2. RADAR OPERATION
2-3
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.
2.5 Reducing Sea Clutter
2.5.1 How 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.
A/C SEA adjusted;
sea clutter suppressed
Sea clutter at
screen center
Effect of A/C SEA