Fishfinders - DI vs SI

[siwash]

Between the two if you had to pick one, which would to pick and why?

thanks! 

[petersaban]

I rarely use DI. SI is useful for me to find the transitions between the different bottoms

[siwash]

  On 4/15/2025 at 11:24 AM, petersaban said:

I rarely use DI. SI is useful for me to find the transitions between the different bottoms

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Interesting... thanks for the response.  I always figured DI was more important.  I have neither now. Just shopping for one or the other. Can you get both in one unit without taking out a second mortgage?

[siwash]

It seems that this unit has both.. on sale.  I am already rigged up with a helix 5 and a terrova.  May consider this   
Helix 7

Edited April 15 by siwash

[CrowMan]

From what I see out in the market...any unit that has SI also has DI. A lot of units are only DI, but I'm not aware of any units that are only SI.  Perhaps someone can correct me.

Personally, I use SI all the time, but it's not a necessity. DI is a must have...there are a lot situations where I want to know exactly what's directly underneath the boat.

[siwash]

  On 4/15/2025 at 12:51 PM, CrowMan said:

From what I see out in the market...any unit that has SI also has DI. A lot of units are only DI, but I'm not aware of any units that are only SI.  Perhaps someone can correct me.

Personally, I use SI all the time, but it's not a necessity. DI is a must have...there are a lot situations where I want to know exactly what's directly underneath the boat.

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This is what I assumed regarding DI. I just figure that what is under my boat is more important. Although, I guess if you're casting to either side of the boat, SI is useful. Correct me if I am wrong. 
 

that's good to know that the units that have SI also have DI. 
 

thank you! 

Edited April 15 by siwash

[chessy]

I use Si to get me close.. then I use live scope for the rest ...  live scope all the way .. 

 

[BillM]

I use 2D sonar way more then I use DI.   I use SI ALL the time to find weed edges, rock humps, etc etc.

SI all the way over DI for daily fishing duties.

[boombap]

Pay the extra and get SI

[BassMan11]

SI is way more useful than DI. If you can swing it I would make sure to get a unit with SI and the biggest screen you can afford. 

[siwash]

Yes going for SI for sure.... 7" but I'll see if a 9" comes up. Might be a bit too big Do you think the "mega" series hummingbirds are worth the extra $?  I am sticking with hummingbird as I have a terrova and I am already rigged up with a Helix 

Thanks for the input 

[siwash]

So with those hummingbird helix models, if I get the Mega SI how far out does the side image capture? Are we talking several feet? More than 15'?

[siwash]

Another question I have is should I get a "Network" model?  I am assuming this means that the different units on your boat can be linked wirelessly ?  Can they be linked via hard wire?

[petersaban]

My Garmin has a 70' range, slightly more over hard bottoms. The Mega SI is far superior so likely much farther than that

[Fang]

Like Bill says, SI is on all the time on my units. I've found so may new small rock humps, transitions to fish in waters I really thought I knew. When it's dialed in right I am now getting the hang of picking up fish laying on or just off the bottom as they produce a unique radar shadow behind them. Works incredibly well in clean open hard bottom areas. On my humminbird I can waypoint the SI spots and turn back on them. Found a nice bunch of walleyes last summer sitting on a flat gravel bar surrounded by mud by using the SI and the fish just popped off the screen. It was like one of these perfect commercials you see.

[limeyangler]

  On 4/16/2025 at 3:21 PM, Fang said:

On my humminbird I can waypoint the SI spots and turn back on them. 

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I also do this with my ‘bird. I agree with lots on here saying get SI over DI.

[Terry]

Si is great for finding structure and you can go back and fish it 

you have to be moving for it to work effectively but not too fast 

I never had any use for di  my regular sonar does far more for me 

[siwash]

  On 4/16/2025 at 3:04 PM, petersaban said:

My Garmin has a 70' range, slightly more over hard bottoms. The Mega SI is far superior so likely much farther than that

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Oh wow! These things are like mine sweepers!  😁

 

Thanks

[siwash]

Di you guys have the 'N' models (networking) ?

[limeyangler]

  On 4/16/2025 at 4:30 PM, limeyangler said:

I also do this with my ‘bird. I agree with lots on here saying get SI over DI.

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I found some awesome brush piles doing this last fall, took about half an hour to find them all in an area of  about  6 acres with SI set 90’ either side. Circled back and picked them off with FFS in down mode.

 

 

Edited April 16 by limeyangler

[BillM]

  On 4/16/2025 at 5:27 PM, siwash said:

Di you guys have the 'N' models (networking) ?

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Everything after G2 has networking by default.

[BillM]

  On 4/16/2025 at 1:12 PM, siwash said:

So with those hummingbird helix models, if I get the Mega SI how far out does the side image capture? Are we talking several feet? More than 15'?

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I usually keep my SI at 60-80ft per side.  Further out you go, the more degraded the returns will be.   

[siwash]

I wonder why the have a "network" option? It cost more too...

[smitty55]

  On 4/17/2025 at 7:50 PM, siwash said:

I wonder why the have a "network" option? It cost more too...

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It's so you can link all your instruments.

[siwash]

I ended up buying the Humminbird HELIX 7 CHIRP MEGA DI GPS G4 at Cabelas in Barries yesterday.  Will be setting it up over the next week on the boat. And now to decided on where to set it up - bow or console. I currently have. a Helix 5 up at the bow. I have been fishing mostly at the bow with the boat I bought last year. My Terrova is a bit older so doesn't have i-Link. I am most likely going to set this up a the bow and put the 5 at the console. Looking forward to exploring the world of Side Imaging!

 

Thank you to you all - as usual, always helpful and generous with your input and expertise! I am sure I will have some questions along the way!

Edited April 20 by siwash