RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while typing up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
All trademarks, copyrights, patents, and other rights of ownership to images
and text used on the RF Cafe website are hereby acknowledged.
Wax nostalgic about and learn from the history of early electronics. See articles
from Popular Electronics,
published October 1954 - April 1985. All copyrights are hereby acknowledged.
As a case in point about my claim with today's earlier post
Bob Berman's factoids on astronomy, this article from a
1956 edition of Popular Electronics illustrates how
vital electronics are in the various fields of science. It has
only been fairly recently that astronomers have been 'looking'
at stars and planets outside of the visible wavelengths. Renditions
of the sky in both shorter and longer wavelengths show in some
regions a vastly different universe. Earlier this year, a comprehensive
mapping of the entire known
universe in the microwave realm revealed the largest contiguous
feature ever detected - dubbed "The Cold Spot." Such discoveries
could not be made without sophisticated electronics. The same
can be said of medicine, biology, mechanics, finance, etc. Reported
here are some of the earlier detections of radio signatures
from our planets. Information gleaned from planetary and cosmic
studies helps scientists better understand the Earth and its
history, as well as its likely future. In the same manner as
the words from John Denver's song
Calypso suggest, "to live on the land we must learn
from the sea," so, too, must we learn from the heavens.
Radio Waves Heard from Jupiter and Venus
By O.P. Ferrell
Radio Waves spanning interplanetary space are now a certainty.
The dreams of science fiction writers and the predictions of
Nikola Tesla are closer to reality. Positive identification
of radio waves generated, by means unknown on both Jupiter and
Venus has been established. Work is progressing rapidly in this
field by teams of scientists in Europe, Australia and the United
States, where giant radio telescopes are now in use.
Giant antenna atop Naval Research Laboratory
measures 50 feet across. Signals received from Venus are recorded
below by astronomer T. P. McCullough. BTW, notice the 48-star flag American
flag flying over the Naval Research Laboratory!
Radio signals from beyond the earth have been known for about
twenty years. But these came mostly from turbulent areas of
outer space, where intense electrical activity accompanies the
formation of new stars and the gigantic eruptions of distant
suns beyond the reach of even the largest telescopes. Only lately
have radio star-gazers been hearing odd noises from our relatively
quiet and astronomically "dead" next-door neighbors, the planets.
Jupiter. Electromagnetic waves picked up from Jupiter
lack a clearly defined frequency, yet are best heard around
22 megacycles. With their frequency distribution being random
throughout a wide band, the signals sound just like static caused
by storms. Since Jupiter, like Earth, is surrounded by a gaseous
atmosphere, it is quite possible that the radiation it sends
out is a sign of turbulent weather.
Lending probability to this theory is the electrical behavior
of the weather-bearing layers in our own terrestrial atmosphere.
About 50,000 thunderstorms per day pass over the face of the
earth. About 2000 are going strong at anyone moment, giving
off about 100 lightning flashes every second. Each lightning
flash is a 3-millisecond burst of 2000-3000 amperes, reaching
peaks around 10,000 amperes. That's a lot of electrical popping
for our small planet. To radios on Jupiter, it would probably
sound the same way that the waves from Jupiter sound to us.
Hot Venus. Until a few months ago, it seemed
that Jupiter was the only planet to radiate electromagnetic
waves. Yet earlier this year, Dr. John Kraus of Ohio State University
also caught signals from Venus, the planet which is prominent
in the sky as the Evening and Morning Star. The Naval Research
Laboratory in Washington independently made the same discovery.
Signals from Venus reported by the Navy differ from those
of Jupiter. They are not generated by electric disturbances
of the atmosphere, but by the molecular activity of heat. The
wavelength of the Venus signals stays fairly constant at 3 cm.,
which corresponds to a temperature of more than 212° F -
the boiling point of water. Any water existing on Venus would
therefore be in the form of steam. This makes it unlikely that
living organisms as we know them could exist on that planet.
Giant Antennas. No ordinary antenna will
catch these faint signals from the stars. Instead, radio astronomers
employ huge parabolas or dipole arrays to concentrate the dim
stellar mutterings at the receiver input.
Helical antenna array for the radio telescope
at the Ohio State University consists of 96 spiral coil elements
to refract the incoming signals.
For instance, the giant parabola atop the Naval Research Laboratory
Building in Washington acts like the mirror in an ordinary optical
reflector telescope. All the energy is focused in a single point
at the tip of the central pole, from whence it is funneled to
the receiver. The antenna is automatically rotated so as to
keep pointing at the same target in space, regardless of the
motion of the earth. Signal gain attainable with this antenna
is over one million.
The optical refracting telescope, exemplified by ordinary
field glasses, also has its electronic equivalent. Helical antennas,
looking like vast coil-spring mattresses, bend the incoming
radio waves as a deflection coil bends the beam in a TV tube.
In this manner, they concentrate the incident energy at the
pickup point. By stringing a large number of coil-shaped structures
in an array, the gain is multiplied in proportion to the total
antenna size. On this principle, Ohio State University built
the 96-coil unit, which successfully eavesdropped on Venus.
Whether similar waves will be heard from Mars is still an
open question. As Mars draws closer to Earth this year than
it has at any time within the past 20 years, the chances of
intercepting its radio waves, if any, are greatly increased.
Experiments continue as the massive antennas seek out our brother
and sister planets in the solar system.
Ultra-sensitive superhet receivers are checked
by technician to assure low internal noise for clearer recognition
of marginal signal patterns.
John Denver's "Calypso"
Posted June 24, 2015
Footer - RF Cafe
Right Border Content - RF Cafe
Please Support RF Cafe by purchasing
my ridiculously low−priced products, all of which I created.