[amsat-bb] Echoes of Apollo Call for Student Investigators & Adult Engineering Mentors
k9jkm at comcast.net
Sun Jan 23 10:20:45 PST 2011
I received this request too late to include in this week's ANS-023
bulletins so I'm forwarding the message to the amsat-bb to help get
the word out.
Please send your replies directly to Pat: apolloeme at gmail.com
73 de JoAnne K9JKM
k9jkm at amsat.org
Editor, AMSAT News Service
Echoes of Apollo Call for Student Investigators & Adult Engineering Mentors
Pat Barthelow, AA6EG of the Echoes of Apollo Project (the folks who
brought us the 70cm Arecibo EME activity) is working with kids on the
Google Science Fair. The students and adult mentors have devised a
simple experiment to measure the distance to the moon using Moon
Pat has several EME stations committed and is looking for more tech-
nical support. He is also looking for additional young Co-Primary
Investigators (Age 13-18) to participate.
Time is of the essence. Reply directly to: apolloeme at gmail.com
Pat says the students will develop the experiment, lead, analyze.
Adults are needed to nurture, guide, mentor with these goals in mind:
+ Key a CW transmission or alternatively, send an audio impulse via
microphone to EME TX.
+ Starting the time clock on the impulse transmission whether Audio
"Clack" or CW key.
+ Recording for Science Fair presentation, using Multimedia video/audio
eqiupment in the Moon bounce Station.
+ Stopping the clock when the audio/RF does RT to moon (~2.5 Seconds)
and returns, and is demodulated by Moon bounce RX and presented at
Audio speaker terminals.
+ Pre-measure station delays in TX and RX to develop a constant for
internal equipment delays.
+ Measuring the EME interval as closely as possible, with simple
equipment, say, to millseconds. Probably take the Multimedia video/
audio to a Video editor, to measure delay, digitally.
+ Compare distance to the moon in the NASA, or US Naval Observatory
databases for their actual distance to moon, at the moment of the
+ Student analyzes for errors, error sources, discusses return signal
distortion, due to doppler, Libration, pulse stretching, due to
spherical moon, etc.
+ Student suggests follow up experiment, to minimize measurement
errors, or assuming more sophisticated equipment became available.
QUESTION: For an analog RX to audio output, what would be the best
way be to measure the internal propagation delay in an [Analog, Digi-
tal] receiver, from the time of arrival of the RF at the Antenna con-
nector to demodulated output [Analog, Digital] at the speaker, or
For analog receivers, is the internal RX propagation delay, in order
of: microseconds? Milliseconds? For Digital receivers?
Pat Barthelow, Echoes of Apollo
apolloeme at gmail.com
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