Furuno CSH-5L/CSH-8L Fine Tuning the Sonar Picture, Eliminating Unwanted Echoes, How TVG works

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2.FINE TUNING THE SONAR PICTURE

2.1Eliminating Unwanted Echoes

Echoes from targets such as bottom and fish return to the transducer in order of distance to them, and when we compare their intensities at the transducer face, those from nearer targets are generally stronger when their reflecting properties are nearly equal. The sonar operator will be quite inconvenienced if these echoes are directly displayed on the screen, since the actual size of the target cannot be judged from the size of echoes displayed on the screen. To overcome this inconvenience, the TVG function is incorporated. It compensates for propagation loss of sound in water; amplification of echoes on short rang is suppressed and gradually increased as range increases so that similar targets are displayed in the similar intensities irrespective of the ranges to them.

The CSH-5L/CSH-8L incorporates two TVG functions, NEAR and FAR, and they mainly compensate for propagation loss on short and long ranges respectively, centered at the ranges shown below.

NEAR

 

300

m

 

FAR

How TVG works

The TVG is also used to suppress unwanted echoes and noise which appear in a certain range area on the screen such as sea surface reflections and cruising noise. To obtain the proper TVG setting, follow the procedure below.

1.Press the MENU key.

2.Use the [RANGE] control to choose [MENU MODE] at the top of the screen.

3.Use the [GAIN] control to choose SONAR to display the SONAR menu.

4.Use the [RANGE] control to choose TVG NEAR.

5.Use the [GAIN] control to adjust gain.

6.Use the [RANGE] control to choose TVG FAR.

7.Use the [GAIN] control to adjust TVG FAR (setting range: 0-10).

8.When sea surface reflections or plankton layers disturb the picture, adjust TVG NEAR to eliminate them. They will be eliminated by decreasing the setting by “1” or “2.”

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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 Word to the Owner of the CSH-5L/CSH-8L FeaturesForeword Vii System ConfigurationSystem configuration of CSH-5L Viii System configuration of CSH-8LControl unit Operational OverviewControl Unit Remote controller Remote Controller optionLowering the transducer Basic Operating ProcedureTurning on the power Sonar menu TransmittingSystem menu Adjusting backlighting of control unitMode description Description Display Choosing a display modeNorm COMBI-1Sonar display Normal mode display sonar displayCOMBI-1 display sonar display + audio 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 rangeExamples of proper and improper gain Adjusting the gainRetracting the transducer, turning off the power Tilt range Setting the Tilt AngleAutomatic tilt on/off Auto tilt concept Range and tilt angleRange m ±2-10 ±4-14 ±6-20 ±10-26 Bottom and tilt angle How to discriminate fish echoes from the bottomCase 1 Tilt angle 30 to 40 degrees Case 2 Tilt angle 10 to 20 degreesTilt angle and surface fish example CSH-5L Points to considerTilt angle for surface fish Suitable tilt angle Finding Range and Bearing to a TargetDepth, detection range and tilt angle Location of trackball dataSonar Menu Overview Operating procedureDescription Ref. Sonar menu descriptionDescription of sonar menu Description of sonar menu con’t from previous This page intentionally left blank How TVG works Fine Tuning the Sonar PictureEliminating Unwanted Echoes 1 AGC Displaying Surface Fish ClearlySuppressing Bottom Tail 3 2ND AGC Pulse lengthHow to adjust TX output Identifying noise source Rejecting Sonar Interference and NoiseRejecting noise with the interference rejector Rejecting noise with the noise limiterInterference rings Rejecting interference with TX cycleDeleting Weak Echoes Choosing BeamwidthEcho Averaging Horizontal beamwidthThis page intentionally left blank Target lock mark and target lock data Advanced Sonar OperationTracking a Fish School target lock Target lock and tilt angle Detecting Fish Schools Aurally Fish alarm zones Fish AlarmFish alarm zone Fish mark and fish mark data Measuring Fish School SpeedEntering a fish mark Deleting individual fish marks How to use the off-center functionRelocating Fish School for Easy Observation Event Mark, Own Ship Position Mark How to use the event markEvent mark Entering an event markEvent marks Entering an own ship position markDeleting an event mark Ship Collectively Deleting MarksTrack Operating the function keys Function Keys F1-F4Programming for fishing ground or target fish Erase Marks dialog boxUseful programs main items only Programming specific functionTX Output Pulse Length TX Cycle TVG Near TVG FAR HOR Beamwidth Color Curve ResponseFunction key assignment confirmation screen Confirming function key programStabilizer mark Suppressing Effects of Pitching and Rolling StabilizerHow the stabilizer works Advanced Sonar Operation Display range and shift concept Echosounder ModeChoosing the Range Sounder menu Adjusting the GainMeasuring depth Picture Advance SpeedMeasuring Depth Suppressing Low Level Noise Suppressing InterferenceInterference ClutterWeak echoes Erasing Weak EchoesSounder menu description Other Items on the Sounder MenuCurve DraftMarks and data on the normal display Marks and DataMarks and Data on the Normal Display Points to North Heading Mark Description of marks and data on the normal displayMarks 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 Bottom echoes Interpreting the DisplayBottom Echo Fish echoes Fish SchoolWake Sea Surface ReflectionsSea surface reflections WakeNoise and Interference False Echo by SidelobeSidelobe echo Noise and interferenceMarks menu Marks and System MenusMarks Menu Marks menu description System menu Description of System menu System MenuDimmer Disp SelectDescription of System menu con’t from previous Cleaning the Equipment MAINTENANCE, TroubleshootingGeneral Maintenance Lubrication points, zinc plate Hull Unit MaintenanceHull unit maintenance points Hand crank Manually raising the transducerHull unit Fan Replacement Fuse ReplacementUnit Fuse Type Code No Type Code NoSymptom Check, Remedy TroubleshootingMessage Meaning, Remedy Overvoltage Error MessagesTransducer not retracted High speedChoosing a diagnostic test Diagnostic TestsContinuous test example CSH-5L, 55 kHz transducer Description of diagnostic testsSingle test, Continuous test Panel test Panel testWhite RED Green Blue Color testColor test Pattern testSIO test SIO testEcho tests Echo testsSpecifications of Color Scanning Sonar CSH-5L/8L Hull Unit Interface This page is intentionally left blank Sonar menu Menu TreeSounder menu AP-1AP-2 Marks menuSystem menu IN-1 Index

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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