Re: Goubou line, "G-line" (was Tesla Coil RF Transmitter)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: William Beaty <billb@xxxxxxxxxx>

On Thu, 15 Sep 2005, Tesla list wrote:

> Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>
>
> However, neither of those are "guided waves" in the same sense that
> G-line works.  In G-line, the EM propagation is "within" the
> dielectric.

Do you imagine that the G-line's dielectric thinkness is much wider than
one wavelength?  Actually it's much smaller.  The propagating wave cannot
fit inside the dielectric.  Only a small fraction of the wave exists
within the relatively thin dielectric coating around the wire, while the
major part of the wave is propagating in empty space parallel to the wire.
The guided EM wave "dips its toe" into the dielectric surrounding the
wire, and this interaction causes the wave outside the wire to turn
towards the wire.  As Ed says, the slower wave propagation inside the
dielectric makes the radial e-field tilt forwards as it propagates.  If a
900MHz "G-line" uses RG-8, and the wave resembles a fuzzy sausage that's
1/2 wavelength across, then the wave is 80mm thick yet the dielectric is
about 2mm thick.

If G-lines only functioned correctly when using microwaves of
millimeter-wave length, then you'd be right, and they'd be almost
identical to optical fibers.  But they've been used down to UHF freq.


> There HAS been some work with propagating a wave that is "attached"
> to the surface of a dielectric.
>
> http://www.nasatech.com/Briefs/Apr01/NPO21001.html

The explanation in that article is the same one I've heard used to explain
how a G-line of tiny radius can guide an EM wave of huge radius.




> One might be careful here.  Just because you receive a signal doesn't
> mean that a) the wave has actually propagated by the means you
> suggest or b) that the bending is entirely due to what you
> suggest.  Refractive effects are well known (to the point where when
> you do microwave path calculations, you assume that the earth is 4/3
> its actual diameter).

I don't understand.  Are you agreeing that Tesla's World System could have
worked, but it would be based on refraction?  Will VLF waves refract
around the Earth multiple times?  After all, this thread is about
feasibility of worldwide power distribution.

Perhaps I wasn't clear enough earlier: I was speculating that perhaps
Tesla's world system could have worked based on the same wave-entrainment
effect which G-lines employ.  Obviously this requires very low losses, so
a wave which circles the entire earth would only lose a percent or two as
heating, and the Q of the Earth in that propagation mode would then be as
Sutton/Spaniol claim to have measured it: a Q value in the hundreds.

If you start suggesting that it's NOT G-line, but atmospheric refraction,
then it sounds like you're agreeing that Tesla's system might be feasible.
(If you wanted to shoot it down, I'd expect you to suggest that the G-line
groundwave-guiding effect would be even more lossy than ionospheric
ducting.)


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William J. Beaty                            SCIENCE HOBBYIST website
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