Furuno CSH-23 - Manual (Page 32)

3-6
Setting F-shift (data setting window: SONR•BEAM,
SONAR)
If interference cannot be suppressed by the interference rejector
(IR) or Tx cycle, change the setting of F-SHFT from 1 to 2.
Noise limiter (data setting window: SIGNAL, SIGNAL
PROCESS)
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 (NL) can reduce the effects of these
unwanted reflections–raising the setting causes them to become
bluish to background color. Normally a setting of 3 or 4 is suffi-
cient.
Adjusting Beamwidth
Beamwidth can be adjusted at SONR•BEAM, BEAM on the
data setting window.
Table 3-1 Beamwidth adjustment menus
Menu Application
HOR
Set to "0" for normal use. The higher the setting the
narrower the beam. This control may be used
together with the AGC and NL controls to suppress
sea surface reflections and seabed echoes.
VER
0: This is the normal beam. The higher the
setting the narrower the beam. Increase the
setting when searching for small fish schools
or checking seabed condition.
1 or 2: Provides a wide beam. It is useful for
tracking quick moving fish schools such as
bonito or tuna.
3: This setting suppresses upper sidelobes (sea
surface reflections) of the beam to make it
easier to search fish schools.
4: This setting suppresses lower sidelobes (seabed
echo) of the beam to make it easier to search
for fish near the seabed.