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Basic theory
Be aware of that other vessels close to you will also generate reverberation due to the water disturbance caused by the wake, the propellers and the cooling water spill.
Blocking
The movement of your vessel through the water will often
— especially in higher sea states — cause air bubbles to be generated, and these bubbles will move along the hull. This is called blocking. In order to prevent this noise from disturbing your sonar operations, it is important to lower the sonar transducer as far down below the hull as possible.
Check the noise yourself!
If you are bothered with acoustic or electric noise, you can easily run a few simple tests to identify the cause of the problem.
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Check acoustic noise
1 Click the Setup tab to open the menu.
Click the Test button to open the System test menu.
Click the Test config button, and select Noise and VR in the parameter dialogue.
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Click the Close button in the parameter dialogue to close it.
Click the Horizontal tab to open the menu.
6 Observe the Noise level button, and read the noise level.
The level your read in the button is the current noise in the direction of the cursor. The noise is provided in dB, and the number should be as negative as possible. For example, a reading of –50 dB means that you have less noise than if you read –40 dB.
In order to reduce the noise, try to adjust the propeller pitch and the number of revolutions.
Check electrical noise
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Switch off all electric equipment that can cause electrical noise.
Switch the equipment on again one at the time, and check the sonar every time.
With luck, you will spot which of your electrical systems that create the noise. To deal with the problem, consult your dealer and/or a certified ships electrician.
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