Radio, Early Transmissions. Wireless Telegraphy

In the transition from experiments to regular broadcasting, important pioneering efforts in radio transmission took place before the beginning of World War II. Records conflict, and there is some controversy over the primacy of some ‘‘firsts.’’ Some pioneers have likely been forgotten for lack of the promotion available to others. Most of the experimental precursors transmitted telegraphy code; only slowly did the ability to send speech and music through the air become possible.

Wireless Telegraphy. Any consideration of pioneering transmissions must begin with German physicist Heinrich Hertz who, in a series of experiments in late 1887 and early 1888, was the first to demonstrate that prior theorizing about wireless was indeed correct. He succeeded in transmitting telegraph code across a room (using what soon became known as ‘‘Hertzian waves’’) without wire connections. Though he was not interested in the commercial potential of his findings, their publication triggered research by many others.

Guglielmo Marconi learned of his work while reading Hertz’s obituary in early 1894. Within a year, using Hertz’s spark-gap technology with the important addition of an antenna wire, Marconi was transmitting telegraphy signals for several hundred meters on his father’s estate near Bologna, Italy. By 1896 he was in England, demonstrating wireless transmissions over several kilometers to government officials. Transmissions across the English Channel followed on March 27, 1899.

On December 12, 1901, Marconi and several assistants (see Figure 5) succeeded in transmitting the Morse code signal for the letter S (three dots) across the North Atlantic from Poldhu in Cornwall to Signal Hill in St. Johns, Newfoundland. This was the first public demonstration of the feasibility of long-range radio communications, though regular commercial transatlantic wireless telegraph services did not commence until October 17, 1907.

Figure 5. Marconi and his assistants launching the kite-supported aerial at Signal Hill, St. John’s, Newfoundland, December 1901

That wireless would play an important role at sea was acknowledged early on. When the East Goodwin lightship in the English Channel was struck during heavy fog in 1898, a wireless transmission from the vessel helped to save lives— the first of many such radio feats. Regular radio transmissions to and from naval vessels began with Royal Navy operations in 1900, the same year Marconi first equipped several German liners with wireless transmitters.

After several years of experimentation, regular Marconi commercial wireless telegraph transmission to and from merchant shipping began in 1904. Other maritime rescues using wireless became common, including the January 23 1909 saving of more than 1500 people from the S.S. Republic. However, the April 14-15, 1912, Titanic disaster and the role of wireless in saving some 700 survivors captured the public imagination as to the benefits and potential of wireless transmissions and hastened developments. It also ensured adoption of regulations that required passenger vessels to have a radio operator on duty at all times.

In October 1899 the British Army first used wireless transmission during the Boer War in South Africa. Both the Russians and the Japanese made extensive use of wireless transmissions, at sea and on land, during the brief but fierce Russo-Japanese War of 1904-1905. By World War I, wireless transmission was widely used by all combatants, though wireless was still supplementing wired telegraph and telephone connections.

Broadcasting: 1906 to 1941. By connecting a telephone to a high-frequency alternator of his design, Reginald Fessenden became the first to transmit speech and music on Christmas Day and again on New Year’s Eve of 1906, from Brant Rock, Massachusetts south of Boston. His success (which followed wireless telephony experiments dating back to 1902) with an ‘‘audience’’ of shipboard radio operators was widely publicized at the time and was among the first indications that wireless might move beyond telegraph signals. In the next few years, there were many other one-time broadcast demonstrations.

Audion inventor Lee de Forest transmitted speech and music in 1908 from the Eiffel Tower in Paris and the voice of Enrico Caruso from New York’s Metropolitan Opera on January 13, 1910. The first transmissions to and from an airplane in flight took place in both Britain and the U.S. in 1910; the first airliner equipped with radio flew the London to Paris route a decade later. On the West Coast of the U.S., Charles D. Herrold began occasional, and soon regularly scheduled, voice and music broadcasts from a transmitter at his radio school in San Jose, California. The outbreak of World War I in 1914 put an end to all of this experimentation.

Radio broadcasting resumed only after hostilities concluded in late 1918. During 1919 and 1920, initial and occasional broadcast transmissions of speech and music emanated from stations in The Netherlands, Canada, Britain, and the U.S., most of them initiated by amateur radio operators. Marconi began daily broadcasts from Chelmsford, England, on February 23, 1920. While the election night broadcast of November 2, 1920, from station KDKA in Pittsburgh, Pennsylvania, is often credited with being the first regular broadcast transmission, several other stations can make the same claim and cite earlier dates.

The first coast- to-coast broadcast in the U.S. on October 24, 1924, combined telephone wires to transmit a presidential speech from New York to 22 stations across the country, previewing the rise of regular commercial network transmissions just two years later.

The first short-wave radio transmissions were undertaken by Marconi researchers in the early 1920s. Amateur operators sent the first such signal across the Atlantic on December 11, 1921. Regular two-way amateur traffic began on December 8, 1923, and has continued since. Westinghouse used short-wave transmissions to interconnect U.S. broadcasting stations in 1923-1924. By the end of the decade, the first regular cross-border, or international, short-wave propaganda broadcasts were being transmitted by the Soviet Union. Soon other nations began their own such services, including the BBC’s Empire Service on December 19, 1932.

On January 7, 1927 regular commercial transatlantic radio-telephone transmissions began between London and New York using AT&T and British Post Office long-wave circuits. These were supplemented with short wave in early 1927, and full two-way short-wave links opened June 1, 1929, soon replacing the long-wave transmissions. These were the first regular voice telecommunication links across the Atlantic to operate commercially and, updated from time to time, were the only such link until the first submarine telephone cable was opened for service in 1956.

The first public transmission of frequency modulation (FM) radio (prior developments were in AM, or amplitude modulation, radio) came on November 6, 1935, when U.S. inventor Edwin Howard Armstrong demonstrated his new system to a meeting of engineers at the Institute for Radio Engineers in New York. While commercial FM broadcasts began in the U.S. on January 1, 1941 (and on their present VHF spectrum band in 1945), FM stations in Europe appeared only slowly after the war, operating first in Germany. FM took decades to become a commercial success, achieving substantial audiences only in the 1970s in both Europe and the U.S.