If you have long leads to servos in the tail, you need to separate the internal antenna and the leads. I've seen three instances (including my own where I nearly lost a plane) of interference problems when the leads and antenna were left loose. In all cases the problems were cured by putting the leads in a tube at the top or bottom of the fuse and the antenna in a tube on the opposite side.

If the leads are very long, as in a pattern plane, use heavy duty, name brand lead extensions.