Humanities › History & Culture The History of Radio Technology Share Flipboard Email Print The Most Important Inventions of the Industrial Revolution Introduction The American Industrial Revolution Key Elements of the American Industrial Revolution Top Inventors Transportation The Steam Engine The Railroad The Diesel Engine The Airplane The Automobile Communication The Telegraph The Transatlantic Cable The Phonograph The Telephone Radio Technology Industry The Cotton Gin The Sewing Machine Electric Lights The Electric Motor Guglielmo Marconi. The Print Collector/Getty Images By Mary Bellis Inventions Expert Mary Bellis covered inventions and inventors for ThoughtCo for 18 years. She is known for her independent films and documentaries, including one about Alexander Graham Bell. our editorial process Mary Bellis Updated May 11, 2019 Radio owes its development to two other inventions: the telegraph and the telephone. All three technologies are closely related, and radio technology actually began as "wireless telegraphy." The term "radio" can refer to either the electronic appliance that we listen with or to the content that plays from it. In any case, it all started with the discovery of radio waves—electromagnetic waves that have the capacity to transmit music, speech, pictures, and other data invisibly through the air. Many devices work by using electromagnetic waves, including radios, microwaves, cordless phones, remote controlled toys, televisions, and more. The Roots of Radio Scottish physicist James Clerk Maxwell first predicted the existence of radio waves in the 1860s. In 1886, German physicist Heinrich Rudolph Hertz demonstrated that rapid variations of electric current could be projected into space in the form of radio waves, similar to light waves and heat waves. In 1866, Mahlon Loomis, an American dentist, successfully demonstrated "wireless telegraphy." Loomis was able to make a meter connected to a kite cause a meter connected to another nearby kite to move. This marked the first known instance of wireless aerial communication. But it was Guglielmo Marconi, an Italian inventor, who proved the feasibility of radio communication. He sent and received his first radio signal in Italy in 1895. In 1899, he flashed the first wireless signal across the English Channel, and two years later received the letter "S," which was telegraphed from England to Newfoundland (now part of Canada). This was the first successful transatlantic radiotelegraph message. In addition to Marconi, two of his contemporaries, Nikola Tesla and Nathan Stubblefield, took out patents for wireless radio transmitters. Nikola Tesla is now credited with being the first person to patent radio technology. The Supreme Court overturned Marconi's patent in 1943 in favor of Tesla's. The Invention of Radiotelegraphy Radiotelegraphy is the sending by radio waves of the same dot-dash message (Morse code) used by telegraphs. Transmitters, at the turn of the century, were known as spark-gap machines. They were developed mainly for ship-to-shore and ship-to-ship communication. This form of radiotelegraphy allowed for simple communication between two points. However, it was not public radio broadcasting as we know it today. The use of wireless signaling increased after it was proved to be effective in communication for rescue work at sea. Soon a number of ocean liners even installed wireless equipment. In 1899, the United States Army established wireless communications with a lightship off Fire Island, New York. Two years later, the Navy adopted a wireless system. Up until then, the Navy had been using visual signaling and homing pigeons for communication. In 1901, radiotelegraph service was established between five Hawaiian Islands. In 1903, a Marconi station located in Wellfleet, Massachusetts, carried an exchange between President Theodore Roosevelt and King Edward VII. In 1905, the naval battle of Port Arthur in the Russo-Japanese war was reported by wireless. And in 1906, the U.S. Weather Bureau experimented with radiotelegraphy to speed up notice of weather conditions. Robert E. Peary, an arctic explorer, radiotelegraphed "I found the Pole" in 1909. A year later, Marconi established regular American-European radiotelegraph service, which several months later enabled an escaped British murderer to be apprehended on the high seas. In 1912, the first transpacific radiotelegraph service was established, linking San Francisco with Hawaii. Meanwhile, overseas radiotelegraph service developed slowly, primarily because the initial radiotelegraph transmitter was unstable and caused a high amount of interference. The Alexanderson high-frequency alternator and the De Forest tube eventually resolved many of these early technical problems. The Advent of Space Telegraphy Lee de Forest was the inventor of space telegraphy, the triode amplifier, and the Audion, an amplifying vacuum tube. In the early 1900s, the development of radio was hampered by the lack of an efficient detector of electromagnetic radiation. It was De Forest who provided that detector. His invention made it possible to amplify the radio frequency signal picked up by antennae. This allowed for the use of much weaker signals than had previously been possible. De Forest was also the first person to use the word "radio." The result of Lee de Forest's work was the invention of amplitude-modulated or AM radio, which allowed for a multitude of radio stations. It was a huge improvement over the earlier spark-gap transmitters. True Broadcasting Begins In 1915, speech was first transmitted by radio across the continent from New York City to San Francisco and across the Atlantic Ocean. Five years later, Westinghouse's KDKA-Pittsburgh broadcasted the Harding-Cox election returns and began a daily schedule of radio programs. In 1927, commercial radiotelephony service linking North America and Europe was opened. In 1935, the first telephone call was made around the world using a combination of wire and radio circuits. Edwin Howard Armstrong invented frequency-modulated or FM radio in 1933. FM improved the audio signal of radio by controlling the noise static caused by electrical equipment and the earth's atmosphere. Until 1936, all American transatlantic telephone communication had to be routed through England. That year, a direct radiotelephone circuit was opened to Paris. In 1965, the first Master FM Antenna system in the world, designed to allow individual FM stations to broadcast simultaneously from one source, was erected on the Empire State Building in New York City.