Humminbird Side Imaging Forums

Other Humminbird Products => GPS Chartplotters and Non-SI Humminbird Units => Topic started by: XPress12 on March 05, 2014, 11:30:32 AM

Title: 788 HD DI Interference from Ethernet
Post by: XPress12 on March 05, 2014, 11:30:32 AM

I have narrowed my interference on my 788 HD DI down to the ethernet cable which lays in the same duct from the center console to the bow as my Terrova power wires.   There is only one cable duct from the console to the bow.

I have tried ALL the grounding fixes as well as chokes on power/transducer cables.    I know the Terrova is causing the interference because when I run it on 10 the screen on the 788 is clears as can be.   So the PWM is definitely what is causing the RF interference.

While out on the water I decided to start unplugging things and low and behold when I unplug the ethernet cable that connects the 898 to the 788 it is as clear as can be!   So the ethernet cable is picking up interference from the power cables in the duct.

My question is this:  The 788 uses an adapter to connect to the ethernet cable which really looks like an Interlink connection to me...   Can I use one of the Interlink Chokes inline to help with the interference?  I see that I can pick one up pretty cheap on EBay.   Or is there another alternative to eliminate the ethernet interference?

Thanks for the help!!

Title: Re: 788 HD DI Interference from Ethernet
Post by: Rotus623 on March 05, 2014, 02:11:18 PM

Why not try running foil shielded power wires for the trolling motor? Maybe something like this? It will carry 50A with 3 cables, and 15 or 30ft. lengths.
 http://www.trci.net/products/cords-adapters-by-surge-guard/rv-power-supply-cords (http://www.trci.net/products/cords-adapters-by-surge-guard/rv-power-supply-cords)

Title: Re: 788 HD DI Interference from Ethernet
Post by: Humminbird_Greg on March 06, 2014, 10:39:31 AM

Those are different connectors Xpress12.
Have you tried calling the Humminbird Customer Resource folks and ask for some of the ferrite rings to put on the Ethernet cable?

Title: Re: 788 HD DI Interference from Ethernet
Post by: XPress12 on March 06, 2014, 02:32:05 PM

I'm going to call this afternoon if I get a free moment.   I just thought that maybe I had found a cleaner/easier fix...   

After doing some more reading it also looks like there is a Ferrite Bead that can be installed in the head of the Terrova for RFI.  I may ask about that as well.

If I can prevent the RFI from the PWM from traveling down the power wires in the first place, that may keep it from jumping onto the ethernet cable.   I realize that is all theory:).   RFI is a crazy thing!

Title: Re: 788 HD DI Interference from Ethernet
Post by: Humminbird_Greg on March 07, 2014, 01:00:49 PM

"RFI is a crazy thing!"

Yes it is!