Suppressing Bottom And Sea Surface Reflections In Shallow - Furuno FSV-30 Operator's Manual

2.8 Suppressing Bottom and Sea Surface
Reflections in Shallow
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 aforementioned TVG and AGC functions, especially when the TILT is set to a
larger angle in order to track fish schools approaching within 400 m. In such
cases try to reduce the output power by adjusting the Tx output instead of
turning down the gain. The picture becomes clearer when output power is
reduced rather than when the GAIN is decreased as illustrated below.
INCORRECT
METHOD
CORRECT
METHOD
How to suppress bottom and sea surface reflections in shallow waters
1. Press the [MENU] key to open the menu.
2. Select the H-SCAN SETTING menu and press the [MENU] key.
3. Select TX POWER and press the [MENU] key.
4. Adjust setting from the dialog box as appropriate and press the [MENU] key.
The setting range is 0-9. The higher the setting the higher the Tx power.
5. Select QUIT and press the [MENU] key to conclude.
6. Select QUIT at the top of the menu screen and press the [MENU] key to
close all menus.
Fish echo
TVG and AGC
adjusted with
TX POWER kept high
Reduce TX POWER
with GAIN kept
constant
2. HORIZONTAL MODE
Fish echo
weakened
Fish echo
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