History of Radio
The development of the telegraph and the telephone led eventually to the search for a way to communicate without wires. In 1865, James Clerk Maxwell thought that such communication could be possible through a layer of the atmosphere called the ether. In 1888, A German, Heinrich Hertz, proved that this theory was correct. He transmitted a wireless code signal across a room. In 1883-1884, Thomas Edison discovered the principle of the vacuum tube but did not know any application for it at that time.
Nicolas Tesla is the inventor of the wireless radio. However, Guglielmo Marconi did design a practical application for this invention. In 1901, he sent the first wireless message across the Atlantic Ocean. It was the Morse Code letter, S. This invention would soon compete with the undersea telegraph cables.
In 1900, Reginald Fessenden developed an electrolytic detector which could be used for the transmission of voices. He thought Marconi's vision for wireless communication was too limited. Along with Lee de Forest, he formed other wireless companies. They looked for new ideas to compete with Marconi's wireless transmission of code only. Marconi used the 'spark' technology.
Fessenden thought that wave technology could be used to transmit voice and music. He wanted to develop wireless telephony. By 1900, he developed a rotary spark transmitter. It could carry a voice for one mile. When sending a voice signal, the audio signal is first placed onto the radio frequency wave and then removed at the other end. Originally, the sound was not very clear. He thought a cleaner radio wave would make the voice clearer. He then developed a high-speed alternator instead of the rotary spark technology.
Fessenden partnered with a scientist from General Electric Company to create such an alternator. In December 1906, he could send voice and music several miles. DeForest also made some broadcasts of music and voice in 1907. He then developed a three-element vacuum tube called an audion. A new era for radio began.
In 1909, because of wireless communication, 1500 passengers were saved from drowning when the Republic sank. Other ships in the area were notified and provided rescue help. However, when the Titanic struck an iceberg in 1912, the wireless system in use showed fatal flaws. Interruption occurred from other radios which blocked communication with ships which might have come to the rescue of the Titanic. The Wireless Act of 1912 set standards for radio operations. During World War I, all non-governmental radio stations were shut down. The U.S. Navy took over radio.
The Radio Corporation of America was founded after the war by General Electric Company. It took over the Marconi Wireless Telegraph Company. In 1920, Westinghouse Corporation of Pittsburgh started a radio station just for entertainment. The first station was KDKA. Hundreds of new stations followed, as well as government regulation and licensing. Since AM radio experienced a lot of atmospheric noise, FM (frequency modulation) radio began. Transistor radios exploded in the 1950's. They became the mobile device for everyone. By 1979, most radio listening was to FM.
Satellite-digital radio came along in 2000-2001. Most radio stations today 'stream' their programming on the internet. MP3 portable digital devices which store music now are competing with radio music.
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