Furuno FMD-1712 - Manual (Page 13)

5
A common mistake is too over-adjust the
[STC] key so that the surface clutter is
completely removed. By setting up for
maximum STC effect, you will see how
dangerous this can be; 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 surface clutter visible
on the screen. If no clutter is observed (on
very calm waters), choose lowest STC
setting.
STC adjusted;
sea clutter suppressed
Sea clutter at
screen center
Figure 1-7 Appearance of sea clutter
STC may erase weak echoes. Set STC to
LOW when no sea surface reflections are
present.
CAUTION
Automatic sea clutter control
1. Press the [STC] key once or twice to
show the dialog box shown in Figure 1-
8.
AUTO STC MOD
LOW
HIGH
1 2 3
Figure 1-8 Dialog box for
automatic adjustment of STC
2. Press or to set level desired: 1,
Low; 2, Normal; 3, High.
Manual adjustment of sea clutter
control
1. Press the [STC] key once or twice to
display the dialog box shown in Figure
1-9.
MAN STC MOD
LOW
HIGH
32
Figure 1-9 Dialog box for manual
adjustment of STC
2. Press or to set level desired. 61
levels are available.
Note: The dialog boxes for adjustment of
STC are automatically erased when
there is no Omnipad operation for 10
seconds. To erase them quicker,
press the [STC] key after completing
the setting.
1.10 Suppressing Rain Clutter
In adverse weather, clouds, rain or snow
produce spray-like spurious echoes which
impair target detection over a long distance.
These echoes can be suppressed by
turning on the [FTC] (Fast Time Constant)
key. FTC appears at the top right-hand
corner on the screen when the FTC is on.
Turn off the FTC when its use is not
required so as not to miss weak targets.
Rain clutter
at screen center
FTC adjusted;
rain clutter suppressed
FTC
Figure 1-10 Appearance of rain clutter