Sea surface reflections, Wake | Furuno FSV-84 specification

2. HORIZONTAL MODE

2.23.3Sea 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 decreased tilt angle is used, sea surface reflections cover a large area as illustrated below.

	Sea surface	Tilt angle
		Tilt angle
		indication
Tilt: 0°	18°
		Sea surface
	Sea surface	reflections
Tilt: 8°-9°	18°
	18°

Sea surface reflections

2.23.4Wake

A wake produced by own ship or another ship can be a strong reflecting object when a decreased 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	Own ship's wake
	Own ship's	(produced when
	screw noise	own ship turned)

Wake

2-53

Image 87

Furuno FSV-84 manual Sea surface reflections, Wake

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 Features ForewordWord to the Owner of the Furuno FSV-84 Xii Xiii System ConfigurationBlackbox type configuration System with locally supplied monitor Standard type configuration System with Furuno monitorXiv Operational Overview Control DescriptionControl unit Power & Transducer controls Turning the Power On/OffTurning the power on Turning the power off Raising the transducer Lowering, Raising the TransducerScreen Brilliance Lowering the transducer Main menu default Control Panel DimmerOthers menu Dialog box for setting numeric value Display Setting menu Selecting a display mode Mode selection menusDisplay Mode, Display Division Sample display mode pictures Horizontal modeHorizontal mode display Horizontal 2 display H2 mode Slant display combination Slant mode, single displaySlant display single Slant mode, combination display V1 & ES1 ES2 display V1 + ES1 or ES2 modeV1 and V2 modes V1 and V2 displays ES1 display History modeES1 mode History display ES1 + ES2 display ES2 modeES1 + ES2 mode ES2 display shown downward picture 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 Horizontal mode indications and marksIndications and Marks Horizontal2 mode Dialog box for setting combination Landscape Left Inset Range concept Display Range Tilt Angle Setting the tilt angle Automatic tilt Automatic tilt range narrow with Auto Tilt keyAutomatic tilt range wide with Auto Tilt key Auto tilt concept Case 3 Tilt angle 0 to Relation between bottom echo and tilt angleCase 1 Tilt angle 30 to Case 2 Tilt angle 10 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 Rejecting Sonar Interference and Noise Identifying noise sourceInterference rejector Changing Tx interval Shifting Tx frequencyHow TX Interval works Reverberation reduction Setting reference bearing for frequency changeNoise limiter Echo average Sidelobe suppression Adjusting Beamwidth Target lock type dialog box Tracking a Fish School target lockSelecting target lock type Target Lock menu Target lock mark and target lock data Fish school tracking mode How position tracking mode target lock works Position tracking mode Target Lock menu Detecting Fish Schools Aurally Selecting directionRange and audio bearing marks Alarm & Audio menu Selecting audio sectorAudio sector dialog box Automatic training ReverberationIndications related to automatic training Automatic return of own ship mark in true motion Presentation ModePresentation mode description Presentation modes How to select a presentation mode Display Setup menuPresentation 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 How to measure fish school speed Measuring Fish School SpeedEntering fish marks Deleting fish marks through the menu Deleting fish marksFish mark Deleting fish marks with the Delete Mark key Event Mark, Own Ship Position Mark Entering an event markEvent mark data Entering an own ship position mark Deleting an event mark, own ship position markEvent mark description Deleting event marks, own ship position mark from the menu Net Course Mark Inscribing the net course markNet course mark Net behavior Observing Net Behavior Recalling stored picture PRESET, Memory Card menuStoring, Recalling Picture Storing the picture Displaying the Others menu Others Menu Others menu description Color Setting menu Color response curve TVG setting window Interpreting the Horizontal Display Bottom echoesBottom echoes Fish schools Fish schools Wake Sea surface reflectionsWake Sea surface reflections Sidelobe echoes false echoes Noise and interferenceNoise and interference Vertical Mode Overview Vertical Mode ConceptSetting the vertical display Vertical mode concept Vertical Mode Indications and Marks Typical vertical displayVertical 1 display indications and markers Vertical bearing mark, tilt mark Solid Line Dashed LineVertical scan and horizontal scan ranges Auto Train Trackball mark position reference markAuto 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 Approaching Application to Bonito and Tuna FishingSearching Tracking 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 Trackball mark position reference mark Typical Echo Sounder DisplaysEcho sounder 1 display Indications and markers on the echo sounder 1 display Downward-looking net recorder display Echo sounder 2 net recorder or echo sounder display Echo sounder combination mode ES1 + ES2 Echo sounder + net recorder displayEcho sounder combination display Echo Sounder 2 display Upward + downward looking display Upward + downward looking net recorder display ES2 mode Selecting an Echo Sounder Mode Enabling an echo sounder modeDisplay mode dialog box Echo sounder mode configurations and menu setting System menu setting and available displays ES1 SETTING, ES2 Setting menus Selecting Display RangeRange 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 Overview ES1 Setting menuES1 setting menu description 10 ES2 Setting Menu Overview ES2 Setting menu net recorder connectedES2 Setting menu description History Mode Sample History Display History mode concept How to Interpret, Set the History Display How to interpret 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 NUMERIC/GRAPHIC Data Display Full 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 Main menu user menu Customizing the EquipmentUser Menu Deleting items from user menu Programming the user menu Message for registration of user menu item Function dialog box for storing picture Example default function programsFunction Keys F1-F6 Executing a function Function dialog box for erasing fish marks Dialog box for selection of presentation modeDialog box for adjustment of panel dimmer Function dialog box for recalling picture Programming function keys Dialog box for erase ship trackConfirmation for registering function key Function key dialog box Erasing programs User Prog Control Selecting a user programProgramming the User Prog control User program options This page intentionally left blank Erase Marks menu Others Menu Display Settng menu Display Setting menuOpening the Display Setting menu Display Setting menu description Tilt Alarm & Audio menu Opening the Alarm & Audio menuAlarm & Audio menu description PRESET, Memory Card menu Opening the PRESET, Memory Card menuPRESET, Memory Card menu description Mark Display menu Initial Setting menuOpening the Initial Setting menu Initial Setting menu description Heading mark Range ringsBearing scale Data on ship’s track Net movement plotFish marks connected with line Target lock mark Mark Size menuMark Size menu Others Menu Data Display menu Data Display menu Current flow direction settings Current VEC & Wind menuCurrent VEC & Wind menu NET Sonde Setting menu Xmtr Distance setting windowNET 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 Processor unit Storing Image, ConfigurationMemory Card Operations 10-1 Memory Card menu 10-2 Loading, Deleting Files 10-3Memory Card menu, recall, delete dialog box opened 10-4 Formatting Memory Cards 11-1 MAINTENANCE, TroubleshootingPreventive Maintenance Cleaning the equipment Hull Unit Maintenance Hull unit maintenance11-2 Unit Fuse rating Fuse Replacement11-3 Unit and fuse 11-4 TroubleshootingTroubleshooting Symptom Check, Remedy Transducer Error messagesMessage Meaning, Remedy Power supply 11-5 11-6 Error CodesError messages con’t from previous Error code 11-7 Status MessagesTests Test menu Board test 11-8Board test results Interpreting the board test results 11-9 Trackball check Lever check Panel test11-10 Panel test Test pattern 11-11Test patterns Rx test sequence, Rx test message Rx test For service technicianNoise test For service technician 11-12 Raise/lower control box, cover removed Raising the Transducer from the Hull UnitRaising the transducer automatically 11-13 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