ATDTDA (1): De Forest and Kimura (29:32-3)

[Monte Davis]

> Comparing to power transmission without wire, 
> Tesla said sneering that the wireless telegraphy was not at 
> all such a great invention.

The central tenet of the Weird Science cult of Tesla, as I understand it, is
that if you can broadcast *signals*, then you ought to be able to broadcast
*power*. (Science fiction fans might remember the backdrop of broadcast
power in Heinlein's 1942 story "Waldo".) A little bit of speculation is
usually followed by a lot of ideologically charged riffing about how that
would liberate us all from the grasping, evil utility monopolies, about how
the Powers That Be suppressed Tesla's potentially world-changing technology,
etc. etc. 

But there is -- and always was-- a boring, quantitative problem right at the
heart of the idea. The strength of any electromagnetic field that is
omnidirectional (= "broadcast") falls off as the square of the distance from
the source. Sun, lightbulb, KCUF transmitter... visible light, UV, radio,
X-rays, ... all the same. Picture a series of concentric spherical shells,
with a given amout of energy passing through a portion of the surface at
distance X; geometry tells you that at distance 2X the energy flux is 1/4 as
much per unit area, at distance 3X it's 1/9th as much, and so on.

For *signals* that's OK. Your radio doesn't care that its little antenna is
intercepting only a kazillionth of a watt from KCUF's 500KW broadcast,
because what it cares about is the "information* -- the tiny variations in
amplitude (AM) or frequency (FM). It uses *local* power (battery or wall
current) to amplify them multi-kazillionfold (see: De Forest et al) and
drive a speaker. The power can be arbitrarily small; as long as the signal
it carries is reliably distinguishable from other signals and from ambient
electronic noise, you're in business.

But for *power* transmission, that's not the case. If you want your
foot-square Teslantenna (TM) a thousand miles from Wardenclyffe to be able
to draw say 1 kilowatt, the same-sized antenna at 100 miles would experience
a flux of 100 KW... at 10 miles, 10 megawatts... at 1 mile, a gigawatt...
Are we seeing some potential environmental issues here? Is it occurring to
us that while our bodies (and everything else) are effectively indifferent
to femtowatts of *signals* passing through on the way to far-away receivers,
they would hardly be indifferent to nuke-the-ramen  levels of *power*
passing through?

When you talk to Tesla cultists about this, you get a lot of jive about
"ground currents" and "using the Earth as a resonating circuit" and so on.
Well, yes, between terrestrial and solar electromagnetic fields, lightning
and auroras and so on, there *are* some big numbers for power involved. But
now we're talking about currents in circuits, aren't we -- no longer about
"broadcast" at all? And if you want to start manipulating power -- not
signals -- in circuits involving six sextillion tons of planet with two
hundred million square miles of surface area, in a magnetosphere of billions
of cubic miles, you're going to need components that are significant
fractions of that mass, area, and volume. Could run into money.

In his youth and in his prime, Nicola Tesla grasped electromagnetic theory
and practice far better than I ever will, and accomplished things that
changed the world. But gradually, along the way, "change the world" took
priority -- and increasingly in his last decades, whatever bending of the
science might be necessary to make that possible, so be it. 

In other words... fun and titillating as it may be to say "Vibe, Morgan, the
GTE-Siemens Bulb Cabal et al plotted to derail Tesla's efforts and discredit
him as a crackpot"... foax, he really *did* become a crackpot.

-Monte (designated wet blanket)