picture of large mouth bass ??????????

[kosmo]

heres a picture of some fish which is kindof kool all by its self, but i been thinking about something humminbird greg brought up. how does the di picture show something on the screen as if you were looking at it from the side not the top?in this picture, i can see four fish facing the front of the picture slightly angled to the right .i can see there tale fins and the top fish i can see has his mouth open. the bottom fish is showing horizontal and the first fish is almost facing away from the picture .actually i can see some of the fishes dorsal fins.how can di show all of this

[CrappiePappy]

Kosmo ... DI isn't a straight down shot. It's still angled out to the sides ... so it could be picking up signals bouncing off the sides of the fish. It's possible that the fish are not directly under the transducer, and the sonar sweep is catching these fish from an angle.

Just remember that the 2d sonar image in the left screen shot ... is, more or less, a straight down shot ... and therefore is interpreting the returning pings as "arches". You can't really compare the two, since they're different technologies ... so they render the return signals in totally different ways.

... cp

[wilbur]

Nice shots Kosmo.

[mduncan62]

you sure can interpret that hb di. I don't see it, but glad you do....

[Humminbird_Greg]

Glad I got you guys thinking about this. Cp is right; since the DI sonar has some left-right width to its beam you can “paint” the side of a fish with the DI sonar that is not directly under the transducer, even when that fish is vertically oriented (not on its side). This would allow some of the DI sonar to also reflect off of the fins of the fish which may be displayed by the unit if conditions are right. Fish that were directly under the DI transducer would not be able to be shown with as much vertical height as the sonar would only bounce off of the top side and girth of the fish but not its sides.

Think about this now: Most of those fish are shown with their heads pointing to the left of the display. That means that as the boat passed over the fish them that the DI sonar contacted their heads first which means the boat and fish were travelling in opposite directions.


Any chance you made a sonar recording of this Kosmo?
Could you send me the original screen snapshot of this?

[kosmo]

Any chance you made a sonar recording of this Kosmo?
Could you send me the original screen snapshot of this?[/QUOTE]
I can send you the oringinal snapshot but i dont have video

[mduncan62]

which fish has it's mouth open?

[South65]

I'm getting better pics with my di now but still not in the same category as u are. Mostly just seeing dots. But the fish I am catching are not schooled up either so that may b something to do with it. Doing alot better on the si. I will take pics from a recording. When I go next time

[rnvinc]

I'm getting better pics with my di now but still not in the same category as u are. Mostly just seeing dots. But the fish I am catching are not schooled up either so that may b something to do with it. Doing alot better on the si. I will take pics from a recording. When I go next time

You might try experimenting with raising the chart speed a notch or two...

What this does (in effect) is stretch the few successful ping echos across the screen that reflect off the fish...

A good way to test this "stretching" effect is to make a short recording that captures some fish echos... And then play back the recording at different chart speeds to see how speeding up the chart will "stretch" those white "dots" into elongated "ovals"...

(Another way to make the fish echos longer is to slow the boat down ...so more pings can actually hit the fish...)

Rickie

[kosmo]

rickies right about the scroll speed and the streching thing but my personal experience is while fishing the best results will be achieved by keeping the unit on 455khz with the scroll speed 5. on the di screen go to some known structure and when you see it come on the screen use the cursor to freeze the pitcher.once you do that bring up the enhance menu start lowering the contrast and the structure should start becoming more visable while the bottom features will fade . once you like what your seeing just keep it set that way for the most part. you might fiddle around with the sensitivity alittle but not much. now as far as those fish looking like dots or looking like fish dont beat yourself up to much here most of the time dots is what your going to see. you can do the same thing on the si but i think that you will find that the contrast will have to be set higher to get the desired picture. another thing that i just thought of, bottom hardness will affect the returns the unit receives