Understanding SI Frequencies and Coverage Areas

[Doug Vahrenberg]

First you need to understand Frequencies and Cover Areas. 455kHz gives total water column coverage with Humminbird Side Imaging and 800kz is more downward focused and you lose the upper water column coverage to the sides. Why would you not want to see everything???? I'll give up a little detail from the frequency difference so I can get total water column coverage. Isn't this the reason you invest in the technology to see more and everything??? But some may want to look at the structure in more downward focus or looking for more details within the details. That is why Humminbird Offers 2 Frequencies with SI and the coverage differences to give you the choice.

With Humminbird 455kHz coverage is user selected for the amount area covered. With 800kHz since the beam is more downward focused you'll only get about 3 Times the Depth Coverage.

This image that shows Water Coverage of the two frequencies should help you understand more. I colored the SI Coverage: Light Yellow on the 455KHzz on the left and Pink on the 800 kHz. Does this help???



Now for some comparisons...

800kHz of a Rock Quarry (I flipped the image so the details would be the same since I turned around and recaptured the exact same area}



455kHz of a Rock Quarry



So if you are comparing images you need to compare apples-to-apples - same frequency and coverage.

[kraetzer]

Hi Doug,

So are you using the 455/800 combo in shallow water and than switch over to the 800 in deeper water (and if so what's the depth where you would recommend to use the 800 setting)?

[Doug Vahrenberg]

I use 455kHz 90% of the time because I want total coverage of the water column. The only time I use 800khz is for special applications when I want to see more details and a more downward look at the structure.