Reginald Aubrey Fessenden (October 6, 1866 – July 22, 1932), a naturalized American citizen born in Quebec, Canada, was an inventor who performed pioneering experiments in radio, including the first radio transmissions of voice and music. In his later career he received hundreds of patents for devices in fields such as high-powered transmitting, sonar, and television.
Postcard image, from around 1910, of the 128 meter (420 ft) tall Brant Rock radio tower.
In the late 1890s, reports began to appear about the success Guglielmo Marconi was having in developing a practical radio transmitting and receiving system. Fessenden began limited radio experimentation, and soon came to the conclusion that he could develop a far more efficient system than the spark-gap transmitter and coherer-receiver combination which had been championed by Oliver Lodge and Marconi.
The development of a rotary-spark transmitter was something of a stop-gap measure, to be used until a superior approach could be perfected. Fessenden felt that, ultimately, a continuous-wave transmitter—one that produced a pure sine wave signal on a single frequency—would be far more efficient, particularly because it could be used for quality audio transmissions. His design idea was to take a basic electrical alternator, which normally operated at speeds that produced alternating current of at most a few hundred hertz, and greatly speed it up in order to create electrical currents at tens of kilohertz. Thus, the high-speed alternator would produce a steady radio signal when connected to an aerial. Then, by simply placing a carbon microphone in the transmission line, the strength of the signal could be varied in order to add sounds to the transmission—in other words, amplitude modulation would be used to impress audio on the radio frequency carrier wave. However, it would take many years of expensive development before even a prototype alternator-transmitter would be ready, and a few more years beyond that for high-power versions to become available.
Photograph of Rotary Gap transmitter at Brant Rock, Ma. (c.1906).
Fessenden contracted with General Electric to help design and produce a series of high-frequency alternator-transmitters. In 1903, Charles Proteus Steinmetz of GE delivered a 10 kHz version which proved of limited use and could not be directly used as a radio transmitter. Fessenden’s request for a faster, more powerful unit was assigned to Ernst F. W. Alexanderson, and in August, 1906 he delivered an improved model which operated at a transmitting frequency of approximately 50 kHz, although with far less power than Fessenden’s rotary-spark transmitters.
The alternator-transmitter achieved the goal of transmitting quality audio signals, but the lack of any way to amplify the signals meant they were somewhat weak. On December 21, 1906, Fessenden made an extensive demonstration of the new alternator-transmitter at Brant Rock, showing its utility for point-to-point wireless telephony, including interconnecting his stations to the wire telephone network. A detailed review of this demonstration appeared in The American Telephone Journal.
A few days later, two additional demonstrations took place, which appear to be the first audio radio broadcasts of entertainment and music ever made to a general audience—maybe. (Beginning in 1904, the U.S. Navy had broadcast daily time signals and weather reports, but these employed spark transmitters, transmitting in Morse code). On the evening of December 24, 1906 (Christmas Eve), Fessenden used the alternator-transmitter to send out a short program from Brant Rock. It included a phonograph record of Ombra mai fu (Largo) by George Frideric Handel, followed by Fessenden himself playing the song O Holy Night on the violin. Finishing with reading a passage from the Bible: ‘Glory to God in the highest and on earth peace to men of good will’ (Gospel of Luke 2:14). He petitioned his listeners to write in about the quality of the broadcast as well as their location when they heard it. Surprisingly, his broadcast was heard several hundred miles away, however accompanying the broadcast was a disturbing noise. This noise was due to irregularities in the spark gap transmitter he used.
On December 31, New Year’s Eve, a second short program was broadcast. The main audience for both these transmissions was an unknown number of shipboard radio operators along the East Coast of the United States. Fessenden claimed that the Christmas Eve broadcast had been heard “as far down” as Norfolk, Virginia, while the New Year Eve’s broadcast had reached places in the Caribbean. Although now seen as a landmark, these two broadcasts were barely noticed at the time and soon forgotten; the only first-hand account appears to be a letter Fessenden wrote on January 29, 1932 to his former associate, Samuel M. Kinter. There are no known accounts in any ships’ radio logs, nor any contemporary literature, of the reported holiday demonstrations.
(Broadcasting historian James E. O’Neal, in a series of articles on the Radio World website, suggests that Fessenden, writing a quarter-century after the fact, may have confused the dates; O’Neal suggests Fessenden was remembering instead a series of tests he’d conducted in 1909.)
There is solid historical evidence, however, that Fessenden’s demonstrations of “wireless telephony” were well known at the time. Documentation of Fessenden’s demonstration of radio-transmitted voice is provided by a New York Time’s article, dated Sunday, September 1, 1907, titled: “Telephoning at Sea.” It announced that the “Navy Department is about to install wireless telephone apparatus on all battleships destined for the Pacific, this Fall. Practicable wireless telephony over a distance of five miles in all weathers is guaranteed by the company furnishing the instruments. Under favorable conditions, it is reported, a much greater distance for communication is possible.” The article accurately describes the science involved, saying: “The Hertzian waves will penetrate opaque substances, and the amplitude and intensity of the waves may be so varied as to reproduce faithfully the vibrations of the human voice.” The same article further states that: “recently, the Fessenden wireless system demonstrated the practicability of transmitting spoken words from a tall mast at Brant Rock to Plymouth, twelve miles away.” Intense competition among developers of wireless technology, and the expectation of possible government contracts may have limited the scope of public promotion of the apparatus features and capabilities.
Fessenden’s broadcast foreshadowed of the future of radio. (Although primarily designed for transmissions spanning a few kilometers, on a couple of occasions the test Brant Rock audio transmissions were apparently overheard by NESCO employee James C. Armor across the Atlantic at the Machrihanish site). Edited from Reginald Aubrey Fessenden
