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The World Wireless system was Tesla's proposed global system "for the transmission of electrical energy without wires" intended for point-to-point wireless telecommunications, broadcasting, and other purposes.  He first broached this idea in a June 1900 Century Illustrated Magazine article titled "The Problem of Increasing Human Energy" although planning began prior to 1899. The system was to depend upon the high electrical conductivity of the earth. With the initial financial backing of banker J. P. Morgan, construction started in 1901 of the Wardenclyffe Tower, the first part of this system.  The plant was never completed, bankrupting Tesla and ending his plans for a world wireless system.

Transmission of electrical energy

An electric current flowing through a conductor carries electrical energy.  The body of the earth is an electrical conductor, nearly spherical in shape, insulated in space.  It possesses an electric charge relative to the upper atmosphere beginning at an elevation of about 50 kilometers.  When a second body, directly adjacent to Earth, is charged and discharged in rapid succession this causes an equivalent variation of Earth's electrostatic charge, resulting in the passage of electric current through the ground.

The grounded resonance transformer electrical oscillator transmitter, both the single and dual tower forms, is an electrical machine specifically designed to create a displacement of Earth's electric charge.  This is done by alternately charging and discharging the oscillator's elevated terminal capacitance at a specific frequency, generating an alternating electric field, and periodically altering the electrostatic charge of Earth, and consequently, with sufficient power, the electrical potential over its entire surface.  "A connection to earth, either directly or through a condenser is essential." The placement of a grounded resonance transformer electrical energy receiver tuned to the same frequency as the transmitter at another point on the surface results in the flow of electric current through the earth between the two, "while an equivalent electric displacement occurs in the atmosphere." This current can be used at the receiver to drive an electrical load.  In the case of an individual World Wireless Telecommunications System receiver this would be a sensitive device using only a small amount of energy.

In 1891 and 1892, Tesla used the oscillatory transformer that bears his name in demonstration lectures delivered before meetings of the American Institute of Electrical Engineers (AIEE) in New York City" and the Institution of Electrical Engineers (IEE) in London. Of two significant results that were demonstrated, one was that the wireless transmission of electrical energy is possible.  A later presentation, titled "On Light and Other High Frequency Phenomena" (Philadelphia/St. Louis; Franklin Institute in 1893), is a key event in the invention of radio and can also be said to have begun the development of the Wardenclyffe World Wireless System facility prototype.

One-wire transmission

In the early presentations, the first experiment to be demonstrated was the operation of light and motive devices connected by a single wire to only one terminal of a high frequency induction coil, performed during the 1891 New York City lecture at Columbia College.  While a single terminal incandescent lamp connected to one of an induction coil’s secondary terminals does not form a closed circuit “in the ordinary acceptance of the term” the circuit is closed in the sense that a return path is established back to the secondary by “electrostatic induction” or what is now known as 'displacement current'.  This is due to the lamp’s filament or refractory button capacitance relative to the coil’s free terminal and environment; the free terminal also has capacitance relative to the lamp and environment.  At high frequencies, the displacement current through these capacitances is sufficient to light the lamp.

Wireless transmission

The second result demonstrated how energy can be made to go through space without any connecting wires.  This was the first step towards a practical wireless system.  The wireless energy transmission effect involves the creation of an electric field between two metal plates, each being connected to one terminal of an induction coil’s secondary winding.  Once again, a light-producing device (in this case a gas discharge tube) was used as a means of detecting the presence of the transmitted energy.  "The most striking result obtained" involved the lighting of two partially evacuated tubes in an alternating electrostatic field while held in the hand of the experimenter.

Two different types of wireless transmitter were described, both employing a high-tension induction coil.  One has a sheet of metal suspended from the ceiling and connected to one of the induction coil’s terminals, with the other terminal being connected to ground.  The other type of transmitter has two sheets of metal suspended from the ceiling, each being connected to one of the coil’s high-voltage terminals.

Electrical transmission and reception

Early experiments toward development of a world wireless system involved the propagation of ordinary radio waves, that is to say Hertzian waves, unguided electromagnetic waves propagated through space.

In 1919 he wrote,

The popular impression is that my wireless work was begun in 1893, but as a matter of fact I spent the two preceding years in investigations, employing forms of apparatus, some of which were almost like those of today.  It was clear to me from the very start that the successful consummation could only be brought about by a number of radical improvements.  Suitable high frequency generators and electrical oscillators had first to be produced.  The energy of these had to be transformed in effective transmitters and collected at a distance in proper receivers.  Such a system would be manifestly circumscribed in its usefulness if all extraneous interference were not prevented and exclusiveness secured.  In time, however, I recognized that devices of this kind, to be most effective and efficient, should be designed with due regard to the physical properties of this planet and the electrical conditions obtaining on the same.

One of the requirements of the World Wireless system is the construction of resonant receivers. The grounded helical resonator of a Tesla Coil and an elevated terminal can be used in receive mode.

Tesla repeatedly demonstrated the wireless transmission of electrical energy from a Tesla coil transmitter to a Tesla coil receiver.  These concepts and methods are part of his wireless transmission system (U.S. Patent No. 1,119,732, Apparatus for Transmitting Electrical Energy, January 18, 1902, December 1, 1914).  He made a proposal that there would be many more than thirty transmission-reception stations worldwide.

In the principle form of Tesla system receiver, a Tesla coil receiving transformer acts as a step-down transformer with high current output. The parameters of a Tesla Coil transmitter are identically applicable to it being a receiver (e.g.., an antenna circuit), due to reciprocity.

In another form of receiving circuit the two input terminals are connected to a device designed to reverse polarity at predetermined intervals of time and charge a capacitor. This form of Tesla system receiver has means for commutating the current impulses in the charging circuit so as to render them suitable for charging an energy storage device, a device for closing the receiving-circuit, and means for causing the receiver to be operated by the accumulated energy.

"The earth is 4,000 miles radius.  Around this conducting earth is an atmosphere.  The earth is a conductor; the atmosphere above is a conductor, only there is a little stratum between the conducting atmosphere and the conducting earth which is insulating. . . . Now, you realize right away that if you set up differences of potential at one point, say, you will create in the media corresponding fluctuations of potential.  But, since the distance from the earth's surface to the conducting atmosphere is minute, as compared with the distance of the receiver at 4,000 miles, say, you can readily see that the energy cannot travel along this curve and get there, but will be immediately transformed into conduction currents, and these currents will travel like currents over a wire with a return.  The energy will be recovered in the circuit, not by a beam that passes along this curve and is reflected and absorbed, . . . but it will travel by conduction and will be recovered in this way."

The intention of the Tesla world wireless energy transmission system is to combine broadcasting and point-to-point wireless telecommunications along with electrical power transmission, allowing for the elimination of many existing high-tension power transmission lines, facilitating the interconnection of electrical generation plants on a global scale.

One of Tesla's patents suggests he may have misinterpreted 25–70 km nodal structures associated with cloud-ground lightning observations made during the 1899 Colorado Springs experiments in terms of circumglobally propagating standing waves instead of a local interference phenomenon of direct and reflected waves.

His concept of a global wireless electrical power transmission grid and telecommunications network based upon energy transmission by means of a spherical conductor transmission line with an upper three-space model return circuit, while perhaps not practical for power transmission, is feasible, defying no law of physics.  Global wireless transmission by means of a spherical conductor “single-wire” surface wave transmission line and a propagating TM₀₀ mode may also be possible, a feasibility study using a sufficiently powerful and properly tuned Tesla coil earth-resonance transmitter being called for.

Theory of wireless transmission

While working to develop an explanation for the two observed effects mentioned in the 1891 and 1892 lectures, he recognized that electrical energy can be projected outward into space and detected by a receiving instrument in the general vicinity of the source without the need for any interconnecting wires.  He went on to develop two theories related to these observations, which are:

1. By using two grounded Tesla coil transmitter-receivers positioned at distant points on the Earth’s surface, it is possible to induce a flow of electrical current between them.
2. By incorporating a portion of the Earth as part of a powerful dual-elevated-terminal Tesla coil transmitter an electrical disturbance can be impressed upon the Earth and detected “at great distance, or even all over the surface of the globe.”

He also made the assumption that Earth is a charged body floating in space, possibly floating in an oppositely charged medium beyond the atmosphere.

A point of great importance would be first to know what is the capacity of the Earth? and what charge does it contain if electrified? Though we have no positive evidence of a charged body existing in space without other oppositely electrified bodies being near, there is a fair probability that the Earth is such a body, for by whatever process it was separated from other bodies—and this is the accepted view of its origin—it must have retained a charge, as occurs in all processes of mechanical separation.

He was familiar with demonstrations that involved the charging of Leyden jar capacitors and isolated metal spheres with electrostatic influence machines (in modern terms, high-voltage (kV), low-current (µA) electrostatic generators).  By bringing these elements into proximity with each other, and also by making direct contact followed by their separation, the charge can be manipulated.  He surely had this in mind in the creation of his mental image, not being able to know that the model of Earth’s origin was inaccurate.  The accepted model of planetary origin is one of accretion and collision.

If it be a charged body insulated in space its capacity should be extremely small, less than one-thousandth of a farad.  But the upper strata of the air are conducting, and so, perhaps, is the medium in free space beyond the atmosphere, and these may contain an opposite charge.  Then the capacity might be incomparably greater.

We now know that the Earth is a charged body, made so by processes—at least in part—related to the interaction between the continuous stream of charged particles called the solar wind that flows outward from the center of our solar system and Earth’s magnetosphere, and that Earth's upper atmospheric strata are conducting, or can be made so.  Earth's electrical self-capacitance is calculated to be about 708.5 microfarads, somewhat less than one thousandth of a farad.

In any case it is of the greatest importance to get an idea of what quantity of electricity the Earth contains.

An additional condition of which we are now aware is that the Earth possesses a naturally existing negative charge with respect to the conducting region of the atmosphere beginning at an elevation of about 50 km.  The potential difference between the Earth and this region is on the order of 400,000 volts.  Near the Earth's surface there is a ubiquitous downward-directed E-field of about 100 V/m.

It is difficult to say whether we shall ever acquire this necessary knowledge, but there is hope that we may, and that is, by means of electrical resonance.  If ever we can ascertain at what period the Earth's charge, when disturbed, oscillates with respect to an oppositely electrified system or known circuit, we shall know a fact possibly of the greatest importance to the welfare of the human race.  I propose to seek for the period by means of an electrical oscillator, or a source of alternating electric currents.

The Earth resonance method involves the creation of "powerful disturbances" in Earth's natural electric charge.

The Wardenclyffe facility had a dual purpose.  In addition to point-to-point telecommunications and broadcasting it was also intended to demonstrate the transmission of electrical power on a reduced scale.

Wardenclyffe was the first of many installations to be constructed near major population centers around the world.  If plans had moved forward without interruption the Long Island prototype would have been followed by a second plant built in the British Isles, perhaps on the west coast of Scotland near Glasgow.  Each of these facilities would include a large magnifying transmitter of a design loosely based upon the apparatus assembled at the Colorado Springs Experimental Station in 1899.

"The plant in Colorado was merely designed in the same sense as a naval constructor designs first a small model to ascertain all the quantities before he embarks on the construction of a big vessel.  I had already planned most of the details of the commercial plant, subsequently put up at Long Island, except that at that time the location was not settled upon.  The Colorado plant I have used in determining the construction of the various parts, and the experiments which were carried on there were for the practical purpose of enabling me to design the transmitters and receivers which I was to employ in the large commercial plant subsequently erected."

Using a global array of these magnifying transmitters, he planned to establish the "World Wireless System," providing multi-channel global broadcasting, an array of secure wireless telecommunications services, and a long range aid to navigation, including means for the precise synchronization of clocks.  In a more highly developed state he envisaged the 'World System' would expand to include the wireless industrial transmission of electric power.

At the time the power grid was quite limited in terms of reach and the Wardenclyffe prototype represented a way to significantly reduce the cost of "electrifying" the countryside.  This wireless technique is called the "disturbed charge of ground and air method".

There is evidence that Wardenclyffe would have used extremely low frequency signals combined with higher frequency signals.  In practice, the transmitter electrically influences both the Earth and the space above it. 

The process is essentially the same as transmitting electricity by conduction through a wire. The Earth itself is one of the conducting media involved in ground and air system technology.  The other medium is the atmosphere above approximately 5 miles (8.0 km) elevation.  While not an ohmic conductor, in this region of the troposphere and upwards, the density or pressure is sufficiently reduced to so that, according to theory, the atmosphere’s insulating properties can be easily impaired thus allowing an electric current to flow.  Theory further states that the conducting region is developed through the process of atmospheric ionization in which the affected portions thereof are changed to plasma.  The presence of the magnetic fields developed by each plant’s helical resonator suggests that an embedded magnetic field and flux linkage is also involved.  Flux linkage with Earth’s natural magnetic field is also a possibility, especially in the case of an earth resonance transmission system.

The atmosphere below 5 miles (8.0 km) is also a propagating medium for a portion of the above-ground circuit.  Being an insulating medium, electrostatic induction is involved rather than true electrical conduction.  The practical construction limitation imposed upon the height of the elevated terminals can be overcome with a sufficiently high electrical potential.  With a highly energetic transmitter, as was intended at Wardenclyffe, the elevated terminal is charged to the point where the atmosphere around and above the facility becomes strongly ionized.  This leads to a flow of true conduction currents between the two terminals by a path up to and through the upper atmosphere, and back down to the other facility.  The ionization of the atmosphere directly above the elevated terminals can be facilitated by the use of ionizing beams of ultraviolet radiation to form what might be called high-voltage plasma transmission lines. 

Earth's large cross-sectional area provides a low resistance path for the flow of earth currents.  The greatest losses are apt to occur at the points where the transmitting-receiving plants and dedicated receiving stations are connected with the ground.

To close the circuit a second path is established between the two transmitter-receiver plants' elevated high-voltage terminals through the rarefied atmospheric strata above 5 miles (8.0 km).  The connection is made by some combination of electrostatic induction and electrical conduction through plasma. 

While a number of the wireless patents, including "Apparatus for transmitting electrical energy," U.S. Patent No. 1,119,732, December 1, 1914, describe a system which uses the plasma-conduction scheme, his "Art of transmitting electrical energy through the natural mediums," U.S. Patent No. 787,412, April 18, 1905 and some of the Wardenclyffe design notes from 1901 show the overall plan also involves electrostatically induced oscillations in the potential associated with Earth's self-capacitance.  The two tower earth-resonance transmitter is especially designed for this purpose.

According to theory, Earth itself behaves as an electrical resonator when it is excited at certain frequencies.  The operating frequencies at Wardenclyffe were from 1,000 Hz to 100 kHz.  The frequency range up to 30 – 35 kHz was found “to be most economical.” Excitation of earth resonance at an harmonic of the 11.78 Hz fundamental frequency suggests energy transmission by means of a TM₀₀ spherical conductor “single-wire” surface wave transmission line mode.  This involves surface plasmon wave excitation.

The entire Earth can be electrically resonated with a single earth-resonance transmitter, so an earth-resonance based system would require, at a minimum, that only one World Wireless System transmitter be constructed.  Alternatively, two distantly spaced transmitter-receiver facilities could be constructed.  Such a system would not be so dependent upon the excitation of an earth-resonance mode.  In either case a surface wave, similar to the Zenneck wave would be used.

Tesla believed that a fully developed system with large high-power wireless stations based upon the smaller Wardenclyffe prototype would permit industrial power transmission and reception across large distances with low loss.

In spite of ridicule, many of Tesla's ideas have been demonstrated to be essentially correct.  For example he correctly predicted the existence of the ionosphere and electrical resonance of the Earth-atmosphere system.  Resonance of the earth-ionosphere cavity with a fundamental frequency in the vicinity of 7.83 Hz was demonstrated in the 1950s as the Schumann resonance. The latter phenomenon was named after Schumann, for although Tesla had detected a resonance of the Earth-atmosphere system, he was not taken seriously in his time. Furthermore, he appears to have excited a different terrestrial resonance mode with a fundamental frequency of 11.78 Hz.

Misconceptions

World System functionality

It is believed by some that World Wireless System technology is intended only for wireless power transmission.  The prototype Wardenclyffe installation and the second facility planned in Scotland had a dual purpose.  Their primary function was multi-channel point-to-point trans-Atlantic wireless telecommunications and worldwide broadcasting.  The prototype system was also intended for proof-of-concept wireless power transmission demonstrations, although on a greatly reduced scale.

Propagation mode

Resonant inductive coupling

It is believed by some that energy transfer between a grounded resonance transformer electrical oscillator transmitter and a similarly designed grounded resonance transformer electrical energy receiver tuned to the same frequency is by resonant induction between tuned circuits. 

The inferiority of the induction method would appear immense as compared with the disturbed charge of ground and air method."

This was confirmed by a 2008 propagation study using the basic world system transmission-reception circuit, that achieved transmission range efficiencies greater than those achieved using the resonant electrical induction method. 

Electromagnetic radiation

It was once thought the 200 kW Wardenclyffe prototype World Wireless station would have functioned by the production and propagation of electromagnetic radiation also known as the transverse electromagnetic (TEM) radio wave, but this is not the case.  The World Wireless System works by the creation of powerful disturbances in the Earth's natural electric charge and a spherical single conductor transmission line propagation mode.

I am not producing radiation in my system; I am suppressing electromagnetic waves.  But, on the other hand, my apparatus can be used effectively with electromagnetic waves.  The apparatus has nothing to do with this new method except that it is the only means to practice it.  So that in my system, you should free yourself of the idea that there is radiation, that energy is radiated.  It is not radiated; it is conserved.

Schumann Cavity resonance

It has been proposed World Wireless System technology involves energy transfer by means of a concentric spherical shell waveguide composed of Earth's surface and the ionosphere.  This earth-ionosphere cavity is known as the Schumann Cavity.  Natural lightning excites Schumann resonances that are observed at the lowest few resonance frequencies (about 8 Hertz and multiples of that).  Their measured Q's of order 5 to 10 suggest that the electrical disturbances produced by lightning make a few circuits of the Earth before damping out, and create a fairly definite terrestrial standing wave of a few cycles duration.

A consideration of the earth-ionosphere or concentric spherical shell waveguide propagation parameters as they are known today shows that wireless power transmission by direct excitation of a Schumann cavity resonance mode is not realizable.

The conceptual difficulty with this model is that, at the very low frequencies that Tesla said that he employed (1–50 kHz), earth-ionosphere waveguide excitation, now well understood, would seem to be impossible with either the Colorado Springs or the Long Island apparatus (at least with the apparatus that is visible in the photographs of these facilities)."

The maximum recommended operating frequencies of 25 kHz as specified by Tesla is far above the highest easily observable Schumann resonance mode (this is the 9th overtone) that exists at approximately 66.4 Hz. His selection of 25 kHz is wholly inconsistent with the operation of a system that is based upon the direct excitation of a Schumann resonance mode.

What is wanted for wireless transmission of power is for the electrical load connected to the receiver to draw power from the transmitter via the standing wave.  I.e., when the load is switched on, the transmitter should "feel" the load, as it would in a closed circuit, and respond by providing more power via the standing wave.

The current induced in the input impedance of the receiver should reciprocally induce power in the output impedance of the transmitter similar to the power that was transmitted initially.  This is a way of expressing the coupling between the transmitter and receiver required for the transmitter to "feel" the load on the receiver.  The Q is the value that produces an electric field in the cavity strong enough to induce the required current in the input impedance of the receiver.

At higher frequencies, the required Q is larger, but I expect that the Q of the Earth-ionosphere cavity probably decreases because propagation losses in the Earth and ionosphere increase.

Ionospheric conduction

It is believed by some the atmospheric path that would be used in the two-conductor method, i.e., the "second path," is the ionosphere, the uppermost strata of Earth's atmosphere starting at approximately 30 miles (48 km) in daytime and approximately 55 miles (89 km) at night.  The atmospheric strata through which energy can be transmitted has a barometric pressure of 75 mm, equivalent to an elevation of about 15 miles (24 km).  World Wireless System apparatus allows this elevation to be reduced down to approximately 5 miles (8.0 km) because of the exceedingly high potentials involved.

Related patents

• System of Electric Lighting, U.S. patent 454,622, Apr. 25, 1891
• Means for Generating Electric Currents, U.S. patent 514,168, February 6, 1894
• Electrical Transformer, U.S. patent 593,138, November 2, 1897
• Method of Signaling, U.S. patent 723,188, March 17, 1903
• System of Signaling, U.S. patent 725,605, April 14, 1903
• Art of Transmitting Electrical Energy Through the Natural Mediums, U.S. patent 787,412, April 18, 1905
• Apparatus for Transmitting Electrical Energy, January 18, 1902, U.S. patent 1,119,732, December 1, 1914

See also

• Wireless energy transmission
• Terrestrial stationary waves
• Surface plasmon
• Surface-wave-sustained mode
• Transmission medium
• Distributed generation
• Electricity distribution
• Electric power transmission

Apparatus

• Electric generator
• Isochronous electro-mechanical oscillator
• Tesla coil
• Magnifying Transmitter

Notes

1. Margaret Cheney, Tesla: Man Out of Time, page 194
2. Anderson, Leland I., Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony and Transmission of Power, 21st Century Books, 2002, p. 170.

   In Colorado I erected a plant for the practical purpose of arriving at accurate data for the construction of a large plant. . . . I had already planned most of the details of the commercial plant, subsequently put up at Long Island, except that at that time the location was not settled upon.

3. ^ "The Transmission of Electrical Energy Without Wires," Electrical World, March 5, 1904". 21st Century Books. 5 March 1904. Retrieved 4 June 2009.." Cite error: The named reference "Tesla Electrical world" was defined multiple times with different content (see the help page).
4. Anderson, Leland I., Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony and Transmission of Power, 21st Century Books, p. 128.

   The earth is 4,000 miles radius.  Around this conducting earth is an atmosphere.  The earth is a conductor; the atmosphere above is a conductor, only there is a little stratum between the conducting atmosphere and the conducting earth which is insulating.

5. Maury Klein, The Power Makers: Steam, Electricity, and the Men Who Invented Modern America
6. Ratzlaff, John T., Tesla Said, Tesla Book Company, 1984; "The Disturbing Influence of Solar Radiation On the Wireless Transmission of Energy," Electrical Review and Western Electrician, July 6, 1912
7. ^ Ratzlaff, John T., Dr. Nikola Tesla  Complete Patents; System of Transmission of Electrical Energy], September 2, 1897, U.S. patent 645,576, March 20, 1900.
8. Martin, Thomas Commerford, "The Inventions, Researches and Writings of Nikola Tesla", The Electrical Engineer, New York, 1894; "Experiments With Alternating Currents of Very High Frequency, and Their Application to Methods of Artificial Illumination," AIEE, Columbia College, N.Y., May 20, 1891
9. Martin, Thomas Commerford, "The Inventions, Researches and Writings of Nikola Tesla", The Electrical Engineer, New York, 1894; “Experiments With Alternate Currents of High Potential and High Frequency," IEE Address, London, February 3, 1892.
10. ^ Martin, Thomas Commerford, "The Inventions, Researches and Writings of Nikola Tesla", The Electrical Engineer, New York, 1894; "On Light and Other High Frequency Phenomena," February 24, 1893, before the Franklin Institute, Philadelphia, March 1893, before the National Electric Light Association, St. Louis.
11. Electrical Experimenter, January 1919. pg. 615
12. Cheney, Margaret, Tesla: Man Out of Time, Prentice-Hall, Inc., 1981, p. 174.
13. Norrie, H. S., Induction Coils: How to make, use, and repair them. Norman H. Schneider, 1907, New York. 4th edition.
14. Childress, David Hatcher, The Fantastic Inventions of Nikola Tesla, 1993; "The Transmission of Electrical Energy Without Wires" Electrical World, March 5, 1904
15. Ratzlaff, John T., Reference Articles for Solutions to Tesla's Secrets, Tesla Book Company, 1981; "The True Wireless", Electrical Experimenter, May 1919
16. "World System of Wireless Transmission of Energy," Telegraph and Telegraph Age, October 16, 1927
17. Martin, Thomas Commerford, "The Inventions, Researches and Writings of Nikola Tesla", The Electrical Engineer, New York, 1894; "Experiments With Alternating Currents of Very High Frequency, and Their Application to Methods of Artificial Illumination," AIEE, Columbia College, N.Y., May 20, 1891.

    "I suspend a sheet of metal a distance from the ceiling on insulating cords and connect it to one terminal of the induction coil, the other terminal being preferably connected to the ground.  Or else I suspend two sheets as illustrated in Fig. 29 / 125, each sheet being connected with one of the terminals of the coil, and their size being carefully determined.  An exhausted tube may then be carried in the hand anywhere between the sheets or placed anywhere, even a certain distance beyond them; it remains always luminous"

18. Definition of "Hertzian"
19. Seifer, Marc J., Wizard: The Life and Times of Nikola Tesla. p. 228.
20. Tesla, Nikola, "The True Wireless". Electrical Experimenter, May 1919. (Available at pbs.org)
21. Ratzlaff, John T., Dr. Nikola Tesla  Complete Patents; System of Signaling, U.S. patent 725,605.
22. Ratzlaff, John T., Dr. Nikola Tesla  Complete Patents; Apparatus for Transmitting Electrical Energy], January 18, 1902, U.S. patent 1,119,732, December 1, 1914.
23. Seifer, Marc J., Wizard: The Life and Times of Nikola Tesla. p. 472. (cf. "Each tower could act as a sender or a receiver.  In a letter to Katherine Johnson, Tesla explains the need for well over thirty such towers".)
24. ^ Tesla, Nikola (2002). Nikola Tesla on His Work with Alternating Currents and Their Application to Wireless Telegraphy, Telephony, and Transmission of Power: An Extended Interview. 21st Century Books. pp. 96–97. ISBN 1893817016.
25. Carlson, W. Bernard (2013). Tesla: Inventor of the Electrical Age. Princeton University Press. ISBN 978-1-4008-4655-9.
26. William Beaty, 'Energy-sucking' Radio Antennas, N. Tesla's Power Receiver.
27. William Beaty, "Tesla invented radio?". 1992.
28. Nikola Tesla's Contributions to Radio Developments tesla-symp06.org
29. A. H. Taylor, "Resonance in Aërial Systems". American Physical Society. Physical review. New York, N.Y.: Published for the American Physical Society by the American Institute of Physics. (cf. The Tesla coil in the receiver acts as a step-down transformer, and hence the current is greater than in the aerial itself.)
30. U.S. Patent 0685956
31. U.S. Patent 0685955 Apparatus for Utilizing Effects Transmitted From A Distance To A Receiving Device Through Natural Media
32. Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony and Transmission of Power, pp. 128–130.
33. Tesla, Nikola, Art of Transmitting Electrical Energy Through the Natural Mediums, April 17, 1906, Canadian Patent No. 142,352, August 13, 1912
34. "Nikola Tesla  Colorado Springs Notes 1899–1900", Nikola Tesla Museum, Nolit, Belgrade, 1978; July 4, 1899.
35. Elmore, Glenn, "Introduction to the Propagating Wave on a Single Conductor," Corridor Systems Inc., 2009.
36. Marincic, Aleksandar, "Research of Nikola Tesla in Long Island Laboratory," International Scientific Conference in Honor of the 130th Anniversary of the Birth of Nikola Tesla, 1986.
37. Electrical self-capacitance of Earth.
38. Feynman, Richard P., Robert B. Leighton, Matthew Sands, The Feynman Lectures on Physics Volume II. Mainly electromagnetism and matter, Chapters 4-12, Addison–Wesley, 1964.
39. "Proceedings of the 1988 International Tesla Symposium", International Tesla Society, 1988; Corum, James F., et al, "Concerning Cavity Q" (along with other sources, ed).
40. ^ Massie, Walter W. & Charles R. Underhill, Wireless Telegraphy & Telephony, Van Nostrand, 1908; The Future of the Wireless Art,] pp. 67–71.

    It is intended to give practical demonstrations of these principles with the plant illustrated.  As soon as completed, it will be possible for a business man in New York to dictate instructions, and have them instantly appear in type at his office in London or elsewhere.  He will be able to call up, from his desk, and talk to any telephone subscriber on the globe, without any change whatever in the existing equipment.  An inexpensive instrument, not bigger than a watch, will enable its bearer to hear anywhere, on sea or land, music or song, the speech of a political leader, the address of an eminent man of science, or the sermon of an eloquent clergyman, delivered in some other place, however distant.  In the same manner any picture, character, drawing, or print can be transferred from one to another place.  Millions of such instruments can be operated from but one plant of this kind.  More important than all of this, however, will be the transmission of power, without wires, which will be shown on a scale large enough to carry conviction.

41. Nikola Tesla On His Work with Alternating Currents and Their Application to wireless Telegraphy, Telephony, and Transmission of Power, 21st Century Books, 2002, p. 170.
42. "U.S. Blows Up Tesla Radio Tower," Electrical Experimenter, September 1917, p. 293.
43. "Nikola Tesla  Colorado Springs Notes 1899–1900", Nikola Tesla Museum, Nolit, Belgrade, 1978; June 5, 1899
44. Massie, Walter W. & Charles R. Underhill, Wireless Telegraphy & Telephony, Van Nostrand, 1908; "The Future of the Wireless Art]"

    This mode of conveying electrical energy to a distance is not 'wireless' in the popular sense, but a transmission through a conductor, and one which is incomparably more perfect than any artificial one.  All impediments of conduction arise from confinement of the electric and magnetic fluxes to narrow channels.  The globe is free of such cramping and hinderment.  It is an ideal conductor because of its immensity, isolation in space, and geometrical form.  Its singleness is only an apparent limitation, for by impressing upon it numerous non-interfering vibrations, the flow of energy may be directed through any number of paths which, though bodily connected, are yet perfectly distinct and separate like ever so many cables.  Any apparatus, then, which can be operated through one or more wires, at distances obviously limited, can likewise be worked without artificial conductors, and with the same facility and precision, at distances without limit other than that imposed by the physical dimensions of the globe.

45. Barnes, Arnold A., Jr., Robert O. Berthel, "A Survey of Laser Lightning Rod Techniques] AD-A239 988, August 12, 1991
46. Laser-Induced Plasma Channel
47. "Laser-Guided Energy"
48. "Vehicle Disabling Weapon"
49. "Laser Device May Provide U.S. Military Nonlethal Option"
50. Anderson, Leland I., Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony and Transmission of Power, 21st Century Books, p. 203.

    You see the underground work is one of the most expensive parts of the tower.  In this system that I have invented it is necessary for the machine to get a grip of the Earth, otherwise it cannot shake the Earth.  It has to have a grip on the Earth so that the whole of this globe can quiver, and to do that it is necessary to carry out a very expensive construction.

51. Ratzlaff, John T., Dr. Nikola Tesla  Complete Patents; "Art of Transmitting Electrical Energy Through the Natural Mediums," U.S. patent 787,412, April 18, 1905.

    The specific plan of producing the stationary waves, here-in described, might be departed from.  For example, the circuit which impresses the powerful oscillations upon the earth might be connected to the latter at two points.

52. "From Colorado Springs to Long Island Research Notes, Colorado Springs 1899-1900, New York 1900-1901", Nikola Tesla Museum, Belgrade, 2008.
53. "Proceedings of the 1994 International Tesla Symposium", International Tesla Society, Colorado Springs, 1994; Corum, Kenneth L., James F. Corum, "Nikola Tesla, Lightning Observations and Stationary Waves, "Appendix II, "The Zenneck Surface Wave."
54. Nikola Tesla On His Work with Alternating Currents and Their Application to wireless Telegraphy, Telephony, and Transmission of Power, 21st Century Books, 2002, p. 205.
55. Tesla's Big Mistake? William Beaty, September 1999
56. The Discovery of Schumann Resonance
57. Popovic, Vojin, "Nikola Tesla – True Founder of Radio Communications," Nikola Tesla Life Work of a Genius, Yugoslav Society for the Promotion of Scientific Knowledge "Nikola Tesla" Belgrade 1976.
58. Babylon Signal, August 1902.
59. 5 June 1899, NIKOLA TESLA COLORADO SPRINGS NOTES 1899–1900, Nolit, 1978
60. Leyh, G. E. and M. D. Kennan, "Efficient Wireless Transmission of Power Using Resonators with Coupled Electric Fields," 2008 North American Power Symposium.

    The power flowed through the ambient electric fields and returned through Earth, similar to Tesla’s original concept from 1900.

61. "Wireless Power Transfer via Strongly Coupled Magnetic Resonances," André Kurs, Aristeidis Karalis, Robert Moffatt, J. D. Joannopoulos, Peter Fisher, and Marin Soljacic, Science 6 July 2007: 83-86. Published online 7 June 2007
62. "Nikola Tesla and the Diameter of the Earth: A Discussion of One of the Many Modes of Operation of the Wardenclyffe Tower," K. L. Corum and J. F. Corum, PhD 1996
63. Anderson, Leland I., Nikola Tesla On His Work with Alternating Currents and Their Application to wireless Telegraphy, Telephony, and Transmission of Power, 21st Century Books, 2002, p. 133.
64. ^ Henry Bradford in "Nikola Tesla On Wireless Energy Transmission," The Schumann Cavity Resonance Hypothesis
65. Corum, K. L., J. F. Corum, PhD, and J. F. X. Daum, "Spherical Transmission Lines and Global Propagation, An Analysis of Tesla's Experimentally Determined Propagation Model" PV Scientific Instruments, 1996; p. 10.

Further reading

• Anderson, Leland, "Rare Notes from Tesla on Wardenclyffe" in Electric Spacecraft – A Journal of Interactive Research, Issue 26, September 14, 1998.  Contains drawings and selected typescripts of Tesla's notes from 1901, archived at the Nikola Tesla Museum in Belgrade.
• "Boundless Space: A Bus Bar"], The Electrical World, Vol 32, No. 19, November 5, 1898.
• Massie, Walter Wentworth, Wireless telegraphy and telephony popularly explained. New York, Van Nostrand. 1908.
• Tesla, Nikola, "The Transmission of Electrical Energy Without Wires", Electrical World and Engineer, March 5, 1904.
• Tesla, Nikola, "World System of Wireless Transmission of Energy"], Telegraph and Telegraph Age, October 16, 1927.

External links

• PBS Tesla Master of Lightning Tower of Dreams, global wireless telecommunications
• Wardenclyffe Tower at Structurae

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