> Calling someone else's argument "folklore" does not
constitute
> technical argument. The last time I looked, you also
belong to the
> class "folk" and you also are providing accounts of things
that have
> happened.
No need to get upset about it Guy. It is commonly repeated
the noise we hear comes from each individual drop, dirt
particle, snowflake, or whatever hitting the antenna and
discharging...making a noise. Nowhere is there any logical
explaination of WHY that is the cause, nowhere is there
anything offered other than "I believe so it must be".
All I'm pointing out is if that is true, logic would dictate
the intensity and rate of the noise would track the size and
rate of the objects hitting the antenna. If there is a
logical explaination why that claim is correct, then it
isn't folklore (or myth or rumor if you prefer).
The fact is, whether we like it or not, a lot of things are
repeated who's only justification is we've heard other
people repeat it so it must be true.
> I have merely pointed out that one aspect of this
consternation is
> explained by the ground and antennas carrying a greater
charge than
> the medium IN THE CASE OF THE RAIN/SNOW STATIC
PARTICULARLY, that the
> common conversations about this particular case seem to
have the
> supply and demand reversed.
No matter where we assign the charge reference, the results
are the same. If the noise comes from charges rapidly
transferring between the stuff hitting the antenna (sparking
raindrops?) and the antenna, then the noise pulses would
repeat at the rate of contact. A very tiny less conductive
small object hitting the antenna would not be able to sink
or source as many charges as a large object.
> Observation 2: The noise is there while rain or snow is
falling. Noise
> stops when the snow or rain stops. Noise starts up again
when rain or
> snow resumes. If it's not the snow or rain, whatever it is
does not
> occur without the snow or rain.
If it tracks the precipitation rate, than that does indicate
the effect is something to do with the rate of
precipitation. I never find a consistent correlation.
Last night for example there was heavy rain and lightning
about two miles north, but not a drop was falling here. My
upper antennas were sizzling and hissing away. When lighting
would flash, the noise would totally stop at the instant of
the flash and quickly rebuild from a slow popping to full
intensity hissing whine.
When it finally started raining hard here, the noise
actually stopped.
While this doesn't prove noise can't come from precipitation
contacting the antennas, it does seem to indicate the noise
is independent of moisture contact.
What may be useful is to not try to figure out WHY this
happens, but to just make notes of noise vs actual moisture
for a few months and see how it tracks.
I spent a considerable amount of time looking at this back
in the 70's and 80's while trying to mitigate noise on
repeater and two-way antennas, and again in the 90's looking
at it for HF. What I found is:
To reduce noise on VHF antennas, I needed to avoid having
sharp protruding things near the antenna that made audible
corona noise in inclement weather. I also had excellent
result just by making sure the antenna was not the highest
thing or near the highest thing on the structure.
At home, taller towers and higer antennas we more of a
problem, and antennas with sharp protruding points sticking
way out from the strcuture were noisier.
The intensity of noise related more to how rapid and intense
nearby lighting was than the amount of moisture falling.
It would be interesting to see how many people find
disagreement with this.
> Observation 3: Clean dry wind has never caused the noise
we associate
> with rain or snow anywhere I've been. While I have been
kicked on my
> a** as apparently have you by wind building up a charge on
an
> ungrounded antenna, the same 50 mph clear sky dry wind out
of the NW
> did NOT cause the noise we associate with rain or snow.
Agreed. When there are no clouds, we have no corona. When we
have no corona, we have no "precipitation static". This
goes hand-in-hand with my disagreement with Jim's theory
that dust or whatever is blowing in the wind can cause
corona leakage back to whatever is trickle charging the
antenna.
> These simple observations have been reported by many other
hams. The
> explanations need to take them all into account. Beam B is
the monkey
> wrench.
Perhaps not when it is near Beam A. My Beverages and other
directive antennas that are 500 ft or more away from any
towers all pick up "precipitation static" only when beaming
at my towers. Obviously there can be some re-radiation.
Discussion like this are good, because they get us thinking
instead of accepting rumor or folklore as fact. In the 70's,
an old timer who mostly did repeater work warned me to never
pick the highest point on the tallest structure, unless it
was a pager. He said any antenna at the highest point would
be useless whenever a dark cloud approached.
73 Tom
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