[TowerTalk] R8 Vertical Problem

[fred_w._hurd at hud.gov]

My R8 Vertical keeps giving me intermittant SWR jumps on all bands. I have
checked out the feedline, the matching unit, and replaced the traps, but I
still have the problem. The vertical tunes up fine on all bands, but then
the SWR starts to jump as soon as I key the exciter at 100 watts. The R8
sits on top of a 40 foot Universal Tower, which is well grounded, but I
can't apply any power without SWR jumps and reduction of receive power and
transmit power...any clues as to what might be the problem?? I need
HELP!!!....FRITZ W4PKU