Moon Bounce or EME

It wasn't as as climactic as the moon landing, but still signifigant in radio land. The technique is known today as Earth-Moon-Earth (EME) or moonbounce. Signals of very high power are transmitted from antennas pointed at the moon 238,000 miles away. The moon reflects some of the signal and bounces the radio waves back to Earth to be received by listeners about 2.7 seconds later. The moon only reflects back about 7 % of the signal during a Moonbounce so this is harder than it sounds.

On January 10, 1946 , John H. DeWitt Jr. of the US Army Signal Corps bounced a 112 MHz (2.6 meters) radar beam off the moonThis was the first EME transmission. John was from Nashville and had been a Ham since 1921. He joined the US Army Electronic Branch in 1942. Two years later, he became director of the Evans Signal Laboratory at Belmar, New Jersey.

He actually beat out another radioman trying for the same acheivement in Hungary. Zoltan Bay suceeded in his first EME a mere two weeks later with radar of 2.5 m on february 6th. The first scientifically useful radar echoes, however, were those made by Frank Kerr and Shain. On November 1947. Kerr, shain and the crew at CSIRO demonstrated with a 15m echo that the short period variations of Earths rotation were caused by the vibration of the moon.

DeWitt just took that eperience and developed radar for locating mortars and directing counterfire. http://www.elite.net/~k7xq/eme.html He later returned to Nashville and broadcasting, eventually becoming president of commercial radio station WSM.

The EBS Authenticator Word List

Thirty Five years ago, in 1963 the Emergency Broadcast System (E.B.S.) was still relatively new and the cold war was just starting to roll. Virtually every radio and TV station had a teletype machine from which came the Associated Press.

It was a slow peice of crap. It ran at 50 baud, about 66 words per minute, that's slightly over six characters per second at full speed. These puppies were replaced by 1200-baud "high speed" dot matrix printers in about 1978.) The paper rolls in a teletype machine did't come from Office Max. They were supplied by the wire service. It was usually light yellow or beige and came on a thick roll about 8½ inches wide. The thick cylinder-o-peper weighed about four pounds. And it only lasted about a day.

The machine printed all the time because of the slow print speed and was always warm to the touch. But the smell is the memorable part for me. The fragrance was a mixture of lubricating oil and ink like the inside of an old electric cash register.

But unlike the cash register, changing the ribbon or the paper meant losing information forever. This was before PC's .. it had no memory at all. Why am I telling you this?

At every station, somewhere close to the teletype machine, there was an envelope containing the Authenticator Words for activation of the E.B.S. The list was a pointless security measure, even more so than random bag checks. For them to be used illegitamately woudl first require a fake message to come across the teletype, which is unlikely. But if they did, the sender would likely have a superior level of access to the man receiving the teletype. i.e. they already have the Authenticator Words .

As usual there is some killer stuff at Old Radio: http://www.oldradio.com/current/bc_conel.htm