Repost of "Understanding the SI "dark water column"...

[rnvinc]

This is the depiction for the 455kHz beam...

[rnvinc]

This is the depiction for the 800kHz beam...

[rnvinc]

test455



test 800



Rickie

[rnvinc]

Note: this post was copied from http://www.crappie.com/crappie/side-...er-column.html where you may find more discussion.



The SI image "dark water column" has frequently been a topic that is difficult to interpret... and even more difficult to explain....

One of the first things to understand is how the SI unit processor takes a 3 dimensional underwater world and renders it into a 2 dimensional display...
(for info understanding the SI image rendered into 3d...see... http://www.crappie.com/crappie/side-...-tutorial.html

Once we have a grasp on how the unit takes the "vertical dimension" water column (that resides somewhere under our boat) and lays it down flat in the SI image.... then the question arises... What exactly is this "dark water column" and what is it comprised of...??

With a lot of help and advice from some of the guys over at
Humminbird Side Imaging Forums
I hope that the following depictions will give a little better understanding of What exactly is this SI "dark water column"...??

I will refrain from a long drawn out tutorial at first.... and just post the diagrams (one for the 455kHz SI beam and one for the 800kHz SI beam)....

Then, as questions are posted, maybe we all can get a better understanding of ...

What exactly is this SI "dark water column"...??

This is the depiction for the the 455kHz SI beam...


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This is the depiction for the 800kHz beam...



Rickie