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Operation Moon Bounce

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."

30 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...
    --
    Sigs cause cancer.
  2. Packet #2. by SIGALRM · · Score: 5, Funny


    ...latency in the transmission.

    --
    Sigs cause cancer.
    1. Re:Packet #2. by f8ejf · · Score: 3, Funny

      I never thought I'd spill coffee through my nose with anything regarding EME. Well done! 73 de F8EJF

    2. Re:Packet #2. by aaronrp · · Score: 3, Funny

      You're looking at it the wrong way. It's not excessive latency -- it's short-term data storage. For longer-term storage, use Marsbounce.

  3. Move over VOIP.. by harlingtoxad · · Score: 4, Funny

    Moon Bounce is the new wave of telecommunications!

    --
    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. satellite communications by RTPMatt · · Score: 2, Funny

    the technique became an important method of communication for the military that was used until the advent of the communications satellite

    Well, i believe this made the moon a communications satellite. but im just a nit-picker ;)

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

    Laser EME (moonbounce) without using the moon retroreflectors!

    73 de F8EJF

  7. 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!)...

    1. Re:Voice via Moonbounce *NOT* by DF5JT · · Score: 2, Insightful

      " Amateur Radio Enthusiasts do CW (morse) communications using moonbounce, not voice."

      [ ] You know W5UN, or (if you are old enough) K1WHS

    2. Re:Voice via Moonbounce *NOT* by sploxx · · Score: 3, Interesting

      Well, CW *and* voice.
      I know a ham (I also have a ham license, but not the neccessary money for the equipment) who demonstrated this a few years ago and it was just amazing!

      He has a lot of equipment and some agreements with the goverment for increased output power.
      So he was able to do a few kW (5?)@2.5GHz on a 9m fully steerable dish and voice/SSB modulation if I recall correctly.
      Now, the first beautiful thing was seeing the lights fade in sync with the voice because of the high power requirements of the transmitter :)

      The response from the moon was clearly readable but noisy, this is very impressive if you calculate the minimum loss (in dB) that is just given by the geometry...

    3. Re:Voice via Moonbounce *NOT* by Rob+Carr · · Score: 2, Interesting

      Amateur Radio Enthusiasts do CW (morse) communications using moonbounce, not voice. [Note for Non-Hams: SSB is "Single Sideband" (a form of voice communication) and CW is "Morse Code" (the old "di and dah.")] A few years back, I'd set up my 2m SSB/CW unit with a high gain directional antenna and listen in on EME. Most of it was, as you point out, CW, but occasionally there'd be some voice in there as well. Occasionally, you'd even hear an SSB station communicate with a CW station. I don't know why copying the CW portion of a SSB/CW conversation is hard, but for me it's far more difficult than pure CW.

      --
      This sig seemed like a good idea at the time....
    4. Re:Voice via Moonbounce *NOT* by DF5JT · · Score: 2, Interesting

      " I don't know why copying the CW portion of a SSB/CW conversation is hard, but for me it's far more difficult than pure CW."

      It's likely you are not used listening to SSB over a longer period of time. Switching between SSB and CW on the receiving side is extremely difficult, because you need to adapt your "internal" filters from very low bandwidth to rather large bandwidth.

      I can listen to CW for hours and hours, but listening to SSB is extremely tiring and makes me want to throw away the headphones after a couple of minutes. Well, I drew the consequences and have lived without a microphone on my rig for the past 20 years or so.

  8. 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.

    1. Re:47 GHz EME by MuguLover · · Score: 3, Informative

      Funny you should mention that. The first 47 GHz moonbounce echoes have been reported as being observed yesterday. This was done by a Russian (Sergei RW3BP) living in a block of flats in Moscow using a 2.4m offset dish and high power. He had to use DSP techniques to detect his signal.

  9. More info by john_smith_45678 · · Score: 5, Informative
    1. Re:More info by Richard_L_James · · Score: 2, Informative

      Group photo of the 1st HAMS to do Moon Bounce - The dish used came off British Telecom's "Post Office" tower in London. If you wish to see it yourself then come along to FRARS's HAMFEST on Sunday 8th August 2004. More moonbounce photos here.

      FRARS still has some of the leading experts in communications - including M0EYT / Paul J. Marsh who is currently just out in the middle of a field working 10Ghz.... Paul's probably on IRC as well right now so I will see what I can do to highlight this discussion to him in a minute.

  10. 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.

    --
    :(){ :|:&};:
    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

  11. Talking backwards? by Anonymous Coward · · Score: 2, Funny

    If they bounce the signal on the moon would it not be coming back reversed?

    Seriously? (no, not really ;-)

  12. Hand written proof! by Lasuuco+Tulkas · · Score: 3, Funny

    Finally! Proof that people in the 50's had handwriting as bad as my own!

  13. Moon Bounce for imformation storage by BoxOfCuriosity · · Score: 2, Interesting

    I read a SF book that used the moon bounce technique to store data. They had markers on the moon for navigation (just reflectors in the rock) People would use a transmitter on earth to 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. Box

    1. 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
  14. Military Applications by identity0 · · Score: 2, Interesting

    I haven't finished reading through the article, but I remember reading about this in one of James Bamford's book about the NSA, "Body of Secrets" or "The Puzzle Palace". Basically, when you bounce a directional radio beam off the moon, it can't be intercepted by anyone except those near the place on Earth where the beam bounces back to. This would allow Navy ships at sea to send a message from the open ocean, to the moon, then to Washington without having the message picked up by the Russians. Pretty neat trick, actually.

    The reason this was in Bamford's book was that the USS Liberty, the Navy eavesdropping ship that was attacked by the Israelis in 1967, had this type of system on board and it was its primary method of communicating with the NSA people in the US. Unfortunately, the system was unreliable, and the hydraulics or pnumatics controlling the directional antenna often broke, making it unusable. Partly because of this, the ship never got the message to stay away from the conflict zone and was bombed. That's how I remember it, at least.

    Maybe that's the danger of relying too much on bleeding-edge technology.

    Anyone here heard of other stories of this technology?

    1. Re:Military Applications by Rosco+P.+Coltrane · · Score: 2, Interesting

      when you bounce a directional radio beam off the moon, it can't be intercepted by anyone except those near the place on Earth where the beam bounces

      Except it's bullshit, because (1) the beam is hardly directional enough to aim at a location precise enough on the moon to bounce back exactly at a certain point on earth over twice the earth-moon distance (even a well collimated laser makes a big miles-wide splotch on the moon at that distance), and (2) the returning signal is mostly *scattered* back, just like laser light hitting some non-reflective object doesn't come back as a beam, and so you'd be hard-pressed to control the return path anyway.

      You know, there's a reason why Bamford's writings are considered a lot closer to fiction than to history.

      --
      "A door is what a dog is perpetually on the wrong side of" - Ogden Nash
  15. And the words of that first bounce were.... by ro_coyote · · Score: 3, Interesting

    "FIRST POST!!"

  16. Rick Brant did this in 1947... by dpbsmith · · Score: 3, Informative

    and in the fifties I read all about it in "The Lost City," a Rick Brant Electronic Adventure, by John Blaine. (Pseudonym of Harold Leland Goodwin). Like Tom Swift, but more up-to-date and nerdier. This is based on many-decade-old recollections, but they end up stranded on a mountain ledge in Tibet with a hand-crank generator. As I recall the book mentions that they need to crank quite hard to power the filaments in the vacuum tubes. It's Morse Code, of course, not voice. I seem to recall that the radio waves are described as being in the radar wavelength range, but it's really been a long time and I'm into very unreliable memory here.

    I wish I could remember why they need to go to Tibet to test the equipment. Probably because If They Didn't, There Wouldn't Have Been Any Story.

    Rick's father is a dignified scientist. Rick and his father are always accompanied by lovable sidekicks Zircon (?) and, um, can't remember his name exactly, it's not "Chowdah" but something like that--an Indian (not a native American, but a person from India) who speaks amusingly broken English and makes comic errors due to his entire knowledge of the Western world having been obtained from a copy of the World Almanac.

    There seems to be quite a bit more about this at this website

  17. USS Liberty by zogger · · Score: 3, Informative

    they obviously had more than one kind of radio on board. The identity and their location was known to everyone concerned, israelis, the ship itself, and other US assets out in the med and elsewhere, along with various international HAMS who were monitoring what they could of the ongoing war taking place. The attack was delibarate, and designed to pin the blame on egypt (best credible analysis, IMO) in order to garner support for more US intervention and support for the israeli side. They went so far as to strafe survivors for hours in an attempt to kill all the witnesses. They didn't suceed, but to this day the attack continues to be excused as an "accident". The implications in todays politics are there, just extrapolate it as to how far a nation would go to get it's way in international affairs. I know this isn't an exact answer to your question with moon bounce radios, I just wanted to interject about radios in general and on the topic you raised of the attack on the Liberty. Here is a brief history of it for anyone:

    http://www.wrmea.com/backissues/0693/9306019.htm

    June 1993, Page 19

    This Month in History

    The Assault on the USS Liberty Still Covered Up After 26 Years

    By James M. Ennes Jr.

    Twenty-six years have passed since that clear day on June 8, 1967 when Israel attacked the USS Liberty with aircraft and torpedo boats, killing 34 young men and wounding 171. The attack in international waters followed over nine hours of close surveillance. Israeli pilots circled the ship at low level 13 times on eight different occasions before attacking. Radio operators in Spain, Lebanon, Germany and aboard the ship itself all heard the pilots reporting to their headquarters that this was an American ship. They attacked anyway. And when the ship failed to sink, the Israeli government concocted an elaborate story to cover the crime.

    There is no question that this attack on a U.S. Navy ship was deliberate. This was a coordinated effort involving air, sea, headquarters and commando forces attacking over a long period. It was not the "few rounds of misdirected fire" that Israel would have the world believe. Worse, the Israeli excuse is a gross and detailed fabrication that disagrees entirely with the eyewitness recollections of survivors. Key American leaders call the attack deliberate. More important, eyewitness participants from the Israeli side have told survivors that they knew they were attacking an American ship.

    Israeli Pilot Speaks Up

    Fifteen years after the attack, an Israeli pilot approached Liberty survivors and then held extensive interviews with former Congressman Paul N. (Pete) McCloskey about his role. According to this senior Israeli lead pilot, he recognized the Liberty as American immediately, so informed his headquarters, and was told to ignore the American flag and continue his attack. He refused to do so and returned to base, where he was arrested.

    Later, a dual-citizen Israeli major told survivors that he was in an Israeli war room where he heard that pilot's radio report. The attacking pilots and everyone in the Israeli war room knew that they were attacking an American ship, the major said. He recanted the statement only after he received threatening phone calls from Israel.

    The pilot's protests also were heard by radio monitors in the U.S. Embassy in Lebanon. Then-U.S. Ambassador to Lebanon Dwight Porter has confirmed this. Porter told his story to syndicated columnists Rowland Evans and Robert Novak and offered to submit to further questioning by authorities. Unfortunately, no one in the U.S. government has any interest in hearing these first-person accounts of Israeli treachery.

    Key members of the Lyndon Johnson administration have long agreed that this attack was no accident. Perhaps most outspoken is former Chairman of the Joint Chiefs of Staff Admiral Thomas Moorer. "I can never accept the claim that this was a mistaken attack," he insists.

    Former Secretary of State Dean Rusk is equall

  18. Re:What about artificial moons? by mikeb · · Score: 2, Interesting

    It was widely rumoured that in the mid-to-late seventies some of the geostationary TV satellites got hijacked for various purposes. By 'widely rumoured' I mean that my ham radio boozing buddies talked about it quite a lot and several of them were broadcast technicians who used satellite up and downlinks at work. I have no first hand proof but they alleged that early geostationary satellites were simple transponders - if you pushed stuff up on the uplink frequency with the right amount of power and in the right direction it came back on the downlink. A popular trick was to slip a signal just to the side of the audio subcarrier at a modest level and then use it to send data or chat to friends. That is not easy to spot unless you look hard at the downlink spectrum.

    This might all be speculation or not - I'd love to know. Maybe it's an urban legend.

  19. Fight Wars Only 12-hours a Day by Nom+du+Keyboard · · Score: 2, Funny
    technique became an important method of communication for the military

    Okay, shut down the war until the moon rises again.

    Let's see. Stealth fighter-bombers no moon. Communication yes moon. Bomb first, and talk about it afterwards.

    --
    "It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."