[Towertalk] Cushcraft R8 Vertical Loading Problem

[Fred_W._Hurd@HUD.GOV (Fred_W._Hurd@HUD.GOV)]

I just installed a Cushcraft R8 vertical on top of a 40' aluminum tower
with grounding
at the tower base. The antenna works great on all bands until I attempt to
load more
than 100 watts power, at which time the SWR jumps like crazy. I have double
checked the cable connections and they are OK. Any idea of what my problem
could be???