The History of Radio Broadcasting: From Marconi to KDKA
The history of radio broadcasting is the story of a quarter-century of technological development, business experimentation, and regulatory negotiation — culminating in the explosion of commercial radio in the early 1920s. The technology of broadcasting rested on a chain of inventions made over the previous thirty years, and the medium’s rapid growth was made possible by the legal and commercial framework established in 1920 and after. This page traces that story, from Heinrich Hertz’s 1888 discovery of electromagnetic waves to the Radio Act of 1927. For the station most often credited as the first commercial broadcaster, For the social impact of radio on the American home,
The Scientific Foundations: Hertz and Maxwell
The technology of radio rested on the work of a small number of 19th-century physicists. In 1864, James Clerk Maxwell of Scotland predicted the existence of electromagnetic waves traveling at the speed of light. In 1888, the German physicist Heinrich Hertz confirmed the prediction experimentally, generating and detecting radio waves in his laboratory at the University of Karlsruhe. Hertz’s experiments proved that Maxwell had been right, but Hertz himself saw no practical application for the new waves. When asked what use they might be, he reportedly said, “It’s of no use whatsoever.” He died in 1894, at age 36, before he could see the practical consequences of his work.
Marconi: The First Wireless Telegraph
The young Italian inventor Guglielmo Marconi was the first to put Hertz’s discovery to practical use. Building on the work of the British physicist Oliver Lodge, Marconi developed a system for transmitting and receiving radio signals — first across his family estate in Bologna in 1895, then across increasing distances. By 1896 he had demonstrated transmission across about 2 miles in England, and on December 12, 1901, he sent the first transatlantic radio signal, from Poldhu in Cornwall, England, to Signal Hill in St. John’s, Newfoundland.
Marconi’s early radio was wireless telegraphy — pulses of radio energy spelling out messages in Morse code. The technology was used for ship-to-shore communication, especially after the Titanic disaster of 1912 demonstrated its life-saving potential. For two decades, this was the dominant use of radio.
Fessenden and de Forest: The Voice of Radio
The transition from wireless telegraphy to wireless telephony required two further inventions. The Canadian-American physicist Reginald Fessenden demonstrated the first voice transmission in 1900, and on December 24, 1906 made the first radio broadcast — a program of music and speech heard by shipboard radio operators along the Atlantic coast. The audion tube (triode), invented by the American inventor Lee de Forest in 1906, was the first practical amplifier — it could boost a weak radio signal to drive a loudspeaker. The audion, more than any other single device, made radio a mass medium.
The “Wireless” Era: 1900 to 1920
Between 1900 and 1920, radio was a tool of amateur “wireless” operators. The American Radio Relay League (ARRL), founded in 1914 by Hiram Percy Maxim, was the principal national organization. The Radio Act of 1912 was the first comprehensive U.S. radio law, requiring licenses and restricting amateur use to the “useless” wavelengths below 200 meters. During World War I, the U.S. government took control of most radio stations for military purposes, and the Navy became the dominant user. After the war, the government returned the stations to civilian use.
The Armstrong Superheterodyne
The most important radio invention of the 1910s was the superheterodyne receiver, patented in 1918 by the American engineer Edwin H. Armstrong. The superheterodyne used a clever frequency-conversion scheme that produced dramatically better sensitivity and selectivity than earlier receivers. The design is still used in essentially every radio and television set made today. Armstrong, who also invented FM radio in the 1930s, was one of the most important radio engineers of the century.
The Sarnoff Memo: A Vision Ahead of Its Time
One of the most famous documents in the history of American broadcasting is a 1916 memo by David Sarnoff, then a 25-year-old commercial operator for the Marconi Wireless Telegraph Company of America. In a memo to his superiors, Sarnoff proposed the creation of a “radio music box” — a receiver that would bring music and entertainment into the home, on the model of the phonograph. The Marconi management ignored the memo, and Sarnoff eventually left Marconi for RCA, of which he became president in 1930. Sarnoff’s memo, which has been called “the birth certificate of broadcasting,” was 14 years ahead of the medium it envisioned.
The First Experimental Broadcasters
The first American experimental voice broadcasts were made in the late 1910s. The most important were Charles David Herrold in San Jose (station FN, later KQW, from 1909), Lee de Forest (broadcasting from his New York laboratory in 1907 and 1916), and Frank Conrad of Westinghouse (broadcasting from his home station 8XK in Pittsburgh in 1919). The 1920 launch of KDKA as a regularly scheduled broadcaster was the moment that the experimental hobby became an industry.
The KDKA Moment: November 2, 1920
The evening of November 2, 1920 is generally regarded as the beginning of commercial radio broadcasting. On that night, station KDKA in Pittsburgh — operated by the Westinghouse Electric Company and staffed by engineers including Frank Conrad and Harold W. Arlin — broadcast the returns of the Harding-Cox presidential election to a small but historically significant audience. The broadcast demonstrated that radio could carry information, that there was an audience for it, and that the broadcast model — scheduled programming transmitted from a licensed station — could work.
The Radio Craze of 1922
The two years after the KDKA broadcast saw an explosion of interest in radio. The number of new stations grew from a few dozen to more than 500 by the end of 1922, including virtually every major U.S. city. The Department of Commerce, under Secretary Herbert Hoover, struggled to manage the new industry. The existing regulatory structure — the 1912 Radio Act — was not designed for the new world of broadcasting, and the Commerce Department had limited authority to assign wavelengths or resolve conflicts.
A series of court decisions in 1926 — most importantly United States v. Radio Corporation of America and the related White v. Rourke decision — stripped the Department of Commerce of much of its authority, ruling that the 1912 Act did not give the government the power to refuse licenses or regulate broadcast content. The result was a brief period of legal chaos on the airwaves.
The Radio Act of 1927
Congress responded with the Radio Act of 1927, signed by President Coolidge on February 23, 1927. The Act created the Federal Radio Commission (FRC) to license stations, assign frequencies, and regulate the airwaves. The Act established the principle, still foundational, that the airwaves belong to the public and that broadcasters hold licenses “in the public interest, convenience, and necessity.” The 1927 Act was superseded by the Communications Act of 1934, which created the Federal Communications Commission (FCC) and extended federal regulation to telephone and telegraph. The framework established in 1927 and 1934 remained the basis of American communications law for the rest of the century.
The Decade in Review
By 1930, the radio industry was one of the largest in the United States, with millions of receivers, hundreds of stations, two national networks, and a new federal regulatory body. The technology that had been a curiosity in 1900 was a mass medium in 1930. The growth had been made possible by a chain of inventions — Hertz, Marconi, Fessenden, de Forest, Armstrong — and a series of business decisions, legal frameworks, and programming innovations. The history of radio is the history of how a new technology becomes a new institution, and the 1920s were the decade in which that transformation was completed.