VHF antennas are also used by AIS engines. You may see antennas described as AIS aerials (or antennas) and what this means is the VHF antenna is tuned to centre on the AIS frequencies, 161.9 and 162.0 MHz, rather than on the broader range of radio frequencies including the emergency channel, 156.8 MHz.
The Metz Manta covers 156 MHz to 163 MHz, so includes all radio and AIS channels.
Metz makes a dedicated AIS antenna but rarely is it chosen over the Metz Manta because the difference in reception is not very significant. Better to have the option to use either antenna for either purpose, I feel.
