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Operation Moon Bounce

Posted by michael on from the boing dept.

linuxwrangler writes "Today marks the 50th anniversary of the first transmission of human voice via moon bounce. The voice was that of James Trexler and the technique became an important method of communication for the military that was used until the advent of the communications satellite. It is still a popular activity for ham radio operators."

11 of 103 comments (clear)

  1. Packet #1. by SIGALRM · · Score: 4, Funny
    ... transmission of human voice via moon bounce ...

    But then there is always the problem of...
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    Sigs cause cancer.
  2. Packet #2. by SIGALRM · · Score: 5, Funny


    ...latency in the transmission.

    --
    Sigs cause cancer.
  3. Move over VOIP.. by harlingtoxad · · Score: 4, Funny

    Moon Bounce is the new wave of telecommunications!

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    Gravity is not just a law, it's also a good idea.
  4. Satellite! by chrispyman · · Score: 4, Funny

    Oh, so that's why we call the moon a natural satellite!

  5. Even better by f8ejf · · Score: 5, Informative

    Laser EME (moonbounce) without using the moon retroreflectors!

    73 de F8EJF

  6. Voice via Moonbounce *NOT* by Fallen+Andy · · Score: 5, Informative

    Amateur Radio Enthusiasts do CW (morse) communications using moonbounce, not voice. Given the path loss (c.a. 240dB) and power constraints on amateur stations voice is er.. difficult? (Michael: go look at Trexler's antenna spec!)...

  7. 47 GHz EME by pingus · · Score: 5, Interesting

    At my local ham radio club, a guy just gave a talk about how he is attempting to implement a 47 GHz EME system. Is is interesting because of the technical challenges. Only a few other people actually operate 47 GHz stations. The travelling wave tube that most use was originally used for military work, for a project called Milstar. Interesting that at the time none of the traffic was coded to their satellites because it was considered intristically safe because it would be very hard to build a station for it.

    Some operators do use voice, but have to use big time QRO (high power) stations because the path losses are so huge. Then with new DSP methods, voice communications can definetly work.

  8. More info by john_smith_45678 · · Score: 5, Informative

    More info on "Moon Bounce"

    http://www.zetatalk.com/info/tinfo14e.htm
    http://www.af9y.com/

    --
    John Kerry is a Joke!
  9. it's not as easy as it sounds by quelrods · · Score: 4, Informative

    Moon bounce isn't something that one can conjure up at will with the flip of a switch. The amateur radio stations doing moonbounce have uber high gain directional antennas and pump 1.5kw (1500 watts), maximum legal power, into them. What you get back is a signal so faint that you then use various pre-amps and notch filtering to pull the signal out of the noise. I was fairly certain moon bounce on ham bands was limited to CW (contious wave aka morse code.) (Morse code takes a very minimal amount of bandwith and thus the power is focused instead of scattered across a large portion of spectrum.) iirc when the government did moonbounce they would pump something more to the order of 500kW.

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    :(){ :|:&};:
    1. Re:it's not as easy as it sounds by MuguLover · · Score: 5, Interesting

      You are right for the lower frequency bands, but once you start moving up above 1000 MHz then EME is possible with much more modest systems. For example on 23cms (1296 MHz) you can work CW EME with 100W and a 3m dish, if you are peering with someone like HB9Q or HB9BBD then you can use a lot less than that.

      The introduction of digital modes like JT44 and JT65 (using FFTs, correlation and strong FEC) has made a big difference and has made EME available for people with much smaller gardens and purses. Unfortunately there are a number of EME operators who insist that a digital mode somehow isn't "real" or that the contacts count for less. This is a shame and gives newcomers the wrong impression of a fine part of the hobby.

      I intend to get active soon with a marginal system for CW work but more than adequate for the more advanced data modes.

      For info about more reasonable microwave EME systems see G4CCH and N2UO

  10. Re:Moon Bounce for imformation storage by Rosco+P.+Coltrane · · Score: 4, Informative

    send a burst of data to the moon and let it bounce back then retransmit it without storing it. just a loop. You could fit a certain amount of data in the lag. They used it on farther objects to get longer delays. Kind of a strange idea.

    It's nothing strange nor is it science ficton, it's called a delay line memory and it was used in early computers

    --
    "A door is what a dog is perpetually on the wrong side of" - Ogden Nash