False echo by sidelobe, Noise and interference | Furuno FSV-84

4. SLANT MODE

4.22.5False 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.

Bottom

4.22.6Noise and interference

Interference from a sonar on another ship appears on the screen as shown in

(A). (B) shows Interference from electrical equipment on board own ship. Noise from marine life appears on the display as shown in (C).

4-47

Image 157

Furuno FSV-84 manual False echo by sidelobe, Noise and interference

Contents

Color Scanning Sonar 00015742711 Important Notices Safety Instructions Replace anticorrosion zinc plate yearly Iii This page intentionally left blank Table of Contents Safety Instructions Vii Table of Contents Viii NUMERIC/GRAPHIC Data Display MAINTENANCE, Troubleshooting Foreword FeaturesWord to the Owner of the Furuno FSV-84 Xii Blackbox type configuration System ConfigurationSystem with locally supplied monitor Xiii System with Furuno monitor Standard type configurationXiv Control Description Operational OverviewControl unit Turning the power on Turning the Power On/OffTurning the power off Power & Transducer controls Screen Brilliance Lowering, Raising the TransducerLowering the transducer Raising the transducer Control Panel Dimmer Main menu defaultOthers menu Dialog box for setting numeric value Display Setting menu Mode selection menus Selecting a display modeDisplay Mode, Display Division Horizontal mode Sample display mode picturesHorizontal mode display Horizontal 2 display H2 mode Slant display single Slant mode, single displaySlant mode, combination display Slant display combination V1 and V2 modes V1 + ES1 or ES2 modeV1 and V2 displays V1 & ES1 ES2 display ES1 mode History modeHistory display ES1 display ES1 + ES2 mode ES2 modeES2 display shown downward picture ES1 + ES2 display Adjusting the Gain Main menu Menu Overview Menu Title Scan Setting menu Echo sounder picture advance speed dialog box YES This page intentionally left blank Basic Operating Procedure Horizontal Mode Horizontal mode indications and marks Horizontal modeIndications and Marks Horizontal2 mode Dialog box for setting combination Landscape Left Inset Range concept Display Range Tilt Angle Setting the tilt angle Automatic tilt range narrow with Auto Tilt key Automatic tiltAutomatic tilt range wide with Auto Tilt key Auto tilt concept Case 1 Tilt angle 30 to Relation between bottom echo and tilt angleCase 2 Tilt angle 10 to Case 3 Tilt angle 0 to Tilt angle Tilt angle for surface fish Tilt angle and beam coverage Suitable tilt angle Location of trackball data Measuring Range and Bearing to a Target Principle of TVG Eliminating Weak Echoes Numeric data entry dialog box Suppressing Bottom Tail Adjust AGC Decrease pulse length Adjust 2nd AGC Adjust Near AGC Fish echo Identifying noise source Rejecting Sonar Interference and NoiseInterference rejector Shifting Tx frequency Changing Tx intervalHow TX Interval works Noise limiter Setting reference bearing for frequency changeEcho average Reverberation reduction Sidelobe suppression Adjusting Beamwidth Selecting target lock type Tracking a Fish School target lockTarget Lock menu Target lock type dialog box Target lock mark and target lock data Fish school tracking mode How position tracking mode target lock works Position tracking mode Target Lock menu Selecting direction Detecting Fish Schools AurallyRange and audio bearing marks Selecting audio sector Alarm & Audio menuAudio sector dialog box Reverberation Automatic trainingIndications related to automatic training Presentation mode description Presentation ModePresentation modes Automatic return of own ship mark in true motion Display Setup menu How to select a presentation modePresentation mode dialog box Fish alarm status dialog box Fish Alarm How to create desired alarm zone How to set the fish alarm zone Relocating Fish School for Easy Observation How to use offcenter Estimate marks and their data Comparing Fish School Concentration Measuring Fish School Speed How to measure fish school speedEntering fish marks Fish mark Deleting fish marksDeleting fish marks with the Delete Mark key Deleting fish marks through the menu Entering an event mark Event Mark, Own Ship Position MarkEvent mark data Deleting an event mark, own ship position mark Entering an own ship position markEvent mark description Deleting event marks, own ship position mark from the menu Inscribing the net course mark Net Course MarkNet course mark Net behavior Observing Net Behavior Storing, Recalling Picture PRESET, Memory Card menuStoring the picture Recalling stored picture Displaying the Others menu Others Menu Others menu description Color Setting menu Color response curve TVG setting window Bottom echoes Interpreting the Horizontal DisplayBottom echoes Fish schools Fish schools Wake Sea surface reflectionsSea surface reflections Wake Noise and interference Sidelobe echoes false echoesNoise and interference Vertical Mode Setting the vertical display Vertical Mode ConceptVertical mode concept Overview Typical vertical display Vertical Mode Indications and MarksVertical 1 display indications and markers Solid Line Dashed Line Vertical bearing mark, tilt markVertical scan and horizontal scan ranges Trackball mark position reference mark Auto TrainAuto train Measuring range with the trackball Measuring the Range Select V-SCAN Setting and press the Menu key TVG setting dialog box Vertical Mode Suppressing Bottom Tail Adjust 2nd AGC Rejecting Interference and Noise Noise limiter Suppressing sidelobes Dialog box Vertical 1 expansion display Vertical Expansion Display Gain Control Wide Beamwidth Others menu description Setting window Display size Searching Application to Bonito and Tuna FishingTracking Approaching Catching Catching Slant Mode Sensor Slant mode single display Slant mode combination display Dialog box for setting slant combination display H1 display Slant display NUMERIC/ Graphic Data Display Display Range Tilt Angle Automatic tilt Auto tilt concept Auto Training Eliminating Weak Echoes Scan Setting menu Suppressing Bottom Tail Decrease pulse length Adjust Near AGC Fish echo Rejecting Sonar Interference and Noise Changing Tx interval Noise limiter Adjusting Beamwidth Tracking a Fish School target lock Fish school tracking mode Position tracking mode Target Lock menu Detecting Fish Schools Aurally Selecting audio sector Manual offcenter Offcenter Automatic offcenter Fish Alarm How to set the fish alarm zone Numeric Measuring Fish School Speed Deleting fish marks Event Mark, Own Ship Position Mark Entering an own ship position mark Erase Marks menu Net Course Mark 21˚ Others sub menu Others menu description Scan Color TVG setting window Interpreting the Slant Display Bottom fish school Surface fish school Sea surface reflections False echo by sidelobe This page intentionally left blank Echo Sounder Mode Echo sounder 1 display Typical Echo Sounder DisplaysIndications and markers on the echo sounder 1 display Trackball mark position reference mark Downward-looking net recorder display Echo sounder 2 net recorder or echo sounder display Echo sounder + net recorder display Echo sounder combination mode ES1 + ES2Echo sounder combination display Echo Sounder 2 display Upward + downward looking display Upward + downward looking net recorder display ES2 mode Enabling an echo sounder mode Selecting an Echo Sounder ModeDisplay mode dialog box Echo sounder mode configurations and menu setting System menu setting and available displays Selecting Display Range ES1 SETTING, ES2 Setting menusRange and display shift concept Range dialog box Dialog box for setting numeric data ES1 Setting and ES2 Setting menus Picture advance speed dialog box Picture Advance Speed Measuring Depth, Distance Estimating fish concentration with estimate marks Fish histogram Fish histogram ES1 Setting menu ES1 Setting Menu OverviewES1 setting menu description ES2 Setting menu net recorder connected 10 ES2 Setting Menu OverviewES2 Setting menu description History Mode Sample History Display History mode concept How to interpret the history display How to Interpret, Set the History DisplayInterpreting the history display Slant range and tilt angle Setting the history marker Horizontal slice width dialog box Setting the width of the history marker Setting the picture advance mode Full Numeric/Graphic Data Display NUMERIC/GRAPHIC Data DisplayFull Numeric/graphic data display Abbreviated Numeric/graphic display Abbreviated Numeric/Graphic Data Display Numeric/graphic data description Numeric/Graphic Data DescriptionOn next Numeric/graphic data description con’t. from previous User Menu Customizing the EquipmentDeleting items from user menu Main menu user menu Programming the user menu Message for registration of user menu item Function Keys F1-F6 Example default function programsExecuting a function Function dialog box for storing picture Dialog box for adjustment of panel dimmer Dialog box for selection of presentation modeFunction dialog box for recalling picture Function dialog box for erasing fish marks Dialog box for erase ship track Programming function keysConfirmation for registering function key Function key dialog box Erasing programs Selecting a user program User Prog ControlProgramming the User Prog control User program options This page intentionally left blank Erase Marks menu Others Menu Opening the Display Setting menu Display Setting menuDisplay Setting menu description Display Settng menu Tilt Opening the Alarm & Audio menu Alarm & Audio menuAlarm & Audio menu description Opening the PRESET, Memory Card menu PRESET, Memory Card menuPRESET, Memory Card menu description Opening the Initial Setting menu Initial Setting menuInitial Setting menu description Mark Display menu Range rings Heading markBearing scale Net movement plot Data on ship’s trackFish marks connected with line Mark Size menu Target lock markMark Size menu Others Menu Data Display menu Data Display menu Current VEC & Wind menu Current flow direction settingsCurrent VEC & Wind menu Xmtr Distance setting window NET Sonde Setting menuNET Sonde Settng menu NET Shoot Setting menu NET Shoot Setting menuDepth Display menu Stabilization menu Stabilization menuTest menu Initialization menu Initialization menuTime offset dialog box Memory Card Operations Storing Image, Configuration10-1 Processor unit Memory Card menu 10-2 10-3 Loading, Deleting FilesMemory Card menu, recall, delete dialog box opened 10-4 Formatting Memory Cards Preventive Maintenance MAINTENANCE, TroubleshootingCleaning the equipment 11-1 Hull unit maintenance Hull Unit Maintenance11-2 11-3 Fuse ReplacementUnit and fuse Unit Fuse rating Troubleshooting TroubleshootingSymptom Check, Remedy 11-4 Message Meaning, Remedy Power supply Error messages11-5 Transducer Error messages con’t from previous Error CodesError code 11-6 Tests Status MessagesTest menu 11-7 11-8 Board testBoard test results Interpreting the board test results 11-9 11-10 Panel testPanel test Trackball check Lever check 11-11 Test patternTest patterns Noise test For service technician Rx test For service technician11-12 Rx test sequence, Rx test message Raising the transducer automatically Raising the Transducer from the Hull Unit11-13 Raise/lower control box, cover removed 11-14 Raising the transducer manually AP-1 Menu Tree Appendix AP-2 Xmtr Distance AP-3 Tilt Interlock OFF, on AP-4 FSV-84 Specifications of the Color Scanning Sonar Transceiver Unit Power Supply IN-1 Index Indications IN-2 OFF Center key Offcentering IN-3 IN-4 Vertical mode Smoothing V1/S, V2 keys IN-5