Installation manual

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Pre installation checks |10kW and 25kW Installation Manual
However, when a 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
e ectively. 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 it is tilted down at the front,
at an angle that will produce an almost horizontal sweep when the power boat is running at
speed.
The optimum height for the scanner is as close as possible to the A-B line for best
performance.
How to  nd the A-B Line:
The vertical extent of the radar beam is 20°, so most of the radar beam is concentrated within
this angle, meaning that outside of this angle, the radar beam will be very weak.
Scanner power θ° value (half the -3 dB beam width)
10 kW 10
25 kW 10
An example of an A-B Line is shown in the picture. If you install the scanner below the
A-B line, the scanner will be too low. It will be di cult to acquire distant targets and the
superstructure will be more likely to impede the passage of the beam and generate false
echoes.
If the scanner is installed too high above the A-B line, the beam will miss close targets and
increase sea clutter return.
You can  nd the A-B line for any vessel as follows:
• Using a scaled drawing of the vessel, lay a rule along the line of the main deck and continue
this forwards as a dashed line extending beyond the bow.
• Using a protractor, measure the θ° value (for your scanner model) below the dashed line at
the bow and draw in a new line along this angle.
• Extend the new line back beyond the bow of the vessel. This is the A-B line.
How to  nd the theoretical maximum detection range
Propagation of the radar beam can vary, depending on the properties of the air through
which it is traveling. Under normal conditions the maximum distance a target can be
detected at is approimately 10% beyond the optical horizon.