Furuno FSV25S, Operator'S Manual

Page: 43 / 163

2. HORIZONTAL MODE
2-11
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. Click [Gain Setting].
3. Press the
H/V/S key to select the [H1] or [H2].
4. Click [AGC] tto show the setting box.
5. Click
S
or
T
to change the setting.
The higher the setting, the higher the degree of suppression.
6. Click [Quit] on the setting box to close the box.
7. Long-push the
MENU/ESC key to close all menus.
2.7.2 How to shorten pulse length
The pulse length determines the length of the transmission pulse emitted into the wa-
ter. While a longer pulse is advantageous for long-range sounding, it has the disad-
vantage of being poor in discrimination of targets, that is, the ability to separate several
closely located targets. When searching bottom fish, therefore, it is useful to shorten
the pulse length in order to separate fish echoes from bottom reflections.
Note: For search of surface and midwater fish in which bottom reflections are not so
strong, use the longest pulse length "9".
1. Press the MENU/ESC key to show the main menu.
2. Click [TX/RX Setting].
3. Press the
H/V/S key to select the
[H1] or [H2] tab.
4. Click [TX Pulse Length].
5. Click
S or T to change the setting.
The setting range is 0 to 9. The high-
er the setting, the longer the pulse
length.
Note: The pulse length is automati-
cally set to “9” when the reverbera-
tion setting (section 2.9.6) is other
than “0”.
6. Click [Quit] on the setting box to
close the box.
7. Long-push the MENU/ESC key to close all menus.
Quit
Cancel
2
(0.0~10.0)
TX/RX Setting Quit
H1 P1
H2 P1 V P1
TX Interval : 9
TX Pulse Length : 9
TX Power : 9
Reverberation : 0
Freq Shift : Mid
Hor. Beam Width : 4
Ver. Beam Width : 4