Furuno CH-37 - Manual (Page 23)

2-7
2.5 Adjusting Gain
Most equipment malfunctioning claims result from improper
setting of switches and controls. For example, fish, fish habitat
or outcrop can not be readily detected by merely increasing
the gain. Initially set the gain between 3 and 5 with the GAIN
control. Then, fine tune depending on the fishing ground, fre-
quency used, etc.
Few fish found
or difficult to
find fish
habitat.
Random noise
Feeble echoes
Surface noise
Interference
Turn GAIN control clockwise.
Adjust NL control.
Adjust TVG controls.
Turn on "IR" in SONAR menu.
0
2
4 6
8
10
0
2
4 6
8
10
0
2
4 6
8
10
CLEAR
PICTURE!
Figure 2-7 How to set the gain
2.6 Rejecting Sonar Interference and Noise
While observing the sonar picture, you may encounter occa-
sional or intermittent noise and interference as shown below.
These are mostly caused by onboard electronic equipment,
engine, propeller noise, or electrical noise from other sonars
being operated nearby.
(A) Inteference from (B) Interference from
other sonars marine life
Figure 2-8 Noise and interference