Furuno FSV-84 SONAR User Manual


 
4. SLANT MODE
4-20
4.10.5 Noise limiter
Weak, unwanted reflections, colored light-blue or green, appear when the water
is dirty, plankton layers exists, or due to ship’s noise. The noise limiter can
reduce the effects of these unwanted reflections. Raising the setting causes
unwanted reflections to be displayed in colors of blue to background color.
Normally a setting of 3 or 4 is sufficient.
1. Press the [MENU] key to open the menu.
2. Select the S-SCAN SETTING menu and press the [MENU] key
3. Select NOISE LIMITER and press the [MENU] key.
4. Adjust setting from the dialog box as appropriate and press the [MENU] key.
The setting range is 0-15. The higher the setting the greater the degree of
suppression.
5. Select QUIT and press the [MENU] key.
6. Select QUIT at the top of the menu screen and press the [MENU] key to
close all menus.
4.10.6 Echo average
Adjusts echo afterglow, which can be useful for watching echo movement in the
S-SCAN SETTING menu. The setting range is 0-7. The higher the number the
longer echoes remain on the screen.
4.10.7 Reverberation reduction
You may choose the length of reverberation for the echo signal in the S-SCAN
SETTING menu. The larger the value the shorter the reverberation, which
makes it easer to see the echo signal. The setting range is 0-3.
4.10.8 Suppressing gain of bottom echo
None-moving echoes such as bottom echo, plankton echo, etc., may be
suppressed by the setting of BOTTOM SUPPRESS in the H-SCAN SETTING
menu (moving echoes such as fish school are not effected by this setting). The
setting range is 0 to 10. The greater the setting, the greater the suppression
level of the bottom, etc.
Note: Too high a setting may suppress slow-moving fish school as well.
4.10.9 Suppressing sidelobes
Sidelobes are fairly emissions generated outside the main beam. The energy of
the sidelobe is fairly weak but when the water is comparatively shallow and the
bottom is rocky and hard, strong signals are detected by the sidelobe.
To reduce the effect of sidelobes, adjust SIDELOBE SUPPRESS from the
S-SCAN SETTING menu. The setting range is –3 to +3 and the default setting
is 0. The higher the setting the greater the sidelobe suppression. If there is a
difference between the port and starboard side images, use a minus setting.