Huminbird Sonar Interference by Trolling Motor

[Heelman99]

I have a Humminbird 858c Hd Di that I've been trying to correct a bad interference concern from my Huminbird 858c HD Di unit when in the sonar mode for some time now. I've got the down image transducer for this unit mounted to the motor assembly of the MinnKota. The symptoms of the interference only occurs when I press the foot pedal energizing the switch no matter what the speed settings is at. As soon as I step off the pedal switch the interference is gone. there has got to be a fix for this concern?

[Bill Reynolds]

This thread is a good discussion of interference
http://www.bbcboards.net/showthread.php?t=952182

[Wayne P.]

I have a Humminbird 858c Hd Di that I've been trying to correct a bad interference concern from my Huminbird 858c HD Di unit when in the sonar mode for some time now. I've got the down image transducer for this unit mounted to the motor assembly of the MinnKota. The symptoms of the interference only occurs when I press the foot pedal energizing the switch no matter what the speed settings is at. As soon as I step off the pedal switch the interference is gone. there has got to be a fix for this concern?

Are you using the proper DI transducer for a trolling motor application, a trolling motor puck?
XTM 9 DI 25 T

[Heelman99]

Yes Wayne I am using the transducer that came with the 858. I have installed this transducer as instructed by a certified Humminbird tech.

[akaslyguy]

Usually the "one that came with the unit" is not the best transducer for mounting on a trolling motor. There is a trolling motor specific puck for that application that has better shielding built in for that purpose. Using that transducer would be the best start to resolving interference, if you don't already have it.

[Jonestrollingmotor]

This is the one that Wayne is refering to. It does not come with the units, but when you purchase a new unit, Humminbird either still has or did have a transducer swap where you could send the old transducer in and get the correct one. However, the 858 is old enough it isn't going to qualify for the swap, but if you have this transducer someone may have swapped when the unit was new.

[catdude28]

This is the one that Wayne is refering to. It does not come with the units, but when you purchase a new unit, Humminbird either still has or did have a transducer swap where you could send the old transducer in and get the correct one.

I was just recently wondering if HB still does the swap on the new units?

[Wayne P.]

I was just recently wondering if HB still does the swap on the new units?

Yes, new transducers, unused, and unopened mount package.

[catdude28]

Yes, new transducers, unused, and unopened mount package.

Nice. Thanks

Of course, Canada is usually an exception

[Heelman99]

Mr Jones or whom ever, what are the part numbers of the transducer developed by HB that would work correctly with my HB 858c HD DI?

[DougL58]

Mr Jones or whom ever, what are the part numbers of the transducer developed by HB that would work correctly with my HB 858c HD DI?

TM version of a transducer does not ensure clean operation. Many sources for RFI.

[Wayne P.]

Mr Jones or whom ever, what are the part numbers of the transducer developed by HB that would work correctly with my HB 858c HD DI?

For trolling motor mounting:
I stated one of them in post #3. That one is tuned to the same 2D frequencies as the transom DI transducer.

The other one is tuned to 83/200 kHz 2D sonar and is XTM 9 WIDE DI 20 T. The unit setting for it is DI 83/200 kHz.

[Wayne P.]

TM version of a transducer does not ensure clean operation. Many sources for RFI.

That is true, BUT you have to start with the proper one for the application.
The trolling motor DI pucks have extra internal shielding to help with possible RFI issues. The transom DI transducer does not.

[DougL58]

That is true, BUT you have to start with the proper one for the application.
The trolling motor DI pucks have extra internal shielding to help with possible RFI issues. The transom DI transducer does not.

Definitely agree

[Heelman99]

Hey guys I am on a fixed income and just can't go around throwing $150 for a transducer that I really don't know it will solve my 100% interference concern. I have done updates, routed trolling motor cables and Humminbird cables down opposite sides of boat hull, installed ferrite ring, installed new power cable from HB, checked for fuse in TM control head(none found), checked for any damage on any wires and repaired. Reset HB 858cHD DI unit noise setting to max 3 setting and going to check system on the water tomorrow.

[DougH]

I'm curious if your tranducer cable is wrapped around the trolling motor cable going from the foot control to the head of the unit? My HB was doing the same thing and I had wrapped the tranducer cable around the TM cable. Once I took it off and ran it to the TM mount and straight down the TM shaft that corrected it. Hope this helps.

[Heelman99]

DougH, the transducer cable isn't wrapped around any cables at all. The TM power cable was wrapped around the cables from the foot pedal of the TM to the TM motor assembly that is all. Now I have the new Humminbird transducer, item XTM 9DI 25 T , to be used on my HB 858c HD DI unit. As suggested by Wayne and Jones TM. Hope to receive the transducer Tuesday then check how it improves HB performance and controls interference.

[Wayne P.]

DougH, the transducer cable isn't wrapped around any cables at all. The TM power cable was wrapped around the cables from the foot pedal of the TM to the TM motor assembly that is all. Now I have the new Humminbird transducer, item XTM 9DI 25 T , to be used on my HB 858c HD DI unit. As suggested by Wayne and Jones TM. Hope to receive the transducer Tuesday then check how it improves HB performance and controls interference.

There will not be any better “performance”, it is no different than the transom transducer for Sonar, Imaging and Temp.

[Heelman99]

I investigated original transducer and cable to find outer cable insulation damaged so I got XTM 9DI 25 T ordered and expected delivery on Thursday. Once mounted and installed to 858c HD DI unit will go check out the difference, Got a Transducer Shield & Saver ordered also. Now for the air temps to warm some and no rain to set into the area.