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

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.