[Prev][Next][Index][Thread]

Re: Wireless Energy Transmission

> > Just a small note that I figured I would add.  On a previous post I
followed
> > a link to Tesla Coil sites (from a search engine I believe) and that
brought
> > me to an archive of Tesla pictures.  As a caption to the picture, it
said
> > that Tesla's largest coil put such high voltages into the ground that a
1"
> > spark could be drawn from a drain pipe 300 miles away.  If that was
indeed
> > true, then perhaps this idea would be feasible.  Although I have not
taken a
> > physics course yet in school, making my knowledge greatly lacking, I
thought
> > that I might add that promising point.
> > 
> > -Andy
> 
> Does this happen with the vastly greater energy of a lightning strike?
> What voltage could a coil 10' high really stand? What about an 
> insulator 10' long?
> 

Induced currents from nearby lightning strikes are a well known phenomenon,
as is EMP. Wireless energy transmission is a reality (how else would your
radio work?, you have to consume some energy to transmit information, in a
basic sort of entropy way). Another notable example of wireless energy
transmission is a microwave oven. The food gets hot by resistive heating,
and there aren't any wires connected to it.

It's just that electromagnetic radiation isn't a particularly practical
way, mostly because of inverse square law effects (i.e. you send the energy
out, and it inevitably spreads out, so your receiver has to be bigger and
bigger to capture it all). Sure, you can focus a "beam" with a sufficiently
large antenna, but that just shifts the burden of a big receiver to a big
transmitter. If you had a very large power source, you could just send the
energy out everywhere, and let whoever puts up a receiver intercept it. The
tricky thing there would be to prevent unintended receivers from picking up
the energy. Aside from the profit motive of "commercial power
broadcasters", there is a safety problem: Say I beam a megawatt of
microwave power up the street from my house, for all to use for free. I use
microwaves so that the beam can be reasonably narrow with a reasonable
sized antenna.  My neighbors can put an antenna up and extract some of the
megawatt for their own uses. Unfortunately, my neighbor's cat also
intercepts some share of the megawatt and would suffer unduly (unless it
were a very cold winter, in which case the cats would love it), as would
their trees and plants, the delicate electronic equipment in their
computers, etc.

If you want to move energy around, you need a way that doesn't spread out:
for ElectroMagnetic energy, it is called either a conductor (a wire) or a
waveguide, depending on the propagation means. Or, as is actually done, you
move the energy in another form (i.e. chemical energy in the form of
oil/gas/coal).