Humminbird Fish Finders

[IowaMichael]

In comparing two locators the Sonar Coverage for one model is: 200khz/20degrees-@10db

455khz/(2)35degrees @10db

The second is:

83khz/60degrees @10db

200khz/20degrees @10db

Would one of you be able to explain this info in basic terms that I'll understand.

Thanks

[Tator2k]

Each listing is for a Size and freq of the sonar cone used to scan. In case each one has a dual sonar cones or more.

Without looking at Humminbird's HSOforum and looking at models I would say the top one has side imaging and bottom is standard 2 zone down scanning (not down imaging)

[Ed Carlson]

Basically width (degree) of sonar beam coverage is the big difference here.

First option is best for deep water use...on average.

Second is better suited for more shallow water use as it has a wider spread of sonar coverage.

20 degree is an average cone angle coverage range and serves the angler well in the widest range of depths in freshwater use.

[PerchJerker]

200 khz is generally the best frequency for freshwater lakes and depths we have around here - 200 khz means the frequency at which the sound waves move through the water and reflect back off objects.

The 20 degree transducer tells you how wide the beam is or how big of an area you'll be looking at on the bottom. 20 degrees is also generally the standard, and the rule of thumb is to divide the water depth by 3 to see how big of an area you're looking at on the bottom. For example, in 30 fow you'd be seeing a 10 foot area, or 5 feet out in any direction from the transducer.

The 83 khz 60 degree beam shows you a much bigger, wider area of the bottom, but will not give you as good of definition. This is something you'd typically use in shallow water. I have run my electronics on 83 khz and not liked it, I run them all on 200 khz.

The 455 khz beam is what HB uses for down imaging. If you go with a HB or Lowrance Side Imaging or StructureScan unit, you'll be able to choose between 455 khz or 800 khz. 800 gives better resolution, 455 gives more range and depth. Side imaging and down imaging works at much higher frequencies, and the transducer beams in the water are more like thin sheets of paper shooting out to the side or down, vs conventional sonar which is more like a beam of light from a flashlight (the farther it goes, the wider it gets).

Hope that helps.