Furuno 1623 - Manual (Page 12)

1. OPERATION
5
2. Press
▲
or
▼
to choose AUTO or MANU
as appropriate.
Automatic gain adjustment
a) Press ► to open the automatic gain
options window.
ROUGH
MODERATE
CALM
Automatic gain options
b) Press ▲ or ▼ to choose ROUGH,
MODERATE or CALM depending on
sea conditions.
c) Press
◄
to close the window.
Manual gain adjustment
While observing the screen and the gain
tuning bar, press
◄ or ► to set the gain.
The setting range is 0-100.
3. Press the [MENU/ESC] key to finish.
1.8 Suppressing Sea Clutter
In rough weather, returns from the sea
surface, called sea clutter, are received over
several miles around own ship and mask
nearby targets. This situation can be
improved by properly suppressing the sea
clutter with the A/C SEA control.
In most cases suppress the clutter until it has
disappeared to leeward, but a little is still
visible windward. If the setting is too low,
targets will be hidden in the clutter, while if it
is set too high, both sea clutter and targets
will disappear from the display.
A common mistake is too over-suppress sea
clutter so that it is completely removed. You
can see how dangerous this can be by setting
up for maximum A/C SEA: A dark zone will
be created near the center of the screen,
causing a loss of close-in targets. This dark
zone is even more dangerous if the sensitivity
has not been properly adjusted.
Always leave a little sea clutter visible on the
Screen, first adjusting automatically and then
fine tuning with the manual control as
necessary.
Sea clutter at screen center
1. Press the [GAIN] key consecutively until
the display shown below appears.
A/C SEA
20
[GAIN] : A/C RAIN MENU
[MENU/ESC] : Exit.
AUTO : MODERATE
MANU
A/C SEA adjustment window
2. Press ▲ or ▼ to choose AUTO or MANU
as appropriate.
Automatic A/C SEA adjustment
a) Press
►
to open the automatic A/C
SEA options window.
ROUGH
MODERATE
CALM
A/C SEA options
b) Press ▲ or ▼ to choose ROUGH,
MODERATE or CALM depending on
sea conditions.
c) Press ◄ to close the window.