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337568/A

Thechallengeistondatiltthatpreventstheshechoestobe"buried"inreverberation

andbottomechoes.

•Ifyouuseahightiltvalue(A)theshareeasilydisguisedbybottomechoes.Astrong

RCG(ReverberationControlledGain)settingwillremovethebottomechoes.Asthe

distancefromthebottomtotheshincreases,theshechoesbecomeclearer.However,

thisassumesthattheshechoesareconsiderablystrongerthanthebottomechoes.

•Ifyouuseaverysmalltilt(C)youarenotbotheredbybottomechoes.However,ifthe

seasurfaceisgustyyouwillseeechoesfromthewaves.Theseechoesarenormally

ratherweak,andtheyhardlymoveinrelationtoyourvessel.

•Bymeansofamediumtiltangle(B)youareabletopickupscatteredshorschoolsif

thesearelocatedatsomedistanceabovethebottom.Theupperschoolintheillustration

appearsonthesonarpicturebeforethebottomecho,whilethelowerschoolwilleasily

bedisguisedbythebottomechoes.OnceagainyoucanactivatetheRCGfunctionto

improvethereading.

Tip

WiththevariousbeamsprovidedbytheST90,itmaybedifculttounderstandtheconcept.

Howdothesebeams"behave"inthewater?Bymeansofagraphicpresentation,theBeam

Visualizationdialogboxattemptstogiveyouabetterunderstandingofhowtheacoustic

beamsaretransmittedintothewater .OpentheBeamVisualizationdialogboxfromthe

Setupmenu.

Procedure

1Clickinanyviewtomakeitactive.

Theactiveviewisidentiedwithathickerborder.UnlessyouusetheApplytoall

function,allchangesyoumakewillonlybeappliedtothisview.

2InaVerticalview,clickonthetiltline,keepthemousebuttondepressed,anddrag

thelineupordown.

Optionally:

3ObservetheMainmenu.

ItsdefaultlocationisontherightsideoftheST90presentation.

4SelectTilt.

5Makethenecessaryadjustment.

Selecteithersideofthebuttontochooseavalue.Keepthemousebuttondepressedto

changethevaluefaster.

Gettingstarted

Simrad ST90 Quick Start Guide

Other manuals for Simrad ST90