Some of you might enjoy reading these recollections about the development of Telstar, one of the first active satellites, at Bell Laboratories. The article is by J. R. Pierce, who was a well-known executive and scientist at Bell. http://www.smecc.org/john_pierce1.htm
Here is a very interesting article about the development of Echo, the balloon satellite, also written by Pierce. http://www.smecc.org/john_pierce___echoredo.htm I remember when we at Ohio State recorded President Eisenhower's message relayed by Echo. I have lost the tape, however.
ron
Cool article thanks for the post. There is a lot of interesting information there.
I actually have a full scale model of Telstar above my desk at work. My facility was originally built to provide TT&C operations for Telstar as AT&T Skynet. We still "Fly" Telstar 11,12,14, and 18. from our facility although through the years we have become Loral Skynet, and as of Oct 31 2007, Telesat. We are slated to close the facility though by 30 April 2008.
73 DE Mark KK7CU
Ronald Long wrote:
Some of you might enjoy reading these recollections about the development of Telstar, one of the first active satellites, at Bell Laboratories. The article is by J. R. Pierce, who was a well-known executive and scientist at Bell. http://www.smecc.org/john_pierce1.htm
Here is a very interesting article about the development of Echo, the balloon satellite, also written by Pierce. http://www.smecc.org/john_pierce___echoredo.htm I remember when we at Ohio State recorded President Eisenhower's message relayed by Echo. I have lost the tape, however.
ron
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----- Original Message ----- From: "Ronald Long" rlong3@columbus.rr.com To: amsat-bb@amsat.org Sent: Sunday, November 18, 2007 11:19 PM Subject: [amsat-bb] early satellite history
Here is a very interesting article about the development of Echo, the balloon satellite, also written by Pierce. http://www.smecc.org/john_pierce___echoredo.htm I remember when we at Ohio State recorded President Eisenhower's message relayed by Echo. I have lost the tape, however.
ron
Hi Ronald, W8GUS
Tank you for your information because the story of ECHO-1A launched on 12 august 1960 was a very "amarcord" for me.
ECHO-1A was also equipped with a VHF beacon on 108.00 and 108.03 MHz and I was receiving both signals using a homebrewed converter with two front end low noise triodes 6AN4 in cascode and a 1/2 6J6 as a mixer and a 6C4 as kathode follover.
The local oscillator was a 6.66972 MHz xtal in to a 1/2 12AT7 and the other 1/2 12AT7 was used as a duplier at 13.33944 MHz
The other 1/2 6J6 of the mixer was used as a multiplier by 5 getting 66.6972 MHz for the local oscillator.
Finally 108.00 - 66.6972 = 41.3028 MHz was the IF in to a Hallicrafters SX-28 receiver used with BFO ON
At that time I was not aware on how to measure the noise figure of my converter and the trick to adjust the input of the first 6AN4 for the lowest generated noise was to adjust the antenna coupling while tuning L and C of the input stage for the strongest received noise from the sparks of a near by car.
By the way both signals at 108 and 108.03 MHz where very well received using only a 5 elements yagi aimed by hand with easy because ECHO-1A was visible by naked eye during the night until the batteries of the beacon lasted.
At that epock time in 1960 the 108 MHz band was not used to broadcast FM in Italy and it was completely free of man made noise.
In my town the only noise piked up by the antenna was about 290 kelvin from the ground at 108 MHz so that the noise emitted by our galaxy was received in loudspeaker aiming the antenna toward the milky way.
Actually if I put a finger in to the N connector of my spectrum analyser and I tune the 108 MHz band I receive a lot of FM signals at least 10 to 15 dB over the analyser noise !
In a separate email I will send to you the schematic diagram of this type of low noise converter.
Best 73" de
i8CVS Domenico
participants (3)
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i8cvs -
Mark Lockwood -
Ronald Long