Front fish finder interferenc

[mtstringer]

Hello all, Need some help here. I have a trolling motor mounted fish finder transducer. The old finder I had would get interference when I would run the trolling moter and come back clear as soon as I stopped. I was told this is because of a bad ground. Well I had a seperate ground and still had the problem. So I went and got a new fish finder with a puck mount transducer just for trolling motors and hooked it up to both the original wiring and the new wiring that when from the fish finder right to the cranking batter. Guess what, $250 later and I still have interference when using the tolling motor... any idea's? HELP!

 

[Silvertip]

Re: Front fish finder interferenc

Lesson learned. Don't cut off your leg because you have a headache. The trolling motor is the cause of the interference -- not the locator. Installing a filter in the power leads for the locator probably would not help since the interference is more than likely from the motor which is right next door to the transducer. My suggestion would be to remove the transducer from the motor housing and then just lower it over the side of the boat while you run the motor. If the interference is gone, the puck is picking up the noise. If the interference is still there, the power leads are picking up the interference and a filter circuit in the power leads would probably help. Radio Shack can provide the pieces. Ask for a radio noise suppressor.

 

[Texasmark]

Re: Front fish finder interferenc

Good advice Silver.

I run the Eagle Cuda 168 EX on a 55-70# (forget exact number) Motor guide, strapped to the underside of it. Have no problems.

I don't know the differences between our equipment but what you want to do will and does work.

If you are unsuccessful, I can pull out my troll motor receptacle and see how the wiring is connected. Gonna bet that the flasher is just wired into the TM wiring with no suppression and no separate wiring.

Something else would be physical vibration from the TM. Since the transducer is a vibration to electrical signal generator (piezo crystal) it is possible that it is physically being vibrated by the TM.

If Silvertips tip test works, before you do anything else you might foam insulate your transducer from the case of the TM. Foam water pipe insulation would work great....the slick gray stuff, comes in about a 4-5' stick, with the glue along the mating surface type stuff. It has bubbles in it for insulation (sound and temp) but is firm enough to support a mounting strap. Works excellent in isolating a room air conditioner from the house mounting.

I'd wrap it completely around the TM and put the strap around that. That would keep you from having anything in the way of the transducer and what you want to see.

Good luck.

Mark