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Tom ... I wonder if there's a calculator (or known dimensions) for a DI cone ?? My Lowrance Elite 5DSI throws out elongated (left to right) shaped cones. It would be nice to know how wide of an area I'm covering (left to right & front to back) under the transducer ... vs the depth I'm recording. Knowing that the cone isn't a 2d circle, is paramount to understanding what the unit is showing ... so knowing the length/width vs depth would also be key in understanding what size/shape an area is being shown. At the very least, it would give an idea of where the screen images are coming from ... which would allow better rod, or bait, placement to cover the area's shape & depth.

Specs say the E5DSI is showing a 6deg "slice" ... which I assume is the front to back angle of the elongated cone. I just can't seem to pin down the actual cone angle degree to each side. If it isn't known, or can't be found ... let's err on the side of caution & say it's 40deg. With a 6deg x 40deg elongated cone ... & sitting in 20ft of water ... how wide/thick is the bottom surface I'm seeing from the center point of the transducer's position ?? Oh, and if it makes any difference ... the unit is using 455 & 800 kHz.

... cp

Crappiepappy go to BassFisher1's Storage site : How To Guides there is a structrue scan cone angle chart there.

Originally Posted by Denny

Crappiepappy go to BassFisher1's Storage site : How To Guides there is a structrue scan cone angle chart there.

There are figures in this chart that confuse me...

What confuses me is the column titled "Down coverage"...

Knowing that the DI sonar beam shape is a elongated fan shape..and knowing a fixed depth...shouldn't everything out to the sides of a vertical line straight down be considered "Side coverage"...??

For example...the first example of a known 5ft depth...if we draw a line straight down from the xducer to the lake bottom...then everything left or right of that imaginary vertical line should be in the "side coverage" column....but yet...the chart shows a "down coverage" measurement AND a "side coverage" measurement which comes up to a "Total" side to side coverage length across the lake bottom..

I do not understand how this chart can separate each frequency width (455=75degrees, 800=45degrees) into 2 separate numbers...for each frequency...

There are no 2 separate measurable "sections" of the 455kHz beam...
There are no 2 separate measurable "sections" of the 800kHz beam....

The 455 sonar beam is (allegedly) 75 degrees...which extends out 37.5 degrees to left and right of vertical to a certain distance left and right of vertical....the entire distance between these 2 outbound intersections with the lake bottom is considered the "total DI coverage area"..

The 800 sonar beam is (allegedly) 45 degrees...which extends out 22.5 degrees to left and right of vertical to a certain distance left and right of vertical....the entire distance between these 2 outbound intersections with the lake bottom is considered the "total DI coverage area"..

How does the author of the chart physically divide this "total DI coverage area" into 2 separate lengths to be added together to get the "total DI coverage area"....??

Rickie

Originally Posted by rnvinc

How does the author of the chart physically divide this "total DI coverage area" into 2 separate lengths to be added together to get the "total DI coverage area"....??

Rickie

RIckie, do you mean divide this "total SI area" into 2 seperate lengths? It appears to my small brain that the author fo the chart thinks that the SI signal follows the outside of the DI signal, that they don't overlap. If this is the case, how can I see the same stump on the DI and SI at the same time?

Originally Posted by justinp61

RIckie, do you mean divide this "total SI area" into 2 seperate lengths? It appears to my small brain that the author fo the chart thinks that the SI signal follows the outside of the DI signal, that they don't overlap. If this is the case, how can I see the same stump on the DI and SI at the same time?

OK..Justin's reply got me to thinking...

I think my confusion stems from me "assuming" the chart was for a Lowrance DI unit...(because pappy's question earlier in the thread was asking for a Lowrance Elite 5DSI cone angle chart)...

It looks like this chart that was provided by Denny is for cone angle distances used with the Lowrance Structure Scan...(LSS1 module used with the HDS units)...NOT the cone angle that would be from a Lowrance DI like pappy's Elite 5DSI...

Further..because I have yet to get a Lowrance rep to verify what the cone angles are for the LSS1 (455kHz and 800kHz) and the Lowrance Dedicated DI units (455kHz and 800kHz)...I cannot dispute the chart author's measurements....

I would definitely welcome verified information on the different cone angles of the Lowrance units...

It can be very important for Lowrance users trying to understand what should being showing on their units...

As I've said many times before...
If it ain't in that sonar beam....it ain't gonna show on that sonar screen....

Understanding each specific unit's cone angle is the first step in understanding sonar screen images...

Can anyone provide verified info on the Lowrance cone angles of the different units...?? (Structure scan units and Dedicated DI units with no SS)...

Rickie

I SOOOO confused.

Originally Posted by Locator79

I SOOOO confused.

Me too locator...

If I can ever get verified cone angle info on the Lowrance units... I will be more able to explain coverage area...

HB advertises their different sonar beam angles... Lowrance does not (that I can find)...

I cannot find the cone angles on the Lowrance website...
Jason never came back with verified cone angles....
So far... No one has been able to bring these numbers into the discussion...

Maybe someone should call Lowrance and just ask them....
What is the degree angle of the LSS1 455kHz beam...?
What is the degree angle of the LSS1 800kHz beam...?
What is the degree angle of the DSI 455 kHz beam...??
What is the degree angle of the DSI 800kHz beam...??

Rickie

Rickie
This copied directly from Lowrances site. Transducer Guide | Lowrance

Cone Angle
A transducer's cone angle determines its coverage area of the underwater world. The wider the cone angle, the greater the area that's covered. We offer a variety of 200 kHz transducers with either a wide (20°) or narrow (12°) cone angle. The 50 kHz transducers come with a 35° cone angle. The dual-frequency transducers come with both a narrow (12°) 200 kHz and a wide (35°) 50 kHz cone angles. And the dual-search transducers come with both a narrow (12°) 200 kHz and a wide (35°) 83 kHz cone angles.

Most HDS users that fish less than 100' of water choose the 83/200 khz transducers, 35*/12*. This is NOT the structure scan transducer, 2d only.