Furuno FSV85MK2, Manual

Page: 83 / 199

3. VERTICAL MODE
3-9
3.8 How to Adjust Strong and Weak Echoes
3.8.1 AGC
The AGC functions to automatically reduce the receiver gain only against strong
echoes such as the bottom or a large school of fish. Since weak echoes remain unaf-
fected, 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

or

then push the left-click button to change the set-
ting.
The setting range is -20 to 20. The higher the setting, the higher
the degree of suppresion.
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
and unwanted echoes may be excessively strong. In this case, a school of fish which
is displayed at between 300 m to 500 m and beyond 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

or

then left-click to change the
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 setting range can be changed in the
system menu. For details, contact your dealer.
Quit
Cancel
0
(-20~20)