need help with my sonar getting crazy depth readings

[minicuda]

I have an eagle fish mark 320 on my 16' flatbottom. It works fine in shallow water but when i get into deeper water it gives crazy readings like 1100' when the water is only around 200' deep. I also have a cheapo bottom line that came with my boat, I thought I may have been getting interferance from the transducer on the bottom line 1100. the bottom line transducer frequency is 455KHz the eagle is 200KHz so I'm thinking they shouldn't interfear with each other but I have no experiance with sonar. If anyone has any ideas of what might be wrong I would be very greatfull.

[baitsauce]

Originally Posted by minicuda

I have an eagle fish mark 320 on my 16' flatbottom. It works fine in shallow water but when i get into deeper water it gives crazy readings like 1100' when the water is only around 200' deep. I also have a cheapo bottom line that came with my boat, I thought I may have been getting interferance from the transducer on the bottom line 1100. the bottom line transducer frequency is 455KHz the eagle is 200KHz so I'm thinking they shouldn't interfear with each other but I have no experiance with sonar. If anyone has any ideas of what might be wrong I would be very greatfull.

I've been waiting for a post like this. The mods removed a post of mine on this subject because I didn't sign my name. I knew it would come up again so I waited.

Here goes:

Eagle sonars are junk. I ought to know 'cause I have one. Mine gives the same readings too. I've been told the problem is the 200khz frequency is to high to see the bottom much below 100 ft. However, mine also gives those kinds of readings other times too. I'd get rid of this ***, but it's already mounted in my boat and not worth anything to sell second hand. Besides, my concience won't let me sucker someone like that (by selling or even giving it away to them).

Additionally, the skimmer/tranducer sucks too. They are a weak design. They break easily. To easily. Before I get any PM's saying I don't have it mounted correctly, I won't get into it here but it is mounted correctly. Then if the tranducer doesn't break off it needs to be "reset" often so it is paralel with the waterline. Everytime its "reset" it wears on the mounting making it need to be "reset" even more often.

However, I fixed my Eagle by spending the money and getting a Raymarine dual frequency sonar with a color display. It is like night and day.

Since the *** Eagle is already mounted up in my boat on the dash, I mounted the Raymarine back by the kicker so I can see all the details it shows on the screen with my aging eyes. Believe me there is a lot of detail too.

When the Eagle on my boat finally dies I'll be replacing it with another Raymarine because it's pretty nice having two sonars on board.

I am James Rawls and I approve this message because I want to educate folks so they don't make the same mistake I did in purchasing a *** Eagle sonar.

There. Rant over. Hope this helps.....

//

[Tinman]

Originally Posted by minicuda

I have an eagle fish mark 320 on my 16' flatbottom. It works fine in shallow water but when i get into deeper water it gives crazy readings like 1100' when the water is only around 200' deep. I also have a cheapo bottom line that came with my boat, I thought I may have been getting interferance from the transducer on the bottom line 1100. the bottom line transducer frequency is 455KHz the eagle is 200KHz so I'm thinking they shouldn't interfear with each other but I have no experiance with sonar. If anyone has any ideas of what might be wrong I would be very greatfull.

200 kHz systems can't read bottom in ~200 feet of water. That's why many marine fishfinders use 50 kHz, or better yet, dual-range 50 and 200 kHz. If you want deep water performance, opt for a dual-range unit. I have the Furuno LS4100, which cost ~$300 and has both 50 and 200 kHz. The reason for the 200 kHz is it gives better resolution in shallow water.

[ANDYCOHO]

The best way to cure the 'roaming' depth is to set it to 'manual depth' and set you upper limit to '0' and your bottom limit to '?' (approximately what ever depth you are fishing).

Only run 1 fish finder at a time. I can see other boats fishfinder's 'sonar returns' on mine a solid 100 feet away, so I can imagine that 2 fish finders extremely close together would interfere with each other no matter the frequency.

When I mark other folks fish finder 'returns' its a combo of solid and broken vertical lines through my screen.

[bullshooter]

Originally Posted by ANDYCOHO

.

When I mark other folks fish finder 'returns' its a combo of solid and broken vertical lines through my screen.

Very interesting, I have always wondered what causes that issue. Learn sumpin' new every day.

I too have never had great success with transducers, until i went with the airmar p-66. Now I am seeing my halibut jig on the drop and on the retrieve, I even watched a halibut come up from 300ft. I now have a lot more confidence in my sonar. I also endorse Baitsauce's review of the FF in question.

[hot wire]

I have to jump in here and clear a comment that I just read-

A boat with a transducer operating at 200khz definetly can hit ranges COMFORTABLY at 600'. The problem with SOME units-Lowrance units, is they only have 300watts. That's not alot. The industry midline wattage is 600watts.

Also, the reason that some people may use 50khz (as oppossed to 200khz) in the OCEAN, is two fold.
One, the cone is wider and the rocking in the ocean will allow for a wider cone to consistantly strike the ocean floor--(think of a red laser beam trying to hit the ocean floor instead of a wider flashlight beam.)
Second is signal disbursement within water columns. Heavyer water densities are mare difficult for higher freq's to penetrate.

I almost never use 50khz. When I do, it's to look for bait balls close to the surface where a 200khz transducer would maybe let me see an 8' circle versus a 40' circle with 50khz....