Let see your di and si captures

[JohnMickish]

I used the word "shadow", which is what the shaded area is referred to, but it has nothing to do with sunlight. It has to do with the area that the sound (455Khz in DI) does not hit. If there is an item sticking up in the water column, the leading edge will be brighter (depending on density the brightness will differ) and there will be a "shadow" behind it because the sound waved didn't reach that area. When there is a depression the "shadow" will be on the leading edge.

 

Think of it like a flashlight in the dark. The transducer uses sound, the sound bounces off of stuff and returns, then the processor thru it's algorithms  puts a picture on the graph. It's not light but sound that does the work, but the end results would be similar looking.

 

On ‎5‎/‎11‎/‎2017 at 4:45 PM, leech~~ said:

 

And the crib and it's shadow??  So your saying the sun does not penetrate the water like the shady side of a dock?  If it does like I think it does all the shadows would be behind all objects.  Just like the shadow of a tree out of the water.

With the crib you can see that the "shadow" is behind the object indicating that the structure is sticking up above the bottom. The holes have the shadow on the leading edge, indicating they are below. Think flashlight.

 

SI and DI are a learning process. It's the fine points that will show if it's above or below  the bottom of the lake, plus how hard the structure is.

[leech~~]

Thanks, I think TurnUpTheFishing did pretty well at explaining the process above. 

[Hawg]

Good post and discussion. I'm convinced not more than 10%, and that might be stretching it and I include myself in the 90%, know how to use their equipment. Every fishing site is loaded with similar posts.

[rundrave]

forgot I made this post, I fished a lake here in SD last weekend that has a sunken road way and bridge completely submerged. Its gotten to the point the concrete has fallen apart under water but you can still see most of the structure in tact but also some rebar etc.

 

I wanted to get a screen capture but as usual that exact spot was popular and already occupied with other boats playing bumper boats to anchor and fish near and I didn't want to intrude on their fishing space just for a picture.