Furuno CSH-5L/CSH-8L manual False Echo by Sidelobe, Noise and Interference, Sidelobe echo

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6. INTERPRETING THE DISPLAY

6.5False Echo by Sidelobe

An ultrasonic wave is emitted only in the direction set by the [TILT] lever but, in practice, there are some emissions outside the main beam that are called “sidelobes.” Energy of the sidelobe is fairly weak but when the sonar is used in comparatively shallow water with a hard and rocky bottom, strong target signals are detected by the sidelobe. These are represented on the screen as a false echo as shown below. To weaken the sidelobe echoes, set VER BEAMWIDTH to WIDE, on the SONAR menu.

 

Mainlobe echo

Sidelobe

Sidelobe echo

 

Mainlobe

 

The bottom echo

 

detected by sidelobe

 

appears at a certain

 

tilt angle when the

 

sidelobe points ver-

 

tically. Also, poor

 

soundome projection

 

may result in a similar

 

false echo.

 

Sidelobe echo

6.6Noise and Interference

If the fishing ground is crowded with many fishing boats, the sonar is subject to interference from ultrasonic equipment such as an echo sounder, sonar, etc. on board other boats as well as those on board own ship. For instance, interference from the sonar operated on board other boats will appear as a ring as shown in

(A). This interference can be suppressed by properly changing the TX cycle. Electrical equipment on own ship can also cause interference to the sonar as shown in (B). The noise from some marine life appears on the screen as in (C). Those types of noise can be suppressed with the interference rejector.

(A) Interference from

(B) Electrical

(C) Marine life noise

other sonar

interference

 

Noise and interference

6-4

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Contents Color Scanning Sonar 00080940402 Safety Instructions Turn off the hull unit before using the hand crank Table of Contents Marks and Data Index Features ForewordWord to the Owner of the CSH-5L/CSH-8L System Configuration System configuration of CSH-5LVii System configuration of CSH-8L ViiiOperational Overview Control UnitControl unit Remote Controller option Remote controllerBasic Operating Procedure Turning on the powerLowering the transducer Transmitting Sonar menuAdjusting backlighting of control unit System menuNorm Choosing a display modeMode description Description Display COMBI-1COMBI-1 display sonar display + audio display Normal mode display sonar displaySonar display COMBI-1 display sonar display + audio displayCOMBI-2 display sonar display + echosounder display Choosing the display rangeCOMBI-2 display sonar display + echosounder display Detection rangeAdjusting the gain Retracting the transducer, turning off the powerExamples of proper and improper gain Setting the Tilt Angle Automatic tilt on/offTilt range Range and tilt angle Range m ±2-10 ±4-14 ±6-20 ±10-26Auto tilt concept Case 1 Tilt angle 30 to 40 degrees How to discriminate fish echoes from the bottomBottom and tilt angle Case 2 Tilt angle 10 to 20 degreesPoints to consider Tilt angle for surface fishTilt angle and surface fish example CSH-5L Depth, detection range and tilt angle Finding Range and Bearing to a TargetSuitable tilt angle Location of trackball dataOperating procedure Sonar Menu OverviewSonar menu description Description of sonar menuDescription Ref. Description of sonar menu con’t from previous This page intentionally left blank Fine Tuning the Sonar Picture Eliminating Unwanted EchoesHow TVG works Displaying Surface Fish Clearly Suppressing Bottom Tail1 AGC Pulse length 3 2ND AGCHow to adjust TX output Rejecting noise with the interference rejector Rejecting Sonar Interference and NoiseIdentifying noise source Rejecting noise with the noise limiterRejecting interference with TX cycle Interference ringsEcho Averaging Choosing BeamwidthDeleting Weak Echoes Horizontal beamwidthThis page intentionally left blank Advanced Sonar Operation Tracking a Fish School target lockTarget lock mark and target lock data Target lock and tilt angle Detecting Fish Schools Aurally Fish Alarm Fish alarm zoneFish alarm zones Measuring Fish School Speed Entering a fish markFish mark and fish mark data How to use the off-center function Relocating Fish School for Easy ObservationDeleting individual fish marks Event mark How to use the event markEvent Mark, Own Ship Position Mark Entering an event markEntering an own ship position mark Deleting an event markEvent marks Collectively Deleting Marks TrackShip Programming for fishing ground or target fish Function Keys F1-F4Operating the function keys Erase Marks dialog boxTX Output Pulse Length TX Cycle TVG Near TVG FAR HOR Programming specific functionUseful programs main items only Beamwidth Color Curve ResponseConfirming function key program Function key assignment confirmation screenSuppressing Effects of Pitching and Rolling Stabilizer How the stabilizer worksStabilizer mark Advanced Sonar Operation Echosounder Mode Choosing the RangeDisplay range and shift concept Adjusting the Gain Sounder menuPicture Advance Speed Measuring DepthMeasuring depth Interference Suppressing InterferenceSuppressing Low Level Noise ClutterErasing Weak Echoes Weak echoesCurve Other Items on the Sounder MenuSounder menu description DraftMarks and Data Marks and Data on the Normal DisplayMarks and data on the normal display Description of marks and data on the normal display Points to North Heading MarkMarks and Data Press the R/B key. Own ship position and trackball mark are Marks and Data on the Echosounder and Audio Displays Marks and data on the echosounder and audio displaysOn the System menu Interpreting the Display Bottom EchoBottom echoes Fish School Fish echoesSea surface reflections Sea Surface ReflectionsWake WakeSidelobe echo False Echo by SidelobeNoise and Interference Noise and interferenceMarks and System Menus Marks MenuMarks menu Marks menu description Dimmer System MenuSystem menu Description of System menu Disp SelectDescription of System menu con’t from previous MAINTENANCE, Troubleshooting General MaintenanceCleaning the Equipment Hull Unit Maintenance Hull unit maintenance pointsLubrication points, zinc plate Manually raising the transducer Hull unitHand crank Unit Fuse Type Code No Fuse ReplacementFan Replacement Type Code NoTroubleshooting Symptom Check, RemedyTransducer not retracted Error MessagesMessage Meaning, Remedy Overvoltage High speedDiagnostic Tests Choosing a diagnostic testDescription of diagnostic tests Single test, Continuous testContinuous test example CSH-5L, 55 kHz transducer Panel test Panel testColor test Color testWhite RED Green Blue Pattern testSIO test SIO testEcho tests Echo testsSpecifications of Color Scanning Sonar CSH-5L/8L Hull Unit Interface This page is intentionally left blank Sounder menu Menu TreeSonar menu AP-1Marks menu System menuAP-2 Index IN-1

CSH-5L/CSH-8L specifications

Furuno CSH-5L and CSH-8L are advanced marine radar systems known for their cutting-edge technology and user-friendly interfaces. Designed primarily for maritime applications, these radar units cater to a wide range of vessels, from commercial ships to fishing boats. The primary distinguishing feature of the CSH-5L and CSH-8L radar systems lies in their ability to provide high-resolution images and precise detection of targets, ensuring navigational safety and operational efficiency on the water.

One of the standout technologies incorporated into both models is the pulse compression technique. This feature significantly enhances target resolution and minimizes blind spots, allowing the radar to detect smaller objects at greater distances. With the CSH-5L and CSH-8L's powerful signal processing capabilities, users can expect exceptional performance even in challenging weather conditions, ensuring reliable operation during storms or fog.

The CSH-5L model operates at a frequency range of 5 GHz, while the CSH-8L uses an 8 GHz frequency. Both radars are equipped with a rotating antenna that provides a wide coverage range, allowing for efficient monitoring of the surrounding marine environment. Their high sensitivity and low noise levels enhance target detection, making them particularly useful for locating small fishing vessels or buoys.

Another important characteristic of the Furuno CSH-5L and CSH-8L is their user-friendly interfaces. Both models feature intuitive controls, allowing operators to adjust settings easily and access critical information quickly. The displays are designed for clarity, enabling users to distinguish between targets and navigate effectively.

Additionally, the radar systems include advanced features such as automatic target tracking and target acquisition capabilities. This functionality allows users to monitor multiple targets simultaneously, providing essential situational awareness for safe navigation. The CSH-5L and CSH-8L also support integration with other onboard systems, including ECDIS (Electronic Chart Display and Information System), which enhances the overall effectiveness of maritime navigation.

In summary, the Furuno CSH-5L and CSH-8L radar systems represent the forefront of marine radar technology, offering exceptional detection capabilities, user-friendly controls, and robust integration options. Their advanced features ensure that mariners can navigate confidently, making them a vital asset for anyone operating in the marine environment.
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