[amsat-bb] Explorer I - recordings

Roy rdwelch at swbell.net
Thu Jan 31 12:53:55 PST 2008


I have been asked if any of the Explorer I recordings were still 
available in WAV, etc format.  There is one posted at 
http://www.amsat.org/amsat-new/index.php.  Select the "Select a Topic" 
drop down menu and scroll down to "Sounds from the first satellites." 
There are a few recordings there with the info about the recordings. 
One of them is the Explorer I telemetry.  You will hear several constant 
audio tones with one of them shifting between two tones.  There was a 
geiger counter on board that counted cosmic ray particles according to 
the info I have read.  After a certain number had been counted the tone 
shifted and after another quantity had been counted it shifted back again.

The 108 mHz antenna was a six element colinear arrangement consisting of 
six half waves (wire elements) suspended over a 13x13 ft wooden frame 
covered with chicken wire laying on the roof of my house.  This oriented 
it up about 75-80 degrees above the southern horizon.  No tracking.  The 
satellites had to fly through the main lobe of the antenna pattern.

The receiving arrangement was a modified TeCraft (I think) converter 
with a 6BQ7 TV RF amplifier front end feeding an National NC-300 Amateur 
band receiver.  Not very good as noise figures go today but pretty good 
for 1958.

I still have all of the original reel to reel tapes, some of their 
contents transferred to cassette tape.

-- 
Roy


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