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| Asunto: | [dxcolombia] Sounds from the First Satellites | | Fecha: | Sabado, 13 de Octubre, 2007 04:46:07 (+0000) | | Autor: | HK1AA . <hk1aa @.......com>
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Sounds from the First Satellites
Roy Welch, W0SL, has provided these historical audio recordings
of several "first" satellites as monitored at his station (then W5SLL).
OSCAR 1
Oscar 1 was launched on an Agena B rocket from Vandenberg AFB in California
along with a Discoverer series satellite. KC4USA in Antarctica first
reported signals as it passed over there after being launched. Oscar 1 was
battery powered. Its signals lasted for about two weeks. The batteries
were not rechargeable. The transmissions were on 145.00 MHz. The CW signal
repeatedly sent HI in morse code. The number of HIs per minute, or the
"HI Rate" was the only telemetry sent. The HI Rate gave the internal
package temperature. Amateurs were asked to report the HI rate.
At W5SLL, there was no tracking antenna available. The antenna was cut for
108 MHz for listening to the new USA satellites. It was a six element
colinear array constructed on a 13 by 13 foot wooden frame and suspended above
a "chicken wire" reflector. The whole array was placed on the roof of the
house looking up at about 75 degrees above the southern horizon. Satellites
were captured as they flew through the main lobe of the antenna.
Listen to the normal speed recording
(.WAV (113K) or
RealAudio (14K)).
Each HI is too fast to make out, and sounds more like a cricket chirping.
Now listen to the half speed recording
(.WAV (226K) or
RealAudio (21K)), or if all that noise
hurts your ears, listen to this filtered version
(.WAV (226K) or
RealAudio (21K)).
You can distinctly read the HIs being sent. This recording was made
in Dallas, Texas on December 14, 1961, at 0722Z using a Tecraft converter
in front of a National NC-300 receiver.
See also this newspaper article (120K
GIF) on OSCAR 1.
SPUTNIK 1
Sputnik 1 was the Soviet Union's and the world's first orbiting satellite.
The signals heard in this recording are weak, over the horizon signals,
recorded on a frequency of 20.007 MHz. Other recordings were made with
signals strong enough to permit hearing the oscillator feeding through
during key up periods. These were made with the satellite in line of sight.
The weaker signal recording is presented to show a time
when the keying of the signal was interrupted and a steady carrier was
transmitted. There are two such instances in this excerpt. WWV which was
nearby in frequency shut down their transmitters with each pass on this
evening.
Roy and his two-year-old daughter would put the radio speaker in a
window and then go outside and listen to the strong signals while they watched
the third stage booster tumbling end over end like a bright pulsating star
as it passed over in the evening sky. Listen with them to this
recording of Sputnik 1
(.WAV (113K) or
RealAudio (10K)). This recording was
made in Dallas, Texas on October 7, 1957 at 0457Z using a military surplus
AN/FRR3A HF RTTY receiver.
Here is a strong signal from Sputnik 1
(.WAV (116K) or
RealAudio (11K)).
Here is a newspaper photograph (234K GIF)
of Roy
playing Sputnik signals at the State Fair of Texas on October 9, 1957.
Explorer 1
Explorer 1 was America's first orbiting satellite, launched on an Army
Redstone rocket after several failures to launch the Vanguard Satellite
with the Navy's Vanguard rocket. The telemetry heard in this recording
consists of a combination of three or more relatively stable audio tones
and two alternating audio tones. The alternating tones were indications
of cosmic particle collisions detected by an on board counter. The tones
shift from one to the other when the detector has counted sixteen particles.
It shifts back again with the detection of the next sixteen particles and
so on.
The satellite had two RF frequencies, 108.0 MHz and 108.03 MHz. This
recording is from the 108.0 MHz frequency. The 108.03 MHz frequency had a
similar sounding telemetry, but without the alternating tones.
Listen to the recording of Explorer 1
(.WAV (110K) or
RealAudio (10K)). This
recording was made in Dallas, Texas on February 11, 1958 at 0100Z using a
home-made VHF converter in front of a National NC-300 receiver. The antenna
was as described above for Oscar 1.
Earth-Moon-Earth
These single sideband transmissions were from KP4BPZ in
Arecibo, Puerto Rico via Moon Bounce. The KP4BPZ transmitter was running
about 500 watts on 432 MHz and feeding the 1000 foot diameter radio telescope
dish in Arecibo. Amateur radio operations were made on the two week ends of
July 3, 1965 and July 24, 1965. Both SSB and CW operations were heard.
The receiving setup at W5SLL/0 was assembled quickly after the plans were
announced. The antenna was a home made 32 element colinear array from the
ARRL Antenna Handbook design. The individual small booms were completed, but
they were not mounted on a metal frame. A 2X4 wooden frame was hastily
built and holes drilled to accept the 16 individual element booms. The
transmission feedline was 75 feet of plain old 300 ohm TV twinlead,
terminating in a coax 4:1 balun.
The output of the balun fed the input of a homemade 432 MHz converter
described in the July 1963 QST magazine article, "All Nuvistor Converter."
The Nuvistor was a small vacuum tube, for those of you who don't remember
the Nuvistors. The noise figure was not worth mentioning in view of
today's technology. The output of the converter fed the input of a
National NC-300 Amateur Band receiver.
The antenna was aimed by leaning the wooden frame against a kitchen chair
in the back yard and eyeballing it toward the crescent moon in broad
daylight. Not exactly an ideal Oscar 0 station.
What a signal! Just imagine what it would sound like today with our
low noise preamps in front of our high performance converters and radios
with steerable circular polarized antennas.
Listen to the EME signals
(.WAV (150K) or
RealAudio (14K)).
This recording was made in Florissant, Missouri on Saturday,
July 3, 1965.
Vanguard 1
Vanguard 1 was launched aboard the oft-troubled Vanguard rocket in
March 1958. The transmitters were approximately 10 mW in power and
transmitted on 108.0 MHz and 108.3 MHz. The only telemetry
transmitted was the package temperature. This was indicated by the
difference between the two transmitter frequencies which varied with
temperature. The solar cells were manufactured by Bell Laboratories.
The signals were received on a homemade VHF converter
in front of a National NC-300 Amateur Band receiver. The signals were
continuous carrier with no apparent audio modulation. Therefore, the
recordings were made with the receiver Beat Frequency Oscillator (BFO)
turned on in order to produce an audible tone heard in the recordings.
Listen to these two recordings. In this
recording made shortly after launch
(.WAV (115K)
or RealAudio (11K)) you can
detect a rapid spin modulation on the signal and can determine that
the satellite seemed to be spinning fairly rapidly. In this
recording made approximately one year after launch
(.WAV (115K) or
RealAudio (11K))
you can tell the satellite is turning very slowly. By
this time the batteries had failed and the satellite was powered only
by the few solar cells on the surface of the satellite. The
satellite was very small, not much larger than a large grapefruit, so
there wasn't room for many solar cells. The transmitter frequency
varies as the solar cells slowly turn into and out of the sunlight.
Sometimes the signal would disappear when no solar cells were
exposed to the sun. It was easy to determine when Vanguard 1 went into
the shadow of the earth, by the rapid change in frequency and abrupt loss
of the signal altogether. This is not demonstrated in this recording.
OSCAR 10
OSCAR 10 was the first Phase 3 OSCAR to reach orbit. This
SSB recording from OSCAR 10
(.WAV (113K) or
RealAudio (10K))
demonstrates the
long propagation delay experienced with high orbits.
Updated 15 December, 1996.
Feedback to KB5MU.
The RealAudio sounds on this page are encoded in the 14.4kbps mode, but you
can listen to them over any speed link, since they are being sent to you as
files and not as RealAudio streams. The
RealAudio Player is available for free from
RealAudio.
B O B H K 1 A A
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