|
February 1939 Popular Science
 [Table of Contents]
Wax nostalgic about and learn from the history of early
electronics. See articles from
Popular
Science, published 1872-2021. All copyrights hereby acknowledged.
|
This scheme from a 1939
issue of Popular Science magazine gives a whole new perspective of a "cloud warmer" radio antenna. For
the most part, the portion of a transmitted radio wave that is directed within about
45-90° relative to horizon is generally considered a waste of transmitter power
since the angle of incidence of ionosphere layers is too great for "skip" type broadcasts,
and there are no receivers "up there" to intercept the signal. Exceeding the
critical angle causes
the energy to continue into space rather than to be reflected back toward the ground
for long distance communications (DX). There is a sector of the amateur radio community
that exploits vertically directed beams, called
NVIS (Near Vertical Incidence
Skywave), for local communications, but that's not the intent of the extensive array
of antennas described in this "Moonlight from Radio Waves" article. Basically, it
is a proposal for illuminating America's highways at night with an artificial aurora,
triggered by blasting the upper atmosphere with electromagnetic energy. I've got
an idea - how about installing lamps along the roadway. It would be a lot cheaper,
simpler, and you'd be able to listen to your car's AM radio to boot.
Moonlight from Radio Waves
 By Alden P. Armagnac
Artificial Northern Lights to Turn Night into Day
Artist's conception of a vast radio system for providing artificial moonlight
over immense areas.
Power from WLW's radio mast could create an aurora visible hundreds of miles
away.
Will we light the highways of the future with artificial auroras in the night
sky? Not only is the idea feasible in theory, but it could actually be tried out
with apparatus now available, according to Prof. V. A. Bailey, of the University
of Sydney, Australia.
His startling plan calls for hurling a vertical beam of enormously powerful radio
waves to a height of fifty miles or more. Under their bombardment, the thin air
of the upper atmosphere would shimmer with the bluish or greenish light of the aurora,
just as radio waves make tubes of rarefied gases glow in the laboratory. A whole
countryside could be flooded so brilliantly with this man-made moonlight, the Australian
physicist declares, that street lighting no longer would be necessary for the safety
of motorists and pedestrians.
Both station WLW, in Cincinnati, Ohio, and another high-power station in Moscow,
Russia, have the 500-kilowatt capacity needed to test the scheme, Professor Bailey
points out. The remaining requirement would be a special aerial system consisting
of 800 individual antennas suspended horizontally at a height equal to just half
of their 328-foot length, and forming a huge grid or checkerboard pattern a mile
and a quarter square. With this apparatus, radio engineers could produce in the
sky a synthetic "moon" or circular aurora that would be visible hundreds of miles
away.
How the system works, shown by a lamp bulb held in radio-wave field to make it
glow
The entire output of WLW's 500 kilowatts, strong enough for the "aurora" tests,
is concentrated in this arc
Radio waves from the coil make the gas in this tube glow. The same principle
forms the basis of the proposed man-made moonlight
Posted August 11, 2023
|
