However, when the power boat is traveling at high speed, the bow rises up out of the water and if the
elevation angle (trim) of the bow is raised up so that it equals, or exceeds, 50% of the vertical beam
width of the radar, this can cause two problems:
ahead of the power boat, the beam is projected too high to sweep the water surface
effectively. Targets can be missed completely or appear at a very poor resolution on the
display screen.
astern of the power boat, the beam is projected too low and is concentrated over a small
area of water so that sea clutter becomes a problem on the display screen.
In this case, you're recommended to install the scanner so that is tilted down at the front, at an angle
that will produce an almost horizontal sweep when the power boat is running at speed.
2.1.2
Yacht installations
Normally you should install the scanner horizontally, to produce an equal sweep around the yacht.
However, a yacht heels over to the lee side, and when the heel angle exceeds 50% of the vertical
beam width of the radar, this can cause two problems:
on the windward side of the yacht, the beam is projected too high to sweep the water
surface effectively. Targets can be missed completely or appear at very poor resolution on
the display unit.
on the lee side of the yacht, the beam is projected too low and is concentrated over a small
area of water so that sea clutter becomes a problem on the display unit.
In this case, you're recommended to install the scanner on a gimbal mounting so that it can operate
effectively in a heavy swell or when the yacht is heeled over.
Northstar 6 kW Radar Installation Manual
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