Furuno CSH-84, CSH-83 manual Sea Surface Reflections, Wake

Page 85

Sea Surface Reflections

To reduce sea surface reflections, set the tilt angle to 5° or higher, so the upper edge of the sonar beam does not hit the sea surface, or adjust TVG. When a narrow tilt angle is used, sea surface reflections cover a large area as illustrated below.

Sea surface

Tilt angle

 

 

indication

15°

 

 

Sea surface

Sea surface

reflections

15°

 

Figure 11-3 Sea surface reflections

Wake

A wake produced by own ship or another ship can be a strong reflecting object when a narrow tilt angle is used. As the wake appears as a thick continuous line, it can be easily distinguished from a fish school. A wake contains many air bubbles which attenuate ultrasonic energy, making it difficult to sound beyond the wake.

Other ship

Own ship

Own ship's screw noise

Wake produced

 

by other ship

Own ship's wake

Own ship's

(produced when

screw noise

own ship turned)

Figure 11-4 Wake appearance on the display

11-3

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Contents Color Scanning Sonar 00080806600 Safety Instructions Do not use the equipment for other than its intended purpose Table of Contents PORT/STARBOARD, Horizontal Slice Displays Self Tests This page is intentionally left blank Foreword FeaturesWord to CSH-83/84 Owners Standard Option System ConfigurationControl Description Control Layout on Display Unit and Remote Control BoxMain panel control description Main PanelControl Function END Sub PanelSub Panel 2 data setting window AGC SignalProcess 2AGCSonar AlarmUP/TM Sonrbeam+ + Remote Control BoxAdjusting Screen Brilliance, Control Panel Backlighting Turning the Power On/OffOperational Overview Lowering the TransducerDisplay mode description Selecting a Display ModeSelecting a Display Range Setting the Tilt AngleSeabed echo and tilt angle Points to consider How to discriminate fish echoes from the seabedTilt angle and sea surface reflections Tilt angle for surface fishTilt angle and beam coverage Suitable tilt angleMeasuring Range and Bearing to a Target Adjusting the GainPage How to adjust TVG Fine Tuning the PictureEliminating Unwanted Feeble Echoes Page Pulselength data setting window TVGTX,PL AGC data setting window SIGNAL, Signal2AGC data setting window SIGNAL, Signal Process Suppressing Seabed TailRejecting Sonar Interference and Noise Data setting window TVGTX, OutputIdentifying noise source Cycle Changing Tx cycle data setting window TvgtxSetting Noise limiter data setting window Signal Adjusting BeamwidthNormal display mode Marks, Data and Display ModeMarks and Data Echo sounder combination display Normal display mode w/textHistory display Permanently Displayed Marks and DataMark/Data Description Erasable Marks and DataBearing marker Mark Description Range R Auto Tilt Auto Scan Gain Brill TVG TVG DIM Page User Menu Operation Menu OverviewUser Menu Hist DSP/GRPH Menu screen location and display modeUser Menu Description Save Picture Current VECFAR TVG System Menu DescriptionTM DSP Target LockMark Size BRG ReadoutMenu Description Color Curve Data SET Menu DescriptionChange Color Plan NET ShootNET Sonde NET Plot CorrInit SET/TEST Menu Description Echo Test DefaultsNET REC Others Event KEYProgramming the Function Keys Function KeysReplaying a Function Key Function Key Fine TuningReplaying Function Key Settings from a Memory Card Saving Function Key Settings to a Memory CardThis page is intentionally left blank Advanced Level Operation How to find fish school centerFinding Fish School Center Tracking a fish school Tracking a Fish School target lockTarget lock mark appearance Choosing target lock modeErasing target lock mark Target lock and tilt angle Tracking target lock markSystem Menu Target Lock Setting target lock conditionsDescription of target lock items Detecting Fish Schools Aurally How to set the fish alarm zone Fish AlarmRelocating Fish School for Easy Observation How to relocate fish schoolsEstimate marks and their data Comparing of Fish School ConcentrationMeasuring Fish School Speed How to measure fish speed10 Event marks Event MarkErasing an event mark Entering an event mark12 True motion display True Motion Display13 Net location mark Plotting Net Location Mark14 Net behavior Observing Net BehaviorNo. Display Information Applications Target Slice DisplayThis page is intentionally left blank Port/Starboard display PORT/STARBOARD, Horizontal Slice DisplaysHorizontal slice display Horizontal slice displayInitializing Memory Cards Memory Card OperationsTransferring Echo Data from Internal Memory to Memory Card Saving the PictureSaving Net Shooting Data Net shooting data contentsHow net shooting data is saved Transferring net shooting data to memory cardReplaying Saved Data Deleting Memory Card ContentsTurning MARKS, Data ON/OFF Turning marks on/off through the data setting windowTurning marks on/off through the user menu 10-2 Seabed Echoes Interpreting the DisplaySea surface fish Fish SchoolsWake Sea Surface ReflectionsNoise and Interference False Echo by SidelobeUnretracted Transducer Warning Overvoltage WarningHow to manually raise the transducer Opening the Self Test Menu Self TestsSingle test Self Test DescriptionContinuous test Color test Panel testSIO test Gray testInterface unit CS-120A, cover opened Interface Unit CS-120A Self Test13-6 Selection of Data at Interface Unit CS-120A Input Data SelectionHow to set net sonde transmitter distances Setting Distances Between Net Sonde TransmittersDisplay Unit Maintenance MaintenanceZinc block near the transducer must be replaced yearly Hull Unit MaintenanceUser Menu Menu TreeData SET Menu Init SET/TEST Menu System Menu Previous Page SP-1 SpecificationsSP-2 DisplaySP-3 Hull UnitSP-4 11-2 IndexIN-2
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