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Re: Terry's New Plane Wave Antenna



Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Paul.

At 01:27 AM 1/5/2006, you wrote:
Stork wrote:

> Let us not forget though that the electric field from
> the TC is alternating between negative and positive charge

Sure, but (we presume) the electrometer is responding to
an additional (non-oscillating) field from bunches of
ions left hanging after the bang.  The TC topload and
coil winding will have zero charge after the event
(maybe not so the coil surface), so any residual electrometer
reading is attributed to the space charge - if the
instrument is working!

> from my direct observation of Richard's experiments and
> from conversations with him, he finally deduced that there
> is inborn error in the Keithly 610C electrometer design.

Well that's a good bit of info.  You were there?  What
electrode was used, and how far from the TC?   From that
we can estimate the peak potential of the 610C input,
and see if it exceeds 100V.   If it does, and grid or gate
current flows as a result, the device will report a residual
charge of opposite sign to that which caused the overload.

I should mention that the "plane" in my perhaps ill named "plane wave" antenna was meant to pick up a large "current area". As I noted in yesterdays bandwidth verification experiment:

http://hot-streamer.com/temp/pw-000.JPG

A simple "wire" does not provide a very good "current drive source" to drive the antenna's capacitive dividers. Thus, the larger "area" of the conductive plane captures more "current" to provide a good signal drive source. I was using just a foot long #22 wire for the test and the signal was "poor"!!! As Maxwell tells us, we need a "plane" to get a good amount of "area" to get good current drive to the rest of the electronics... The bigger the plane, the more drive current to the capacitive diver... There is a source R, to C drive, limit there.


> by eletrostatic induction the normally neutral probe will
> obtain a negative charge from a negative space charge.

A positive (say) source charge induces a negative charge on
a test probe and (by charge conservation) a positive charge
on the input of the electrometer.  Having thought about it,
I don't think there's any ambiguity here - the instrument
would read + in this case.    If the charge was collected
by the probe (rather than just induced), the probe would be
positive and the electrometer input would (this time) also be
positive again.

Yeah. But there are like a thousand things that could go wrong in that measurement stuff!!! We need to "double check" it all "real good"!!...


Terry wrote:
> Sounds like we might need some new experiments to resolve
> that since the old and present data is a little too messy
> to go from...  I would not be surprised to find that coils
> can charge either negative or positive depending an many
> things....

I agree with all that.  Also, we know that if the coil base
terminal is grounded via a DC blocking capacitor,

!!  I think that would be very rare!!!  We normally ground solid to ground...

there will
be some residual voltage across that cap.  If space charge is
being generated, for total charge conservation, the space
charge should be equal and opposite to that left stored on the
blocking C, should it not?   As Dmitry mentioned, other things
will collect charge too, and also have charges induced.  The
electrometer can only respond to the total field, so an
electrically 'simple' enviroment would be nice for these kind
of experiments.

Yeah!!! "real simple"!!! It is very easy for electrostatics to charge into chaos... We need to be real careful about what the meters are measuring and where they lay in the "big picture" circuits!!! Insulators are like batteries, conductors may distort fields, house flies may carry massive charges... Sensitive, close to DC, electrostatics are fraught with errors... We must be very very careful!!!


> I thought this was all figured out in the past, but it
> appears that it is not at all...

I don't think we (here) know much about this.  I'm sure there's
much in the literature, but sometimes it's nice to measure
these things ourselves, and see that they work.

Marco tells use that there are many previous clues here!!! ;-)))

Some of the things I'm not clear about are
a) What's the nature of the space charge, is it always one
polarity or the other?

I think not... Too many factors can "force" a positive or negative charge. let alone to how that charge is measured... I still note that my RF generator coil "refuses" to produce NOx and Ozone type smells... That may very well be due to it's "adjusting" currents in real time "equally" and thus eliminating net charges needed for NOx production... There is still a great mystery to that...

b) After the bang, the grounded coil has no charge, therefore
for overall charge conservation, there should be some opposite
charge lying around somewhere. I mean, if the bang goes off inside
a Faraday cage, and (say) there's a bunch of positive ions left
hanging in the air, where has the negative charge gone?

:-))) Yeah. that is a really messy one :o))) "Static" E fields may not be right... We probably have to consider "dynamic" E-fields... All that coulomb charges "here and there" stuff... Where does it all go...

c) How fast does this static charge distribution decay?

I am sure it follows natural laws of physics :o))) I suspect it is "messy" :o)))

d) Does it affect the next bang?  Does anything 'build up' over
a series of bangs?

Yeah probably... It would be "tooooo easy" otherwise :o))) Marco has directly noted this mess too!!!

Weeeeeeee!!!!

Cheers,

        Terry


--
Paul Nicholson
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