Thread: FYI Sonar interference with MinnKota's

I know a couple people have sonar interference that use an AutoPilot trolling motor. I recently installed an AP and also getting sonar interference.

MinnKota sent me a couple wires to install. One was for connecting the negative posts from the starting battery and the trolling battery. The other was for grounding the brush plate in the motor to the ground on the control box in the head. This 'fix' did not reduce the interference.

Out of curiosity today, I turned the depth finder on while running the trolling motor. I unscrewed the hose clamp for the transducer and immediately noticed the interference had stopped. I thought I would put a thick piece of rubber between the transducer and the motor to see if that helped. It did not. While the soanr and tm was on, I re-connected the hose clamp and the interference was back. I removed the "metal" hose clamp and installed the transducer with a large zip tie. No more interference.

I believe the hose clamp was picking up the magnetic field in the motor. If you are having this issue, try the zip tie.

Good Post Bet That Helps Someone Out Even Save The Some Time And Money Good Work.

I still get a little int. on the 777 but I have the built in transducer. any thoughts on that ?

Originally Posted by beagle man

I still get a little int. on the 777 but I have the built in transducer. any thoughts on that ?

No sorry, but I would call MK and request the kit they have for interference, it may or may not work on the built-ins.

Great post Charger. That type if information is what makes this such a great site.

Wonder if there is any problems when using a separate battery to power each system. I like my TM to be powered by a different battery. I also like having juice left after a solid day of fishing to fire up the big boy motor.

i power my auto pilot with a seperate battery and i get some interference when i move the speed bar to a certain point. im gonna get me some zip ties and see if that will stop it. thanks for a great tip.

I had some interference on MY 797 also and I called the number listed and they sent me a kit to stop it and it worked. Just read the text from Humminbird above the video.
Side Imaging Demo Video 3 | www.***************

Good luck