loooks like a nice pile of Crappie .
did you get any of them ?
One after another, on small crankbaits, small spy baits like the Duo Tetra Works Perakko, and jigs. Most of 'em were 10"-13".
look like they were holding on a clean bottom? no structure?
Cover-wise, if you look at the side image, there's a downed tree among them. It shows as a shadow on the down image, too, if you look closely near the bottom of the image.
Looking at images from prior passes, I thought there might not be anything there, as the fish were so densely packed in a school, obscuring the tree. This image shows the tree.
Structure-wise, this was at the edge of a 10-12 foot flat dropping off into 35-40 feet.
What depth finder are you using. Thanks foe any info
This image is from an HDS-9 Carbon.
Nice score
question
The image on the left,sonar,is that the school showing from 10’ down to bottom at 14’
Trying to learn how to interpret the readings.
thanks
Yes, it is.
In the/a 2D sonar image, or any sonar image for that matter, the unit will show a return echo for everything at a given distance from the transducer that is within it's cone.
In this particular 2D image, there are many, many crappies, and tree branches, returning an echo at all of those distances between 10-14 feet, and they are all displayed on the screen at the same time.
looks like you had some fun catching a few. that is great !
I can see that now. thanks for pointing it out.Originally Posted by 188Musky
Rookie question,
So the crappie shown on the down image below the boat ( bottom image ) can also be seen on the side image above ? Or do I have this all wrong ? Is the above image of left and right ? Can you elaborate on the upper structure image ? Sorry for my confusion, thanks for anything that you can offer.
Tony
~Tony
TonyL, yes, the crappies shown on the down image can also be seen on the side image. The upper image is indeed left and right, with the bottom directly below the boat is depicted by the straight-line orange/black transition on either side of the (upper) L-R side image.
In simple terms, the crappies shown in the down image are the ones shown between the center line and the bottom, in the side image. The water column to the bottom below the boat, is depicted by the black portion of the side image.
In the down image, as well as the side image, anything shown suspended within the black, is suspended between the bottom and the transducer; in this case, it's crappies.
The side image, the upper one, just shows more crappies, and cover, because it is showing fish and the tree off to the side of the transducer also.
188 Musky ,
Awesome ! Thanks for taking the time. I'm finally trying to get a grip on this subject and use my investment best as possible, as opposed to just glancing in passing! I guess I assumed that side image was just that, an image of the side, left or right. Now with your help, I think I am realizing that these "cameras" are actually of a very wide angle and although the focus is of the side, due to the wide angle of the "camera" some of the bottom is also captured?? Does that sound right ?
Thanks again !
~Tony
Well, yes it may be somewhat useful to think of it that way, However, it is not a camera, and we must remember that it does not take images like a camera does.
I think it's more useful to think of the image as a measure of distance from the transducer, with the display unit displaying the strongest return echo at any given distance, at any given moment in time.
If our boat is in, say, 20 feet of water, picture a string 20 feet long tied to the transducer. With it, make an arc from the surface on the starboard side to the surface on the port side. Echoes within this arc will be displayed between the center line of the side imaging image, and the bottom at 20 feet; the "black" portion, so to say. The L-R elements in the transducer will determine which side to display the echo on the screen.
Beyond 20 feet in our example, echoes will be displayed within the orange (or whatever palette you've chosen) portion of the image, because bottom will return an echo beginning at 20 feet.
With a longer string, still using our arc, along with the elements within our transducer to determine left or right, all echoes at any given distance, at any given moment in time, will all be displayed right on top of each other, and the strongest will show the most. Should there be a crappie 23 feet out to the side at 75 degrees, and a rock 23 feet out at 15 degrees, we are going to see the rock, not the crappie.
Where our image takes a 3D visual effect is the shadows caused by strong echo sources that block our sonar from having any echo data beyond the source of the initial echo. Thus, making that portion of the image darker, provided there are no other sources of echoes at that same distance elsewhere within that arc. Drop that crappie down to where it blocks the sonar tick from ever getting to that rock, and we'll likely see the crappie, and a crappie-shaped shadow where the rock should be.
Here's a couple musky shaped shadows, one on a rock/sand/gravel bottom, and one on softer substrate.
188 Musky,
Great explanation and starting foundation! Thanks alot, your time is appreciated.
~Tony
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