How To Adjust Sensitivity; How To Reduce Sea Clutter; How To Select The Method Of Clutter Adjustment - Furuno FAR-2218 Operator's Manual

1.19

How to Adjust Sensitivity

The gain control adjusts the sensitivity of the receiver.
The proper setting is such that the background noise is just visible on the screen. If
you set up for too little sensitivity, weak echoes may be missed. On the other hand
excessive sensitivity yields too much background noise; strong targets may be missed
because of the poor contrast between desired echoes and the background noise on
the display.
To adjust receiver sensitivity, adjust the gain control so background noise is just visible
on the screen.
How to adjust the GAIN from the control unit (RCU-014)
Rotate the GAIN knob. Rotate anticlockwise to decrease the gain, or clockwise to in-
crease the gain.
How to adjust the GAIN from the on-screen box
1. Place the cursor in the [GAIN] box at the top of the screen.
GAIN
2. Spin the scrollwheel to adjust the gain. The setting range is [0] to [100].
1.20

How to Reduce Sea Clutter

Echoes from waves cover the central part of the display with random signals known
as sea clutter. The higher the waves, and the higher the antenna above the water, the
further the clutter extends. When sea clutter masks the picture, reduce it with the A/C
SEA control, either manually or automatically.
Note 1: When both sea clutter and rain clutter are reduced, the sensitivity is de-
creased more than when only one is changed. For that reason adjust them carefully.
Note 2: The echo average function (see section 1.24) is useful for reducing reflections
from the sea surface. However, high-speed targets are harder to detect than station-
ary ones when echo average is active.
1.20.1

How to select the method of clutter adjustment

1. Place the cursor in the [SEA AUTO] or [SEA MAN] (whichever is shown) level in-
dication at the top of the display.
2. Left-click to display [SEA AUTO] or [SEA MAN] as appropriate.
40
Place the cursor on the [ AUTO ] or
[ MAN ] indication, then left-click.
SEA MAN
1. OPERATIONAL OVERVIEW
Place the cursor inside the gain
level indication, then spin the
scrollwheel.
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