Adjusting The Sensitivity; Suppressing Sea Clutter - Furuno FR-2105 Operator's Manual

1.12 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 speckled background 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 notice
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.
POWER
ON
PM
ANTENNA
OFF
TUNE
EBL
DEGAUSS ERR

1.13 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 A/C RAIN
#1 #2
OFF ON
#3 #4
EBL
GAIN CONTROL
BRILLIANCE A/C RAIN A/C SEA
#1 #2
ON
#3 #4
RANGE
A/C SEA CONTROL
A/C SEA GAIN
STBY
TX
RANGE
GAIN
STBY
TX
A/C SEA control
off
-1.16-
A/C SEA control
adjusted