83 khz vs 200 khz. sonar depth fish finders. dual frequency vs single frequency

okay, I'll be lazy here. I'm asking about the dual frequency feature on the eagle 245 DS.

what's up with the dual frequency stuff on the DS? it seems like I have to choose one frequency or the other? I thought they would both be used at the same time?

J

Can you split the screen to run both frequencies?

I'm pretty sure the lower freq is better for deeper water or salt and the higher was better suited for shallow or fresh.  Don't quote me on that tho.   

well, low frequencies generally travel further (longer wavelength/period). so I think you are on the right track...

But no, I don't think you can see both at the same time cause there is a configuration screen where you choose between 200Khz and 80khz for the sonar.

on my other kayak I have the model that is almost identical, but a little less power and only 200Khz, the cuda 242. I think other than turning off the temp display and turning on zoom, I use one button on that guy: on/off and am very happy with it.

I got the 245 DS in an internet only deal on cabelas ($70!) and got no manual. but did get an extra mounting bracket...

I know a lot of folks use this one like jelly and KZ, so I'm curious about the settings they use.

Maybe I'll have to find the online doc for this unit to understand when to use 80 and when to use 200...

okay, here we go:

http://www.eaglesonar/com/Products/Sonar/FishEasy245DS.htm

manual:

http://www.eaglesonar.com/Downloads/Manuals/Files/FishEasy245DS_0143-832_60607.pdf

the other one I have:

http://www.eaglesonar.com/Products/Sonar/Cuda242.htm

manual:

http://www.eaglesonar.com/Downloads/Manuals/Files/CUDA242_0143-842_3-02-06.pdf

this says up to 800 feet**. but at moss in 400 feet it gave up... was good to about 220 feet in jelly-infested saltwater! but works great rockfishing and freshwater and I have been out 8 times this year without recharging my 8 amp/hour battery!

J

 

the manual is somewhat contradictory...

early it has a marketing style blurb that suggests 83 khz is better all around, but later we
get the brittle technical writer's version of the what dilbert is telling her:

Frequency

Your sonar unit can transmit signals at 83 kHz and 200 kHz. The default
frequency is 200 kHz, best used in shallow water (about 300 feet
or less). This frequency is the best choice for about 80 percent of the
fresh and salt water sport fishing applications. When you get into very
deep salt water, up to 1,000 feet, the 83 kHz frequency will work best.
The 200 kHz transducer will give you better detail and definition, but
less depth penetration. You will not get as much detail or definition with
the 83 kHz frequency, but it has greater depth penetration and up to
120° of wide fishing finding coverage. Remember, all sonar units typically
read deeper in fresh water than in salt water.
To switch the Frequency, repeatedly press MENU until the Frequency
menu appears. Press ↑ to select 200 KHZ or press ↓ to choose 83 KHZ. Press
PWR to clear the Frequency menu from the screen.

So to me, that means the DS is a waste of money, as you will always use the single 200khz beam
for coastal kayak fishing. go with the cuda 242! unless you are salmon fishing a lot
and want to know that you are in 400 feet of jelly infested water.

since I have both the cuda 242 and fisheasy 245 DS, I can tell you that the 242 uses less battery power.

Also I know two experienced guys that had their fish-symbol feature on, but the manual pretty much says:

Fish I.D.™
The Fish I.D.™ feature displays — as fish — targets that meet certain
conditions. The microcomputer analyzes all echoes and eliminates surface
clutter, thermoclines and other undesirable signals.
The Fish I.D. feature displays symbols on the screen in place of the actual
fish echoes. There are three symbol sizes: small, medium and
large. These show the relative size between targets. In other words, it
displays a small fish symbol when it thinks a target is a small fish, a
medium fish symbol on a larger target and so forth.
Fish I.D. is an easier way for a sonar novice to recognize a fish signal
return when he sees it. But, locating fish by symbol only does have
some limitations.
Your sonar unit's microcomputer is sophisticated, but it can be fooled. It
can not distinguish between fish and other suspended objects such as
trotlines, turtles, submerged floats, air bubbles, etc. Individual tree limbs
extending outward from a group of limbs are the hardest objects for the
Fish I.D. feature to distinguish from fish.
To see what is under your boat in maximum detail, we recommend you
turn off Fish I.D. and begin learning to interpret fish arches.
You may see Fish I.D. symbols on the screen when actually, there are no fish.
The reverse is also true — Fish I.D. can actually miss fish that are present.
Does that mean Fish I.D. is broken? No — the feature is interpreting sonar
returns in a specific way to help take some of the work out of reading
the screen. Remember: Fish I.D. is one of the many tools we provide so
you can analyze your sonar returns for maximum fish finding information.
This and other features can help you "see" beneath the boat under
varied water and fishing conditions. So, practice with the unit in both the
Fish I.D. mode and without to become more familiar with the feature.
This unit's default Fish I.D. setting is on.
Fish I.D. is most handy when you are in another part of the boat or performing
some task that prevents you from watching the sonar screen.
Then, you can turn on Fish I.D. and the audible fish alarm. When that
lunker swims under your boat, you will hear it!
Fish I.D. can also be useful when you want to screen out some of the sonar
detail gathered by your unit. For example, it can help cut through
the clutter of suspended bubbles caused by wave action or boat wakes.

manual also says FISH ID is on by default, but it was not on my two units (as I recall).

Best,
J

Manual also says the unit will operate at speeds up to 70 mph.....

Manual also says the unit will operate at speeds up to 70 mph.....

manuel (he's a guy I know in miami) suggests using only the best trolling motor to hit these speeds...