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Re: Physics of Wireless Transmission



Original poster: "Gary Peterson" <gary@xxxxxxxxxxxx>

Langer,

After reading "Electric Waves" by J.J. Thomson I retract my assertion that the term "electric wave" is synonymous with "electromagnetic radiation. On page 207, § 9. Waves in Wires, Thompson discusses apparatus for investigating "electric waves along wires." (View the page at http://www.newscotland1398.net/radio40/encybrit1911v09p207.html .) The term "electric wave" is actually synonymous with "electromagnetic wave."

Strictly speaking, all forms of electromagnetic radiation exist as an electromagnetic wave, but not all electromagnetic waves are electromagnetic radiation. An example of EM wave propagation that is not electromagnetic radiation is the flow of electrical energy across a transmission line, such as coaxial cable.

Gary Peterson


----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Sunday, April 09, 2006 3:43 PM
Subject: Physics of Wireless Transmission


Original poster: "Gary Peterson" <gary@xxxxxxxxxxxx>

Langer,

The physics of wireless transmission of electrical energy by "radio wave," also known as the "electric wave," aka "electromagnetic (EM) radiation," aka "Hertzian radiations" is described by Maxwell's Field Equations. These terms refer to the emanation of a dipole radio antenna. An explanation of this dynamic process, including a short movie, is available online at http://www.colorado.edu/physics/2000/waves_particles/wpwaves6.html .

Electromagnetic radiation carries energy and momentum which may be imparted when it interacts with matter. Absorption takes place as a radio wave passes from a dielectric medium into a conducting medium, such as the earth, the ionosphere or a radio wave receiving antenna, resulting in a conversion of radiated energy back into electrical current..

A term related to "electromagnetic radiation" is "electromagnetic wave." This term is used to broadly describe electrical energy propagated through either free space or a material medium. Examples of free-space electromagnetic wave propagation are radio waves, infrared radiation, visible light, ultraviolet radiation, X rays, and gamma rays; all of these are forms of electromagnetic radiation. An example of electromagnetic wave propagation that is not in the form of electromagnetic radiation is the flow of electric and magnetic fields and their associated electric current along and through an electrical conductor.

There is an alternate to EM radiation for wireless transmission of electrical energy. As Matt D. points out, "Two [Tesla] coils . . . can couple capacitively." The transmission of electrical energy is in the form of an EM wave, specifically an alternating current flowing through the earth, along with its associated electric and magnetic field energy, between the ground terminal of the Tesla coil RF transmitter and the ground terminal of the Tesla coil receiving transformer. In addition to current flowing through the earth, current also flows between the transmitter's elevated terminal and the receiver's elevated terminal. This transmission-reception system is called "wireless" in that does not involve the propagation of an electric current through a wire as might be purchased from an electrical wire manufacturer. The energy flows throughout the system as electric current and, in some cases, displacement current as well.

The physics of wireless transmission of electrical energy by conduction is also described by Maxwell's Field Equations, in combination with the Navier-Stokes Equations of Fluid Dynamics. As Bob (R.A.) Jones points out, "There are some fine details if . . . capactively coupled is electromagnetic propagation. . . ," that it's "terribly complicated. . . ," and, "There are people that insist . . . the method is . . . simply not electromagnetic waves." Of course the Tesla-coil energy transmission method must involve electromagnetic waves--there is no other overarching mechanism available.

Gary Peterson


Subject: physics of wireless transmission?

Original poster: "Langer Giv'r" <transworldsnowboarding19@xxxxxxxxxxx>

Hello, I am just curious on the physics of how electrical energy is
transmitted wirelessly.  Is it like the propagation of electromagnetic
radiation like radio transmission or is it not waves at all?  Are there
any sites out there that would be helpful towards this inquiry?  It would
be great to figure out how tesla coils do what they do, thanks for the
help!