Simrad SU90 - Page 32

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381291/C
see.However,sinceyoualsoincreasetheacousticnoiseinthereception,theSU90
presentationswillalsoshowthisnoise.Toomuchgainmaytherefore"distort"the
presentation.
Comparingthegainfunctionwiththevolumecontrolonyourcarradioisnotvery
accurate.Infact,thegainintheSU90isconstant.TheGainfunctionisusedtoadjust
thesensitivity
.Thisdonebycontrollingtheminimumlevelofdetection.Whenyou
increasethegainlevel(morepositivenumber),youreducetheminimumlevel,andthus
increasethesensitivity.
Theechostrength(A)changeswithtime.Theminimumlevelofdetection(B)isadjusted
upordownwiththeGainfunction.IncreasingtheGainwithamorepositivenumber
reducestheminimumlevel,andthisincreasesthesensitivity.Onlyechoesoverthe
minimumlevelareshownintheechogram(C).
DonotconfusethisGainsettingwiththeTVG(TimeV ariedGain)setting.
Tip
Duringnormaloperatingconditionswerecommendthatyoukeepthegainbetween15
and30.Ifyouneedtoadjustthegain"fromscratch"disableAGC(AutomaticGain
Control)andRCG(ReverberationControlledGain)toseetheimmediateeffectofthe
gainadjustments.Whileyouadjustthegainyoumaynditusefultohaveaknown
target(forexampleanisland)asreference.
Procedure
1Clickintheviewyouwanttoactivate.
Theactiveviewisidentiedwithathickerborder.UnlessyouusetheApplytoall
function,allchangesyoumakewillonlybeappliedtothisview.
2Turntherelevantrotaryswitchtomaketheadjustment.
Tip
TheOperatingPanelisttedwiththreerotaryswitches.Theswitchesareidentied
withnumbers.Eachswitchcanbeassignedafunctionrelatedtorange,gainor
bearing.InvestigatethefunctionalityprovidedontheOperatingPanelpage.This
pageislocatedintheInstallationdialogbox.
SimradSU90OperatorManual