The term “radio” can refer to either the electronic appliance that we listen with or the content playing from it. In any case, it all started with the discovery of “radio waves” or 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 radio, microwaves, cordless phones, remote controlled toys, television broadcasts and more.
The Roots of Radio
During the 1860s, Scottish physicist James Clerk Maxwell predicted the existence of radio waves. 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 those of light and heat.
In 1866, Mahlon Loomis, an American dentist, successfully demonstrated “wireless telegraphy.” Loomis was able to make a meter connected to one kite cause another one 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. By 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.
This was the first successful transatlantic radiotelegraph message in 1902.
In addition to Marconi, two of his contemporaries, Nikola Tesla and Nathan Stufflefield, 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 Radiotelegraph
Radio-telegraphy is the sending by radio waves the same dot-dash message (morse code) used in a telegraph. Transmitters at that time were called spark-gap machines. It was developed mainly for ship-to-shore and ship-to-ship communication. This was a way of communicating between two points. However, it was not public radio broadcasting as we know it today.
The use of wireless signals increased when it was proved to be effective in communication for rescue work whenever a sea disaster occurred. 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 instituted between five Hawaiian Islands. By 1903, a Marconi station located in Wellfleet, Massachusetts carried an exchange or greetings 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.
In 1909, Robert E. Peary, an arctic explorer, radiotelegraphed “I found the Pole.” In 1910, Marconi opened 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 that discharged electricity within the circuit and between the electrodes 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 Deforest invented space telegraphy, the triode amplifier and the Audion.
In the early 1900s, the big requirement for further development of radio was to have an efficient and delicate detector of electromagnetic radiation. It was De Forest who provided that detector. This made it possible to amplify the radio frequency signal picked up by the antenna before application to the receiver detector. This meant that much weaker signals could be utilized than had previously been possible. De Forest was also the person who first used the word “radio.”
The result of Lee DeForest’s work was the invention of amplitude-modulated or AM radio that allowed for a multitude of radio stations. The earlier spark-gap transmitters did not allow for this.
True Broadcasting Begins
In 1915, speech was first transmitted 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 with 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.
Telephone connection by radio and cable is now accessible with 187 foreign points.
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.