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Help 455 vs 800 khz
The lake I normally fish has a maximum depth of about 20 feet. I have been running a 798 with SI set at 50 feet. Will I be able to run the 800khz sonar and set the range at 75+ feet and get the same amount of coverage with better resolution? I am also interested in your width/freq settings that you use in normal fishing conditions and if you change those when you are doing screen captures.
Thanks for all the good info and pics in previous posts. It gives me an idea of what to shoot for.
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The 798 is not capable of producing the 800kHz frequency....it just doesn't have the processor needed to run the 800 frequency ...
Some have replaced their stock compact SI xducer for the longer XHS 9 HDSI 180 T but the 798 will still not be able to use the 800kHz ...
The physically longer elements in the HDSI xducer can produce more detailed images..(longer element means thinner beam which means better detail...)
Whether you can actually see the difference on the 798's 5 inch screen may or may not be evident to your eyes...
Others may chime in to offer their experience with the HDSI xducer on the 798...
(I set my SI Range farther when looking for new structure...drop a waypoint on interesting stuff and then set the SI Range shorter when I get closer to the new structure ...because shortening the SI Range makes structure look bigger on the display...sometimes I even set the display to 1 side only to enlarge the structure on the display even more)...
Rickie
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I've just added a 998 to my network, and was wondering how much better the 800khz view is. Hopefully I'll be able to get on the water sometime before the weekend and see if there is any difference. The Ethernet connection is working well between the 798 and 998 so I'll be able to try the 455 on the larger transducer as well as the 998 on the smaller transducer. What I am hoping is that I can run the 998 at 800khz with a wider side to side width and get the same coverage as the 455 on the 798, but with better resolution.
I just reread my original post and it seems I never mentioned the 998. :biggrin
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Here is a comparison depiction I captured of the same structure using 455kHz vs 800kHz...(all settings and criteria were exactly the same except for frequency choice ... )
Each frequency choice has advantages and disadvantages...
*455kHz is brighter all the way out to the sides of the SI image...but overall blurrier..
*800kHz is crisper in detail of the structure ... But darker out to the sides of the SI image ...
http://i477.photobucket.com/albums/r...ps8630f91a.jpg
Frequency choices are tools best used for certain tasks in certain situations...
*Because the 455 is brighter out to the edges of the display...it is really good for seeing suspended fish out to the sides of the boat ...or marking structure out to the sides for further "close" inspection with the 800kHz...
*Because the 800 is crisper...it is really good for deciphering the structure close to the boat...or picking individual fish out of structure..
Choose the frequency in each of your fishing tasks that best accomplishes what you need the sonar unit to tell you for that specific task ...
Rickie
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Thanks Rickie. That is exactly what I was looking for.