How To Shorten Pulse Length; How To Suppress Unwanted Echoes - Furuno FSV-25 Operator's Manual

2. HORIZONTAL MODE
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
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.
2.7.3

How to suppress unwanted echoes

This sonar's noise suppressor removes weak echoes such as sea surface reflections,
plankton, weak echoes from distant bottom echoes, and screw noise from other
ships*. Because the noise suppressor does not work against strong echoes it is useful
for detecting schools of fish.
* Screw noise from other ships may produce strong echoes at distant range, depend-
ing on gain setting.
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 [Noise Suppress] or [Noise Supp. (SHIP)] to show the
setting box.
• [Noise Suppress]: Use this item to suppress sea surface re-
flections, plankton, and distant bottom echoes.
• [Noise Supp. (SHIP)]: Use this item to suppress screw noise
from other ships.
5. Click
The higher the setting, the higher the degree of suppression.
6. Click [Quit] to close the box.
7. Long-push the MENU/ESC key to close all menus.
2-12
or to change the setting.
or to change the setting.
TX/RX Setting
H1 P1
H2 P1
TX Interval
TX Pulse Length
TX Power
Reverberation
Freq Shift
Hor. Beam Wid
Ver. Beam Wid
Quit
V P1
: 9
: 9
: 9
: 0
: 0
: 4
: 4
Quit
Cancel
2
(0.0~10.0)