
Chapter 3: Standard Radar Operations 3-9
Adjusting Gain, Sea
Clutter, Rain Clutter
and Tune
Sea Clutter Control
Radarreturnsfromwavesaroundyourvesselcanclutterthecentreoftheradar
picture(see Figure 3-7,makingit difficultto detectrealtargets. Such sea
clutterusuallyappearsasmultipleechoesonthedisplayatshortrangescales,
andtheechoesarenotrepetitiveorconsistentinposition.Withhighwindsand
extremeconditions,echoesfrom sea cluttermay cause densebackground
clutterin theshape of an almost soliddisc.
Figure 3-7: Sea Clutter
TheSEA controlreducesthegainlevelintheareasnearyourvessel,extending
upto3to5nmdependingonthewaveandseaconditions.Thishastheeffectof
reducing the sea returns to intermittent smalldots, while small targets are still
visible.Gainlevelsfurtherfromyour vesselremainunchanged.
YoucanusetheGainandSeacontroltohelpminimizetheeffectsofsidelobes
(seeIdentifyingFalseEcho Returnson page3-5).
Note:On short range scales,do not settheSeacontrol so highthat allclutter
isremoved, sincethis couldstopyou seeing echoesfromclosetargets.
Tuning the Receiver
TheTUNE controlis usedtofinetunethereceiverinthescannerformaximum
targetreturnsonthedisplay.InAutomode,theradartunesitselfautomatically
onallrangescales.WerecommendthatyouleavetheTUNE controlinAuto
mode.
Ifyou do setthe TUNE control toManual,you willneed to adjust itabout10
minutesafteryou haveturnedonthe radar, sincetherequiredsettingchanges
oncethe magnetron has warmed up.
Youshouldadjust the controlto obtain themaximum signalstrength,as
indicated inthe 8-stepbarabovethe slider. If you cannottunethe radar
successfully, referto Section 7.6forinformationontheTunePresetfunction.
SEA
MANUAL
75%
D3968-1
TUNE
A
U
T
O
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