Context
The current tilt is shown with a solid line in the Vertical view. In the Horizontal view, the current settings for range, gain and tilt are shown in the top left corner of the view.
With 0° tilt the sonar beam is transmitted in parallel with the sea surface. With +60 degrees tilt the beam is directed towards the bottom.
The challenge is to find a tilt that prevents the fish echoes to be "buried" in reverberation and bottom echoes.
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If you use a high tilt value (A) the fish are easily disguised by bottom echoes. A strong RCG (Reverberation Controlled Gain)
setting will remove the bottom echoes. As the distance from the bottom to the fish increases, the fish echoes become clearer.
However, this assumes that the fish echoes are considerably stronger than the bottom echoes. |
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If you use a very small tilt (C) you are not bothered by bottom echoes. However, if the sea surface is gusty you will see
echoes from the waves. These echoes are normally rather weak, and they hardly move in relation to your vessel. |
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By means of a medium tilt angle (B) you are able to pick up scattered fish or schools if these are located at some distance
above the bottom. The upper school in the illustration appears on the sonar picture before the bottom echo, while the lower
school will easily be disguised by the bottom echoes. Once again you can activate the RCG function to improve the reading. |
TipWith the various beams provided by the SU90 system, it may be difficult to understand the concepts. How do these beams "behave" in the water? By means of a graphic presentation, the Beam Visualization dialog box attempts to give you a better understanding of how the acoustic beams are transmitted into the water. Open the Beam Visualization dialog box from the Setup menu.