Simrad ES80 - Fishing Gear Noise; Electrical Self Noise; Some Means to Reduce Acoustic Noise

406273/C
467
Relatedtopics
Acousticnoise,page462
BITE:Noisepage,page409
Fishinggearnoise
Wheneveryourshinggearisinuse,itwillcreatenoise.
Abottomtrawl,forinstance,isaconsiderablesourceofacousticnoise.Still,this
noisefromtheshinggearwillseldombealimitingfactorforhullmountedsonarsor
echosounders.However,foroperationofacatchmonitoringsystemoratrawlsonar,
withthetransducerplacedonthetrawl,thegearnoiseisoneofthemaincontributors
tothenoiselevel.
Relatedtopics
Acousticnoise,page462
BITE:Noisepage,page409
Electricalselfnoise
Electricalorelectronicselfnoiseispickeduporgeneratedinanyotherpartofthe
equipmentthanthetransducer.
Humpickedupbythetransducercablesorpickedupfromthepowersupplyisusually
themostcommonsourceofelectricalselfnoise.Athigherfrequencies–whererather
widebandwidthsarenecessary–thenoisefromcomponents,transistorsorother
analogueelectronicmaybealimitingfactor.
Relatedtopics
Acousticnoise,page462
BITE:Noisepage,page409
Somemeanstoreduceacousticnoise
Severalfactorsarecontributingtotheperformanceofthehydroacousticequipmentused
onboardavessel.CarefulplanningoftheES80installationmayreducetheacoustic
noise.
Unfortunately,itisimpossibletosimplyprovideanumberofspecicproceduresto
reducethenoise.
Animportantfactoristhephysicallocationofthetransducers.Thisdependsonthe
vessel'sdesignandconstruction,howthehullisshaped,andhowthewaterrunsalong
thehull.Otherfactorsdealwithotherequipmentmountedonboard,andthiswillalsobe
vesseldependant.Atmoderateshipspeedsthemachinerynoiseisusuallydominant.At
mediumspeedstheownoiseincreasesmorerapidlyandtakesover,whileathigher
speedthepropellernoisewillbethemaincontributor.
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