
Chapter 2: Installation
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Radar interference
Even at distances greater than “d min.” in the previous section the radar might still be able to
degrade the performance of the SAILOR Fleet One system.
The presence of one or more X-band radars within a radius up to 100 m could cause a minor
degradation of the signal-to-noise ratio during high speed and data calls. The degradation will
be most significant at high radar pulse repetition rates.
As long as receiving conditions are favourable, this limited degradation is without importance.
However, if receiving conditions are poor – e.g. due to objects blocking the signal path, heavy
rainfall or icing, low satellite elevation and violent ship movements – the small extra
degradation due to the radar(s) could cause poor call quality. A voice call might become noisy
or fail while a data connection might decrease in speed and performance.
The presence of S-band radar(s) is unlikely to cause any performance degradation – as long as
the minimum distances (d min.) listed in the previous section are applied.
It is strongly recommended that interference free operation is verified experimentally before
the installation is finalized.
Other Inmarsat systems
Recommended minimum safe distance to other Inmarsat antennas is 10 m.
GPS receivers
Good quality GPS receivers will work properly very close to the antenna - typically down to one
meter outside the main beam, and down to a few meters inside the main beam. However,
simple GPS receivers with poor frequency discrimination could be affected at longer range
(typically 10 m). It is always recommended to test the GPS performance before the installation
is finalized.
VSAT systems
For optimum performance we recommend a minimum distance of 3 meters from the BGAN
antenna to VSAT antennas.
Auxiliary Terrestrial Component (ATC)
The SAILOR Fleet One system is resilient to ATC base stations (future terrestrial mobile
systems) that operate inside the Inmarsat band and that may be located near the coast.
Other transmitters
See Minimum distance to transmitters on page 112 in Appendix A for minimum
recommended distance to transmitters in the frequency range below 1000 MHz.
CAUTION! The antenna must never be installed closer to a radar than “d
min.” - even if experiments show that interference free operation can be
obtained at shorter distances than “d min.” in the previous section.
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