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The Ideas that Made Radio Possible
By the late 1800's, Americans had nearly 50 years of experience with a new communication device that used electricity and magnets to instantly "write at a distance." The success of the telegraph led Alexander Graham Bell to develop an "electrical speech machine" in 1876 that also used electricity and magnets to capture and send the sound of the human voice over long distances. But as wonderful as these amazing devices were, they shared a common weakness - their messages could only go where their wires led.
So what was a ship at sea or a sheriff on an open range to do when they urgently needed to summon help? Could mankind communicate over great distances without wires?
Today we know that wireless communication using the radio frequencies of the electromagnetic spectrum answered these questions. But, in 1885 German physicist Heinrich Hertz thought his proof of Maxwell's theories;
had no practical value since he could only send signals a few yards. Further, he saw no way of improving or amplifying the signal so that it could be received at a greater distance. Finally, his experiments showed that if two transmitters operated in the same proximity, the nearby receiver found both signals, producing nothing but static and hiss.
Thus, Italian inventor Guglielmo Marconi's 1901 transmission of a wireless signal from Ireland to Canada was an expression of faith as well as applied science. Marconi later described the prevailing skepticism of learned individuals by noting that achieving long distance wireless transmission of sound:
But the "pip-pip-pip" (Morse code for the letter "s") that Marconi reported he heard at 12:30 p.m. on December 12, 1901 was just one of many remarkable events that gave true meaning to Oliver Lodge's proclamation that wireless communications had created a new "epoch in history." For wireless telegraphs had begun to appear on ocean-going vessels as early as 1891 - many of them donated for demonstration purposes by Marconi. For it was the opportunity to save lives and property on large ships that provided much of the early impetus to develop wireless communications via the radio waves. The 1899 collision between the coal-laden R. F. Matthews and the East Goodwin Lightship was just the first instance where the use of wireless radio saved lives. Because of the extremely dense fog and strong tides present that day, the lifeboats that came to the rescue might not have seen flares in time to get to the crash site prior to some loss of life. Thankfully the Trinity House Corporation, owner of the East Goodwin, was participating in a demonstration of Marconi radio systems and the ship's captain was able to quickly signal for help.
Thus, Marconi's integration of the work of Hertz, Righi, Branly, Lodge, and others led to an improved radio system based upon:
These innovations paved the way for the next big breakthrough in wireless radio transmissions - sending the sound of a human voice over the air waves instead of just the dots and dashes of wireless telegraphy.
Canadian Reginald Fessenden was the larger than life man whose work, in combination with those discussed in the next section, introduced, in 1906, what we think of today as radio: music, news, talk, in fact any sound human beings can make. Experiences as the chief chemist in Edison's labs, work at Westinghouse, professorships in electrical engineering at Purdue University and the University of Pennsylvania, research in North Carolina for the U.S. Weather Bureau, and, finally, a founding partnership in the National Electric Signaling Company uniquely qualified him to solve the riddle of how sound waves traveled and what was necessary to transmit those waves wirelessly from one point to another.
Although best known for his 1906 Christmas Eve broadcast of music and voice from Brant Rock, Massachusetts, Fessenden actually made the first transmission of voice in 1900 while under contract to the Weather Bureau. His continuous wave theory - whereby a sound wave is combined with a radio wave and transmitted to a receiver where the radio wave is removed so that the listener hears only the original sound - describes how radio works today.
Fessenden proved his theory on December 23, 1900 from an island in the Potomac River. Speaking to an associate who was a mile away with a receiving unit, Fessenden said:
Thiessen replied in the affirmative and the rest, as they say, is history.
With technologies for both long-distance and voice transmissions in place, one final event served as the capstone that made radio an essential technology for the 20th century. That event was the sinking of the Titanic in 1912. The "unsinkable" Titanic was equipped with a state-of-the-art Marconi radio system: a rotary spark transmitter, powered by a 5 kilowatt alternator that fed off the ship's lighting circuit, a four wire antenna hoisted 250 feet in the air between the ship's masts, and even a battery powered emergency transmitter. There was a guaranteed transmission range of 250 miles, but at night transmissions could go up to 2000 miles. The two radio operators expected to spend all their time sending and receiving personal communications from the wealthy passengers. And, in fact, from the April 12 sailing until the ship hit the iceberg just past midnight on April 15 they sent 250 such messages.
During the two hours from the first distress call until the radio operators abandoned the radio room they sent 30-35 messages, which were heard as far away as Italy; but not by a ship four miles away, because the radio operator was off duty.
While over 1,500 people were lost in this tragedy, about 700 survived - with credit going, largely, to the wireless distress messages that the Titanic broadcast. In the aftermath of this international event several new regulations were put in place for every ship carrying more than 50 people. Included among these were requirements to provide sufficient lifeboats, hold drills, and maintain round the clock radio coverage.
Radio had truly come to stay.
|last reviewed/updated on 11/21/05|
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