3-10 hsb
2
PLUS Series LCD Display
Adjusting Gain, Sea
Clutter, Rain Clutter
and Tune
Rain Clutter Control, using RAIN and FTC
Theradarcanseeechoesfromrainorsnow.Returnsfromstormareasand rain
squallsconsist of countless small echoes that continuously change size,
intensity,and position.Thesereturns,showninFigure 3-8,sometimesappear
as large hazy areas, depending on the intensity of the rainfall or snow in the
stormcell.
The RAIN and FTC controls are usedto reduce this clutter, so that targets
maskedby the cluttercan be seen on the radar picture.
•TheRAIN control is used to reduce largecluttermassesaround your vessel
causedby rain or snow.
•TheFTC (Fast Time Constant) control is used to reduce rain clutterat a dis-
tance from your vessel,such as that shown below.
Figure 3-8: Rain Clutter
When the FTC controlis turned up, onlythe leading edge of large(rainclutter)
echoesis displayed, while the effect on smaller(ship) echoes is only slight.
Thismeans that you can also use the controlon shorter ranges to distinguish
betweentwo very close echoes on the same bearing, which may otherwise
mergeand appear as one echo.
When the FTC control is turned up, the receiver is less sensitive,and there is a
reduction of backgroundnoise and fill-in returns from land and large targets.
You should thereforeturn thecontroldown when its use is not required.Since
stormcells areusually visiblefor long distances due to their extreme altitude,
you may wish to leave them displayedso that you can observe the location of
bad weather.
If you turn the RAIN or FTC controlOff(equivalent to setting the level to 0%),
theactual settingis stored,and restored when you turn the control on again.
Note: RAIN and FTC are reset to Off at power-on.
RAIN
O
F
F
D3967-1
FTC
O
F
F
81186_3.book Page 10 Thursday, August 22, 2002 8:23 AM
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