Furuno FR-2105-B - Manual (Page 34)

-1.17-
Automatic anti-clutter control
The easiest way to suppress the surface clutter
is to use the automatic control. Press the A/C
AUTO key. 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
OFF
1
OFF
CENTER
4
EBL
7
TARGET
TRAILS
CANCEL
PANEL
BRILL
2
VECTOR
5
CHART
ALIGN
8
CU, TM
RESET
0
MODE
3
LOST
TARGET
6
MARK
9
A/C
AUTO
ENTER
TARGET
CANCEL
TARGET
DATA
AC
AUDIO
OFF
RADAR
MENU
PLOT
MENU
NAV
MENU
A/C AUTO key
CAUTION
The auto A/C function can erase weak target echoes.
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 a very
calm water), set the control at the fully counterclockwise position.