Structure scan frequency

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Rob
Posts: 141
Joined: Sun May 08, 2005 12:57 pm

Structure scan frequency

Post by Rob »

What is the best structure scan frequency for most freshwater fishing? I thought it was 400 but in the post about overlaying downs can on sonar it was mentioned that 800 is best. Can you explain the differences? Thanks
Ken Sauret
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Re: Structure scan frequency

Post by Ken Sauret »

With any sonar frequency, the higher the frequency, the better the detail. On Lowrance Structure Scan, 800 khz will be better definition and detail down to about 80 to 100 feet, then switch to 400 khz.

Water wants to absorb sound. The higher the frequency, the quicker the sound is absorbed and there will not be any return or very spotty return from the bottom and the unit can't keep a bottom lock or draw the bottom on your unit.
The lower the frequency, the better the depth penetration but you loose a little of the definition. Although, it is better to see the bottom with a slight lose of detail than not to get the bottom at all.

Short answer, 800 khz is generally better for freshwater, especially bass fishing. 400 khz is better for salt water or deep trolling in fresh water.

It takes just a couple quick button pushes or screen touches to change from 800 khz to 400 khz and back again so just change back and forth and see which khz if giving you the best picture and return of the structure on any given day. Then leave it on that frequency until you need to check which is better again as you move from place to place.
Ken Sauret
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Rob
Posts: 141
Joined: Sun May 08, 2005 12:57 pm

Re: Structure scan frequency

Post by Rob »

Thanks Ken!!
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