The history of radio spans only a little more than a century. But in that time it has grown from brief bursts of static-rich signals over short distances to today’s satellite radio that spans broad swathes of the globe from orbit. First used to provide direct communications, much like the telegraph and telephone, it is now a complex industry that drives consumer behavior and political discourse.
In its earliest days radio was known as “wireless telegraphy.” When theorists began to better understand the nature of electromagnetic waves in the 1860s they laid the foundation for pioneers such as Guglielmo Marconi, Nikola Tesla, Nathan Stufflefield, Karl Ferdinand Braun, and many others to tinker and experiment with the basic hardware of primitive radio.
By the 1890s the first radio signals — waves on the electromagnetic spectrum that are longer than infrared light, which is why “radio” is derived from the Latin word for ray or beam — were being sent over short distances. In 1901 Marconi oversaw the first trans-Atlantic radio transmission.
The initial use of radio focused on ship-to-shore and ship-to-ship communication. What was transmitted was Morse code, a wireless version of the telegraph. Eventually, this technology was adapted for other uses, such as reporting weather conditions by the U.S. Weather Bureau and trans-Atlantic communications.
It took further advances for radio to begin to take the form known to us today. One of the most important was Lee de Forest’s work in the early 1900s creating ways to “amplify” radio signals picked up by antennas. This allowed transmitters to be less powerful and cut down on the extreme amount of electrical interference that marked early radiotelegraph “spark-gap” transmitters.
The ability to amplify radio waves at the receiving end resulted in amplitude-modulated (AM) radio. This was a necessary step to allow the transmission of the human voice and music over the radio spectrum, which was necessary for radio to become a mass consumer item.
Around the world, the first radio stations began broadcasting in the early 1920s, with PCGG in the Netherlands first broadcasting on November 6, 1919. But trying to define the specific “first” radio broadcast is tricky and depends on debating what exactly defines a public broadcast.
It is widely accepted that in the United States the broadcast by KDKA — located in Pittsburgh, PA, and owned by the Westinghouse Electric Corporation — of the national election returns on November 2, 1920, was one of the first true “radio broadcasting” moments.
Advertising had not yet developed for these early radio stations, so companies — such as Westinghouse — that sold radio receivers owned and operated the stations. The first commercial radio stations were, in effect, created in order to create a market for radios.
Radio took off rapidly in the 1920s across the United States and the rest of Europe. It is believed that in just seven years — 1923 to 1930 —the percentage of American families with radios went from virtually zero to 60 percent. The British Broadcasting Company (BBC) went on the air in 1922.
In the first quarter of the 20th century, technological advances continued to be made. Edwin Howard Armstrong improved on de Forest’s work, creating the regeneration circuit that eventually allowed for the easy tuning of radio receivers (and eventually televisions). He is also credited as being the inventor of frequency modulation (FM) radio.
FM radio was a serious improvement over AM radio in sound quality and the first FM station in the United States — W47NV in Nashville, Tennessee— went on air in 1941. But World War II and subsequent issues delayed the wide use of FM until the 1950s.
Another outgrowth of World War II was the development of radio as a tool of governments, especially shortwave radio. The ability of shortwave broadcasts to travel great distances by being bounced off of the ionosphere made them a favorite tool of governments, both to communicate with their far-flung holdings and also to transmit directly to the citizens of adversaries. The BBC World Service is the best-known shortwave service, but the Voice of America and Radio Moscow World Service faced off against each other throughout the Cold War.
With the end of the Cold War and then the launch of satellite radio and Internet radio feeds, shortwave radio has become less and less important. Likewise, commercial AM and FM radio have faced a shrinking audience under the pressure of the Internet. It remains to be seen what the future holds for both commercial and amateur radio in the Internet age.