Cecil,

First things first.

Ionization threshold has nothing to do with "voltage". It has everything
to do with field strength. This topic has been studied extensively for
centuries. Don't believe everything you find on the web, especially if
it requires "glow-in-the-dark" or "thousands of volts" as a determinant
for ionization.

73,
Gene
W4SZ

Cecil Moore wrote:
Gene Fuller wrote:

I am not entering this debate one way or the other. I do have a
question, however.

How do you determine when the ionization threshold has been reached?


Corona invariably causes a glow at night. I have witnessed
such a glow but not very often. I came across a calculation
of the ionization threshold in volts yesterday while on the
web. I don't remember the exact figure but it was in the
thousands of volts for average air conditions and varied
with the geometry of the conductor.

But the point is that, by definition, it is not corona until
ionization occurs. A wire in the air during high wind conditions
can accumulate charge from the charged particles but until it
accumulates enough charge to cause ionization of the air, it
is NOT corona, by definition.

W8JI is confusing cause and effect. The transfer of charge
from wind-driven charged particles can cause localized corona
but that's just an effect, NOT a cause. And if the antenna
wire is not allowed to reach the air ionization level,
charge may accumulate but corona will not occur.

Under thunderclouds, corona often occurs. I wouldn't try
to speculate whether rain or snow noise is caused by
charged particles or corona. But I will certainly speculate
that in a state without a cloud in the sky, a charge can
be deposited on an antenna by charged particles.