Kongsberg cNODE Micro - General Acoustic Considerations

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Generalacoustic
considerations
Acousticrange
Thedepthratingshouldnotbeconfusedwithacousticrange.Theacousticrangeis
dependentonmanyfactors,andsomeofthefactorsareoutsidecontroloftheuser.
Vesselsystem
Thedirectivityandcoverageareaforthevesselsystemisdifferent,dependingonwhich
systemyouareusing.Somesystemshavehighdirectivityandomnidirectionalcoverage,
whileothersystemshasreducedcoverageandlessdirectivity.Thetranspondershould
alwaysbewithinthecoverageconeofthevesselsystem.
Transducertype
Therearedifferenttypesoftransducersusedonthetransponders.Anomnidirectional
transducer(suchasaTD180)coversalargearea,buthaslessacousticpower
comparedtoafocusedtransducer(e.g.TD50V).However,afocusedsignalgivesless
footprint/coverage.Thevesselshouldalwaysbewithinthesignalfootprintofthe
transponder.
TXpower
Theabilitytodetectsignalsdependsonthesignalstrength.Thetransmissionpowercan
beadjusted,bothforthevesselsystemandforthetransponder.
Acousticnoise
Acousticnoiseispresentatallvessels.Atgivenconditions,thenoiselevelcanbe
excessive.Acousticnoiseiscausedbymainpropellersandthrusters,andinsome
instancesalsofrommachinery/pumpsonboard.Heavypropeller/thrusteruseoralso
wavescanalsogenerateairbubbles,whichcangetinfrontofthevesseltransducerand
blocktheacousticsignal.
Generalacousticconsiderations