Simrad RA771UA, Instruction Manual

Page: 32 / 46

5 . 4 Proper Location for Installation of Radar
5 . 4 . 1
Scanner unit
The target detection capabilities of shipboard
radars are governed by the location of the Scanner unit.
An ideal location would be a point as high as possible
above the keel line, where there are no obstacles in all
azimuthal directions which might interfere with the
transmission of radar pulses and reception of returning
echoes.
limitations, sufficient consideration must be given
before selecting an optimal point.
1 .
The "radio ranging" distance-increases with the
Although all ships are subject to various
height of the scanner installation. Install the
scanner as high as possible, after investigating
the structural features of the ship and
maintainability of the scanner unit.
2.
If a part of the funnel or mast is in the same
horizontal plane as the scanner unit, radar pulses
will be intercepted and it causes to produce a
"blind" angle.
3 .
To avoid formation of a "blind" angle in the "bow"
direction, install the scanner closer to the bow
than any blinding obstacle.
scanner is impracticable, because of the ship's
structure, install the scanner more or less o f f
the keel line
or elevate the scanner
so
that a
dip, or an angle of declination, can be taken
between a horizontal line, and the line
connecting the antenna and the top of the obstacle.
(1) Method for displacing scanner off keel line.
4 . If obstacles on the bow side of the
Displacing the scanner in some distance to the
starboard side, displaces the blind spot
towards the port side on the scope,
which gives a clear view in the bow
direction. The displacement can be
calculated by the following equations:
o r
where
Ls
= 0 . 4 R
+
......
15
Ls
=
0 . 0 2 5 ~
+
. . . .
.
15
=
displacement from keel line
D
=
diameter
of
an obstacle on keel line
R
=
distance between scanner and obstacle
,
.
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