TESLA
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If we wrap a single-layer coil of wire upon a very long plastic tube, we have
a Tesla resonator as in Fig 1. In essence, this is an an electrical transmission
line. We can inject AC into one end with a little primary coil wrapped around.
Now look at Fig 2 below. We've placed a SECOND "primary coil" at the far end.
This second coil can act as a "receive" coil, and can collect the energy we had
injected into the "transmit" coil at the other end. Since the long thin coil is
actually a single piece of wire, we've managed to send electrical energy along a
single wire. There is no electric circuit involved! This only works because the
long, thin coil can support slowly-moving EM waves, and the electron-sea within
the wire of this coil behaves as if it has become compressible.
Now put a metal sphere on either end to prevent corona from spewing out of
the dangling wire tips, and we've built a simple electrical power system. Put
high-freq AC into the first "primary coil", and the same AC comes out of the
second "primary coil" at the far end. Choose the correct load resistor for the
"receive" coil, and all of the electromagnetic energy flowing along the long
thin secondary will be absorbed without reflecting.
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Note that this is a SINGLE WIRE transmission line! It apparantly uses
LONGITUDINAL WAVES! However, there is nothing crackpot about it, since it obeys
conventional physics: the propagating electric fields and magnetic fields which
surround any part of the long coil are always at 90 degrees to each other.
Successive waves of positive and negative charge move along the coil, and these
waves are connected to each other with EM fields. The EM fields are transverse.
The only thing that acts like a "longitudinal" wave or compression wave is the
density of free electrons in the wire. Is this crazy? No. Within a normal piece
of coaxial cable, the electrons of the metal move as part of a compression wave,
even though the EM fields within the cable's dielectric remain part of a
transverse wave.
In conventional cables there are two conductors, and the voltage between them
forms the "E" part of the EM wave. In the above one-wire coil device, the
voltage between the travelling lumps of net-charge distributed along the long
thin coil forms the "E" part of the wave. The single wire acts as its own
"circuit." The motion of the net-charge is an electric current, and this creates
the "M" part of the EM wave.
Interesting? A single wire transmission line! It doesn't violate the rule
forbidding longitudinal EM waves. However, it violates the fundamental rule
regarding electric circuits in that there *is* no circuit here. The two ends of
the system are connected by a single wire. The charges within the coil flow back
and forth, while the electrical energy flows along the coil from source to
load.
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HOWEVER, this is not unique. Once long ago I encountered an article about a
single-wire transmission line. This had nothing to do with Tesla; it was about
an old microwave transmission scheme called a Goubau transmission line or
"G-line." The article was in an old copy of QST magazine (amateur radio mag) in
the 1960s or '70s.
It turns out that you can send microwave or UHF signals along a *single* wire
as long as that wire is coated with a dielectric. To do this, you start out with
a normal coaxial cable. You strip the shield from a central section, then solder
on a pair of large, cone-shaped copper horns which attach to the coax shield at
either end of the coax cable. The dielectric-coated single wire extends between
the ends of the coax. Sort of like this:
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In the above diagram, the single-wire section between the two hollow cones
can be as long as desired, but it must be fairly straight. Those cone-shaped
parts must be about one wavelength across (or was it 1/2 wavelength? I don't
remember exactly.) The metal cones act as "wave launchers" or "wave catchers".
As the EM waves come out of the coax cable, the cones allow the waves to spread
out and attach to the "G-line" part. There must be a plastic coating on the
"G-line" wire, otherwise the waves will not lock onto it, and they will tend to
wander away into space. The article noted that you COULD put a bend in the
G-line, as long as it was a long, smooth bend of large radius. Because of the
plastic coating, the waves would follow the bend. If there was no plastic
coating, the waves would miss the bend and go straight out into space, missing
the "catcher cone" entirely.
Obviously this can only work with AC. There is no electric circuit, instead
we have waves of "electron compression" which propagate along a single wire.
Let's briefly look at a fluid analog. The fluid analogy of a conventional
electric circuit is a closed loop of water-filled hose. To send energy to
any part of the loop, we simply force the water in one part of the loop to begin
flowing, and all the water in the entire loop must therefore flow as well. It
acts like a drive belt. Might it be possible to break the circuit and use a
non-circular hydraulic system? Can we send compression waves through the
electrical "water" in the "hose" made of wire? Sure! That's what the G-line
does. If we have a long hose with closed ends, we can send "sound waves" through
the "water" of the hose, although we cannot create constant flowing DC as we can
with the closed circuit hose-loop. These single-wire systems are inherently AC
systems. They are analogous to sending sound energy along a fluid-filled
tube.
Because there is only one conductor in the G-line, the "E" part of the EM
wave must extend between successive lumps of net-charge which propagate along
the wire. The "voltage" on the transmission line extends outwards as radial
e-field flux, but rather than connecting with a coaxial shield as it does in a
normal cable, it curves around and connects with the opposite flux-lines which
extend from another place on the wire. The "M" component of the wave acts like
the magnetic field around any normal wire: the magnetic flux lines act like
circles which surround the wire. The energy flows lengthwise along the wire as
is commonly shown by Poynting's vector (E x B).
__ | _____ | ___ \ | / \ | / \ | / \ | / | | | | | | | | | | | | | | | | | | wire ============ --------- =========== +++++++++ =========== | | | | | | | | | | | | | | | | | | / | \ / | \ ___/ | \_____/ | \___ fig. 5 The e-field of the "G-Line", extending between regions of moving chargeSo, here we have a one-wire transmission line based on transverse EM wave in space, and electron density waves within the wire. Inside the metal of that single wire, the electrons wiggle back and forth while the EM wave propagates outside at about the speed of light. It's almost like sound waves moving on the string of a tin-can telephone, but electrons take the place of those cellulose fibers, and the sound waves are replaced by transverse EM waves. But in the case of the "G-line," the energy is stored in the EM fields connected to the electrons, rather than being stored in the kinetic energy and potential energy of the string.
How does this relate to Tesla? Well, once we have the ability to send energy
along a single wire, we should also have the ability to send energy along any
conductor at all, as long as that conductor has a dielectric coating. Like
this:
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Any large, metallic hunk could be stuck in series with the "G-line". Yes,
there might be wave-reflections where the thin wire connects to the big metal
hunk. But that's beside the point. With the above setup, we can send waves along
the surface of a conductive object, while within the object itself the "electron
sea" vibrates longitudinally. Hmmm. Where have I heard THAT before? I know.
Nikola Tesla's "World System," in which he intended to transmit usable
electrical energy to any receiver anywhere on the Earth.
In the above diagram, suppose the "hunk of conductor" is the entire planet
Earth! Suppose the "cone shaped" launchers are replaced with an elevated sphere
which supplies a "virtual ground" reference capacitance? Suppose the frequency
of the waves is below the UHF band in frequency? The entire Earth will then
behave as a "G-line" single wire transmission system.
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In his writings, Tesla was convinced that his devices did NOT use the same
physics as Hertzian waves. He was right... and wrong. When radio- frequency
energy propagates through empty space, the E and the M components are
transverse, and the waves propagate at 90 degrees to both of them. However, when
EM energy is sent along a cable, we also have electrons involved: the
electron-sea within the metal wires. The electrons slosh back and forth in the
cable while the EM waves flow along outside of the metal surfaces. Why is this
important? Because the physics of a transmission line is the physics of the
"near field" of a coil or capacitor, not the physics of freely-propagating
"Hertzian" waves. When Tesla sent energy around the Earth, he was treating the
Earth as an electrical cable. His waves were coupled to the charges within the
surface of the Earth. He was not transmitting pure radio waves, even though the
frequency of the wave-energy might be the same as any normal radio wave. Instead
he was using a one-wire transmission system where the conductive Earth served as
the wire. Tesla's technology used "near field" effects of coils, capacitors, and
transmission lines, not the dipole antennas that Hertzian waves use, and in that
sense his waves were "non-Hertzian."
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But wait a minute. This stuff can only work if there is a dielectric
substance coating the Earth. Without that coating, the waves will not follow the
curve of the Earth, they will just fly out into space. The atmosphere supplies
this coating. And even better, there is a conductive ionosphere which will act a
lot like the "shield" of a coaxial cable and force the waves to go around the
Earth.
Tesla was using the ground as a transmission line. He was correct when he
insisted that he was producing longitudinal waves in the "natural medium." He
was correct in saying that the ground was not just a voltage reference. In this
case the "natural medium" is the population of mobile ions in the dirt and
oceans which cause the Earth act as a conductor. He was converting the Earth's
surface into a "G-line" conductor. Any electrical device could intercept a
portion of that energy, as long as that device was connected to the ground and
to an elevated metal object.
So, what was Tesla's big mistake? Initially he did not realize that the
Earth's atmosphere was critically important for his system to work. If the Earth
had acted like a metal ball hanging in a vacuum, then Tesla's power-transmission
system would not have worked. The waves would have travelled along the ground
and then shot out into space rather than curving around the Earth. His system
would have been like a "G-line" with a sharp bend in the middle: except for a
bit of diffraction, the waves ignore the bend and go right off the cable and are
lost. Because of the "dielectric" effect of the atmosphere, and also because a
conductive ionosphere was present, Tesla's system was feasible. Yet any
scientist of the time would "correctly" see that Tesla's system totally violates
well-known theory. If Tesla had started out from known theory, he would never
have pursued the path he did. Tesla actually started out with empirical
observations that the Earth resonated electromagnetically like a struck bell.
The atmosphere and the ionosphere made this so, but Tesla only knew that it
worked, and he really did not know why, at least at first.
Tesla's other big mistake was in thinking that his wireless transmission
system had nothing to do with "Hertzian" waves. In fact, the waves in a coaxial
transmission line are not much different than the waves which fly off any dipole
antenna connected to the end of that transmission line. Whether it is ruled by
"near field" or "far field" equations, electromagnetism is electromagnetism.
Tesla's mistake was not really so big. Especially not a big mistake when
compared to those contemporary scientists who were absolutely certain that the
Earth *didn't* have any resonant frequencies, who *knew* that radio waves would
not travel around the curve of the Earth, and who dismissed Tesla's wireless
transmission system as crackpottery; as an unworkable violation of known
physics. When "Schumann" VLF earth-resonance was rediscovered in the 1950s,
nobody in the conventional sciences dared court the embarassment of admitting
that Tesla had been right all along.
Tesla is mostly a hero among the non-scientist "underground," while in
conventional circles he is still ridiculed for trying to distribute electric
power without using wires, or rather, by sending it through the ground. Everyone
(still) knows that this is impossible, even in theory.
Yeah, right.
Geog Goubau, "Surface waves and their Application to Transmission Lines," Journal of Applied Physics, Volume 21, Nov. (1950)