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When installing two antennas, provide a height difference so that those two antennas do not
enter each other's vertical beam width range.
x To avoid interference with other equipment and to prevent radio noise from generating, do
not place the VHF antenna, GPS antenna, and INMARSAT's dome within the range of the
vertical beam width.
x Keep a record of installation height data. The data is necessary for the initial setting of the
display unit.
x Minimize the blind sector, and ensure the adequate view angle so that the blind sector does
not exist in the range 22.5q from side to rear (Fig. 5). Specifically, ensure a sufficient view
field in the straight front (relative bearing 000q).
Fig. 5 Ensuring view angle
x Magnetron which has strong magnetic force is included in the antenna. Install the antenna
at least 3 meters away from nautical instruments including magnetic compasses and
chronometers.
* If there is a concern that structural objects existing within the vertical beam width may
generate false images, equip the structural objects with a radio wave absorber. (There are
two types of absorbers: broadband type having no specific resonant frequency and
narrowband type which can absorb a band with a specific frequency. Use those where
applicable.) Furthermore, it is effective to install a metal reflector, which reflects radio
waves upwardly, between the antenna and a structural object so that the radar's radio wave
will not directly come in contact with the structural object.
Note:
Because most radio wave absorbers have poor durability, some must be
replaced every year. When installing a reflector, the area to the rear of the
reflector becomes a blind sector. Therefore, minimize the size of the reflector.
* The above procedures for selecting an antenna installation position are described based on
the radar's antenna. Comprehensively select the antenna position by considering other
antennas' installation procedure manual, hull's structure, strength of the selected position,
and vibration.
3) Confirmation during test run
If the antenna vibrates a lot during test run, try to reduce or prevent vibration by reinforcing
the antenna mount base or using wire stays attached to the radar mast.
0q direction
Make no blind sector
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