Slashdot Mirror

← Back to Stories (view on slashdot.org)

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."

6 of 103 comments (clear)

  1. Packet #2. by SIGALRM · · Score: 5, Funny


    ...latency in the transmission.

    --
    Sigs cause cancer.
  2. Even better by f8ejf · · Score: 5, Informative

    Laser EME (moonbounce) without using the moon retroreflectors!

    73 de F8EJF

  3. 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!)...

  4. 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.

  5. 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!
  6. 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