Furuno NAVNET GD-1920C - Manual (Page 33)

2. RADAR OPERATION
2-4
2.5.2 Adjusting the A/C SEA
A/C SEA should be adjusted so that the clutter is broken up into small dots, and small
targets become distinguishable.
1. Press the GAIN key.
2. Press the A/C SEA soft key to show the A/C SEA setting window.
A/C SEA
¡ AUTO ROUGH
¡ AUTO MODERATE
¡ AUTO CALM
¤ MAN 0
A/C SEA setting window
3. Use the Trackball to select AUTO ROUGH, AUTO MODERATE, AUTO CALM, or MAN
(manual) as appropriate. Select an AUTO option according to the sea state.
4. For manual adjustment, rotate the ENTER knob to adjust. The range of adjustment is
0-100. Do not overadjust – weak echoes may be missed.
5. When the radar source is the Model 18x4 or 19x4, A/C SEA and A/C RAIN can be
automatically adjusted, with the A/C AUTO ON/OFF soft key. Press the key to highlight
ON or OFF as appropriate. Note that A/C AUTO adjustment is done at MAN indicator in
the A/C SEA window.
6. Press the GAIN key on the front panel or RETURN soft key to finish.
2.6 Reducing Precipitation Clutter
The vertical beamwidth of the antenna is designed to see surface targets even when the
ship is rolling. However, by this design the unit will also detect precipitation clutter (rain,
snow, hail, etc.) in the same manner as normal targets. Precipitation clutter shows as
random dots on the screen.
2.6.1 Adjusting the A/C RAIN
When echoes from precipitation mask solid targets, adjust the A/C RAIN to split up these
unwanted echoes into a speckled pattern, making recognition of solid targets easier.
1. Press the GAIN key.
2. Press the A/C RAIN soft key to show the A/C RAIN window.
A/C RAIN
0
A/C RAIN setting window
3. Rotate the ENTER knob to adjust the A/C RAIN. The current level is shown on the A/C
RAIN level bar in the A/C RAIN window, and the range of adjustment is 0 to 100(%). Do
not overadjust – weak echoes may be missed.
4. Press the GAIN key on the front panel or RETURN soft key to finish.