Thread: Sonar Quiz #18

I pulled this diagram out of a Lowrance installation manual...



Revisiting the image in the OP below ... We see that the echoes are consistantly only showing the right half of the arch (trailing off to the right)...



So this is an indication that the xducer is riding "tail high" ....
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Now...to get a better understanding of how and why this takes place....let's take a look at the math involved in this scenario....(we all love math now don't we ...??)

We know that echos painted on the display are a representation of the "Range" from the xducer to the target...

It is the difference in this "Range" to the target as it passes thru the sonar cone that gives us the "arch" we see on the 2d image display...

In the diagrams below I have divided the fish passing thru the sonar beam into 3 separate diagrams...:

(The sonar cone is drawn as green to represent a "tail high" orientation of the xducer mounting)...

Diagram 1 is the fish entering the sonar cone ...
Diagram 2 is the fish centered in the sonar cone ...
Diagram 3 is the fish leaving the sonar cone....

(The displayed 2d image is depicted in the lower right of each diagram...to show the rendering of the target echo's arch into the 2d image as the fish passes thru the sonar cone)


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Rickie