Water temp. effecting sonar?

[John J.]

I headed out to my home Lake (Lake Orange) yesterday evening where the air temp was 50 and the water temps was the mid to upper 40s. I launched my boat and immediately noticed my sonar unit (which is a suction cup mount) was giving an inaccurate reading of 8'9" no matter where I went on the lake.

I even went to the dam where I knew it was 25' deep (because over the summer my sonar gave the reading) and the sonar still showed 8'9" water...It displayed the temperature correct: 45 degrees at the surface, but the sonar readings were wrong.

I read in an article I believe for the North American Fishing Club magazine that I get that cold water temps makes the sonar read inaccurately or something.

Does anyone have any idea? And at what water temps is the sonar going to function properly?

ps: I made sure I had everything set up correctly. The suction cup was in place right and everything, so it wasn't the set up.

[Bud]

Something is wrong with your DF.  Sould not make any difference.

[Wayne P.]

I have never heard of that effect and have not experienced it either. I have used several brands of sonar units with readouts as Flasher, LCR, and Paper in water temps from 38 to 95. As a guess, you may have low battery power, damaged cable, or bad transducer.

[Jig Man]

Yep I'd say you have a problem.  Colder water is usually clearer and the sonar works better.

[Wayne P.]

John, what brand/model of sonar do you have? I may have a set up to match for trouble shooting.

[John J.]

Hey Wayne, the model is a Eagle Fishmark 480 portable unit.

Maybe the battery was dying, I will recharge it and see. I never thought that cold water would have any influence either, but I do remember reading one article about cold water and sonars, I don't remember if I read that it helped or hurt it...

That's probably it, the battery is running low...it would make sense to me.

[Wayne P.]

John, I have a Fishmark 320 and the cable matches yours. If you need to test your unit after you do the battery charge, just let me know and I'll meet you in the Orange area.

[John J.]

I talked about it with my folks and they say that there's no way the sonar is affected during cold water. Then I found my manual and I looked in the troubleshooting section and it said that if it was giving innacurate readings or hardly any reading at all that the battery must be low.

And it does make sense because I charged it once I got it during the summer I think in July...and used it the rest of the summer. So yeah I believe it was just the battery.

Not to mention the times I ran it on the demo mode when I first got it, trying out how each function works and what certain modes, levels of sensitivity and how everything looked on the screen.

I don't need to waste your time Wayne, I know you got more important things to do. It's in the charger now and I will pick another day either during this winter that's warm to test it out or wait until spring. The one year warranty hasn't even expired so I still got it.

If it doesn't accurately read this spring then I will let you know. I truly believe it was just the battery...my mistake lol!!!

Sometimes I feel like banging my head against the wall over stupid things I do lol!

Thanks for the offer anyway Wayne! How's the fishing been doing? Have you had any luck?

[Wayne P.]

In case you did not know, you can download a simulator for your unit and practice on your computer with the settings to become familiar with it. So far this year I have caught the most number of bass I have ever had in a year's time (2,479). Being retired has it's advantages. Randy and Kevin fished with me in the Joseph Thompson Memorial Tournament held in November. We won it again as a team. Did you get a chance to fish Hunting Run Lake before it closed for the winter?

[mayassa]

http://books.google.com/books?id=jKOooXbigT4C&pg=PA36&lpg=PA36&dq=thermal+ducting+water+sonar&source=web&ots=dmJZeKf0-N&sig=3drVZzcPmdeo_QAcHbdl5kuJ8cQ

Water temps do effect sonar, thermal ducting,  never seen the hunt for red October, but its usually at sea.

[John J.]

In case you did not know, you can download a simulator for your unit and practice on your computer with the settings to become familiar with it. So far this year I have caught the most number of bass I have ever had in a year's time (2,479). Being retired has it's advantages. Randy and Kevin fished with me in the Joseph Thompson Memorial Tournament held in November. We won it again as a team. Did you get a chance to fish Hunting Run Lake before it closed for the winter?

Yeah I downloaded the demo version on the PC too but that was after I had already tried it on the sonar lol. Not surprised you guys won it lol!

No I didn't get a chance to fish Hunting Run Lake, I had college...I have a little break now until the 7th of Nov. before my next term starts...

I am sure you'll catch plenty more bass! I am kind of waiting out the winter. I am going to get a trailer for my 12' jon boat before spring that way I don't have to man handle my 200 pound jon boat by myself.

Good luck!

[Sam]

John,

Get that degree.

Get a good career.

Save your money.

Don't get married.

Buy nice bass boat.

Put a Lowrance unit with the WASS on it.

Catch a lot of fish.

Get Married.

Buy house; buy furniture; get dog; have a bunch of kids.

Put boat in garage.

Forget boat but play with sonar and WASS unit from time to time while in driveway.

But what ever you do, get that Lowrance unit on your boat, professionally installed.  It is super.  I love my unit.

And the best thing about it is that you cannot get lost.  It tracks where you have been and where you launched.  

[George Welcome]

Temperature affect: only a thermal gradient, (thermocline) has an effect in that it will cause a return of signal. Above and below the gradient however will give the same return dependant on the bottom. So, in essence, temperature does not affect the sonar reflection.