Tube? There was no tube in the kit nor in the instructions that I saw... Maybe this is the problem.... Metall to Metal rubbing does cause interference so I can't see how you're not getting this if you have it setup the way I did.

The ground check got better when I uncrossed the cables but I didn't want to take any chances. Flew again today without any glitches.

BTW, do you know what they use on these? Is it monocote or ultracoat? I've got a piece of covering that has come loose from just under the cowl and torn so I need to replace it.