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

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:dono

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 :kewl

Nice shots Kosmo.

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

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?

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

which fish has it's mouth open?

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

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Originally Posted by 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

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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

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

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Originally Posted by 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 :kewl

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Get off the purse strings and get one of those HB rotating pole rigged transducers and you could know where da fishes is.:tongue

just thought of one more thing......keep your regular 2d sonar in the 200khz only . this way if you see structure on it, it should show up on the di . if it doest t then you need to adjust the di.

So there is no need to run the 83 then? Does the 200 have the same cone as the si interpretation of the di? Think ill go to the lake after while and try some of this stuff out.

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Originally Posted by South65

So there is no need to run the 83 then? Does the 200 have the same cone as the si interpretation of the di? Think ill go to the lake after while and try some of this stuff out.

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I think what kosmo was referring to was that because the 200kHz 2d sonar beam is only a 20° cone... If it shows on the 200kHz 2d sonar - it should show on the DI...

Conversely the 83kHz 2d sonar beam is a 60° cone... Returns could be picked up in the outer fringes of this 60° cone, but yet "not" show on the DI...

Here is the HB Dualbeam 83/200 2d sonar cones..

http://i477.photobucket.com/albums/r...reenshots1.jpg

Also realize that these cone sizes are for the DI from SI series units...

The HB dedicated DI units have different cone angles (and frequencies) for the 2d cones...

Here is the specs for the HB Dedicated DI units...

http://i477.photobucket.com/albums/r...c/45c336a5.jpg

(Kosmo has 1 of each type HB unit..998c SI & 597c HD DI...but I'm pretty sure he was talking about his 998c SI as the "split view" in his original post is "side by side" like a 998...instead of a "split view" of "over and under" like the 597...I think...lol)...

Rickie

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Originally Posted by South65

So there is no need to run the 83 then? Does the 200 have the same cone as the si interpretation of the di? Think ill go to the lake after while and try some of this stuff out.

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south65.... i not very good explaining myself but ill try.di from si is what it is...... what im doing with my 998,while fishing im taking pictures of the structure that i fish so i can post here.these are actual pictures that i get while fishing. most of these waypoints i already have saved on my garmin handheld unit , some are new places that i find along the way.i want my marker to be real close to the structure when i drop it so by using the 200khz 2d with the 455khz di there should be ,for the most part the same thing showing on both. if i were to use the 83khz it would be easer to locate the structure but i might be off a little more when i mark it.now i will say this i dont miss the structure very often doing it this way,i dont want to brag but im pritty good navigating my boat.now back to you. im trying to help you get the best out of your 998di that you can.you might want to use the 83khz. it will help you to find the structure even if you didnot go dirrectly over it.if you use only the 200khz 2d while your learning the di it will help you no what to expect to see on di vs. 2d and it will help in your settings. remember what i said in a previous post, if you see structure on the 200khz 2d and you dont see it on the di 455khz well enough to your liking just freeze the unit by using the 4 way courser .if you lower the contrast it should make the structure more visible. once you get it to the best you can, just leave it that way just use you sensitivity as needed

Wat about if I see it on the si and di but not the 2d. I've got screen shots to post when I get home

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Originally Posted by South65

Wat about if I see it on the si and di but not the 2d. I've got screen shots to post when I get home

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yes that will happen, but its not under the boat

in this picture, the structure that i passed over is within a 4.55 ft. area under the boat at the deft of 11 ft.

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Originally Posted by Cane Pole

Get off the purse strings and get one of those HB rotating pole rigged transducers and you could know where da fishes is.:tongue

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From what I heard today, they are going to announce the Humminbird 360 at the 2013 Icast.