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Re: Tesla Coil RF Transmitter



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

Sam,

1.1 As Terry points out, many an early radio transmitter was simply a Tesla coil with the topload replaced by a vertical piece of wire, 1/4 wavelength long; using a flat-spiral Tesla coil was a popular way to go. If the resonator's opposite terminal is grounded, then you have what is called a grounded or "Marconi antenna." This type of antenna behaves in a similar fashion to a 1/2 wavelength dipole in free space. Read up on antenna theory to learn how these structures emit radio waves. Early on in his work Tesla himself experimented with this type of transmitter.

1.2 There are two additional types of wireless transmitter that you can build using a Tesla coil. The first is quite similar to the classic Tesla coil that nearly everyone on this list has assembled. The main difference is in the placement of the topload. Instead of mounting it close-in just above the resonator's top turn, the topload is elevated somewhat above the top turn. Unlike the radio transmitter described in paragraph 1.1, this transmitter requires that a precisely tuned helical resonator type receiver be set in place in order for it to function. This is why in the related wireless patents Tesla always shows both the transmitter and the receiver (see http://www.teslaradio.com/images/645576-1a.gif for example). In the case of this type transmitter, the transfer of electrical energy is between the two ground terminals in the form of true conduction currents, and also between the elevated terminals. In a low power system, the transfer of energy between the elevated terminals is, in effect, the result of displacement currents, much like the transfer of electrical energy which takes place between the plates of a capacitor in an AC circuit. I call this the type-one transmitter.

1.3 The second of the Tesla-type transmitters consists of a type-one transmitter plus an unloaded helical resonator receiver, both placed in close proximity to each other, each with an independent ground connection. Tesla first illustrates the improved type-two transmitter in his Colorado Springs laboratory notes (see http://www.teslaradio.com/images/csn-200-6a.gif for example). The two illustrations at http://www.teslaradio.com/images/image004.jpg and http://www.teslaradio.com/images/TS-261-1a.gif show type-two transmitters in operation. In operation, a powerful current flows through the earth between the two ground terminals. The coupling between the transmitter's two elevated terminals is by electrostatic induction or, in the case of a high-power transmitter, by true electrical conduction through plasma. There is also some degree of inductive magnetic coupling between the two helical resonators. The type-two transmitter is particularly well suited for exciting earth resonance modes. I think it's interesting to see that in the related patent ART OF TRANSMITTING ELECTRICAL ENERGY THROUGH THE NATURAL MEDIUMS, Tesla shows a form of receiver that does not involve a helical resonator.

Gary


----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx> To: <tesla@xxxxxxxxxx> Sent: Friday, September 09, 2005 1:41 PM Subject: Tesla Coil RF Transmitter


Original poster: d a <btoc3000@xxxxxxxxxxxx>


Hey all,

How does a Tesla coil actually function like a RF Transmitter?

Is it due to the fact that at the secondary topload, the frequency of the output is very high - so much so that RF are produced?

Can anybody introduce me a website that summarises the principles of Tesla Coil (in say, 10 lines or less)? Most of the ones I came across are really lengthy..

Thanks!
Sam