Simrad ES80 User Manual

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406273/C
thicknessdependsonshipsspeedandontheroughnessofthehull.Allobjectssticking
outfromthehull,ordentsinthehull,willdisturbtheowandwillincreasethethickness
oftheboundarylayer.Whentheowspeedishigh,theturbulencecanbeviolentenough
todestroytheintegrityofthewater.Smallvoidsorcavitiesinthewaterwilloccurand
thisiscalledcavitation.
Rattlenoise
Rattlenoisemaybecausedbylooseobjectsinthevicinityofthetransducer,likexing
bolts.Therattlemayalsocomefromlooseobjectsinsidethehull.
Interference
Interferencefromotherhydroacousticequipmentonboardthesamevesselmaybean
annoyingsourceofdisturbance.Unlessthesamefrequencyisusedformorethanone
pieceofequipmentonlythetransmittedpulsewillcontributetotheinterference.
Inphysics,interferenceisthephenomenoninwhichtwowavessuperposeeach
othertoformaresultantwaveofgreaterorloweramplitude.Interferenceusually
referstotheinteractionofwavesthatarecorrelatedorcoherentwitheachother,
eitherbecausetheycomefromthesamesourceorbecausetheyhavethesameor
nearlythesamefrequency.Interferenceeffectscanbeobservedwithalltypesof
waves,forexample,light,radio,acoustic,surfacewaterwavesormatterwaves.
https://en.wikipedia.org/wiki/Interference_(wave_propagation),April2016
Relatedtopics
Acousticnoise,page462
BITE:Noisepage,page409
Ambientnoise
Ambientnoiseisusuallynotalimitingfactortotheperformanceofsonarsandecho
sounders.
Theambientnoisemaybesplitupasfollows:
•Seanoise:Airbubbles,seismicdisturbances,waves,boundaryturbulence,etc.
•Biologicalnoise:Fish,mammals
•Manmadenoise:Othervessels,interference
•Precipitationnoise:Heavyrainorhail
Insomeareas,wheremanyvesselsoperatetogether,theengineandpropellernoisefrom
othervesselsmaybedisturbing.Interferencefromhydroacousticinstrumentslocated
inothervesselsmayalsobealimitingfactor.Theseanoisedependsontheweather
conditions.Inbadweathertheseanoisecanbequitehighduetothewaves.
SimradES80ReferenceManual

Simrad ES80 Specifications

General

Operating Temperature	-15°C to +55°C
Type	Echosounder
Transceiver	External
Applications	Fisheries research, commercial fishing
Depth Range	Up to 3000 meters
Interface	Ethernet, NMEA 2000
Frequency Range	18 kHz, 38 kHz, 70 kHz, 120 kHz, 200 kHz, 333 kHz