Adjusting The Gain - Furuno CHS-5LMARK-2-55 Operator's Manual

1.3.7

Adjusting the gain

The GAIN control adjusts receiver sensitivity. It should be adjusted to see fish echoes
clearly with minimal noise on the screen. Too high a setting not only causes excessive
noise on the screen and makes it difficult to discriminate wanted fish echoes but also
causes bottom echoes to be painted in strong colors, resulting that the echoes from
bottom fish are masked by bottom reflections. A setting between 3 and 7 is usually
suitable. Each time the control is operated the newly selected gain appears in large
characters for five seconds at the top of the sonar display. The current gain is always
displayed at the top right corner of the sonar display.
1.3.8 Retracting the transducer, turning off the power
1. Set speed under 16 knots and then press the  switch to retract the transducer.
The lamp above the switch blinks while the transducer is being retracted. Trans-
mission is stopped automatically. If you press the  switch when the speed is over
16 knots and the speed warning is turned on in the [SYSTEM] menu, the message
"Max allowable speed for extended transducer is 16 kn. Max allowable speed
during raising lowering transducer is 16 kn." and the audio alarm sounds. Press
the R/B key to silence the audio alarm.
2. When the lamp above the  switch goes off, meaning the transducer is completely
retracted, press the POWER switch on the control unit to turn off the power.
3. Turn off the monitor.
Note 1: The transducer is automatically retracted into the tank whenever the power
switch is turned off. However, for safety purposes, make it a habit to retract the trans-
ducer before turning off the power.
Note 2: The equipment can be set to automatically retract the transducer when the
ship exceeds the operator-set speed. (Speed data required.) The transducer may be
retracted at a different speed than set if the speed data is different from actual speed.
In all cases, reduce the speed below 16 knots and then retract the transducer.
Gain too low Gain proper
Examples of proper and improper gain
1. OPERATIONAL OVERVIEW
Gain too high
1-9