
4381295/B
SelectingNormalmodetostart"pinging"..............................................................55
SelectingReplaymode...........................................................................................56
SelectingInactivemode.........................................................................................57
SettinguptheSN90formaximumechorefreshrate.............................................58
Transmittingsinglepings.......................................................................................59
Transmittingwithxed-timeintervals...................................................................59
Adjustingtheoutputpowertomatchvaryingconditions......................................60
Selectingthebestoperatingfrequency...................................................................61
Controllingthegainandrangesettings...........................................................................63
Adjustingthegain(echosensitivity)......................................................................63
AdjustingtheTVG(TimeVariableGain)setting..................................................65
Adjustingthesonarrange.......................................................................................65
Adjustingtheintensityoftheechopresentations...................................................67
Changingthetilt.....................................................................................................67
Adjustingthebearing.............................................................................................69
Usingthemarkersandtrackingfeatures..........................................................................71
Startingapositiontrack..........................................................................................71
Startingatargettrack..............................................................................................72
Placinganewmarker.............................................................................................73
Deletingamarker...................................................................................................74
Measuringthesizeofaschoolrelativetothepurseseine.....................................75
Usingvisualaidsduringthepurseseinecatchphase.............................................75
Choosingtheshinggearinuse.............................................................................77
Changingtheshinggearpropertiestomatchyourownequipment.....................78
Improvingtherecognitionofshandschoolsusingreceiverlters...............................79
AboutthereceiverltersequenceintheSN90......................................................79
ReducingnoiseandreverberationwiththeAGC(AutomaticGainControl)
function..............................................................................................................80
ReducingpropellernoiseandinterferencewiththeNoiseFilter...........................81
ReducingbottomandsurfacereverberationwiththeRCG(Reverberation
ControlledGain)function..................................................................................82
ReducingnoiseandfalseechoeswiththePing-PingFilter...................................84
ReducingnoiseandreverberationwiththeAGC(AutomaticGainControl)
function..............................................................................................................85
Adjustingtheintensityoftheechopresentations...................................................86
Recordingandreplayingechodata..................................................................................87
Deningtheleandfoldersettingsfordatarecording..........................................87
Recordingechodata...............................................................................................88
SelectingReplaymode...........................................................................................89
Choosingwhichechodatale(s)toreplay............................................................90
Accessingtheechodatalestodelete,moveorcopythem..................................91
SimradSN90