Just can't get rid of the interference.....HELP!

[Nate4Fishing]

I have a motorguide tour 82 and a Lowrance Hook2 7 tripleshot on the bow. I have added chokes, ground the trolling motor and moved wires away from other wires and I just cant seem to get rid of the darn interference on the bow graph. When I grounded the trolling motor it helped some and made the lines across the screen darker, but nevertheless still there. On high bypass I have no interference due to it not running through the digital controller. Any suggestions? I also unhooked the battery charger from my graph battery so as to not make a "bridge" to my trolling motor batteries. Do I really have to run dedicated power wires all the way up to the graph?

[Champ 2001]

I would say YES!

[clayrhye]

That should be the first thing you do when adding a graph. It makes a huge difference. Is your interference only when the troller is running? Do you have any screenshots we could look at?

[Bill Reynolds]

Is it your 2D sonar that has the interference?
If so try these settings: ping speed max, scroll speed normal, noise Rejection high, surface clarity medium

[bobcoy]

More times than not the transducer cable is the carrier of the signal to your fishfinder. Where did your put your chokes? How have you routed your transducer cable? maybe unhook the cable ties from the transducer cable and move it away from the power cables on the TM harness to confirm if that is the source of your interference. Bob

[Nate4Fishing]

That should be the first thing you do when adding a graph. It makes a huge difference. Is your interference only when the troller is running? Do you have any screenshots we could look at?

yes, only when running.

[Nate4Fishing]

Is it your 2D sonar that has the interference?
If so try these settings: ping speed max, scroll speed normal, noise Rejection high, surface clarity medium

side scan interference only

[Nate4Fishing]

More times than not the transducer cable is the carrier of the signal to your fishfinder. Where did your put your chokes? How have you routed your transducer cable? maybe unhook the cable ties from the transducer cable and move it away from the power cables on the TM harness to confirm if that is the source of your interference. Bob

I will try this!

[bobcoy]

Another thing I found troubleshooting is if the boat and trolling motor are not in the water you will see more interference. For testing you really can't do it in the garage. The water acts as a ground and kills most of the electrical noise. The higher the frequency the sonar is the more susceptible it is to interference. 800khz will show it more than 455 and usually the 200khz of 2D is the least effected. Very common for imaging only to show the problem. One of your chokes should be on the transducer cable right by the fishfinder. Bob

[lpugh]

It sometimes helps to wind all the extra transducer cable in to a figure eight, then several wire ties to maintain that shape, as mentioned above as far away as possible from other wiring, I actually use several ferrite rings on both the transducer cable and power supply, Also the power wires going to unit should be twisted about 6 twist per foot, I also have trolling motor cables twisted as well (google twisted pair for more info on this) These are all noise canceling methods, and quite often will clear it up
I have my noise rejection set to low and no interference

[Marc Marcantonio]

There are other considerations than cable management and grounding. Make sure your trolling motor prop shaft is spinning perfectly true, and that your prop is not damaged (out of balance, knicks, out of round, etc.).

Additional old school tricks to try include putting lead sheeting (from roofing) between the transducer and the motor, and also putting a screw in the skeg to attach a ground wire.

Best solution, buy a Ghost trolling motor with built-in Sonar and DownScan. Zero interference with brushless motor that doesn't emit radio frequency.

[Nate4Fishing]

Update: So I tried a separate power source and still had interference. I took the transducer off and noticed that the closer I get the transducer to the head of the trolling motor is when I get my interference. When I take it away about 2 feet then I get zero interference. Do I need a better ferrite ring? I just ordered cheap clip on chokes from amazon and they did nothing.

[lpugh]

Post # 8 in red , if it does not work, have the motor checked out

[Nate4Fishing]

Update: So I tried a separate power source and still had interference. I took the transducer off and noticed that the closer I get the transducer to the head of the trolling motor is when I get my interference. When I take it away about 2 feet then I get zero interference. Do I need a better ferrite ring? I just ordered cheap clip on chokes from amazon and they did nothing.

[Slim95]

Dont buy the cheap clip on chokes from amazon. got to mouser.com and order your Torroid 77 and 75 rings and try them. I know the make clip on Torroid 75 rings and 77 but they are much more expensive. You said you tried a seperate power source, did you run new 10 or 12awg wire from the battery to your unit? or just tap into a new source?