Adjusting The Sensitivity; Suppressing Sea Clutter - Furuno FR-2125V Operator's Manual

1.13 Adjusting the Sensitivity

The [GAIN] control is used to adjust the sensitivity of the receiver, and thus the intensity of
echoes as they appear on the screen. It should be adjusted so that the speckled back-
ground noise is just visible on the screen.
To become acquainted with the way the [GAIN] control works, try rotating it between fully
counterclockwise and clockwise positions while observing the radar picture. You will no-
tice that clockwise rotation increases the echo intensity level. A low gain setting results in
the loss of weak echoes and a reduced detection range. If you turn the [GAIN] control too
far clockwise for an excessive gain setting, desired echoes will be masked in the strong
background noise.

1.14 Suppressing Sea Clutter

In rough weather conditions returns from the sea surface are received over several miles
around own ship and mask close targets. This situation can be improved by properly
adjusting the [A/C SEA] (Anti-Clutter Sea) control.
BRILLIANCE
#1
OFF ON
#3
EBL
POWER
BRILLIANCE
ON
PM
ANTENNA
OFF ON
TUNE
EBL
DEGAUSS ERR
Figure 1-13 Control head
[A/C SEA] control
A/C RAIN A/C SEA GAIN
#2
STBY
TX
#4
RANGE
Figure 1-14 Control head, A/C SEA effect
[GAIN] control
A/C RAIN A/C SEA
#1 #2
#3 #4
RANGE
[A/C SEA] control off
GAIN
STBY
TX
[A/C SEA] control
adjusted
1-15