Site preparation
3-12
Chapter 3: Installation
98-166784-A
3.2.7
Interference from radar, GPS, L-band and other transmitters
Mount the ADU as far away as possible from the ship’s radar and high power radio
transmitters, because they may compromise the ADU performance. RF emission from
radars might actually damage the ADU.
The SAILOR 600 Viasat Ka ADU itself may also interfere with other radio systems.
Radar
It is difficult to give exact guidelines for the minimum distance between a radar and the
ADU because radar power, radiation pattern, frequency and pulse length/shape vary from
radar to radar. Further, the ADU is typically placed in the near field of the radar ADU and
reflections from masts, decks and other items near the radar vary from ship to ship.
However, it is possible to give a few guidelines:
1. Since a radar radiates a fan beam with a horizontal beam width of a few degrees and a
vertical beam width of up to +/- 15°, you can avoid the worst interference by mounting
the ADU at a different level – meaning that the ADU is installed minimum 15° above or
below the radar antenna.
Due to near field effects the benefit of this vertical separation could be reduced at short
distances (below approximately 10 m) between radar antenna and the SAILOR 600
Viasat Ka ADU.
2. Provide as much vertical separation as possible when the SAILOR 600 Viasat Ka ADU
has to be placed close to a radar antenna.
Note
Do not place the ADU close to interfering signal sources or receivers. We
recommend to test the total system by operating all equipment simultaneously
and verifying that there is no interference.
Figure 3-12: Interference with the vessel’s radar
Min. 15°
Min. 15°
Radar
