[A-DX] (dxld) 60 years in space today!
RogerMi Okt 4 20:45:51 CEST 2017
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Am 04.10.2017 um 16:33 schrieb Mike Terry [dxld]: > In October 1957, amateur radio operators monitored the first signal > from a spacefaring civilization —— and it was us. > Sputnik 1, the first satellite to orbit the Earth, launched on Oct. 4 > of that year from a site in Kazakhstan, then a part of the USSR. That > site is now the Baikonur Cosmodrome; at the time it was site 1/5 at > the Tyuratam range. > Article here: > Sputnik's Beeping Legacy: Satellite's Simplicity Made It Iconic 60 > Years Ago > <https://www.space.com/38357-sputnik-launch-60th-anniversary-space-age.html?utm_source=notification> https://timesmachine.nytimes.com/timesmachine/1957/10/05/84769354.html?pageNumber=1 https://web.archive.org/web/20090210052952/http://www.arrl.org:80/news/features/2007/09/28/03/?nc=1 ".......The meaning of the D-200 designation is unclear and our research thus far has failed to produce a schematic of this transmitter, but Tikhonravov, in a presentation before the 24th International Astronautical Congress in 1973, characterized the transmitters as “vacuum valve-type” with a power of 1 watt...." ".....One transmitter operated on a frequency of 20.005 MHz and the other on 40.002 MHz. The choice of these frequencies not only allowed reception by amateurs using existing equipment but also enabled a receiver set at exactly 20 or 40 MHz to produce an audio tone plus or minus the Doppler shift without ever going through zero Hz. This insured that the telemetry was audible throughout an entire pass without additional tuning of the receiver. "..... WWV’s Role Radio Station WWV also played a role in early space flight. There are numerous recollections among ham operators who were active in 1957 that radio station WWV suspended its 20 MHz time signal transmissions during some night-time passes of the satellite in order to avoid interference with the 20.005 MHz telemetry signal. Roy Welch, W0SL (then W5SLL) recalls this to be the case on October 7 when he recorded the Sputnik I signal during a pass over the North America. This recording can be heard at the AMSAT link listed at the end of this article. An exact record of how many times and for how long the WWV may have turned off its 20 MHz broadcast while Sputnik I was in orbit has been difficult to document. According to Michael Lombardi, KB0VOI, a time and frequency metrologist at the National Institute of Standards and Technology and a WWV historian, the log books for WWV operations during 1957 no longer exist making it difficult to verify that the 20 MHz broadcasts were stopped. However, Lombardi notes that during the Sputnik era, the WWV schedule included a silent period during which transmissions were interrupted every hour for approximately four minutes. These periods began about 45 minutes past the hour. Also well-documented is that during many passes, the WWV signal remained on and was recorded in tandem with the Sputnik telemetry beacon. This provided a stable time reference from which the Doppler shift of the satellite’s signal and its orbital parameters could be calculated. ...." http://sjhrc.org/beeps.html "Play the Sputnik Audio Clip and Hear the Doppler Shift! This audio clip is about 94 seconds long with a pronounced downward change in pitch at 47 seconds demonstrating the "Doppler Shift" that occurs just as it passed over. Make sure to be watching a clock with a "second hand" as you listen! ...." ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Based on this 60 year old audio recording I detected a Doppler-Sfift of about 60 Hz. In a wave editor you can see the cycle of about 2 beeps per second. So in STUDIO1 the 20,005 MHz signal would have been seen - in 1957. Back in time: http://www.rhci-online.net/radiogram/SW_Radiogram_2017-09-30.htm#Sputnik roger
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