Re: Ground current experiments

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "John H. Couture by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>
> 
> Jon -
> 
> Your grandson will be working on a very important project in electrical
> science.
> 
> Tesla probably used this type of experiment many times to illustrate why he
> said that his world electrical system used currents instead of Hertzian
> waves (electromagnetic radiation). Currents require a retun path but
> Hertzian waves do not. The return path in this experiment is the air between
> the two secondary terminals. However, with Tesla's system the return path
> would be the ionosphere, a massive conductor volume of very low resistance.
> In both cases the earth is the other path.
> 
> Tesla said that he had solved the problem of connecting the two paths
> together (earth to ionosphere) but apparently never accomplished the feat.
> However, NASA has performed a related experiment with the shuttle and the
> tether tests. An insulated metal conductor is dragged thru the earth's
> magnetic field to create a voltage. The return path is the ionosphere. The
> test produced about about 5 KW of power.
> 
> John Couture

	Tesla clearly stated that his system used ionized air as a transmission
path, as he demonstrated with his experiments where two resonators were
connected through long evacuated tubes. As he states, the resistance was
fairly high. In effect, the spherical ionosphere and the spherical earth
formed a transmission line, and his "longitudinal waves" must have been
nothing more than the power flowing in one side of that transmission
line.  Nothing mysterious there at all.  His patent descriptions seem
too explicit for any other mechanism to have been in his mind.

	There are a few little problems with his system which can be
demonstrated with a few minutes of "figgering". For simplicity in the
calculations, and for rough order of magnitude estimates, ignore the
fact that that transmission line is at least a few wavelengths long.
Suggested first steps:

1. Calculate the capacitance of the capacitor formed by the ionosphere
(at a height more nearly like 50 miles than the 25,000 feet he
suggested) and the earth.  It is a good fraction of a farad.  To make
the problem even simpler, assume the capacitor is just a flat plate
capacitor with area equal to that of the earth's surface.

2. Calculate the reactive current which would have flowed if that
capacitor were excited by a 100,000,000 volt AC signal as he suggests. 
He mentions frequencies as low as around 900 Hz, so make the calculation
there; the results will be horrific enough.

3. Estimate the power loss associated with that current, using available
models for the resistivity of the ionosphere and measured earth
conductivity.  Alternately,

4. Calculate the total equivalent series resistance to keep the power
losses down to a megawatt or so.

5. Calculate the loss due to the well-known equivalent ionosphere to
earth leakage resistance of only 200 ohms.

6. Think about the results.

Ed 

Results of calculations welcome!