Socoeye, I realize that this post is from more than one year ago; however, did the ferrite ring solve your problem? If so, would you please provide a manufacturer and model number for the ferrite ring. Thanks in advance for your information.
https://www.amazon.com/gp/product/B00CR5HHD4/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
Dr. J, I picked this up through Amazon. It helped some but if I remember right I still had some interference. I also routed my power to the TM on the opposite side as far as possible from the ducer cable. Again, seemed to help a little.
I had a Gen 2 in the bow connected to the Xi5 and I now have a Gen 3 (this year). Through software updates and settings my interference is pretty much gone in the bow. When fishing deeper say over 30 feet I get interference but that’s due to multiple transducers and not the Xi5 IMO.
Hope this helps!