Thread: Getting The Most From Your Graph (Sonar, Sounder, Fishfinder Thangy, etc.)

thanks jerry for the info it was very informative and i will try to adjust my lowrance this weekend thanks again

I cannot tell you how it works technically, but it does have to do with the reflectivity of the scales.
here is the original thread i saw it on.
http://www.catfish1.com/forums/archi...p/t-19421.html

You can also google.. catfish "double echo" and get some returns.

-SS

Originally Posted by crappiepappy

Why is that ?? Do you know ? I was always under the impression that the depth finder was reading the air in the fish's air bladder ... and that was the "return" signal that was processed into a arch or fish symbol. Catfish have an air bladder, as does any "scaled" fish ... so, why would there be no second echo ? Fish are like us, in that they are mostly made up of water ... and the signal goes thru the body of the fish, almost as easily as it goes thru the water the fish is in. The air in the air sac is what (I believe/been told) "interrupts" the signal ... so why would it be different for a "skin" fish, over a "scaled" fish ??
I'm really interested in any substanciated info on this "pearl of wisdom". It would be great to know "how" this works !! Got any articles or web links that you can direct me to ?? ......... cp

If the air pocket is what reflects back to the transducer, then why does brush and other water-logged structure show up on the sonar?

I've never heard of the air bladder producing the signal. Do you have any articles or web links to support your "impression"?

We have needed a class on this for a long time...Very informative and very well described....Even I can understand....It would be nice to see some pictures especially on the Lowrance. I use Lowrance or Eagle and this would really be a help...

I think this should be saved under "Articles" or etc. for future use....

Excellent Jerry & thanks again..

Here's some pics and links that offer tutorials on fishfinders and how sonar works and how the arches are created.

How Fish Arches are Made - http://www.lei-extras.com/tips/sonartut/fisharches.asp


Creates the arch as the fish passes though the cone or the boat passes over and past the fish. If the boat or the fish is relatively still in the cone it will paint the return as a line running across your screen instead of an arch. Either way, once you recognize it, you'll know it's a fish.

Sonar, How it works - http://www.lei-extras.com/tips/sonartut/howitworks.asp



Cone Angles - http://www.lei-extras.com/tips/sonartut/coneangles.asp

Sonar - Basic Operation - http://www.lei-extras.com/tips/sonartut/operation.asp

Yeah, that's what I was trying to say! Took me a lot longer though.

I hearby declare to kickstart the "Jerry Blake for President" campaign. I will hereby appoint his Vice President to be named Darryl Morris. First order of business once elected, every outdoorsman gets one week paid vacation to pursue his/her tablefare of choice.

Hey Allen:

Thanks but no thanks - I just wanna go fishin! How's your youngun doing? Is she ready to go fishing yet?