AIS checks

Following our piece last month on VHF radio checks, RATS has come across the use of National Coastwatch Institution (NCI) stations to check AIS transmissions. This seems to us to be good practice, certainly at the beginning of the season. A vessel’s AIS transceiver may use the same antenna as the VHF set or a separate one. As with VHF radios the most likely cause of any fault is the antenna or cable or the splitter (if the antenna is shared with VHF).

Such a call could be combined with a radio check. The procedure would be as follows:

Vessel: Rame Head NCI Rame Head NCI. This is yacht Hanson. Radio check please. Over.
NCI station: Yacht Hanson you are loud and clear. Over.
Vessel: Rame Head NCI thank you. Could you please check my AIS transmission? I am approximately five miles west of the Eddystone. Over.
NCI station: Yacht Hanson your AIS transmission is clear. You are showing course 075 speed 4.9 knots. Over.
Vessel: Rame Head NCI thank you. This is yacht Hanson. Out.


Not all NCI stations have the facility to monitor AIS. Reed’s has a listing of the facilities at each NCI station. AIS is not failsafe and can have inaccuracies.