Furuno GP-1640F, Operator'S Manual, Page: 23 / 108

2-7
2.8 Suppressing
Interference
Interference from other acoustic equipment
operating nearby or other electronic equipment
on your boat may show itself on the display as
shown below.
To suppress interference, do the following:
1. Press the [MENU] key and the SOUNDER
SETUP OPTIONS soft key.
2. Select NOISE LIMITER and press the EDIT
soft key to show the noise limiter window.
NOISE LIMITER
OFF
NL1
NL2
NL3
Noise limiter window
3. Press ▲ or ▼ to select degree of
suppression desired; OFF, NL1, NL2 or
NL3. The higher number the greater the
degree of suppression.
4. Press the RETURN soft key and the
[SNDR] key to finish.
Interference from
other sounder
Electrical interference
Types of interference
Turn the noise limiter circuit off when no
interference exists, otherwise weak echoes
may be missed.
2.9 Suppressing Low Level
Noise
Dots may appear over most of screen. This is
mainly due to dirty water or noise. This noise
can be suppressed by adjusting CLUTTER on
the SOUNDER SETUP OPTIONS menu.
When the sounder mode is Auto, the clutter
suppression setting is fixed at AUTO. To
suppress low level noise in manual sounder
operation do the following:
1. Press the [MENU] key and the SOUNDER
SETUP OPTIONS soft key.
2. Select CLUTTER and press the EDIT soft
key to show the clutter window.
CLUTTER
3
Clutter window
3. Press ▲ or ▼ to select clutter rejection
level desired; 0 (OFF) through 9. The
higher the number the higher the degree of
suppression. Note that weak echoes may
not be displayed when the clutter circuit is
on.
4. Press the RETURN soft key and the
[SNDR] key to finish.