just in case anybody was wondering here are a couple of ferrite ring options.
small one is the humminbird free one, large one is the mix 77 from http://www.kf7p.com/KF7P/Ferrite_chokes.html
the large one works well, haven't been able to compare the 2 directly.
great video explaining ferrite and what it does a some application examples
https://www.youtube.com/watch?time_c...&v=LuMlM8zWQFk