Installation manual

Table Of Contents
SimradSH90
Theechoesfromthebottomwillvarywithhowuneventhe
bottomis,whatkindofbottomyouhaveunderyourvessel,
(rock,mud,sandetc.)aswellasyourcurrenttiltsetting.The
echofromtheseasurfacewillvarywiththecurrentseastateand
yourcurrenttiltsetting.
Theillustrationdemonstrateshowthebottomandtheseasurface
returnechoesbacktoyoursonartransducer.Insituation(A)you
willseeseveralweakechoesfromthewavesandfromtherockon
thebottom,youwillstillbeabletoidentifytheschoolofsh.In
situation(B)youwillbeabletoidentifytheupperschoolofsh,
butthelowerschoolwillbehiddenintheshadowoftherock.
Beawareofthatothervesselsclosetoyouwillalsogenerate
reverberationduetothewaterdisturbancecausedbythewake,
thepropellersandthecoolingwaterspill.
Blocking
Themovementofyourvesselthroughthewaterwilloften
especiallyinhigherseastatescauseairbubblestobegenerated,
andthesebubbleswillmovealongthehull.Thisiscalled
blocking.Inordertopreventthisnoisefromdisturbingyour
sonaroperations,itisimportanttolowerthesonartransduceras
fardownbelowthehullaspossible.
Checkthenoiseyourself!
Ifyouarebotheredwithacousticorelectricnoise,youcaneasily
runafewsimpleteststoidentifythecauseoftheproblem.
Howtochecktheacousticnoise
Thisprocedureprovidesasimplemethodtochecktheacoustic
noise.
1ClicktheSetuptabtoopenthemenu.
2ClicktheTestbuttontoopentheSystemtestmenu.
3ClicktheTestcongbutton,andselectNoiseandVRinthe
parameterdialog.
4ClicktheClosebuttonintheparameterdialogtocloseit.
5ObservetheEcholevelbuttonontheSystemtestmenu.
6Readthenoiselevel.
Thelevelyourreadinthebuttonisthecurrentnoiseinthe
directionofthecursor.ThenoiseisprovidedindB,andthe
numbershouldbeassmallaspossible.
Inordertoreducethenoise,trytoadjustthepropellerpitch
andthenumberofrevolutions.
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