Furuno csh5l SONAR User Manual


 
2. FINE TUNING THE SONAR PICTURE
2-4
2.4 Suppressing Bottom and Sea Surface Reflec-
tions in Shallow Fishing Grounds
In shallow fishing grounds with hard or rocky bottom, bottom reflections often interfere
with wanted fish echoes and they can not be eliminated sufficiently with the aforemen-
tioned TVG and AGC, especially when the tilt angle is large in order to track fish
schools approaching within 400 m. In such cases try to reduce the output power with-
out turning down the gain. The picture becomes clearer when the output power is re-
duced rather than when the gain is decreased as illustrated below.
1. Press the MENU key. The last-used menu appears.
2. Use the RANGE control to choose [MENU MODE] at the top of the screen.
3. Use the GAIN control to choose [SONAR] to display the [SONAR] menu.
4. Use the RANGE control to choose [TX OUTPUT].
5. Use the GAIN control to set TX output. The higher the setting (setting range: 0-
10) the greater the TX power.
6. Press the MENU key to close the menu.
For long-range detection, set [TX OUTPUT] to 10.
How to adjust TX output
Improper
Proper
Bottom echo masks
fish echo.
TVG and AGC
adjusted, OUTPUT
high.
OUTPUT decreased,
gain maintainted
Fish echo
Fish echo
weakened