Simrad EK80 - Fishing Gear Noise; Electrical Noise; Some Means to Reduce Acoustic Noise

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•Precipitationnoise
Insomeareas,wheremanyvesselsareoperatingtogethertheengineandpropellernoise
fromothervesselsmightbedisturbing.
Interferencefromhydroacousticinstrumentslocatedinothervesselsmayalsobealimiting
factor.
Theseanoiseisascanbeexpecteddependentontheweatherconditions.Inbadweather
theseanoisecanbequitehigh.
Fishinggearnoise
Wheneveryourshinggearisinuse,itwillcreatenoise.
Abottomtrawl,forinstance,isaconsiderablenoisemaker.
Still,thisnoisewillseldombealimitingfactorforhullmountedsonarsorechosounders.
However,foroperationofacatchmonitoringsystemoratrawlsonar,withthetransducer(s)
placedonthetrawl,thegearnoiseisoneofthemaincontributorstothenoiselevel.
Electricalnoise
Electricalorelectronicnoiseispickeduporgeneratedinanyotherpartoftheequipment
thanthetransducer.
Humpickedupbythetransducercablesorpickedupfromthevoltagesupplyisusuallythe
mostcommonsourceofelectricalnoise.
Athigherfrequencies–whereratherwidebandwidthsarenecessary–thenoisefrom
components,transistorsorotheranalogueelectronicmaybealimitingfactor.
Somemeanstoreduceacousticnoise
CarefulplanningoftheEK80installationmayreducetheacousticnoise.
Unfortunately,itisimpossibletosimplyprovideanumberofspecicprocedurestoreduce
thenoise.
Animportantfactoristhephysicallocationofthetransducer.Thisdependsonthevessel's
designandconstruction,howthehullisshaped,andhowthewaterrunsalongthehull.
Otherfactorsdealwithotherequipmentmountedonboard,andthiswillalsobevessel
dependant.
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