User's Manual

13
4.3 VHF/GPS Antenna Installation
The quality and positioning of the antenna are the most important factors dictating
AIS performance. It is recommended that a VHF antenna with omnidirectional
vertical polarization be specifically tuned for AIS operation band. Since the range of
VHF signals is largely decided by line of sight distance, the VHF antenna should be
placed as high as possible and at least 5 meters away from any constructions made
of conductive materials. It is recommended to keep the VHF antenna at least 3
meters away from the GPS antenna.
Figure 2 VHF/GPS antenna locations
WARNING: The safe distance from a transmitting VHF antenna is 60cm.
5˚
High power transmitting antenna
3m
10m
Ensure the GPS antenna is not
within the transmitting beam of
other high power transmitting
antenna.
Ensure a free 360˚ horizon with a
vertical observation of 5˚.
The recommended
horizontal distance
between GPS antennas
and other antennas is 3m.
VHF Antenna
Other VHF Antenna
The recommended vertical distance
between antennas is 2m.
The recommended
horizontal distance between
antennas is 10m.
Other transmitting
antenna