On Apr 10, 2:14*pm, Art Unwin wrote:
The coax ground and the reflector is grounded at the same place
at the top of the tower. All horizontal coax is buried.
___________

An r-f ground does not exist at the top of your tower,
or any tower.

Unless some means is provided to prevent r-f current flow
on the outside of the coax and on the tower structure,
they will radiate/receive r-f energy.

This probably accounts for most of the pattern effects
that you didn't expect to have (regardless of the real
pattern that your cone and helix generates).

RF