Humminbird 570 dual beam questions
First off, this will be my first post, I've been a member for a week or two, I've just been reading and enjoying all the knowledge. I would like to say what a great site this is and would like to express my appreciation for all the posts, tips and stories. I found out about the site from a post on Arkansashunting.net, I cant recall who posted it over there but thanks to whoever that was. I'm a fisherman but I'm lacking in crappie knowledge, I didn't really get serious about them until last year and I have a lot to learn. Now that duck season is over and turkey isnt here yet I'm ate up with the crappie fever....problem is I'm just not that good at catching them yet. This website is helping.
Excuse the rambling and on to my question about sonar:
I have a Humminbird 570 dual beam with a transom mount transducer, it is about two or three years old. It seems to work great 10' and deeper. I've been getting frustrated with it lately (and last fall), I feel like its lying to me on depth sometimes in shallower water. It'll read 3' or less and I cant touch the bottom with a paddle. Sometimes it'll go from 7' to 2' and dance all around in the same general area. I think that may stem from some really soft silty bottoms? It'll show structure but sometimes I can never find it with a jig. Also, I can go over the same spot and never get the same looking structure/bottom contour. I am not that knowledgable about sonar untis, settings, reading them etc but I have been reading the wealth of knowledge on here. Are the issues above just to be expected, am I looking at this all wrong? I dont know if there is a software update for my unit? I also wonder if the dual beam has something to do with it. Am I picking up brush that is not directly under the boat? It is my understanding that the 20 degree beam lays out the bottom detail and the 60 degree beam shows fish in that cone and not structure or bottom detail, is this correct? The sporadic depth readings in shallow water really frustrate me, any thoughts on this?