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

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
	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	Own ship's wake
	Own ship's	(produced when
	screw noise	own ship turned)

Figure 11-4 Wake appearance on the display

11-3

Image 85

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

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 Configuration Control Description Control Layout on Display Unit and Remote Control Box Main panel control description Main Panel Control Function END Sub Panel Sub Panel 2 data setting window AGC SignalProcess 2AGC Sonar AlarmUP/TM Sonrbeam + + Remote Control Box Adjusting Screen Brilliance, Control Panel Backlighting Turning the Power On/OffOperational Overview Lowering the Transducer Display mode description Selecting a Display Mode Selecting a Display Range Setting the Tilt AngleSeabed echo and tilt angle Points to consider How to discriminate fish echoes from the seabed Tilt angle and sea surface reflections Tilt angle for surface fish Tilt angle and beam coverage Suitable tilt angle Measuring 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 Tail Rejecting Sonar Interference and Noise Data setting window TVGTX, OutputIdentifying noise source Cycle Changing Tx cycle data setting window Tvgtx Setting Noise limiter data setting window Signal Adjusting Beamwidth Normal display mode Marks, Data and Display ModeMarks and Data Echo sounder combination display Normal display mode w/text History display Permanently Displayed Marks and Data Mark/Data Description Erasable Marks and Data Bearing marker Mark Description Range R Auto Tilt Auto Scan Gain Brill TVG TVG DIM Page User Menu Operation Menu Overview User Menu Hist DSP/GRPH Menu screen location and display mode User Menu Description Save Picture Current VEC FAR TVG System Menu DescriptionTM DSP Target Lock Mark Size BRG Readout Menu Description Color Curve Data SET Menu Description Change Color Plan NET ShootNET Sonde NET Plot Corr Init SET/TEST Menu Description Echo Test DefaultsNET REC Others Event KEY Programming the Function Keys Function Keys Replaying a Function Key Function Key Fine Tuning Replaying Function Key Settings from a Memory Card Saving Function Key Settings to a Memory Card This 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 lock Target lock mark appearance Choosing target lock modeErasing target lock mark Target lock and tilt angle Tracking target lock mark System Menu Target Lock Setting target lock conditions Description of target lock items Detecting Fish Schools Aurally How to set the fish alarm zone Fish Alarm Relocating Fish School for Easy Observation How to relocate fish schools Estimate marks and their data Comparing of Fish School Concentration Measuring Fish School Speed How to measure fish speed 10 Event marks Event Mark Erasing an event mark Entering an event mark 12 True motion display True Motion Display 13 Net location mark Plotting Net Location Mark 14 Net behavior Observing Net Behavior No. Display Information Applications Target Slice Display This page is intentionally left blank Port/Starboard display PORT/STARBOARD, Horizontal Slice Displays Horizontal slice display Horizontal slice display Initializing Memory Cards Memory Card Operations Transferring Echo Data from Internal Memory to Memory Card Saving the Picture Saving Net Shooting Data Net shooting data contentsHow net shooting data is saved Transferring net shooting data to memory card Replaying Saved Data Deleting Memory Card Contents Turning 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 Display Sea surface fish Fish Schools Wake Sea Surface Reflections Noise and Interference False Echo by Sidelobe Unretracted Transducer Warning Overvoltage Warning How to manually raise the transducer Opening the Self Test Menu Self Tests Single test Self Test DescriptionContinuous test Color test Panel test SIO test Gray test Interface unit CS-120A, cover opened Interface Unit CS-120A Self Test 13-6 Selection of Data at Interface Unit CS-120A Input Data Selection How to set net sonde transmitter distances Setting Distances Between Net Sonde Transmitters Display Unit Maintenance Maintenance Zinc block near the transducer must be replaced yearly Hull Unit Maintenance User Menu Menu Tree Data SET Menu Init SET/TEST Menu System Menu Previous Page SP-1 Specifications SP-2 Display SP-3 Hull Unit SP-4 11-2 Index IN-2