Raymarine E90W - Page 166

offtheseabedagain.Thiscanhappenifthewaterisshallow,the
seabedishard,orthegainissethigh.
Factorsinuencingthesonardisplay
Thequalityandaccuracyofthedisplaycanbeinuencedbya
numberoffactorsincludingvesselspeed,depth,objectsize,
backgroundnoiseandtransducerfrequency.
Vesselspeed
Theshapeofthetargetchangesalongwithyourspeed.Slower
speedsreturnatter,morehorizontalmarks.Higherspeedscause
thetargettothickenandarchslightly,untilatfastspeedsthemark
resemblesadoubleverticalline.
Targetdepth
Thecloserthetargettothesurface,thelargerthemarkonscreen.
Note:Thedepthofindividualtargetscanbedisplayedby
switchingontheTargetDepthIDintheshndersetupmenu.
Thenumberoftargetdepthsdisplayedisinuencedbythesh
alarmsensitivitylevel.
Waterdepth
Asseadepthincreasessignalstrengthdecreases,resultingina
lighteron-screenimageofthebottom.
Sizeofthetarget
Thelargerthetarget,thelargerthereturnontheshnderdisplay.
Thesizeofashtargetisalsodependentuponthesizeofthesh’s
swimbladderratherthanitsoverallsize.Theswimbladdervariesin
sizebetweendifferentbreedsofsh.
Transducerfrequency
Thesametargetwillappeardifferentlywhenthetransducer
frequencyischanged.Thelowerthefrequencythebroaderthe
mark.
Clutter/Backgroundnoise
Theshnderpicturemaybeimpairedbyechoesreceivedfrom
oatingorsubmergeddebris,airbubblesoreventheboats
166E-SeriesWidescreenUserreference