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Furuno CSH-53 manual False Echo by Sidelobe, Noise and Interference, 5 Sidelobe echoes

Models: CSH-53

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False Echo by Sidelobe

False Echo by Sidelobe

An ultrasonic wave is emitted only in the direction set by the TILT lever, however there are some emissions outside the main beam. These are called sidelobes. The energy of the sidelobe is fairly weak but when the water is comparatively shallow and the bottom is rocky and hard, strong signals are detected by the sidelobe. These are represented on the display as a false echo as shown below.

		Mainlobe
Sidelobe	Sidelobe	echo
	Sidelobe
		Sidelobe
		echo

The seabed echo detected by sidelobe appears at a certain tilt angle when the sidelobe points vertically.

Figure 11-5 Sidelobe echoes

Noise and Interference

Interference from a sonar on board another ship appears on the screen as shown in (A) below. This interference can be suppressed by changing the CYCLE setting in TVG•TX on the data setting window. Interference from electrical equipment on board own ship appears as shown in (B) below. Noise from marine life ap- pears on the display as shown in (C). Electrical interference and marine life noise can be suppressed with IR on the SIGNAL menu in the data setting window.

(A) Interference from	(B) Electrical	(C) Marine life noise
other sonar	interference

Figure 11-6 Noise and interference

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Furuno CSH-53 manual False Echo by Sidelobe, Noise and Interference, 5 Sidelobe echoes, 6 Noise and interference

Contents

COLOR SCANNING SONAR MODEL CSH-5300080807301 00080807301 OME13070E00 OME13070E00Pub. No. OME-13070 DAMI CSH-53SAFETY INSTRUCTIONS Do not open the equipmentDo not disassemble or modify the equipment Do not place liquid-filled containers on the top of the equipmentTABLE OF CONTENTS SYSTEM CONFIGURATIONFINE TUNING THE PICTURE FOREWORDFUNCTION KEYS ADVANCED LEVEL OPERATIONPORT/STARBOARD, HORIZONTAL SLICE DISPLAYS SAVING, REPLAYING PICTUREMAINTENANCE WARNINGSSELF TESTS INPUT DATA SELECTIONFeatures FOREWORDA Word to CSH-53 Owners System Configuration STANDARDOPTION Control Layout on Display Unit, Processor Unit and Remote Control Box CONTROL DESCRIPTIONFigure 1-1 Display unit, processor unit and remote control box Same as Sub-panelMain Panel Figure 1-2 Main panelMain panel control description ControlControl FunctionSub Panel Figure 1-3 Sub panel Sub panel 1 control descriptionControl FunctionSub Panel 2 data setting window 7 8+ + + + + +Continued on next page SettingSetting MainSetting SettingMain DescriptionRemote Control Box Figure 1-5 Remote control boxTurning the Power On/Off Adjusting Screen Brilliance, Control Panel BacklightingTurning the power on Turning the power offSelecting a Display Mode Table 2-1 Display mode descriptionMode DescriptionSetting the Tilt Angle Selecting a Display RangeSeabed echo and tilt angle How to discriminate fish echoes from the seabed Figure 2-1 Fish echo and tilt anglePoints to consider Tilt angle for surface fish Figure 2-2 Tilt angle and sea surface reflectionsSuitable tilt angle Figure 2-3 Tilt angle and beam coverageAdjusting the Gain Figure 2-4 Gain settings and resulting pictureMeasuring Range and Bearing to a Target Figure 2-5 Location of range and bearing indicationsThis page is intentionally left blank FINE TUNING THE PICTURE How to adjust TVGEliminating Unwanted Feeble Echoes Figure 3-1 Principle of TVG4. When sea surface reflections or plankton layers disturb the picture, decrease appropriate TVG option by one or two steps by pressing - minus key AGC data setting window SIGNAL, SIGNAL PROCESS Pulselength data setting window TVG TX, PL2AGC data setting window SIGNAL, SIGNAL PROCESS Suppressing Seabed TailData setting window TVGTX, OUTPUT Suppressing Seabed and Sea Surface Reflections in Shallow WatersRejecting Sonar Interference and Noise Identifying noise sourceInterference rejector data setting window SIGNAL, SIGNAL PROCESS Changing Tx cycle data setting window TVGTX CYCLEFigure 3-3 How CYCLE works Setting F-shift data setting window SONRBEAM SONAR Noise limiter data setting window SIGNAL, SIGNAL PROCESSMarks, Data and Display Mode Normal display modeFigure 4-1 Marks and data appearing in the normal display mode MARKS AND DATANormal display mode w/text Figure 4-2 Marks and data appearing in the normal display mode w/textFigure 4-3 Marks and data appearing in the echo sounder display mode Echo sounder combination displayFigure 4-4 Marks and data appearing in the history display mode Permanently Displayed Marks and DataHistory display Continued on next pageErasable Marks and Data Continued on next pageMark/Data DescriptionContinued on next page Mark/DataDescription Latest Fish MarkContinued on next page MarkDescription Estimate markMark Description10 pts. max This page is intentionally left blank MENU OVERVIEW USER Menu OperationFigure 5-1 USER menu Menu screen location and display mode Figure 5-3 Menu screen location and display modeFigure 5-2 HIST DSP/GRPH menu USER Menu Description Table 5-1 User menu descriptionContinued on next page MenuMenu Menu ItemDescription SYSTEM Menu Description The SYSTEM menu can be displayed by pressing MENU + cContinued on next page MenuContinued on next page MenuDescription Menu DescriptionDATA SET Menu Description Color curve setting is completedTo cancel change and close the menu, press END key Continued on next pageColor curve setting is completed To cancel change and close the menu, press END keyContinued on next page DescriptionMenu Description5-10 INIT SET/TEST Menu Description Continued on next pageMenu Description5-12 MenuDescription FUNCTION KEYS Programming the Function KeysFigure 6-1 FUNCTION KEY menu Function Key Fine Tuning Replaying a Function KeyFigure 6-2 REGISTER menu Saving Function Key Settings to a Memory Card Replaying Function Key Settings from a Memory CardFigure 6-2 CARD UTILITY menu This page is intentionally left blank Figure 7-1 Tilt angle setting How to find fish school centerADVANCED LEVEL OPERATION Finding Fish School CenterTracking a Fish School target lock Tracking a fish schoolFigure 7-2 Target lock mark and target lock data Choosing target lock mode Target lock mark appearanceFigure 7-3 Target lock mark appearance Erasing target lock markTracking target lock mark Figure 7-4 Target lock and tilt angleSetting target lock conditions Figure 7-5 Target lock menuDescription of target lock items Detecting Fish Schools Aurally The Fish Alarm Figure 7-6 How to set the fish alarm zoneFigure 7-7 How to relocate fish schools Relocating Fish School for Easy ObservationComparing of Fish School Concentration Figure 7-8 Estimate marks and their dataFigure 7-9 How to measure fish speed Measuring Fish School SpeedThe Event Mark Figure 7-10 Event marksEntering an event mark Figure 7-11 Event mark descriptionErasing an event mark True Motion Display Figure 7-12 True motion displayPlotting Net Location Mark Figure 7-13 Net location markObserving Net Behavior Figure 7-14 Net behaviorBoosting Tx Power Reducing Sea Surface ReflectionsThis page is intentionally left blank Port/Starboard display Figure 8-1 Port/starboard displayPORT/STARBOARD, HORIZONTAL SLICE DISPLAYS Horizontal slice display Figure 8-2 Horizontal slice displaySAVING, REPLAYING PICTURE Initializing Memory CardsSaving the Picture Transferring Echo Data from Internal Memory to Memory CardNet shooting data contents Saving Net Shooting DataHow net shooting data is saved Transferring net shooting data to memory cardDeleting Memory Card Contents Replaying Saved DataWhole picture or echo inside estimate mark Net shooting dataTurning marks on/off through the data setting window TURNING MARKS, DATA ON/OFFTurning marks on/off through the user menu 10-1This page is intentionally left blank INTERPRETING THE DISPLAY Seabed EchoesFigure 11-1 Seabed echoes Fish Schools Figure 11-2 Fish schoolsSea Surface Reflections WakeFigure 11-3 Sea surface reflections Figure 11-4 Wake appearance on the displayFalse Echo by Sidelobe Noise and InterferenceFigure 11-5 Sidelobe echoes Figure 11-6 Noise and interferenceWARNINGS Overvoltage WarningUnretracted Transducer Warning Figure 12-1 Raise/Lower Control Box of the Hull Unit 12-2SELF TESTS DANGEROpening the Self Test Menu 13-1Self Test Description Single testFigure 13-2 Single test Continuous testPanel test Figure 13-4 Panel testColor test Figure 13-5 Color testGray test Figure 13-6 Gray testSIO test Figure 13-7 SIO testInterface Unit CS-120A Self Test Figure 13-8 Interface unit CS-120A, cover openedThis page is intentionally left blank Figure 14-1 DIP switch settings in the interface unit INPUT DATA SELECTIONSelection of Data on Interface Unit CS-120A 14-1Setting Distances Between Net Sonde Transmitters Figure 14-2 How to measure distances between transmittersHow to set net sonde transmitter distances Figure 14-3 Data set menuMAINTENANCE Display Unit Maintenance15-1 Figure 15-1 Display Unit MmaintenanceHull Unit Maintenance Figure 15-2 Hull Unit Maintenance15-2 Replacement of Fuse, Memory Card Battery Fuse replacement15-3 How to ReplaceMemory card battery replacement 15-4How to replace the battery in the memory card MENU TREE USER MenuDATA SET Menu INIT SET/TEST Menu SYSTEM Menu Continued on next pageprevious page Continued fromThis page is intentionally left blank SPECIFICATIONS 1. GENERALSP-1 2. DISPLAY SP-24. POWER CONSUMPTION 3. HULL UNIT5. ENVIRONMENTAL CONDITION 6. COATING COLORINDEX