Kongsberg Seatex AIS 100, Instruction Manual

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Seatex AIS 100 Instruction Manual, rev. 5 Installation
44
VHF antenna cable lengths
Maximum cable lengths depend on the attenuation factors of the
cables used. The total attenuation of the VHF antenna cables should
be less than 3 dB for proper operation as higher attenuation will
reduce the coverage area of the mobile station. The cable connectors
must be of a type that is designed for the actual cable.
Cable type Max. length
RG214 30 metres
Low loss ½" Superflex 100 metres
5.7 AIS 100 GPS antenna
GPS antenna installation
Optimum location of the GPS antenna is important to ensure
continuously track of all visible GPS satellites used for time
synchronisation and computation of backup position fix. The
following should be taken into consideration during installation:
•
The GPS antenna must be installed where it has a clear view of the
sky and thus the objective is to see the horizon freely through 360
degrees with a vertical observation of 5 to 90 degrees above the
horizon.
•
Small diameter obstructions, such as masts and booms, do not
seriously degrade signal reception but such objects must not
eclipse more than a few degrees of any given bearing.
•
Locate the antenna at least 3 metres away from and out of the
transmitting beam of high power transmitters (S-band radar and/or
Inmarsat systems). This includes the ship's own AIS VHF antenna
if it is located separately.
High power transmitting
antenna
3.0m
GPS AIS Antenna
10 deg.
Mast
Figure 20 Recommended GPS antenna installation