How To Adjust Strong, Weak Echoes; Agc; Near Agc - Furuno FSV-85 Operator's Manual

3.8

How to Adjust Strong, Weak Echoes

3.8.1

AGC

The AGC functions to automatically reduce the receiver gain only against strong ech-
oes such as the bottom or a large school of fish. Since weak echoes remain unaffect-
ed, a small school of fish becomes easier to detect. Adjust it so that the AGC works
only on bottom reflections. Do not set it too high; weak echoes may be missed.
1. Press the MENU/ESC key to show the main menu.
2. Select [Gain Setting] then push the left-click button.
3. Press the H/V/S key to select the [V] tab.
4. Select [AGC] then push the left-click button.
5. Select
The setting range is -20 to 20. The higher the setting, the higher the degree of sup-
presion.
6. Select [Quit] on the setting box then push the left-click to close the box.
7. Long-press the MENU/ESC key to close all menus.
3.8.2

Near AGC

When the water is shallow or heavily sedimented, the reflected echoes from close-in,
unwanted echoes may be excessively strong. In this case, a school of fish which is
displayed at between 300 and 500 m may disappear gradually when the ship starts
approaching the school of fish.
Use the Near AGC feature to suppress this strong echo. Normally set it between 3 and
4, however, this setting depends on the sea area. Do not set it too high; all echoes
(including noise) from near distance may be painted in red.
1. Press the MENU/ESC key to show the main menu.
2. Select [Gain Setting] then push the left-click button.
3. Press the H/V/S key to select the [V] tab.
4. Select [Near AGC] then push the left-click
button to show the setting dialog box.
5. Select [Near AGC] again then push the left-
click button.
6. Select
setting.
The setting range is -20 to 20. The higher the setting, the stronger the echo level
on near range.
7. Select [Quit] on the setting box then push the left-click button to close the box.
8. Long-press the MENU/ESC key to close all menus.
Note: Set the effective range of [Near AGC] with [Near AGC Distance]. The setting
range is 20 - 2000 m, in 20 m increments. The settin range can be changed in the sys-
tem menu. For details, contact your dealer.
or then push the left-click button to change the setting.
or then left-click to change the
3. VERTICAL MODE
3-9