Furuno FCR-2119-BB, Руководство по эксплуатации

Страница: 70 / 541

2. RADAR, CHART RADAR OPERATION
2-4
2.5.1 How to reduce sea clutter automatically
Auto A/C SEA allows for fine-tuning of the A/C SEA circuit, within ±20 dB. Accordingly,
with the bar reading set to 100, gain is not lowered to minimum as with manual A/C
SEA on close-in ranges. Further, the auto A/C SEA level is low because the average
value of the original input echo is low in areas where there are no sea surface reflec-
tions. For example, when the ship is alongside a quay and the radar picture shows
echoes from both land and sea, you can observe the size of echoes because the STC
curve is different depending size of echoes.
To get automatic adjustment of sea clutter, do one of the following:
Control Unit : Push the A/C SEA control to display
[AUTO] on the [SEA] mode indication on the Status
bar.
Trackball module : Click the [SEA] mode indication
to display [AUTO].
2.5.2 How to reduce sea clutter manually
The A/C SEA control reduces the ampli-
fication of echoes at short ranges (where
clutter is the greatest) and progressively
increases amplification as the range in-
creases, so amplification will be normal
at those ranges where there is no sea
clutter.
The proper setting of the A/C SEA
should be such that the clutter is broken
up into small dots, and small targets become distinguishable. If the setting is set too
low, targets will be hidden in the clutter, while if the setting is too high, both sea clutter
and targets will disappear from the display. In most cases adjust the control until clut-
ter has disappeared to leeward, but a little is still visible windward.
Be careful not to remove all sea clutter, because you may erase weak echoes. Fur-
ther, the possibility of losing weak echoes is greater when you use both A/C SEA and
A/C RAIN to reduce clutter.
To reduce sea clutter manually, do one of the following:
Control Unit : Push the A/C SEA control to display [MAN] on the [SEA] mode indica-
tion on the Status bar. Rotate the A/C SEA control to adjust the sea clutter.
Trackball module : Click the [SEA] mode indication on the Status bar to display
[MAN]. For coarse adjustment, put the cursor within the slider bar area then push the
left button. For fine adjustment, put the cursor at the end of the slider bar then roll the
trackball while pushing and holding down the left button. Release the button to finish.
SEA mode indication
Sea clutter at
screen center A/C SEA adjusted; sea
clutter suppressed