Quote Originally Posted by genec View Post
Rickie,on 800 khz,what do first null mean?
Rickard at sideimagingsoft explains it much better than I can...

The null is a mathematical thing and in theory no sound at all is transmitted or received in that particular direction. However, in a practical transducer this silent point doesn't really exist. It is filled to some extent with sound, but weaker than in other directions. The effect of the null is a dark or dull band, usually near the middle of the sonar image.
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I think most would see this darker band in the image and think that it's simply a different bottom composition....

I wish I knew an small iota of the "wave theory" that Rickard knows...and he's a great guy too...always willing to help...

Rickie