Originally Posted by Richard Ferryman

I have come by a Tonna 9 element yagi for 430MHz to 440MHz. The driven
element is a folded dipole and has an n-type connector attached. SWR looks
correct and it works but there is a slight skew to the radiation pattern.
The n-type connector is potted in a plastic or epoxy and looks too small to
have any sort of balanced to unbalanced device in it. I intend putting a
ferrite choke on the feed cable to help. Tonna antennas have a good
reputation and I am surprised at the apparent feed method. Does anyone know
if I have missed something?
Dick G4BBH