Furuno FSV-84 manual Fish echo

2. HORIZONTAL MODE

2.8Suppressing Bottom and Sea Surface Reflections in Shallow Waters

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	Fish echo
METHOD
	TVG and AGC	Fish echo
		weakened
	adjusted with
	TX POWER kept high

CORRECT

METHOD

Fish echo

Reduce TX POWER with GAIN kept constant

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.

6.Select QUIT at the top of the menu screen and press the [MENU] key to close all menus.

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