Corona discharge

[Alberto Di Bene]

>...
  > Since getting back on 136 kHz with my new VFO, higher power TX, I have
  > experienced a problem which I think may be due to corona discharge
somewhere
  > on my aerial system. As I increase the TX output above about 175 watts, I
  > have a wide-band noise appear on local RX's, which sounds like a cross
  > between sparking and white-noise. I have experienced the same effect with
my
  > Topband mobile whip, but the corona is easy to see at the top of a ten foot
  > whip, and easily cured with a small ball.
  > ...

Shooting in the dark:
Instead of a corona discharge, couldn't it possibly be a wide-band oscillation
caused by stray RF pick-up somewhere in your rig? As I said, just a wild guess.

Alberto di Bene, I2PHD