Interferance Problems

I currently installed a new Elite 7 HDI and a MinnKota powerdrive 24 Volt (does not have universal sonar) on my boat. Everything works properly when the TM is not going. As soon as I hit the go button on the foot pedal I have bad interferance. It distorts the picture best described as it looks like turbulance in the water. I heard putting a ground from TM batteries to cranking batteries but my TM batteries are in front of my boat. Ive also heard of an RF choke. Or ive also thought about putting a piece of rubber between by cable clamp for transducer and motor. Any thoughts?

Are you getting power for the Elite 7 from the starting battery? Here is a sticky on RF problems http://www.crappie.com/crappie/showt...F-Interference

Yes. Power for Elite 7 is from starting battery. So you think a simple RF choke from radio shack will fix the problem.

It has on a lot of units.

I will say I do have my transducer wire ran thru my curly cable of my powerdrive.
So where exactly do i need to put the choke. On ground on powerdrive by plug...on elite 7 power cable? sorry im new to this high tech electronics. :)

Post pictures of the screen. It may not be interference. Could it be prop wash and a transducer mounting issue. If it is interference it will do it when not in the water. Just turn the unit on and hit the power on the trolling motor and see what it does.

Thanks for the ideas guys.great help!will post pics soon!

I have had interferance problems for years on both lorance and humminbird units it is caused by the variable speed switch on the trolling motor , the only surefire way I found to cure the problem is to use 3 ferrite rings on the transducer cable , then ground the sonars units ground wire to the trolling motor skeg by running a length of wire that should solve your problem, all other things I ever tried never worked

I just had some issues with a new HB and used the ring on the transducer cable for unit. Then I put a stripped wire under the hose clamp for the transducer, put another hose clamp on the shaft and tied in there with a wire ran from the negative side of the TM battery. (made all the metal parts on the TM common with the negative of the TM batter) I also put a wire between battery negatives but you can try it without first....bottom line is you are going to need to ground the TM. I also split up the transducer cable and power cable for the TM. I am working like a charm now

The ferrite ring helped a little on my bow 998 but what finally got rid of the interference when I hit to TM pedal was rerouting the transducer cable from along the TM steering cable to along the TM bracker itself. I also better organized and separated the wiring under the bow panel. I don't have my 998 power cable wired directly to the battery. It is wired to the power block under the bow panel.