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: apollo...@gmail.com -- 73 de JoAnne K9JKM k9...@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 Bounce. 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: apollo...@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 experiment. + 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 computer screen. For analog receivers, is the internal RX propagation delay, in order of: microseconds? Milliseconds? For Digital receivers? Best Regards, Pat Barthelow, Echoes of Apollo apollo...@gmail.com _______________________________________________ Sent via AMSAT-BB@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
