Raymarine c97 - Dual Channel Ping Modes; The Sonar Image

15.8Dualchannelpingmodes
TheCP570sonarmodulefeatures2CHIRPsonar
channelsthatcantransmitandreceiveindependently
ofeachother.Pingmodesareavailablethatbalance
thepingrateVsinterferencebetweenthe2channels.
Pingmodes:
•Auto—Thesystemselectsthebestmodebased
onyourchosenrangesettings.
•Independentpings—Maximumpingrate,but
greaterchanceofinterference.
•Simultaneouspings—Reducedpingrate,
basedonthedeepestrangesetting,butreduced
chanceofinterference.
Note:Pingmodeswillonlybeavailablewhen
thesonarmoduleisconnectedtoa2channel
transducer.
Selectingapingmode
FromtheFishnderapplicationmenu:
1.SelectSet-up.
2.SelectSounderSet-up.
3.SelectDual-ChannelPingModes.
Thepingmodeselectionpageisdisplayed.
4.Selecttherequiredpingmode.
15.9Thesonarimage
Interpretingthebottomusingsonar
Itisimportanttounderstandhowtocorrectlyinterpret
thebottomstructurerepresentedon-screen.
Thebottomusuallyproducesastrongecho.
Thefollowingimagesshowhowdifferentbottom
conditionsarerepresentedon-screen:
D6855-3
1
2
3
ItemDescription
1
Ahardbottom(sand)producesathinline.
2
Asoftbottom(mudorseaweedcover)produces
awideline.
3Arockyorunevenbottomorawreckproduces
anirregularimagewithpeaksandtroughs.
Thedarklayersindicateagoodecho;thelighter
areasindicateweakerechoes.Thiscouldmeanthat
theupperlayerissoftandthereforeallowingsound
wavestopasstothemoresolidlayerbelow.
Itisalsopossiblethatthesoundwavesaremaking
twocompletetrips–hittingthebottom,bouncingoff
thevessel,thenreectingoffthebottomagain.This
canhappenifthewaterisshalloworthebottomis
hard.
Factorsinuencingthesonardisplay
Thequalityandaccuracyofthedisplaycanbe
inuencedbyanumberoffactorsincludingvessel
speed,depth,objectsize,backgroundnoiseand
transducerfrequency.
Vesselspeed
Theshapeofthetargetchangesalongwithyour
speed.Slowerspeedsreturnatter,morehorizontal
marks.Higherspeedscausethetargettothicken
andarchslightly,untilatfastspeedsthemark
resemblesadoubleverticalline.
Targetdepth
Thecloserthetargettothesurface,thelargerthe
markonscreen.
Waterdepth
Aswaterdepthincreasessignalstrengthdecreases,
resultinginalighteronscreenimageofthebottom.
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