----- Original Message -----
From: "Jim Lux" <jimlux@earthlink.net>
> At 07:13 AM 9/1/2005, Keith Dutson wrote:
>>Jim wrote:
>> >The other aspect is that it might not be the antenna that's doing the
>>discharging, but the tower next to the antenna, and the antenna is just
>>picking up the noise.
>>
>>Jim, have you ever observed precip static on an antenna supported by a
>>balloon?
>
> No, but I have observed fairly noticeable charging on a wire on a kite.
>
> And, also on a guy wire (that happened to be insulated at both ends)
> traversing middle of an artificial dust devil some 50 ft tall.
>
I think perhaps both mechanisms (coronal discharge due to electric field
gradient and particle induced charging) can occur in antenna systems
depending on the environmental circumstances. Back in the late 80's
when I was attending Ohio State, Steve Miller, N8SM (SK) and I
observed on one particular winter day (windy sleety weather) that the
open-wire feeder to the 600' long wire strung between Ohio Stadium
and the McCracken power plant was arcing in the shack. When we
investigated, we found that we were able to draw 4 to 5" arcs off the
ladder line. At the time I didn't give too much thought as to the
mechanism (I just thought it was really cool), but in thinking back to
all the times I operated from that QTH in all kinds of weather conditions,
that particular phenomenon only happened once. There was no
thunderstorm activity on that particular day. There was a steady wind
and it was a freezing rain if I remember correctly. Maybe it was just
that one side of the ladder line had come loose from the tuner and
there was no path to ground (I can't recall), but I have a sneaking
suspicion (can't prove it) that on that particular day we were
observing some kind of particle induced charging. OTOH, I have
personally observed "percipation static" at contest stations with stacks
where the lower antennas were quiet as well as more recent observation
here in the LA area. These observations strike me as being a better fit
with the coronal discharge due to electric field gradient model.
In any case, an interesting discussion.
73 de Mike, W4EF.................................
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