Furuno 1934C-BB, GD-1920C-BB manual Reducing Sea Clutter, How the A/C SEA works, Effect of A/C SEA

2. RADAR OPERATION

Adjusting the FTC (When the radar source is the 17x4 series radar)

To suppress rain clutter from heavy storms or scattered rain clutter, adjust the FTC.

In addition to reducing clutter, the FTC can be used in fine weather to clarify the picture when navigating in confined waters. However, with the circuit active the receiver is less sensitive. Therefore, turn off the FTC, by setting it for “0”, when its function is not required.

1.Press the GAIN key.

2.Press the D: FTC soft key to show the FTC window.

3.Rotate the ENTER knob to adjust. The range of adjustment is 0-100(%). Do not overadjust the FTC – weak target echoes may be missed.

4.Press the GAIN key on the front panel or E: RETURN soft key to finish.

2.5Reducing Sea Clutter

2.5.1How the A/C SEA works

Echoes from waves can be troublesome, covering 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 will extend. Sea clutter may affect radar performance because real targets are sometimes hidden by the echoes of small waves. (See the left-hand figure in the figure below.) When sea clutter masks the picture, adjust the A/C SEA to reduce the clutter.

The A/C SEA reduces the amplification of echoes at short ranges (where clutter 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.

Sea clutter at	A/C SEA adjusted;
screen center	sea clutter suppressed

Effect of A/C SEA

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