The AIS shipborne equipment, like any other shipborne transceiver
operating in the VHF maritime band, may cause interference to a ship's
VHF radiotelephone. Because AIS is a digital system, this interference
may occur as a periodic (e.g. every 20 s) soft clicking sound on a
ship's radiotelephone. This affect may become more noticeable when
the VHF radiotelephone antenna is located near the AIS VHF antenna
and when the radiotelephone is operating on channels near the AIS
operating channels (e.g. channels 27, 28 and 86).
Attention should be paid to the location and installation of
different antennas in order to obtain the best possible efficiency.
Special attention should be paid to the installation of mandatory
antennas like the AIS antennas.