DownScan v.s DownImaging by Fishton

Date: 13 January 2010

Time: 11h00

Venue: Inanda Dam Kwa-Zulu Natal South Africa

Test: Lowrance HDS8 with LSS-1 v.s Humminbird 1197cxSI with Hi-Def Side Imaging with software 4.750 (Down Imaging)

Setup: Both transducers are mounted side by side on the starboard side of the transom

Conclusion: The Humminbird definitely performs better in the 455kHz range than the 800kHz, but still lacks somewhat when compared to the Lowrance LSS-1.

HB DI 800kHz

Lowrance DS 800kHz

HB DI 800kHz

Lowrance DS 800kHz

HB DI 455kHz

Lowrance DS 455kHz

AMAZING!!! How is the fishing???

WOW I bet if there were leaves on the trees the lowrance would show them

More information needed. He may need to hire Dr. Halfen to go along and run that Humminbird unit.

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More information needed. He may need to hire Dr. Halfen to go along and run that Humminbird unit.

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Why because the lowrance looks better than the HB and that just can’t be?

No, cause Halfen’s scans look much better than his. As with any sonar unit, how you set it up, angle of transducer, etc. all matter.
Just room for bias, that is all.

No doubt that there will be more comparisons to come. I’m leaning towards Lowrance, but still haven’t made a purchase — so I really look forward to seeing them!

I havent kept up with the latest in electronics,are the new HD Lowrance units with side & down scan actually up & running for the public yet with all of the necessary upgrades and or downloads?

Dean,

They’ve got it for sale, so I assume that’s the case. You just have to buy an add-on box and transducer which attaches to any HD unit.

Hope to see you soon!

John

I have to agree I think we need more information. When looking at the pics they are not the same distances from the boat. Some pics show more and less of the hump between the 2 units. Mounted side by side and set to the same distances should equal the same out side edges.

first set of images…
HB does not show thermocline at 40′ but the LOw does…adjust your machine. HB is atleast capable of that.
–Mark

I am sure with time we will learn how to use the ‘Down’ imaging by HB more effectively, but it is very important to understand that it IS the SIDE Imaging that is making up the ‘Down’ Image.

I love both my units (HDS8 & 1197cxSI), and have used Lowrance and Humminbird on my boats for many years.

If anyone has any tips or ideas on how to improve the Down Imaging, it will be appreciated.

This thread is not about mud slinging, its about all of us learning together.

I made this banner to add a bit of fun to the thread, so lets keep it light and fun. Thanks Guys!

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I made this banner to add a bit of fun to the thread, so lets keep it light and fun. Thanks Guys!

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I meant nothing mean by my comments Fishton. Awesome job on the banner, it’s cool as heck.

Thanks Ruger2506

Fishton,

THANKS for taking the time to show us the work that you have done. Being able to have both of those units on one boat to compare is a huge advantage. Please keep posting your observations between the two units!

Hope the fishing is as good as the pictures.

FDR

Thanks FDR, and I sure will.

*I never even put a line in the water yesterday, just fiddling with electronics. But the weekend is just around the corner …

Fishton,

Thanks for posting these comparisons. I hope that you will continue. It may help (or confuse me even more) with my upcoming decision on which brand to upgrade to. Seeing products perform side by side gives us the best information to make a decision.

I tried some new settings today with some pleasing results.

Settings:

Unit: 1197cxSI
Frequency: 455kHz
Chart speed: 4
DI view: wide
DI Sensitivity: 17
Pallette: Brown
Speed: 2.1kph

Comment:
The higher sensitivity certainly makes a massive difference to the cover (trees). The ground however becomes a bit washed out.

Thanks for the post, I’m a HB SI and a Lowrance owner and this is very interesting to me.

Here’s a question, did you spend much time setting up the Lowrances’ settings or were the results you got pretty much with default type settings?

This is the kind of comparisons we need, keep up the good work! Definately not the final say but good first try comparisons.

Just a quick question… Why do you have both setups mounted in the boat? I’m not trying to be contrary and I love the images you posted… Just curious how/why someone gets to have duplicate multi-thousand dollar units side by side… (Of course, if I had the cash, I’d probably do it to, but since I haven’t won powerball yet…) What was the motivation??

Anyway, I noticed that the terrain in your lake is really something. Goes from shallow to quite deep (80 plus feet) with lots of structure througout… At least in the lakes that I normally fish in WI/MN, most of the time anything over 30-40 is getting pretty deep… I have noticed that when changing depths using my 997 side imaging (i haven’t used the DI yet in my boat…) I certainly have to adjust sensitivity to get the best images. I’m wondering if some of the readings you are getting might have something to do with the rapid and somewhat extreme depth changes.

That being said, the Lowrance images look awesome. But to be fair, there are a ton of variables that go into play when you are doing a comparison like this, most of which we are just taking your word for… Although there may be many intangible variables that aren’t even considered in such comparisons…… Not that I don’t appreciated the effort (like I said, I love the images!!), but a comparison like this posted on a public website, to be fair, should probably be taken with a grain of salt….

Again, not intending to be contrary, and you have some awesome images. The Lowrance stuff looks very promising indeed, and would have been considered when I bought my 997 if they hadn’t been so slow to market and if I havn’t had such bad customer service experiences in the past with Lowrance…. I appreciate the posting – post more when you can!! BTW… Awesome thermocline!!!!

Thanks,
Mike

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Just a quick question… Why do you have both setups mounted in the boat? I’m not trying to be contrary …

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Yes you are. LOL

I got to see Humminbird’s Down Imaging directly under the boat today! I jacked my sensitivity right up to 20 (MAX) and there it was, you are quite right. Apologies go out to T Mike.

My GPS receiver and SI Hi-Def transducer are within very close proximity.

LOL… I guess I WAS trying to be a little contrary… BTW, you didn’t answer my question why you have both mounted on the same boat????

Anyway, are most of your shots in meters??? On your last image, it says 30.0 feet in the bottom left, but 31M in the bottom right… What does that M stand for? I had originally assumed meters and thought your were targeting some really deep structure which might give odd returns based on need to adjust sensitivity the deeper you go… But now I’m just wondering what that M means… I guess I don’t know my own sonar well enough….

Thanks – again, thanks for the images. Do date, I’ve been extremely impressed with my 997 SI and can’t wait for the DI shots this spring!

heres some pictures from a 997 fr.455 amber2 factory defaults.pictures taken on 1-13-10.had to convert from png to jpeg to upload to this site. the program that i used left water spot because i didnt want to buy the program.no big deal

Strengths and Coverage:

Most of us anglers are pretty much up to speed on how the conventional 2D cone shaped sound wave works. I.e 20° @ 200kHz, 60° @ 83kHz, stronger in the centre and weaker around the edge. This is why we get an arc with thin tails on either end. The other thing we know about these ‘cones’ is that the transducer listens to a lot more than what is labeled as 20° @ -10dB, and these outer ‘areas’ are called the ‘outer lobes’. It is these outer lobes that generally cause all the clutter seen on your screen. Humminbird’s technology filters this clutter, but can be switched on or off with the SwitchFire feature.

When it comes to high frequency sonar, we are generally not all that clued up on the inner workings due to lack of transparency by the manufacturers for obvious security reasons. And therefore opinions and presumptions become the only source of information like this one I’m feeding you right now.

This diagram below is taken from the Humminbird 1197c SI user manual page 53 under the heading ‘Understanding Side Imaging’. (2009 model)

Like the 83kHz and 200 kHz I believe the 455kHz too has a higher and a lower strength area. I have added shading to demonstrate the 455kHz beam’s higher and lower strength areas as I have come to understand them.

From the top of the side beam (closest to the surface) to lets say in this example, an angle of an estimated 45°, the beam strength will slowly increase from lets say 5/20 to 20/20, like an eye test. After all, sonar is really just our ‘eyes’ under the water. From this angle to nearly directly beneath the boat, the strength of the beam decreases rapidly once again. This is why I believe Humminbird say 84° coverage in the 455kHz, and not 90°, due to this rapid drop in strength.

This is however not a constant angle to the left and right, but rather one that changes depending on depth. The sound wave, being a mechanical wave, and will bounce off objects, especially big objects like the sea bed or bottom of the dam especially in the shallows.

My 997 user manual shows 86 degree coverage not 84 degree. Sometimes the devil is in the details.

My information, direct from the engineers, is that the quoted sonar cones are all measured at the (industry standard) -10 dB level, and that there is useful, usable information outside of those quoted cones.

Interesting speculation above, that’s for sure.

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My information, direct from the engineers, is that the quoted sonar cones are all measured at the (industry standard) -10 dB level, and that there is useful, usable information outside of those quoted cones.

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Like this image explains Jason ……….. sorry for the repeated image gentlemen.

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Interesting speculation above, that’s for sure.

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I see my transducer like a directional microphone, which it really is if you come to think of it.

If I was standing in the wide open great outdoors (deep water), pointing my microphone at lets say a bird in a tree, that microphone is designed to concentrate primarily on the bird. Of course it’s going to pick up other noises too, but the bird is the target and that should be the ‘loudest’.

Take the same directional microphone and use it in a subway tunnel (shallow water), and I think you are going to hear all sorts of noises from all over the place.