Great Lakes Bass Fishing Forum

About Fishing Products including Make Your Own => Electronics Talk => Topic started by: Big dreams on November 16, 2011, 07:33:17 AM

Title: DI vs. SI
Post by: Big dreams on November 16, 2011, 07:33:17 AM
I am fixing to purchase one more sonar unit within the next week or so.  What are the advantages of Side Imaging compaired to Down Imaging?  Seems to me DI would be better as you know for sure where the structure is.  For those who have them, what are your thoughts?
Title: Re: DI vs. SI
Post by: Waterfoul on November 16, 2011, 07:48:24 AM
Get a unit with both and get the best of both worlds.
Title: Re: DI vs. SI
Post by: motocross269 on November 16, 2011, 08:03:14 AM
You know exactly where the structure is in DI and SI mode....Just click on the structure and it gives you a GPS coordinate....

I am just getting started with the new Humminbirds so I can't comment which mode is more useful......
Title: Re: DI vs. SI
Post by: Big dreams on November 16, 2011, 08:26:12 AM
Get a unit with both and get the best of both worlds.

SI is a lot more expensive.  I wasn't sure if DI would be sufficient.
Title: Re: DI vs. SI
Post by: thedude on November 16, 2011, 09:40:57 AM
i find SI way more useful. DI just helps distinguish cover/structure as you drive over it. SI helps you locate that structure or key features 100yds from the boat. You can also get a nice road map of an area (ie channel swings, irregular weed lines, isolated cover etc).
Title: Re: DI vs. SI
Post by: Big dreams on November 16, 2011, 09:54:51 AM
i find SI way more useful. DI just helps distinguish cover/structure as you drive over it. SI helps you locate that structure or key features 100yds from the boat. You can also get a nice road map of an area (ie channel swings, irregular weed lines, isolated cover etc).

That helps a lot.  I did not know how much DI would help where as SI imaging is obvious.  Guess that makes up the price difference.
Title: Re: DI vs. SI
Post by: thedude on November 16, 2011, 10:17:50 AM
once you find it with SI - regular graph mode will show you what you want. I thought about DI for the front of the boat, but a regular graph will show you more ( or at least similar info) in terms of fish and suspended bait under the boat. DI really just shows you a different angle of definition in compliment to what you see on the SI -  for instance you might see something that looks like a boulder on the SI - drive right over it and find out its actually a tire or a refrigerator or something.
Title: Re: DI vs. SI
Post by: Waterfoul on November 16, 2011, 11:36:33 AM
i find SI way more useful. DI just helps distinguish cover/structure as you drive over it. SI helps you locate that structure or key features 100yds from the boat. You can also get a nice road map of an area (ie channel swings, irregular weed lines, isolated cover etc).

Exactly.  I've found things on lakes I've been fishing for years and years that I never knew were there using the SI.
Title: Re: DI vs. SI
Post by: bigmojet on November 16, 2011, 02:26:05 PM
I purchased the HB 798 with both SI and DI this year and can definitley say i use the SI a ton more. My default screen I set at regular switchfire sonar on top with side imaging on bottom left and right. I can't believe the amount of cover on my favorite lake there is that I didn't know about until SI. I wish I could afford the bigger screen but this will have to do. If you would be just running DI you would probably never get a full picture of everything down there.

I run this setup on my console with a cheaper non-color sonar up front. I might upgrade to a color GPS model up front that I can network with the 798 si/di next year.

I was reading on some HB forums on the technology behind the differences between DI and SI before I made my purchase and seemed the HB models use the SI information to create the DI image as the SI imaging pretty much covers directly under the boat as well. Many of the users agreed with comments below of using standard down sonar vs the DI for identifying fish.

I'm still am not quite sure how to identify fish on the SI unless it is really obvious (like the fish casting a shadow on the SI).

Title: Re: DI vs. SI
Post by: SethV on November 17, 2011, 09:47:58 AM
I hardly ever use DI.

SI is the real deal - use it to locate the structure.  Get over the top of it and use your regular color 2D sonar.  See the fish, hit him i the head, catch the fish.  That simple.
Title: Re: DI vs. SI
Post by: LennyB on November 17, 2011, 12:46:30 PM
Quote
i find SI way more useful
I agree 100%. SI is great for combing the flats and looking for weed patches, rocks, etc... off to the sides. Two times this year it turned a tough day into a bonanza. Once in the spring and again in the fall.

The spring trip was to a shallow muddy lake were I scanned a small patch of weeds that was about 50 yards to the side of me on a barren weedless flat in 3 feet of water. The water was dirty from the wind so I couldn't spot them by eye until I was right on top of them and that patch was loaded with fish.

The fall trip was the same scenario but it was a rock field way off to the side on a huge shallow flat. 
Title: Re: DI vs. SI
Post by: REEL_MAN on November 17, 2011, 07:05:50 PM
If I had to make a choice, SI is the only way to go. You already have the sonar shooting down, but the SI gives you the advantage to find structure way out (and mark it) from the boat not directly under you.

REELMAN
Title: Re: DI vs. SI
Post by: Big dreams on November 18, 2011, 08:03:25 AM
You all helped me in making my choice.  Thank you all for your input.  It has been ordered.
Title: Re: DI vs. SI
Post by: Waterfoul on November 18, 2011, 09:46:37 AM
What did you order??
Title: Re: DI vs. SI
Post by: Redbone on November 18, 2011, 11:47:15 AM
http://www.amazon.com/Fish-Eyes-Underwater-Video-Camera/dp/B004T4RG3M/ref=sr_1_8?ie=UTF8&qid=1321634802&sr=8-8
Title: Re: DI vs. SI
Post by: Big dreams on November 18, 2011, 08:48:48 PM
What did you order??

I know there are a bunch of Hummingbird fans here so I tried not to say.  I purchased the HDS 8 and 5 with the Structure Scan.  I use to own a 5 a couple of  years ago and it worked great so I figured I would stick with them.
Title: Re: DI vs. SI
Post by: Waterfoul on November 19, 2011, 10:50:09 AM
Oh the Humanity!!!   :o HDS???   :o :o   Why!!???!!!   ??? :-[ ??? :-[

LOL!!!  Just kidding.  The one drawback I see with the Lowrance units is the need (and cost) of the LSS1 unit needed for the SI.  Other than that they work much the same.  Now you will find all those unknown places the fish hang out and amaze your friends with your fishing skills!
Title: Re: DI vs. SI
Post by: dartag on November 19, 2011, 11:46:35 AM
Got a Lowrance Elite5 DSI this summer.  Not that impressed with it.  Works great as a depthfinder and GPS  but the DI was nothing special.  Side scan seems the way to go.  Remember they only work at low speed.  You still need something for high speed running. 

Now the decision is Lowrance or HB.   
Title: Re: DI vs. SI
Post by: LAPORTE on November 19, 2011, 01:12:09 PM
After seeing whay kind of service you get at the bassmaster open last year. It's not even a close. HB all the way.... I didn't even see a service trailer for the Lowrance units....
Title: Re: DI vs. SI
Post by: Big dreams on November 19, 2011, 07:34:17 PM
I have a small Lowrance in the dash so the HDS will be on the side.  Looking forward to checking out the local lakes that I "thought" I knew to see why the fish are really where they are.  The LSS1 is a bit expensive.  That was almost a show stopper for me and almost made me switch to HB.  But it didn't :)
Title: Re: DI vs. SI
Post by: FishermanJohn on November 19, 2011, 08:16:31 PM
This summer was my first experience with HB and SI.  Previously I had run a Lowrance 522C which I was very satisfied with, but I upgraded to a 798 SI/DI.  In terms of the SI, it is awesome and I have identified so many new spots on lakes I thought I was familiar with.  The standard sonar seems to work well, but I am still getting used to the HB format and I prefer the Lowrance at this moment.  I found the DI to be rather useless, however.



Title: Re: DI vs. SI
Post by: REEL_MAN on November 20, 2011, 07:40:17 AM
It's amazing how we have our loyalties. I'm lucky to have access to either the Lowrance or the HB and have ran both. Both manufactures make good units, so I look beyond the unit and look at support. It used to be the when Lowrance had Linda Colt there was none better but now that Lowrance drove Linda, out service has gone down. Prior to Linda's leaving Humminbird knew that she was the main competition so they stepped up to the challenge and made service a priority. no matter which brand you use there will be problems and it comes to service. When my first 998 went out I called HB and two days later I had a new unit with a prepaid return shipping label.
I'm now in the market for a new unit for the front of the boat and not even looking at Lowrance going to go with the 597 (not a lot of room).
Just my 2 cents worth for what.

Reelman
Title: Re: DI vs. SI
Post by: Firefighter Jeff on November 20, 2011, 11:27:41 AM
It's amazing how we have our loyalties. I'm lucky to have access to either the Lowrance or the HB and have ran both. Both manufactures make good units, so I look beyond the unit and look at support. It used to be the when Lowrance had Linda Colt there was none better but now that Lowrance drove Linda, out service has gone down. Prior to Linda's leaving Humminbird knew that she was the main competition so they stepped up to the challenge and made service a priority. no matter which brand you use there will be problems and it comes to service. When my first 998 went out I called HB and two days later I had a new unit with a prepaid return shipping label.
I'm now in the market for a new unit for the front of the boat and not even looking at Lowrance going to go with the 597 (not a lot of room).
Just my 2 cents worth for what.

Reelman

   I agree a 100% especially about Linda Colt.  My reasons for going with HB....  Customer service, heard from others that it was easier to navigate the different screens and features with HB and easier installation.  No Interlink system.  Ethernet cable.  :)

  I like the DI but I don't think it has really helped much.    I have the 898 and a 788
Title: Re: DI vs. SI
Post by: 1javelin on November 20, 2011, 11:34:21 AM
I find myself rarely using my sonar on my HB, either leaving it as SI and GPS or DI and GPS.  I love how you can really distinguish detail with the DI where you almost guess with the sonar.  Maybe you guys all have a better understanding of what your sonar is showing, but I really enjoy the DI image.  My decision was solely based on price and knowing I had others with the same technology to help me if I had questions.  The only downside I have to my units, both 898's, is I find it hard to see the screen from certain angles when it's bright out, and it is not the easiest to see when I have on my polarized glasses either.  I find myself taking them down to look at the screen a lot.  This was one of the main reasons I heavily considered Lowrance, because the unit is useless if you can't see what you're looking at.  I really hope they come up with a fix for this over this off-season.

1jav
Title: Re: DI vs. SI
Post by: Frank-o on November 20, 2011, 02:59:30 PM
I have to agree with 1Jav - i love my DI as much as my SI. I have an HDS Lowrance and i find structure on the SI, i move over it and switch to DI to get an almost perfect picture of what's really there. When i first got it, i played with it like a kid on xmas morning. I went from DI to pre sonar just to see the differences, and there is no comparison. Sonar makes a tree in 80 FOW look like a huge upside down octopus with a few blob like tentacles...but on DI it's definitely a tree with a hundred branches and the fish arcs are unmistakeable. if you have DI on either HB or lowrance, don't sell yourself short - go figure it out! it's worth the time.

Frank-o
Title: Re: DI vs. SI
Post by: Big dreams on November 20, 2011, 07:41:46 PM
I was going to go with a HB unit for the dash due to price but I already had a HDS 5 at the bow.  I figured I could use the ethernet to link them together so the waypoints can be shared. 

I do not see a reason to use the SI on the bow at this time.  What do you guys think?  Is it worth linking even the SI to the front or just leave it in the back?
Title: Re: DI vs. SI
Post by: Firefighter Jeff on November 20, 2011, 09:26:39 PM
   I've heard both opinions on whether or not to put SI at the bow.  Some say that the picture is not very clear at the bow because you aren't moving very fast.  Then others say they love it up there.
    I don't have it at the front, mostly because I didn't think it would be worth the additional money.  I do know that a tip I got on getting a good read on the SI is to have the speed set as close as possible to the speed of the boat.  I usually idle at 4 to 5 mph using SI at the dash.  You'd have to set it pretty low for use on the TM.  Also realize that the best picture using SI is when moving in a straight line.  If you turn either direction much it will distort the picture.  Best of luck.  :)
Title: Re: DI vs. SI
Post by: Big dreams on November 21, 2011, 07:07:09 AM
   I've heard both opinions on whether or not to put SI at the bow.  Some say that the picture is not very clear at the bow because you aren't moving very fast.  Then others say they love it up there.
    I don't have it at the front, mostly because I didn't think it would be worth the additional money.  I do know that a tip I got on getting a good read on the SI is to have the speed set as close as possible to the speed of the boat.  I usually idle at 4 to 5 mph using SI at the dash.  You'd have to set it pretty low for use on the TM.  Also realize that the best picture using SI is when moving in a straight line.  If you turn either direction much it will distort the picture.  Best of luck.  :)

Thanks again.  I was not aware of the speed settings.  That seems like it would cause an issue for the front.  The unit is on the truck and out for delivery today.  Can't get here soon enough.  The bad thing is I will have to wait until next year to test out the SI  :-\'  Should be worth it.
Title: Re: DI vs. SI
Post by: bigjc on December 25, 2011, 11:19:10 PM
once you find it with SI - regular graph mode will show you what you want. I thought about DI for the front of the boat, but a regular graph will show you more ( or at least similar info) in terms of fish and suspended bait under the boat. DI really just shows you a different angle of definition in compliment to what you see on the SI -  for instance you might see something that looks like a boulder on the SI - drive right over it and find out its actually a tire or a refrigerator or something.


What model do you have on the Avelanche?  Did you mount it in dash?  I am likely adding an HB to the Legend in a couple of months.  Thinking about a 998c SI at the console and just a color gps combo on bow.  Is it worth spending the extra for SI on the bow?  My only thought was the ability to connect the two units.