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Old February 25th 09, 11:51 PM posted to rec.radio.amateur.antenna
Jim Lux Jim Lux is offline
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First recorded activity by RadioBanter: Mar 2007
Posts: 801
Default @0 Meter Vertical Collinear

Richard Clark wrote:
On Wed, 25 Feb 2009 04:04:39 -0800 (PST), wrote:

The advantage of the half wave is exactly for its high impedance in
relation to the loss of ground. The far ground still dominates low
angle launch characteristics, but if (like the large number of radials
offers) you lose less to ground, you have more in the air in all
directions.

...
this leads to 1100Vp voltage (at 1500 Ohms). Without careful
construction, E-field at sharp edges will exceed 3000V/mm easily.

...
This
will not result in full air breakdown (due to strong nun-uniformity of
E-field, but will result in undesired corona discharge.


I would have thought they were the same. (Corona discharge is NOT air
breakdown? Is there some distinction to "full?")


One often makes a distinction between a corona discharge which exists as
a steady state sort of thing and the streamers which precede a "spark".
Both are air breakdown phenomena, but qualitatively different, and
both are different from a low pressure discharge like that found in a
fluorescent lamp or neon bulb, or from phenomena like St Elmo's Fire.

Field uniformity is only part of it, of course.

Bazelyan & Raizer, "Spark Discharge" from CRC Press, 1998, is probably
one of the better books on this.