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RE: Wireless Energy Transmission

Just a small note that I figured I would add.  On a previous post I followed
a link to Tesla Coil sites (from a search engine I believe) and that brought
me to an archive of Tesla pictures.  As a caption to the picture, it said
that Tesla's largest coil put such high voltages into the ground that a 1"
spark could be drawn from a drain pipe 300 miles away.  If that was indeed
true, then perhaps this idea would be feasible.  Although I have not taken a
physics course yet in school, making my knowledge greatly lacking, I thought
that I might add that promising point.

-Andy

> -----Original Message-----
> From: Tesla List [mailto:tesla-at-pupman-dot-com]
> Sent: Tuesday, May 18, 1999 7:24 PM
> To: tesla-at-pupman-dot-com
> Subject: Wireless Energy Transmission
>
>
> Original Poster: Wallace Edward Brand <webrand-at-brandlaw.dgsys-dot-com>
>
> Dear Malcolm, Bert, and all:
>
> Henry M. Bradford sent me a copy of Part 2 of his excellent article
> on wireless energy transmission.  It appeared in the May edition of
> the Old Timer's Bulletin of the Antique Wireless Association at p.
> 28.  Part I was in the February edition at p. 28.  I have reproduced
> some interesting portions of Part 2:
>
> The Tesla magnifying transmitter appears to be an ingenious means of
> injecting a large current into the ground from a single terminal.
> The key question was (and still is) how far from the ground terminal
> this current and its associated electrical disturbance can be
> detected at frequencies high enough for practical communications --
> a few metres, a few wavelengths, around the world?  Although the
> same phenomenon occurs at the ground terminls of radio transmitters,
> the answer is not known because radio engineers assume it to be of
> no practical interest.
>
> At frequencies much smaller than the lowest whole earth resonant
> frequencies of several Hertz to several tens of Hertz, the charge
> from the ground terminal would obey the laws of electrostatics and
> spread uniformly over the surface of the whole earth.  The current
> caused by the flow of this charge would decrease with distance, but
> its extent also would be worldwide. At the lower earth resonant
> frequencies, which Tesla calculated, one would expect global
> oscillations and standing waves as he described, if the resistance
> losses in the earth were small enough.  These oscillations likely
> would be modified somewhat by interaction with the spherical cavity
> between the earth and the ionosphere.  At much higher frequencies,
> the charge would still tend to flow to the surface of the earth, but
> the current would be confined to within tens of hundreds of metres
> of the surface by the "skin effect", and the range of the
> disturbance would be reduced by the I squared R losses.
>
> * * * * * * * * *
>
>
> Radio transmitters with good antennas and real ground connections,
> not just ground screens or counterpoises, radiate both radio waves
> from their antennas and Tesla-type earth currents from their ground
> terminals.  They provide a useful means of comparing the
> effectiveness of the two types of wireless signal produced by the
> same source, provided that the signals cn be distinguished from one
> another.  In particular, they raise the question:  if earth current
> signals travel far enough to have practical value, why have they not
> been received from the ground terminals of radio transmitters -- or
> have they?
>
> The answer may depend on which type of electrical disturbance
> associated with the earth current is being received.  (Tesla was
> never very clear about this aspect of the proposed receiver.)  For
> example, if it is the vertical electric field of the charge on the
> surface of the earth that flows from the transmitter's ground
> terminal, then either the sphere and ground of a Tesla receiver or
> the aerial and ground of a radio receiver should respond to it.  At
> frequencies above about 30 kilohertz, radio signals can be
> distinguished from possible earth signals because of the difference
> between day and night reception and other ionospheric effects.  In
> the very low frequency range the differences may not be so obvious,
> but we will assume here for purposes of discussion that over the
> years constant major deviations from expected radio signal strengths
> and characteristics would have been noted.  This implies that at
> large distances from low frequency radio transmitters the vertical
> electric field of their radio waves are stronger than those
> generated by the surface charge from their ground terminals.
>
> In addition to the vertical electric field of the surace charge, the
> current from the ground terminal would produce a horizontal
> potential gradient or electric field due to the resistance of the
> soil or water.  At the receiver, this field would be parallel to the
> great circle joining the transmitter and receiver.  This is the
> direction in which James H. Rogers apparently obtained the best
> reception in experiments with underground antenna wires. ["America's
> Greates War Invention -- The Rogers Underground Wireless," by H.
> Winfield Secor, Electrical Experimenter, March 1919. Also reprinted
> in: Part II -- Reference Articles for Solutions to Tesla's Secrets,
> compiled by John T. Ratslaff; Tesla Book Co., Millbrae, Cal., (415)
> 697-4903.  Probably available from 21st Century Books)  The
> underground antennas were intended to improve the signal-to-noise
> ratio by reducing atmospheric interference , and according to
> documented reports of long distance reception of low frequency radio
> stations around the time of World War I, they were quite
> successful.  The signals detected by these antennas may be evidence
> of a practical Tesla earth current mode of communications at low
> frequencies.  However, it should be noted that radio waves
> travelling over a conducting soil induce currents and voltages in
> the same direction.
>
>