Furuno GD-280, Operator'S Manual

Page: 169 / 280

11-5
11.3 Radar Picture Adjustment
11.3.1 Sensitivity (gain) adjustment
The [GAIN] control adjusts the sensitivity of the radar receiver. This control works precisely in the
same manner as the volume control of a broadcast receiver, amplifying the signals received.
Adjust it so that 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; weak targets may be missed because of the poor contrast between desired echoes and
the background noise on the display.
11.3.2 Suppressing sea clutter
In rough weather, returns from the sea surface are received over several miles around own ship
and mask nearby targets. This situation can be improved by properly using the[ A/C SEA] control.
In most cases adjust the [A/C SEA] control until clutter has disappeared to leeward, but a little is
still visible windward.
Sea clutter at screen center A/C SEA control adjusted;
sea clutter suppressed
11.3.3 Suppressing sea 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 adjusting the [A/C RAIN]
control.
Precipitation clutter A/C RAIN control adjusted;
precipition clutter suppressed