I had interference with my Fortrex and Lowrance units. I used the US 2 for 2d and a LSS 1 mounted on the trolling motor and the interference showed up on all screens. I tried moving wires, checked the fuse in the head of the TM, ferrite chokes from radio shack and finally the big one from Minn Kota, nothing worked. I just lived with it until I got my Ghost, no more interference.

I've read that a non-current carrying ground will help, but at the time I was running the Fortrex I didn't know that, so I can't say if it'll work or not.