[amsat-bb] Re: using a microsat as a potential high altitude VHFreflector
One drawback of the design was the high drag from such a large structure, coupled with the low mass. The end result was a satellite with a low ballistic coefficient and hence a short lifetime. John WA4WDL -- From: Samudra Haque samudra.ha...@gmail.com Sent: Wednesday, October 28, 2009 3:46 PM To: Amsat-bb amsat-bb@amsat.org Subject: [amsat-bb] using a microsat as a potential high altitude VHFreflector Hi all, I read with interest an article on the web ECHO - America's First Communications Satellite By John R. Pierce which is available here: http://www.smecc.org/john_pierce___echoredo.htm I know ham radio operators love using their hand helds to communicate using active transponders or active repeaters in space... no issue with that. were there any ham radio projects (either through amsat-na or abroad) that implemented a passive reflector on an orbital vehicle like Project Echo I quote from http://www.satmagazine.com/cgi-bin/display_article.cgi?number=490218137 The Echo-1 Balloon Satellite as it sits, fully inflated, at a Navy hangar in Weeksville, North Carolina. The spacecraft measured 100 feet across when deployed, and was nicknamed a ‘satelloon’ by those involved in the project. The mylar film balloon acted as a passive communications reflector for transcontinental and intercontinental telephone (voice), radio and television signals. Echo 1 re-entered the atmosphere May 24, 1968. What strikes me is the implications of a large large very large antenna (reflector), if only it could be reflective on one side of the sphere only (any ideas?) The Echo 2 was a 135-foot rigidized inflatable balloon satellite. The satellite is shown undergoing tensile stress test in a dirigible hanger at Weekesville. The satellite, 50 times more rigidized than Echo I. When folded, the satellite is packed into the 41-inch diameter canister shown in the foreground. Did early amsat folks consider duplicating / adding to any of these projects or launch their own 'satelloon' that did not carry an active RF payload ? Could we outfit one of our future microsats to provide a reflector to aid in Earth-LEO DXing like meteor-scatter ? 73 de Samudra, N3RDX ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: using a microsat as a potential high altitude VHFreflector
- Original Message - From: Samudra Haque samudra.ha...@gmail.com To: Amsat-bb amsat-bb@amsat.org Sent: Wednesday, October 28, 2009 8:46 PM Subject: [amsat-bb] using a microsat as a potential high altitude VHFreflector Hi all, I read with interest an article on the web ECHO - America's First Communications Satellite By John R. Pierce which is available here: http://www.smecc.org/john_pierce___echoredo.htm I know ham radio operators love using their hand helds to communicate using active transponders or active repeaters in space... no issue with that. were there any ham radio projects (either through amsat-na or abroad) that implemented a passive reflector on an orbital vehicle like Project Echo I quote from http://www.satmagazine.com/cgi-bin/display_article.cgi?number=490218137 The Echo-1 Balloon Satellite as it sits, fully inflated, at a Navy hangar in Weeksville, North Carolina. The spacecraft measured 100 feet across when deployed, and was nicknamed a ‘satelloon’ by those involved in the project. The mylar film balloon acted as a passive communications reflector for transcontinental and intercontinental telephone (voice), radio and television signals. Echo 1 re-entered the atmosphere May 24, 1968. What strikes me is the implications of a large large very large antenna (reflector), if only it could be reflective on one side of the sphere only (any ideas?) The Echo 2 was a 135-foot rigidized inflatable balloon satellite. The satellite is shown undergoing tensile stress test in a dirigible hanger at Weekesville. The satellite, 50 times more rigidized than Echo I. When folded, the satellite is packed into the 41-inch diameter canister shown in the foreground. Did early amsat folks consider duplicating / adding to any of these projects or launch their own 'satelloon' that did not carry an active RF payload ? Could we outfit one of our future microsats to provide a reflector to aid in Earth-LEO DXing like meteor-scatter ? 73 de Samudra, N3RDX Hi Samudra, N3RDX Early 13 august 1960 about 50 years ago I have received the ECHO 1A 45 mW beacons transmitting at 108.00 and 108.03 MHz and also I got an excellent visual of the big satellite balloon only looking at it in the sky with naked eye Receiving radio signals and looking at the orbiting satellite at the same time it was a very exciting experience and I newer forget ! I was using a home brewed downconverter for 108 MHz with two low noise triodes 6AN4 in a front end grounded grid circuit. The second IF receiver tuned at 27.963 MHz was an Hallicrafters SX-28 and the antenna was a qubical quad. By the way the NASA and GSFC ground stations where transmitting to the reflecting surface of the above passive satellite a very very high EIRP at 960 MHz and 2390 MHz using big dishes. The experience gained with the passive ECHO satellites demonstrates that they are not convenient at all so that the project was soon abandoned. 73 de i8CVS Domenico ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: using a microsat as a potential high altitude VHFreflector
Domenico, I had no idea absolutely that you would have responded with such relevant experience !!! It is an amazing story to hear. The recent interest and work on inflatable antennas may be the most interesting chapter yet (ref: JPL DESCANSO publications) in antenna theory. Thanks -samudra Hi Samudra, N3RDX Early 13 august 1960 about 50 years ago I have received the ECHO 1A 45 mW beacons transmitting at 108.00 and 108.03 MHz and also I got an excellent visual of the big satellite balloon only looking at it in the sky with naked eye Receiving radio signals and looking at the orbiting satellite at the same time it was a very exciting experience and I newer forget ! I was using a home brewed downconverter for 108 MHz with two low noise triodes 6AN4 in a front end grounded grid circuit. The second IF receiver tuned at 27.963 MHz was an Hallicrafters SX-28 and the antenna was a qubical quad. By the way the NASA and GSFC ground stations where transmitting to the reflecting surface of the above passive satellite a very very high EIRP at 960 MHz and 2390 MHz using big dishes. The experience gained with the passive ECHO satellites demonstrates that they are not convenient at all so that the project was soon abandoned. 73 de i8CVS Domenico ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
