Noise level between two ant types
 

Cecil Moore wrote:
Tom Donaly wrote:

Yes, but there are fewer particles.


I don't think that is true. Dust is sucked high into
the air during the formation of a dust storm. I
have seen a wall of dust hundreds of feet high in
Arizona. It didn't look any denser closer to the
ground. In any case, it is not the number of
particles that matter but the average charge per
particle which increases with wind speed.

How do you know that?
73,
Tom Donaly, KA6RUH

Noise level between two ant types
 

Noise level between two ant types
 

Cecil Moore wrote:

wrote:

.....or doing some actual experiments like I have done.


I have been reporting actual experiences from when
I lived in the Arizona desert and I can guarantee
you that charged particles exist in the dry-air
desert wind. Where does the charge on an antenna
come from if not from charged particles?

It probably comes from charged particles and the earth's
electric field, but you won't know anything for sure unless
you can come up with a mechanism for showing how dust particles
get their charge in the first place. Then you have to measure
it. In some old issue of Scientific American there's an article
showing how to make a simple gadget to measure the electric
charge on a raindrop (about .3 volt, average). I expect you
could use the same idea to measure the charge on a dust particle
during a dust storm. Then you'd have to calculate. That shouldn't be
too hard for you to do, Cecil, you're an engineer.
73,
Tom Donaly, KA6RUH

Noise level between two ant types
 

Tom Donaly wrote:
It probably comes from charged particles and the earth's
electric field, but you won't know anything for sure unless
you can come up with a mechanism for showing how dust particles
get their charge in the first place.

When I was working on repeater systems trying to figure out how to make
an omnidirectional antenna (mounted ABOVE the tower or mounted above
other things on a roof) not get wiped out by p-static I talked to an
person at NASA who delt with problems NASA had.

I've forgotten most of the numbers he quoted for electric field
intensity as height increased and the effects of things that modified
the impedance of that voltage, but I left those conversations and the
experiences with an entirely different view than when I entered.

Moving the antenna just a few feet lower than other objects made a
large difference in p-static, and that was at heights between 200 and
800 feet above ground.

It's a nice guess by Cecil that there is less wind or less particles at
180 feet rather than 200, or 780 feet rather than 800 AGL, but in real
life there probably isn't much difference.


When people spend a few thousand bucks changing to dc grounded
antennas, antennas in radomes (Super Stationmasters) with only a metal
tip exposed, and folded dipoles... only to find the only thing that
helps is making the antenna NOT the tallest or most protruding
point....it's tough to accept something that didn't ever make a
difference.

Of course if I viewed the world through a 80 meter dipole at 50 feet
with only dust to worry about and never talked to the fellow at NASA,
or if I never had multiple antennas on multiple tall towers or worked
on all those commercial systems, I might agree with Cecil.

All the problems I saw related to corona.

73 Tom

Noise level between two ant types
 

Tom Donaly wrote:
How do you know that?

Simple physics. I don't believe in magic.
--
73, Cecil http://www.qsl.net/w5dxp

Noise level between two ant types
 

wrote:
Of course if I viewed the world through a 80 meter dipole at 50 feet
with only dust to worry about and never talked to the fellow at NASA,
or if I never had multiple antennas on multiple tall towers or worked
on all those commercial systems, I might agree with Cecil.

When the only tool one has is a corona hammer, all problems
look like corona nails. Fortunately, I am familiar with both
corona problems and dry-air wind-driven charged particle
problems.

All the problems I saw related to corona.

At least that's what you assumed. Just because all the cars
parked in your driveway are white doesn't mean all the cars
in the world are white.
--
73, Cecil http://www.qsl.net/w5dxp

Noise level between two ant types
 

Cecil Moore wrote:
Tom Donaly wrote:

How do you know that?


Simple physics. I don't believe in magic.

I thought simple physics was magic.
73,
Tom Donaly, KA6RUH

Noise level between two ant types
 

Cecil Moore wrote:

wrote:

Of course if I viewed the world through a 80 meter dipole at 50 feet
with only dust to worry about and never talked to the fellow at NASA,
or if I never had multiple antennas on multiple tall towers or worked
on all those commercial systems, I might agree with Cecil.


When the only tool one has is a corona hammer, all problems
look like corona nails. Fortunately, I am familiar with both
corona problems and dry-air wind-driven charged particle
problems.

All the problems I saw related to corona.


At least that's what you assumed. Just because all the cars
parked in your driveway are white doesn't mean all the cars
in the world are white.

Whether it's dust, snow, or the atmospheric electric field charging the
antenna, the noise is still corona discharge. At least that's what most
of the sources say. Tom says height makes all the difference. That would
make a lot of sense given the way the earth's electric field is structured.
73,
Tom Donaly, KA6RUH

Noise level between two ant types
 

Tom Donaly wrote:
Whether it's dust, snow, or the atmospheric electric field charging the
antenna, the noise is still corona discharge. At least that's what most
of the sources say.

The argument is not what it is called. The argument is whether
charged dry-air dust particles can transfer charge to bare-wire
antennas.
--
73, Cecil http://www.qsl.net/w5dxp

Noise level between two ant types
 

Cecil Moore wrote:
Tom Donaly wrote:

Whether it's dust, snow, or the atmospheric electric field charging
the antenna, the noise is still corona discharge. At least that's what
most
of the sources say.


The argument is not what it is called. The argument is whether
charged dry-air dust particles can transfer charge to bare-wire
antennas.
Man, you guys really crack me up. I must admit I kinda enjoy reading
your posts, though.

\There must be some source citing experimental evidence of charged
particles in a dust storm transferring their charges to a collector of
some sort (antenna). I alluded earlier to a practical use of such
collection...
Cecil, you said you have no idea how many Joules were represented (or
something along those lines).

Seems to me, that Joules per unit time is precisely the measure that's
needed in this "analysis". Is this Voltage, or am I mistaken?

Compare the density of the dust cloud with the charge collected. There
should be a correlation. What about velocity of the cloud: more charges
transferred per unit time.

If your rug was scorched, some "work" was done. My college physiscs is
only a nightmare away: what is the relation of Joules to work?

What was the other issue: number of particles versus the charge per
particle? Got me.

As the particles are swept off the surface of the desert, would their
charge (per particle) be distributed (as Gauss or some other )?

I would think the # particles would be more important.

If a given volume of dust particles moves through the field of an
antenna (it would have a field, wouldn't it? ... even if grounded?
perhaps field is the wrong word), increasing velocity of the volume
would mean more particles per unit time passing the antenna. Hence more
charge transferred: more charge per unit time. Again, is this Voltage?

I guess I can't part with my trickle charger idea.

You guys have at it. Thanks for letting me butt in.

John