Re: Tesla Coil RF Transmitter

["Tesla list" <tesla@xxxxxxxxxx>]

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