Reading through my manual on my new 1197 and it says that when in the SI screen I have a choice of either 800 KHz for a sharper image or 455 KHz for better bottom structure. Thats all it states. So is it telling me that if I set it at 800 I won’t be able to see the bottom?
I use 455 98% of the time.
If you run 800, be prepared to dial down your sensitivity vs. your normal 455 settings.
I’ve only powered up my unit twice so I don’t really have any normal settings yet. Just trying to get a handle on this SI thing. Have you found while running the higher of the two that you lose bottom structure detail?
No, you will not lose bottom information using 800. It will, however, tend to wash things out, which is why you’d need to dial down the sensitivity to start to see contrast again (instead of just a field of bright white).
The effective range of the 800 kHz is less than that of the 455, but in typical places that we all fish, that difference won’t impact your ability to image the bottom.
Jason,
why the 455 v/s the 800.
If the 800 will give better detail, wouldn’t that be better-even with the range being less?
Also, can you run the 800 for down imaging and 455 for the side imaging? I could see the 800 being great for down imaging portion with the sharper resolution.
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Jason,
why the 455 v/s the 800.
If the 800 will give better detail, wouldn’t that be better-even with the range being less?
Also, can you run the 800 for down imaging and 455 for the side imaging? I could see the 800 being great for down imaging portion with the sharper resolution.
Doc, I’ll attempt to answer. In medical ultrasound, the higher frequencies = better resolution however they will not penetrate as deep. I’ve tried to correlate this to fish-finders with limited success. However that’s how I’ve traditionally used my HBs. Shallower water imaging (switch over to 800 kHz) IF I’m interested in detail of some structure. However I’ve never really found the 455 kHz lacking in ability to image and provide quality data.
The gains (sensitivity) seems to be defaulted way to high on the 800 kHz. Every time I turn it on, I get a WOAH in my head. If the gains are set to high, you could actually loose data as it can be bled out with overriding signals from brighter structures.
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However I’ve never really found the 455 kHz lacking in ability to image and provide quality data.
I haven’t either..
To echo Jason, I’ve used the 455khz about 99% of the time on the water. Very detailed and seems less picky about settings.. Really not much reason to mess with the higher freq, although admitedly I just haven’t played with that setting much at all…
Does anyone have a feel for what is too deep for the 800 setting?
No, but I’ve used the 455 in water over 100 foot with no problems…
Thanks guys, think you answered it.
The Humminbird and Lowrance units are quite different in their respective performances using these 2 frequencies. The Humminbird is best in on the 455kHz (unless very shallow), and the Lowrance is best on 800kHz.
800 kHz SI images:
Doug, which do you prefer the 800 or 455?
I use 455 kHz probably 80% of the time for the added coverage area. 455 kHz covers 180°. The 800 kHz is more downward focused and covers about 110° (55° to each side). I use the 800 KHz to learn more about what I find and need more intricate details.
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