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Dateline: Radio Transmission Across the Atlantic at 100 - 2001-12-12


Wednesday Dec. 12 is the 100th anniversary of the first radio transmission across the Atlantic Ocean. On December 12, 1901, Italian-born radio inventor Guglielmo Marconi, at St. John's, Newfoundland, heard three dots the Morse Code letter "S" sent by his company transmitting station at Poldhu, Cornwall, England.

Well, at least Marconi claimed to have heard those three dots. Several radio historians, and even some of Marconi's descendents, have doubts about whether Marconi actually heard the letter S from Poldhu. This is because radio signals on the likely frequency of that transmission, around 500 to 800 kilohertz, normally do not travel ocean spanning distances during daylight. Marconi's experiment was in the middle of the day. And, according to Radio Historian John Belrose of Canada's Communications Research Center, the crude transmitter and receiver Marconi used may not have been up to the task of long distance communication."He compromised himself by his peculiar spark transmitter. It was a two stage spark transmitter. A transmitter which he sort of never used again beyond the winter of 1901 and 1902, because he couldn't get a decent spark rate," he said.

Here in the United States, the Marconi Radio Club in Massachusetts is a group of radio amateurs who specialize in events celebrating the history of radio. Not surprisingly, they believe that Marconi did hear the transmission from Poldhu in 1901. Bob Doherty is president of the Marconi Radio Club. "The suggestion for the skeptics would be reproduce it and see if you could prove it, that it couldn't be done," he said. Today, the Marconi Radio Club is reproducing at least some aspects of the Marconi transmission from Eastham, on Cape Cod, in Massachusetts, near the site of another early Marconi installation. From 13 to 21 Universal Time, the club will be contacting radio amateurs at Poldhu and St. John's, using an antenna hoisted by a kite weather permitting.The frequency is 14052 kilohertz, and if you know Morse Code, listen for the call letters W1AA slant CC. The CC da di da dit da di da dit stands for Cape Cod and was the call sign used by Marconi's company from Cape Cod.

The most authentic reenactment of the transmission in 1901 has been organized by the Thunderer Squadron, the engineering education command of the British Royal Navy.Students at the Thunderer Squadron have built transmitting equipment similar to that used by Marconi in 1901.That equipment will transmit from the Marconi historic site at Poldhu. Students at the Canadian Forces School of Communications and Electronics and the United States Naval Academy will be at St. John's to listen for the transmissions from Poldhu, using historically accurate equipment that they have built. This includes an antenna suspended from a kite.

The Thunderer Squadron's transmissions begin today at 16 Universal Time on 1700 kilohertz. That's at the top end of the medium wave broadcast band, so people in Europe, and perhaps even North America, may be able to hear this transmission, even if they don't own a shortwave radio. Listen for the Morse Code letter S dit dit dit. The transmission will be repeated every hour on the hour until it becomes dark in North America, perhaps 21 or 22 Universal Time. That 1700 kilohertz is more likely to propagate across the Atlantic when it is dark on both shores. On Thursday, between 0200 and 0300 Universal Time, Canadian radio amateur David Wilson will transmit on 3550 kilohertz using the old fashioned spark gap method, similar to Marconi's technology of 1901. It will produce a raspy sound, compared to the smooth tones of today's Morse Code transmissions. Mr. Wilson will send this message several times: MARCONI S, commemorating the transmission of the letter S in 1901. Even if you do not know Morse Code, you can listen for the S dit dit dit. At 2 to 3 UTC, the signal on 3550 might be audible in Europe, the Middle East, and Africa. You will notice that it cuts a swath on your radio dial about twenty kilohertz wide. That's why Mr. Wilson had to receive special permission from the Canadian government to transmit using spark gap, a mode otherwise no longer allowed, to celebrate the 100th anniversary of the first transAtlantic radio transmission.

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