[amsat-bb] Re: Vanguard 1 Reception?
domenico.i8cvs at tin.it
Thu Dec 20 11:55:37 PST 2007
----- Original Message -----
From: "Robert Bruninga" <bruninga at usna.edu>
To: <amsat-bb at amsat.org>
Cc: <GilMoore12 at aol.com>
Sent: Thursday, December 20, 2007 2:26 AM
Subject: [amsat-bb] Vanguard 1 Reception?
> Anyone with an EME dish that can mount a 108 MHz feed?
> Rumor has it that Vanguard 1 should still be emitting a tiny
> singal on 108.00 MHz since it was directly powered by solar
> cells. It has gotten weaker and weaker over the last 50 years
> using the 1957 solar cell technology, but what the heck. It
> would be a nice challenge for someone with a really big dish..
> Just thought I'd post, since I had not heard of this frequency
> and the fact that it is radiating.. You just have to have good
> ears. And with some of the really good sound-card DSP stuff
> these days, maybe it would show up on a waterfall. The exact
> frequency depends on temperature... But it was at 108.00 MHz
> last time it was heard.
> My dish is kaput right now, so I'm out...
> Bob, WB4APR
Hi Bob, WB4APR
Early 1957 the frequency 108 MHz was used for space to ground
communications and in august 1960 I was receiving the 50 mW
beacon from ECHO-1 at 108.000 and 108.030 MHz
At that time 108 MHz was free of any commercial communication and
the galactic noise was received with easy using only a 5 element yagi
and a downconverter with a cascode front-end made of two low noise
triodes 6AN4 at best a 5 dB noise figure.
Very soon 108 MHz was abandoned and space to ground communications
switched to 136 MHz
Actually the lower edge of 108 MHz is used for commercial and FM
broadcasting and try to receive a weak signal less than 5 mW from
Vanguard-1 requires an EME dish in a properly selected location.
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