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