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June 1961 Popular Electronics
 Table of Contents
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.
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Breakthroughs in space
electronics dominated this 1961 "Space Electronics" report in Popular Electronics
magazine. A 10,000-watt radar transmission using a maser amplifier successfully
bounced signals off Venus, marking the first clear return from the planet. This
improvement in receiver sensitivity demonstrates significant progress in space-based
radar technology. NASA’s S-15 satellite, equipped with solar-powered nickel-cadmium
batteries and dual-frequency transmitters (107.97 mc and 108.06 mc), is set to relay
gamma-ray data. RCA has proposed an all-purpose solar-powered communications satellite
for telephone, TV, and telegraph signals. Advances in digital TV transmission methods
promise more efficient transatlantic broadcasts. Despite some mission failures,
progress in satellite power systems, signal clarity, and data transmission continues
to drive the field forward. Note: "Veries" (see Q&A) is an abbreviation for
"verifications," which in the world of amateur radio and shortwave listening (SWL),
a "verification" was a QSL card or written confirmation sent by a radio station
to a listener who successfully reported receiving their broadcast. These verifications
served as proof of reception and were highly valued by enthusiasts.
Space Electronics
 By Oliver P. Ferrell, Editor
Around the middle of March, 10,000 - watt radar signals were bounced off the
planet Venus and picked up by an 85 -foot dish antenna in Goldstone, Calif. Using
a frequency of 2388 mc. and a beam width of only 0.4 degree, the radar pulses took
6 minutes to make the round trip.
Although weak radar echoes have been picked up before from Jupiter, Saturn, Venus
and the sun, this is the first time that they have been strong enough to be immediately
recognizable. Credit for this extra margin of sensitivity goes to the maser amplifier
(see POP'tronics, April, 1960, page 41) used to reduce receiver noise to an extremely
small quantity.
Radar observations of Venus will tell us if this cloud-covered planet is really
revolving and how fast, and they will give us some idea of the density of the clouds.
The experiments are being undertaken by the Jet Propulsion Laboratory and the National
Aeronautics and Space Administration (NASA).
An all-purpose communications satellite has been proposed by
RCA having the physical design shown above. Capable of relaying telephone, TV, telegraph
or facsimile signals, it would orbit about 22,000 miles above the earth's surface,
the antenna at far right automatically aiming itself at a particular point on the
surface. Solar cells would recharge the receiver and transmitter batteries.
New Signal on FM Band
The NASA S-45 satellite (mentioned in the April column, page 65) failed to achieve
an orbit- Had this satellite gone into orbit, it would have provided SWL's and experimenters
in space science with at least one easily identifiable (20.0-mc.) radio signal.
NASA has now scheduled for launching (as this column is being written ) its S-15
satellite. This 82-pound satellite is destined to detect and measure the intensity
of gamma rays while swinging around the earth in a 98 -minute orbit. (Gamma rays
are known to be generated by nuclear activity and are of such high energy levels
that they are unaffected by magnetic fields - as radio waves are, for example.)
The S-15 is really a "telescope," and will spend part of its orbit life in scanning
the sun.
Although not a "glamour" satellite - in terms of the publicity-conscious Soviet
launchings - the S-15 will provide one or two readable signals that may be heard
with the aid of an outdoor antenna and sensitive FM broadcast receiver. A weak signal
for tracking-about 20 milliwatts-will be radiated on 108.06 mc. A considerably stronger
signal (125 milliwatts) relaying gamma-ray data to earth will be on 107.97 mc.,
and should be heard throughout most of North America with minimum difficulty. The
two transmitters will probably not be in continuous operation, but will be controlled
by ground-level command signals. Solar batteries (probably silicon cells) will recharge
12 nickel cadmium batteries, giving the satellite a "life" of about one year.
If the S-15 goes into orbit, check the top end of your FM tuning dial-this is
one that can be heard.
Radio Signal Status
Three satellite signals may be deleted from the listing of "Radio Signals from
the Satellites which appeared on page 65 of our April column and was supplemented
in May on page 76. The weak signal on 107.97 mc. from Echo I, the balloon reflector
launched last August, is no longer heard; Samos II, a reconnaissance satellite,
has ceased transmitting; and Discoverer XXI went off the air in late February. Frequencies
used by the latter two satellites were never revealed by the Department of Defense.
Transit III -B and LOFTI, which never detached from their launch rocket, went
into a wildly eccentric orbit. Radio signals were heard from both and proved to
be of considerable value to American scientists. These two satellites re-entered
the earth's atmosphere on March 30 and burned up.
Scheduled for launching this spring, NASA's S-15 satellite is
expected to transmit data to earthbound receiving stations on 107.97 mc.
The Russian Venus probe was heard with a very weak signal on February 22nd, but
has not been heard from since. Soviet Sputnik IX, launched on March 9th to test
recovery mechanisms, did not transmit on any of the usual channels.
Reading Matter
Albert Parry's new book entitled Russia's Rockets and Missiles (Doubleday &
Co., Garden City, N. Y., 382 pages, $4.95) provides some thought-provoking reading
on Soviet rocketry. Unlike many other communist claims of "prior invention," a Russian
by the name of Tsiolkovsky really did pioneer the field of rocketry-well before
Germany's Oberth and our own Robert H. Goddard. Parry analyzes what the Soviets
have achieved (Sputniks, Luniks, etc.) through mid-1960, and presents some positive
ideas on what the American research policy should be if we want to catch up. We
recommend this book for its solid factual background and the digest of Soviet rocketry
and satellite launchings.
A somewhat similar book, called Soviet Space Technology and written by Alfred
J. Zaehringer, has been released by Harper & Brothers (49 East 33rd St., New
York 16, N. Y., 180 pages, $3.95). While Dr. Parry is a regular writer on Soviet
affairs ("Missiles & Rockets" magazine), Mr. Zaehringer is president of the
American Rocket Company and studies Soviet rocket activities as a hobby. His book
is a faster-paced but less fact-filled account of what the Russians have done.
Satellite "Voices."
To my knowledge, there is only one informative LP recording of what satellite
signals really sound like. This is a 10" disc titled "Voices of the Satellites,"
sold for $3.95 through Taben Recordings, Box 224, Ardmore, Pa. The satellite radio
signals were recorded by Professor T. A. Benham of Haverford (Pa.) College. Included
are sounds of the signals from Explorer I, II and III, Vanguard I, plus Sputnik
I and Sputnik II.
Professor Benham's narration on this disc tells much about the receiving conditions,
the Doppler effects, sounds of telemetering, and - last but not least - the heartbeats
of the Soviets' little dog Laika a passenger on Sputnik II.
The TIROS II is typical of several satellites to be launched
by NASA for weather studies. Data collected from TIROS observations are made available
to all co- operating foreign countries.
As TIROS satellite orbits the earth, ground command stations
tell it when and where to take TV pictures. Although the TIROS transmitters are
now off the air, similar satellites are to be launched later this year.
A novel "sun-seeker" has been devised by Technology Instrument
Corporation. Silicon cells at base of long arm are shaded by disc to cast shadow,
and voltage developed by the cells is fed into a bridge circuit, driving small motors
that track the sun. Such a device can be used with satellites which rotate at about
2 revolutions per minute.
I use this recording to demonstrate the sound of signals from Vanguard I. This
is the 10-milliwatt satellite still transmitting on 108.020 mc. whose solar batteries
are likely to last another seven or eight years. Receiving this satellite is a good
test of your FM receiver sensitivity - I have heard Vanguard I using the Scott and
Harman-Kardon FM tuner kits.
"Voices of the Satellites" (although dealing with 1957-58 satellites) is a collector's
item well worth the small investment it requires.
At Minus-One
Transatlantic television may not be far off now because of a new method of transmitting
TV signals. Called "digital TV," the new system provides a better picture quality
while using considerably less frequency space. Radio signals carrying digital modulation
can easily be handled by present-day active satellite repeating equipment. You had
to be on your toes to hear the first Russian man-in-space aboard the Vostok satellite
on April 12. Besides the beacon and TV transmitter on 143.62 mc., the Soviets used
their old-favorite frequency (about 20.00 mc.) plus a brand-new frequency for c.w.
transmission (9.019 mc.).
"That's funny, I thought earthmen would look a lot different."
Space Q & A
Here are the answers to some of the "space" questions you have been asking.
Q: Although the Soviets have frequently used telemetering signals
near 20, 40 and 183 mc., haven't I seen newspaper reports of other frequencies being
used ?
A: During the first few days after the launching of Lunik I
(Jan. 2, 1959), radio signals apparently associated with this satellite were heard
on 70.2 and 212.0 mc. The recent Soviet Venus probe (announced as being on 922.8
mc.) may instead have been transmitting in the 120.0-mc. band. The Soviets have
neither confirmed nor denied use of these frequencies.
Q: Is it true that we don't know the launching sites of the
Soviet satellites?
A: Yes and no. Officially, the Soviets have not revealed this
information, though it is more than likely that the launchings take place at large
ICBM sites. Aralsk and Kapustin Yar are the most likely sites.
Q: A friend of mine has an SWL verification from Vanguard I.
How did he get it?
A: George Jacobs, a good friend of the SWL's, took it on his
own shoulders to supply veries through the facilities of the Voice of America; but
he was forced to discontinue the practice due to the pressure of his other duties.
No plans have been made to resume this service in the near future.
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