Installation manual

Antenna Unit Antenna Site
8 Apr 2004
3
3.2 Antenna Site
3.2.1 Obstructions
The antenna unit rotates 360° and down to –25° in pitch
and roll to allow for continuous pointing even during the
worst sea states. Any obstructions within this volume can
cause signal degradation.
The amount of degradation depends on the size of the
obstruction and the distance from the antenna. As a rule of
thumb any obstruction, which subtends an angle of less
than 3° at the antenna will have limited effect. The table
below gives a guideline for obstruction sizes, which will
cause limited degradation.
Distance to Obstruction Size of Obstruction
3 m 16 cm
5 m 26 cm
10 m 52 cm
20 m 105 cm
3.2.2 Interference
The antenna unit must be mounted as far away as possible
from the ship radar and other high power radio
transmitters, as these can severely compromise the system
performance.
Radar
It is difficult to give exact guidelines for minimum distance
between the radar and the TT-3008G - as radar power,
radiation pattern, frequency and pulse length/shape varies
widely from radar to radar. Since a radar radiates a fan
beam width a horizontal with of a few degrees and a
vertical width up to +/-15°, the worst interference can be