How To Fine-Tune Sea Clutter Reduction; How To Manually Reduce Sea Clutter - Furuno FAR-1513-BB Operator's Manual

1.19.2

How to fine-tune sea clutter reduction

Auto A/C SEA allows for fine tuning of the A/C SEA circuit, within ±20 dB. Accordingly,
with the bar reading set to 50, gain is not lowered to minimum as with manual A/C SEA
on close-in ranges. Further, the auto A/C SEA level is low because the average value
of the original input echo is low in areas where there are no sea surface reflections.
For example, when the ship is alongside a quay and the radar picture shows echoes
from both land and sea, you can observe the size of the echoes because the STC
curve changes with the size of the echoes.
Note: The auto A/C function can erase weak target echoes. Adjust the control care-
fully, watching the display.
How to fine-tune sea clutter reduction from the control unit (RCU-028)
Rotate the AC/SEA knob (F2). Rotate anticlockwise to decrease the AC/SEA, or
clockwise to increase the A/C SEA.
How to fine-tune sea clutter reduction from the on-screen box
1. Select [SEA AUTO], following the procedure in paragraph 1.19.1.
2. Place the arrow on level indicator inside the A/C SEA box at the top of the display.
3. While observing the A/C SEA level indicator, rotate the ADJUST knob clockwise
to increase the A/C SEA or counter-clockwise to decrease it. The setting range is
[-50] to [50].
1.19.3

How to manually reduce sea clutter

The A/C SEA control reduces the amplification of echoes at short ranges (where clut-
ter is the greatest) and progressively increases amplification as the range increases,
so amplification will be normal at those ranges where there is no sea clutter.
The proper setting of the A/C SEA should be such that the clutter is broken up into
small dots, and small targets become distinguishable. If the setting is set too low, tar-
gets will be hidden in the clutter, while if the setting is too high, both sea clutter and
targets will disappear from the display. In most cases adjust the control until clutter has
disappeared to leeward, but a little is still visible windward. Be careful not to remove
all sea clutter, because you may erase weak echoes. Further, the possibility of losing
weak echoes is greater when you use both A/C SEA and A/C RAIN to reduce clutter.
How to reduce sea clutter manually from the control unit (RCU-028)
Rotate the AC/SEA knob (F2). Rotate anticlockwise to decrease the AC/SEA, or
clockwise to increase the A/C SEA.
Sea clutter at
screen center
1. OPERATIONAL OVERVIEW
A/C SEA control adjusted;
sea clutter reduced
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