Raymarine c97 - Radar Display Overview

BlindSectors
Obstructionssuchasfunnelsandmastsneartheradarantenna
mayobstructtheradarbeamandcauseradarshadowsor‘blind
sectors’.Iftheobstructionisrelativelynarrow,therewillbea
reductionofthebeamintensity,thoughnotnecessarilyacomplete
cut-off.However,forwiderobstructionstheremaybeatotallossof
signalintheshadowarea.Theremayalsobemultipleechoeswhich
extendbehindtheobstruction.Blindsectoreffectscannormallybe
minimizedbycarefulselectionofthescannersitepriortoinstallation.
SeaClutter
Radarreturnsfromwavesaroundthevesselcanclutterthecentre
oftheradarpicture,makingitdifculttodetectrealtargets.Such
‘seaclutter’usuallyappearsasmultipleechoesonthedisplayat
shortrangescales,andtheechoesarenotrepetitiveorconsistent
inposition.Withhighwindsandextremeconditions,echoesfrom
seacluttermaycausedensebackgroundclutterintheshapeof
analmostsoliddisc.
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RainorSnowClutter
Theradarcanseeechoesfromrainorsnow.Returnsfromstorm
areasandrainsquallsconsistofcountlesssmallechoesthat
continuouslychangesize,intensityandposition.Thesereturns
sometimesappearaslargehazyareas,dependingontheintensity
oftherainfallorsnowinthestormcell.
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Interference
Whentwoormoreradar-equippedvesselsareoperatingwithin
rangeofeachothermutualradarinterferencecanoccur.This
usuallyappearsasaspiralofsmalldotsfromthedisplaycentreThis
typeofinterferenceismostnoticeableatlongranges.
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12.5Radardisplayoverview
Withyourradarscannerconnectedandtheradarintransmitmode,
theradarpictureprovidesamap-likerepresentationofthearea
inwhichtheradarisoperating.
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ItemDescription
1Range
2Waypoint
3Datacell
4Databar
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Rangering
6Target
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Orientation
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Ship’sHeadingMarker(SHM)
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Ship’sposition
10Motionmode
11Radarscannerstatus
12Rangeringspacing
Additionalfunctionalityoftheradarapplicationincludes:
•Colorpalettes.
•AddingAISoverlay.
•MARPAtargets.
Typically,yourvessel’spositionisatthecenterofthedisplay,and
itsdeadaheadbearingisindicatedbyaverticalheadingline,known
astheShip’sHeadingMarker(SHM).
Note:IfthecursorisplacedovertheSHM,theSHMwill
temporarilyberemovedtohelpplacingmarkersoracquiring
targetsetc.
On-screentargetsmaybelarge,small,brightorfaint,dependingon
thesizeoftheobject,itsorientationandsurface.Ifusinganon-HD
digitalradomescanner,strongesttargetreturnsaredisplayedin
yellowwithweakerreturnsin2shadesofblue.IfusinganHDor
SuperHDdigitalradarscanner,strongertargetreturnsshowas
differentcolorsfromarangeof256colors,providingbetterclarity.
Beawarethatthesizeofatargetonscreenisdependentonmany
factorsandmaynotnecessarilybeproportionaltoitsphysicalsize.
Nearbyobjectsmayappeartobethesamesizeasdistantlarger
objects.
Note:Colorsstatedaboverefertothedefaultcolorpalette.
Withexperience,theapproximatesizeofdifferentobjectscanbe
determinedbytherelativesizeandbrightnessoftheechoes.
Youshouldbearinmindthatthesizeofeachon-screentargetis
affectedby:
•Thephysicalsizeofthereectingobject.
•Thematerialfromwhichtheobjectismade.Metallicsurfaces
reectsignalsbetterthannon-metallicsurfaces.
Usingradar
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