Furuno FSV-35S, Operator'S Manual

Page: 36 / 144

2. HORIZONTAL MODE
2-12
2.7 How to Adjust Strong, Weak Echoes
2.7.1 AGC
The AGC function automatically reduces the receiver gain only against strong echoes
such as the bottom or a large school of fish. Since the AGC function does not affect
weak echoes, 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 the [Gain Setting] then push the left-click button.
3. Press the
H/V/S key to select [H1] or [H2].
4. Select [AGC] then push the left-click button to show the setting box.
5. Select
S
or
T
then push the left-click box to change the setting.
The setting range is -9 to 9. The higher the setting, the higher the degree of sup-
pression.
6. Select [Quit] on the setting box then push the left-click button to close the box.
7. Long-press the
MENU/ESC key to close all menus.
2.7.2 Near AGC
When the water is shallow or heavily sedimented, the unwanted and scattered echoes
from close-in may be excessively strong. In this case, a school of fish which is dis-
played at between 300 and 500 m may disappear gradually when the ship starts ap-
proaching 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 condition. 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 the [Gain Setting] then push the left-click button.
3. Press the
H/V/S key to select [H1] or [H2] tab.
4. Select [Near AGC] then push the left-
click button to show the setting box.
5. Select
S
or
T
then push the left-click
button to change the setting.
The setting range is -30 to 30. The higher
the setting, the stronger the echo level
on near range.
6. Select [Quit] on the setting box then push the left-click button to close the box.
7. Long-press the
MENU/ESC key to close all menus.
Note: The range which Near AGC covers is set at [Near AGC Distance] in the [Near
AGC] menu. The setting range is 20 to 500 m (20 m step). The setting range can be
changed. For details, contact your dealer.