Simrad SP90 - REV E, Installation Manual

Page: 172 / 232

Simrad SP90
160
851-164510 / Rev.E
Speed
(Knots)
Bearing
(Knots)
--120
°
--60
°
0
°
+60
°
+120
°
+180
°
0
2
4
6
8
10
12
14
Table 8 Noise measurements
8 When the measurements are finished, make a plot of the
noise for 0 degrees bearing into the
Noise speed plot .
- The noise level at full speed should preferably not
exceed the 0 dB line.
→
Refer to the plot provided on page 162.
This noise/speed curve can give a picture of the ship’s best
search speed.
Problems with flow noise
In case of very high ship noise levels, the RCG function will
automatically regulate the receiver gain down. This lower gain
will then cause a reduction in the receiving range.
To find out if this high noise level is caused by flow noise from
the vessel’s hull or by the engine/propeller, perform the
following test.
1 Enter the noise level for 0 degrees bearing from the Noise
measurements table into the column for Stable speed in
the Noise verification table.
→
The Noise measurement table is given as table 8 on page
160.
→
The Noise verification table is given as table 9 .
2 From 0 knots, give full engine thrust, and make a readout
of the noise level for
Acceleration when the vessel
reaches each of the listed speeds. Enter the readouts into
the table.