Tesla described his wireless power transmission method by three characteristics:
1) the reduction or elimination of electromagnetic radiations,
2) that it operated through the earth, and 3) that the mechanism
of transmission is an electric current - as contrasted with radiations.
Modern analysts, on the other hand, model Tesla's transmission
system on present day broadcast radio technology. This model assumes
an antenna propagating electromagnetic waves into the air where
these radiations either will not or will, depending on the presuppositions
of the writer, bring about the effects claimed by the inventor.
Anachronistic interpretation - applying the assumptions of today's electrical
theories to Tesla's original turn of the century researches -
is only half the problem of understanding the inventor's wireless
method. The situation is further complicated by the similar sounding
descriptions Tesla gave to his earlier and later transmission
In his early work Tesla attempted electronic transmission by modifying
the atmosphere. This is the case in his patent entitled Method
of Intensifying and Utilizing Effects Transmitted Through Natural
Media, #685,953, applied for in June 1899. In this patent he proposes
a very powerful signal generator to ionize atmospheric gases and,
by that, create a conductive path between the transmitter and
receiver through which a current could be sent. Later, when Tesla
disclosed what he described as through-the-earth (or water) transmission
with essentially the same type of apparatus and operating at ELF
frequencies, it has been assumed by modern authorities that Tesla
was mistaken about his method of propagation and was really witnessing
earth-ionosphere cavity resonance at Schuman frequencies [1,2].
was more than an engineer of conventional methods. He was an electrical
researcher who investigated fundamental issues of the science.
It will be shown that the three characteristics of Tesla's wireless
transmission system describe an electrostatic wireless method
that used the earth as a conductor and transmitted displacement
currents. At moderate power levels the system could
be used for communication. At greater levels, power could be sent by wireless.
During 1899 - 1900 Tesla set up a laboratory in Colorado Springs to investigate
wireless signal transmission. It was during this period he discovered
that a properly configured receiver could detect waves, initiated
by lightning strikes, propagating through the earth. When he incorporated
this discovery into a patent he differentiated the earlier technology
dealing with "effects transmitted through natural media"
from the new form of signaling that involved the transmission
of energy. This is seen in his patent Art of Transmitting Electrical
Energy Through the Natural Mediums, #787,412, applied for 11 months
after the previous patent, in May 1900.
A great deal of detail about the apparatus for generating and receiving
electrical signals (tuned resonant circuits that were recognized
in 1943 by the Supreme Court as the basis of commercial radio
designs) is given in the patent but it assumes, or more
likely, avoids revealing, the physics behind the mode of propagation.
Tesla does point toward his novel transmission technique when
he notes in the patent that the "globe may ... behave ...
as a conductor of limited size;" and that low frequency
oscillations keep the "radiation of energy into space in
the form of hertzian or electromagnetic waves... very small."
These two claims, alone, indicate a technology different from
The illustration (see Figure 1
on the next page)for the patent is of
a transmitter consisting of an elevated capacitance, a coil, a
signal generator, and a single electrode in the earth. The receiver
is pictured as having a mechanism to oscillate at the same period
as the transmitter, a capacitor, a detector, and two earthed plates.
To understand Tesla's wireless transmission
system it is necessary to look at his technical writings on the
physics behind his engineering. One of his lectures on evacuated
tube illumination provides a good example.