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#1
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That's amazing. Who thought about doing that? Who invented that idea?
Did the Russians ever found out? SR SeeingEyeDog wrote: Before satellites became available for eavesdropping the moon was used to listen to the USSR. "SR" wrote in message ... The last few evening the moon was almost full and the evening sky was fairly clear here in New York. I then transmitted on my CB but no DX only locals. I read something somewhere that mention about Moon Bouncing. Meaning that a signal can travel far. But I am not sure if that is true. 73 SR! |
#2
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In article , SR wrote:
The last few evening the moon was almost full and the evening sky was fairly clear here in New York. I then transmitted on my CB but no DX only locals. I read something somewhere that mention about Moon Bouncing. Meaning that a signal can travel far. But I am not sure if that is true. It's a VHF and microwave thing. You actually illuminate the Moon with enough power that another station back on Earth can pick up the reflection. But that requires an antenna that can focus most of your power on the Moon, a target only 1/2 degree across. Hams, with 1 kilowatt, can get morse code and slow digital signals (on the higher bands). Before satellites the Defense Department was able to send several teletype channels at at time, maritime mobile. That was with a big dish and probably 10's of kilowatts. (The best description of using that equipment, that I've seen, was in a description of the incident where the USS Liberty, the radio intelligence ship, was attacked by the Israelis. In the Atlantic Monthly about 10-15 years ago, as I remember). Mark Zenier Googleproofaddress(account:mzenier provider:eskimo domain:com) |
#3
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#4
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![]() "matt weber" wrote in message ... On Sat, 22 Oct 2005 00:33:19 GMT, (Mark Zenier) wrote: [snip] Before satellites the Defense Department was able to send several teletype channels at at time, maritime mobile. That was with a big dish and probably 10's of kilowatts. (The best description of using that equipment, that I've seen, was in a description of the incident where the USS Liberty, the radio intelligence ship, was attacked by the Israelis. In the Atlantic Monthly about 10-15 years ago, as I remember). Yes, but that wasn't moonbounce, it was tropo scatter. YOu can only use Moonbounce when the moon is visible to both ends. Troposcatter works just about anytime, anywhere. The change in permittivity at the top of the toposphere will actually bounce a tiny portion of the microwave signal back down quite reliably. You can get about 600 miles that way. But you need the sort of big dish, and tens of kilowatts to do it reliably. Only the military could really afford to use it. The USS Liberty is said to have had moonbounce capability. The moonbounce antenna is supposed to have been one of the distinctions seperating it from the Egyptian ship the Isrealis said they thought they were attacking. The large parabolic antenna in the picture, pointing straight up, seems to be that moonbounce antenna. http://www.history.navy.mil/photos/i...00/u123118.jpg Frank Dresser |
#5
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![]() "Frank Dresser" wrote in message news:ZCH6f.169781$qY1.131220@bgtnsc04- The USS Liberty is said to have had moonbounce capability. The moonbounce antenna is supposed to have been one of the distinctions seperating it from the Egyptian ship the Isrealis said they thought they were attacking. The large parabolic antenna in the picture, pointing straight up, seems to be that moonbounce antenna. http://www.history.navy.mil/photos/i...00/u123118.jpg Frank Dresser Isn't the internet a constantly amazing resource? By crikey, there is not a thing you cannot find on it! Brad. |
#6
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![]() "Frank Dresser" wrote in message ... The large parabolic antenna in the picture, pointing straight up, seems to be that moonbounce antenna. http://www.history.navy.mil/photos/i...00/u123118.jpg Frank Dresser You know, that could just be the position the antenna is parked. It might be a bit of an assumption that the moon is straight up! ;-) Brad. |
#7
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![]() "Brad" bradvk2qq AT w6ir.com wrote in message ... "Frank Dresser" wrote in message ... The large parabolic antenna in the picture, pointing straight up, seems to be that moonbounce antenna. http://www.history.navy.mil/photos/i...00/u123118.jpg Frank Dresser You know, that could just be the position the antenna is parked. It might be a bit of an assumption that the moon is straight up! ;-) Brad. I'd assume that antenna could be pointed anywhere from horizon to horizon. Frank Dresser |
#8
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On Sun, 23 Oct 2005 18:25:07 +1000, "Brad" bradvk2qq AT w6ir.com
wrote: "Frank Dresser" wrote in message ... The large parabolic antenna in the picture, pointing straight up, seems to be that moonbounce antenna. http://www.history.navy.mil/photos/i...00/u123118.jpg Frank Dresser You know, that could just be the position the antenna is parked. It might be a bit of an assumption that the moon is straight up! ;-) Brad. Reading closely, you would see that there was no implication in the previous posting that the antenna was actively in use. Yes, it may have been parked, under maintenance or so positioned for any number of other reasons. |
#9
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On Sun, 23 Oct 2005 08:13:45 GMT, "Frank Dresser"
wrote: "matt weber" wrote in message .. . On Sat, 22 Oct 2005 00:33:19 GMT, (Mark Zenier) wrote: [snip] Before satellites the Defense Department was able to send several teletype channels at at time, maritime mobile. That was with a big dish and probably 10's of kilowatts. (The best description of using that equipment, that I've seen, was in a description of the incident where the USS Liberty, the radio intelligence ship, was attacked by the Israelis. In the Atlantic Monthly about 10-15 years ago, as I remember). Yes, but that wasn't moonbounce, it was tropo scatter. YOu can only use Moonbounce when the moon is visible to both ends. Troposcatter works just about anytime, anywhere. The change in permittivity at the top of the toposphere will actually bounce a tiny portion of the microwave signal back down quite reliably. You can get about 600 miles that way. But you need the sort of big dish, and tens of kilowatts to do it reliably. Only the military could really afford to use it. The USS Liberty is said to have had moonbounce capability. The moonbounce antenna is supposed to have been one of the distinctions seperating it from the Egyptian ship the Isrealis said they thought they were attacking. The large parabolic antenna in the picture, pointing straight up, seems to be that moonbounce antenna. http://www.history.navy.mil/photos/i...00/u123118.jpg Frank Dresser Having it pointed straight up is the standard stowed position. At lot less load on the mounting that way. However it could just as easily be a tropo scatter antenna, and tropo scatter has the advantage that the moon doesn't have to visible at both ends of the path. however it could also have used a communication satellite. I think only Syncom III was in Geo Syncrhonos orbit at that time, however there were a number of other sats in LEO and MEO (such as Telstar) that could have been used, and they would come into view every few hours and would be usable for 15-30 minutes at a time with a usable bandwidht of a few MHZ. The Syncom III video wasn't so great, since it was a 2 Mhz transponder IIRC, and analog Television is 6Mhz. .. The first Telstar went up in 1962, and I would be indeed surprised is several Military sats didn't have similar capabilities at that time. In the fall of 1967 I remember a professor of Meteoroloby at the University of Wisconsin telling me about a single UHF transponder they had put on one of the Tiros weather sats in orbit that could be used (and was used as a voice channel). The roof of the Meteorology department at UW had a modest steerable corner reflector to use it.. As it was in LEO, it only took about 50 watts on each end. |
#10
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![]() "matt weber" wrote in message ... On Sun, 23 Oct 2005 08:13:45 GMT, "Frank Dresser" wrote: Having it pointed straight up is the standard stowed position. At lot less load on the mounting that way. However it could just as easily be a tropo scatter antenna, and tropo scatter has the advantage that the moon doesn't have to visible at both ends of the path. Wouldn't a moonbounce setup, with high power and a steerable antenna, also have tropo scatter capability? It wouldn't necessarly go the other way, however. Equipment which works well enough for tropo scatter might not do the moonbounce job. however it could also have used a communication satellite. I think only Syncom III was in Geo Syncrhonos orbit at that time, however there were a number of other sats in LEO and MEO (such as Telstar) that could have been used, and they would come into view every few hours and would be usable for 15-30 minutes at a time with a usable bandwidht of a few MHZ. The Syncom III video wasn't so great, since it was a 2 Mhz transponder IIRC, and analog Television is 6Mhz. . The first Telstar went up in 1962, and I would be indeed surprised is several Military sats didn't have similar capabilities at that time. In the fall of 1967 I remember a professor of Meteoroloby at the University of Wisconsin telling me about a single UHF transponder they had put on one of the Tiros weather sats in orbit that could be used (and was used as a voice channel). The roof of the Meteorology department at UW had a modest steerable corner reflector to use it.. As it was in LEO, it only took about 50 watts on each end. Again, what works for moonbounce ought to more than meet the standard for satellite work. The Liberty was said to have had moonbounce capability. I'd figure they used that large parabolic antenna for that purpose. There's no obvious reason they couldn't have used it for the less demanding tasks of tropo scatter and satellite comms. Frank Dresser |
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