Simrad SU90 - Selecting Operating Frequency for Minimum Noise

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Selectingoperatingfrequencyforminimumnoise
TheFrequencyfunctionisusedtocontrolthecentrefrequencyoftheacoustic
transmissions(pings).Thecentrefrequencycanbechangedfrom20to30kHzinsteps
of1kHz.Alltypesofnoisematterwhenyouwishtondthebestoperatingfrequency.
Context
Alowerfrequencygivesyouabetterdetectionrangebecausetheattenuationlossis
smaller.Ahigherfrequencygivesyoubetterrangeresolution.Ahigherfrequencyalso
givesyounarrowerbeamsanda"sharper"image".
Noisefrominternalandexternalsourceshaveanimpactonthechoiceofoperating
frequency.Onespecicfrequencymayperformbetterthantheothersonyourvessel.
Tomeasurethenoiselevel,observethevaluepresentedontheNoisepageintheBITE
dialogbox.
Werecommendthatyoudothistesttwice.First,dothetestwithallotherhydroacoustic
systems(echosounders,ADCP ,sonars)turnedoff.Second,dothetestwithnormal
operatingconditions.Thisallowsyoutoseehowtheotherhydroacousticsystemsaffect
theSU90operation.
Procedure
1OntheMainmenu,selectUserSettings.
aSelectSU90FactoryDefault.
bSelectActivateSelectedSetting.
cSelectOKtoapplyyourchangesandclosetheUserSettingsdialogbox.
2OntheMainmenu,setRangeto1000m.
3OpentheOperationmenu.SetTxPowertoOff.
4OpentheActivemenu.SetPulseTypetoCWMedium.
5OpentheSetupmenu.
6SelectBITEtoopenthedialogbox.
aSelectNoisetoopenthepage.
bSelectStartNoiseMeasurements.
cOntheActivemenu,changetheFrequencysettingwhileobservingthenoise
value.
dNotefrequencieswithhighnoiselevels,andtrytoavoidusingthem.
Tip
Thefactorydefaultsettingsincludeoperatingfrequency.Ifyouapplythesesettings
remembertomaketheappropriatechangesafterwards.
Gettingstarted