Down imaging question

How wide is the down imaging beam below the boat? Does it vary as much with depth as regular sonar or far more specific? Does the “slice” go forward-backward or side-side?
Reason for asking is, I read somewhere that it shows directly what is below your boat v/s regular sonar in which the objects displayed could be anywhere in the cone.

If it is very specifically, directly below the boat, that would also explain my not marking near as many fish with DI as I noted in a previous post.

Jeremy

The man to ask is jason halfen sp???? Sorry jason…. after listening to him last night at walleye searchers he certainly knows his stuff on these units and will be my “go to” guy when I quit beingv cheap and get one of them! Very cool units tho!

Sorry Doc, missed your question.

Fishwater has a pretty good feel for the issues. Humminbird won’t be releasing the specific measurements of the DI coverage areas, but it’s clear to me, after about 6 months of use, that the Wide setting definitely shows more (and captures objects that are just off to the sides) than does Narrow.

Thanks, and think that explains my going over fish and only marking one or two with DI as noted in a previous post. I’ll play with the settings.

Doc here is what Humminbird told me on this question when I asked about my 987csi.

Quote
“Denny O,
Just like the other Si units we have or have built; the Di sonar comes from the Si sonar so it would be the full width of the Si sonar if set to the Wide mode. I don’t know what the width would be when on the other Down Imaging Beam Width menu settings.

_________________
Greg Walters at Humminbird”
Unquote

Quote:

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Doc here is what Humminbird told me on this question when I asked about my 987csi.

Quote

“Denny O,

Just like the other Si units we have or have built; the Di sonar comes from the Si sonar so it would be the full width of the SI sonar if set to the Wide mode. I don’t know what the width would be when on the other Down Imaging Beam Width menu settings.

_________________

Greg Walters at Humminbird”

Unquote

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100%

So here’s my question, and I know the answer is in here somewhere, but I can’t find it.

How do you get DI? Is DI only available on certain units? Or will they come with it as well as SI? For instance, would 898cSI have it? The 998cSI?

New units (2010-798, 898, 998, 2010-1197) will have DI pre-installed.

Older, yet still compatible units (including 797, 798, 997, pre-2010 1197s) get DI though a free software update from the Humminbird website.

Thanks for the clarification, Jason.