Re: Tesla's Wireless Power Transmission ==> was Re: Non-tech Qu
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Tesla's Wireless Power Transmission ==> was Re: Non-tech Qu
> Date: Saturday, May 20, 2000 4:17 PM
> Original Poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br>
> Tesla List wrote:
> > Original Poster: "Dan Kunkel" <kunk77-at-juno-dot-com>
> I am avoiding to comment in this area, that I'm really sure to be
> pure nonsense, and the reason why Tesla is remembered more as the
> prototype of the "mad scientist" than as the father of many useful
> inventions, but...
> > You're right about the inverse square law (i = 1 / r * r ) aplying to
> > Tesla Coils. The fact is, they due make lousy radio transmitters. But,
> > fortunately that is not how Tesla envisioned them to operate. He wanted
> > them to pump low frequency current into the earth at the earth's
> > resonance.
> This "Earth natural resonances" are just the frequencies where a signal
> that propagates in totally conventional ways returns to the transmitting
> spot in phase with the transmitted wave, after going around the entire
> Earth. Considering Earth's circumference as 40000 km and the propagation
> speed as 300000 km/s, this results in 7.5 Hz as the first resonance
> frequency. The energy spreads to almost nothing a short distance from
> the transmitter, and concentrates again only around the transmitter
> after going around the Earth. Considering resistive losses in the
> imperfect conductors along all the way and the many different paths
> followed by the signal around the irregular surface of the Earth,
> the attenuation along all the way is too large for any useful purpose.
> The returned signal is surely barely detectable with very sensitive
Actually, the signal is easily detectable. Omega signals are in the 10 kHz
area and detecting both short and long path is possible without too much
trouble with inexpensive equipment. These signals propagate in a mode that
is essentially a waveguide between surface and ionosphere. A more
significant problem with this around the world thing is that the earth is
NOT a sphere, particularly not at RF. If you were to pick an arbitrary
direction, the propagation path would neither be straight, nor uniform
speed, nor match the path in another starting direction.
At HF frequencies (>3 MHz <30 MHz) long path propagation is quite common,
although it is a multihop skip off the ionosphere and surface. Typical
instantaneous variation in path length is on the order of milliseconds,
which results in a characteristic frequency selective fading on HF paths.
There is a worldwide lightning detection network that relies on the fact
that the RF energy from lightning everywhere in the world propagates
worldwide. In fact, this is a big constituent of the background noise in
the LF, MF, and HF radio bands.
> > To recieve your electrical service, you pound a ground rod in
> > the ground and tune your "recieving coil" to the same freq. And viola,
> > you have power.
> Where is the return path for the ground current?
You actually don't need a return path, per se, any more than a standard
radio receiving antenna has a path to the radio transmitter. Think of an
antenna as a "energy scoop".
> > Tesla also knew and proved that gas under low pressure (or "rarified
> > as he called it) was indeed very cunducting. In fact just as conducting
> > as a wire (if not more efficient). That is why that neon sign
> > transformers are current limited, a neon sign tube is an almost perfect
> > dead short.
> With 600 V across it, dissipating tens or hundreds of Watts.
Ionized gas is nowhere near the conductivity of metal...
> So with this in mind, he wanted to excite the ionisphere (or
> > the Schuman cavity as we know it today). The Schuman cavity has a
> > and proven resonance.
> With very low Q.
Out of curiosity, how low... I'll bet it is <1.. The multiple paths and
high loss make it more of a group of noncoherent time delays that happens
to clump around 1/7 second.
> Antonio Carlos M. de Queiroz