS-equipped vessels.

The Comar Systems R250 AIS Receiver, for example, provides an NMEA 0183 VDM output for connection to compatible chartplotters and navigation equipment.

Can I connect an AIS receiver to a computer?

Yes. Many AIS receivers provide a USB or network connection, allowing AIS data to be sent directly to a PC.

The Comar Systems R250 Dual-channel AIS Receiver provides USB, NMEA 0183 and built-in Wi-Fi connectivity. When connected via USB, it can be powered directly from the computer while simultaneously streaming AIS data, making it a simple option for PC-based AIS monitoring.

The R250 can also stream AIS and NMEA data wirelessly over Wi-Fi to compatible PCs and mobile devices.

Can AIS data be sent over Ethernet or the internet?

Yes. For professional and shore-based applications, a network AIS receiver can send AIS data over a local network or internet connection to PCs, servers, monitoring systems and vessel tracking platforms.

The Comar Systems R450 Series is designed specifically for professional shore-based vessel monitoring. Models such as the R450-X Network AIS Receiver provide Ethernet, Wi-Fi and USB connectivity and can forward received AIS data across a network or over the internet.

For applications requiring both AIS and positioning data, the R450-XG adds an integrated GNSS receiver.

What AIS receiver should I choose?

The best AIS receiver depends primarily on how and where the AIS data will be used.

For leisure vessels and straightforward onboard installations, the Comar Systems R250 provides a compact solution with NMEA 0183, USB and Wi-Fi connectivity. It can receive and decode AIS transmissions from Class A and Class B vessels, AIS SARTs and Aids to Navigation.

For ports, harbours and professional shore-based AIS monitoring, the R450 Series provides Ethernet and Wi-Fi network connectivity for forwarding AIS data to PCs, servers and remote monitoring systems.

For more advanced commercial applications, the R550Ni Intelligent Network AIS Receiver combines AIS reception with onboard processing and can filter, process and forward AIS data across a network. Multiple units can also be deployed as part of a larger coastal or port monitoring network.

Where AIS and GNSS data are both required, the R550NGi Intelligent Network AIS & GNSS Receiver provides integrated GNSS reception alongside AIS processing and network connectivity.

How far can an AIS receiver receive signals?

There is no single fixed range for an AIS receiver. AIS uses VHF radio and is largely line-of-sight, so reception range depends heavily on antenna height, antenna quality, cable losses, surrounding terrain and the height of the transmitting vessel’s antenna.

As a general guide, typical AIS reception ranges might be:

• Small vessel / low-mounted antenna: approximately 5–15 nautical miles (9–28 km)
• Larger vessel / higher-mounted antenna: approximately 15–30 nautical miles (28–56 km)
• Shore-based AIS station with an elevated antenna: approximately 20–50+ nautical miles (37–93+ km)

In favourable conditions, a well-positioned coastal receiving station with a high antenna may receive AIS transmissions from 50 nautical miles or more, particularly from large vessels with antennas mounted high above sea level.

These figures are only indicative. Because VHF signals are primarily limited by the radio horizon, antenna height is one of the most important factors affecting AIS reception range. Raising an antenna by even a few metres can significantly increase the area an AIS receiver can monitor.

For ports, harbours and coastal monitoring applications, careful antenna positioning can therefore be just as important as the choice of AIS receiver itself.

Does an AIS receiver transmit my vessel’s position?

No. An AIS receiver is receive-only. It allows you to receive AIS information transmitted by other vessels and AIS devices, but it does not transmit your own vessel’s identity, position, course or speed.

If you need to both receive AIS data and transmit your own vessel’s information, you will need an AIS transponder rather than a receiver.

For example, the Comar Systems T350 Class B SOTDMA AIS Transponder provides Class B AIS transmission and reception for commercial, fishing and leisure vessels.

Is an AIS receiver difficult to install?

For a basic vessel installation, an AIS receiver can be relatively simple to install. Once the antenna and power connections have been made, the AIS output is connected to the required chartplotter, PC or other compatible device.

More complex installations – particularly shore-based AIS monitoring networks, remote receiving stations and multi-receiver systems – may require additional consideration of antenna placement, network configuration, data forwarding and remote connectivity.

Comar Systems manufactures AIS receivers for applications ranging from simple onboard monitoring through to professional port and coastal AIS networks.

Which Comar AIS receiver is right for my installation?

Whether you need a compact AIS receiver for a boat, a networked receiver for a port or harbour, or an intelligent receiver for a large-scale vessel monitoring network, Comar Systems offers a range of solutions.

Explore our AIS Receivers, including the R250, R450 Series, R550Ni, R550NGi and COM100, or contact Comar Systems for help selecting the most appropriate AIS receiver, antenna and accessories for your application.