Furuno FR-2125V Operator's Manual page 27

1.14.1 Automatic anti-clutter control
The easiest way to suppress the surface clutter is to use the automatic anti-clutter control.
Press the [A/C AUTO] key to turn the A/C AUTO circuit on or off. A/C AUTO appears at the
bottom left-hand corner of the screen when the A/C AUTO circuit is on.
Use of a function key is also a good method for reducing sea clutter. For this purpose,
presetting is required. Consult a FURUNO representative.
HL
PANEL MODE
AUDIO
OFF BRILL
OFF
1 2 3
OFF LOST
VECTOR
CENTER TARGET
4 5 6
ACQ
CHART
EBL MARK
ALIGN
TARGET
7 8 9
DATA
TARGET CU, TM A/C
TRAILS RESET
AUTO TARGET
CANCEL
CANCEL 0 ENTER
[A/C AUTO] key
1.14.2 Manual anti-clutter control
From the fully counterclockwise position, slowly turn the [A/C SEA] control clockwise. For
optimum target detection, you should leave speckles of the surface return slightly visible.
The anti-clutter sea control is often referred to as STC (Sensitivity Time Control) which
decreases the amplification of the receiver immediately after a radar pulse is transmitted,
and progressively increases the sensitivity as the range increases.
A common mistake is to over-adjust the [A/C SEA] control so that the surface clutter is
completely removed. By rotating the control fully clockwise, you will see how dangerous
this can be; a dark zone is created near the center of the screen and close-in targets can
be lost. This dark zone is even more dangerous if the gain has not been properly adjusted.
Always leave a little surface clutter visible on the screen. If no surface clutter is observed
(on very calm waters), set the control at the fully counterclockwise position.
1-16
RADAR PLOT NAV
MENU MENU MENU
Figure 1-15 Control head
CAUTION
The auto A/C function can erase weak
targets.