AIS units can be accessorised with a range of products including antenna splitters, antennas, man overboard alarms and displays.
Antenna splitters need to be used with Class B devices that don’t incorporate an internal antenna splitter on vessels with only one VHF antenna. When purchasing an antenna splitter, you should consider its power, what accessories it comes with, and whether it has an FM output.
On a vessel with only one antenna, as only one device can use it at a time, a splitter manages the use of that antenna between the VHF radio and AIS system. Most antenna splitters on the market offer a zero signal loss option. If power fails on the vessel, the antenna splitter ensures that the VHF radio is still usable and has access to the antenna. Class A units do not need to use an antenna splitter as the vessels they are installed on tend to have more than one antenna, also Class A units produce 12.5W of power, compared to a Class B’s 2W, which the antenna splitter would not be able to handle.
Antennas are another option to have installed on a smaller vessel. Installing another antenna would mean you would not need to install an antenna splitter. Also, if your AIS device doesn’t have an internal GPS antenna, then an external GPS antenna would need to be installed to allow the unit to see where you are.
Man overboard devices are a relatively new innovation. They work in a variety of ways including monitoring workers and when a device falls out of range an alarm is sounded. Alternatively, when crew fall overboard and reach the sea it starts to transmit automatically. When buying the devices, it is worth considering the dimensions of the unit as it will have to be carried by crew whilst they are working.
Many AIS devices integrate with a number of different displays through complex output connections. The latest standard is NMEA 2000 which allows AIS devices to be connected to the latest radars, chart display and other marine equipment. Other connections include NMEA 0183 and USB.
Recent innovations have included creating wifi networks that allow wireless devices including laptops, mobile phones and ipads to receive the AIS data on especially created apps and marine programmes.