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The early history of radio is the history of technology that produced radio instruments that use radio waves. Within the timeline of radio, many people contributed theory and inventions in what became radio.[1] Radio development began as "wireless telegraphy".[1] Later radio history increasingly involves matters of programming and content.
Invention
Main article: Invention of radio
James ClerkMaxwell showed mathematically that electromagnetic waves could propagate through free space. Heinrich Rudolf Hertz and many others demonstrated, on a laboratory scale, radio wave propagation.
Transmission and radiation of radio frequency energy was a feature exhibited in the experiments by Nikola Tesla which he proposed might be used for the telecommunication of information.[2][3] The Teslamethod was described in New York[4] in 1897.[5][6] In 1897, Tesla applied for two key United States radio patents, US 645576 , first radio system patent, and US 649621 .[7] Tesla also used sensitive electromagnetic receivers,[8][9][10] that were unlike the less responsive coherers later used by Marconi and other early experimenters. Shortly thereafter, he began to develop wireless remote controldevices.
Crystal sets

In the 1920s, the United States government publication, "Construction and Operation of a Simple Homemade Radio Receiving Outfit", showed how almost any person handy with simple tools could a build an effective crystal radio receiver.
The most common type of receiver before vacuum tubes was the crystal set, although some early radios used some type of amplification throughelectric current or battery. Inventions of the triode amplifier, motor-generator, and detector enabled audio radio. The use of amplitude modulation (AM), with which more than one station can simultaneously send signals (as opposed to spark-gap radio, where one transmitter covers the entire bandwidth of spectra) was pioneered by Fessenden and Lee de Forest.
To this day there is a small but avid baseof fans of this technology who study and practice the art and science of designing and making crystal sets as a hobby; the Boy Scouts of America have often undertaken such craft projects to introduce boys to electronics and radio, and quite a number of them having grown up remain staunch fans of a radio that 'runs on nothing, forever'. As the only energy available is that gathered by the antennasystem, there are inherent limitations on how much sound even an ideal set could produce, but with only moderately decent antenna systems remarkable performance is possible with a superior set.
FM and television start
In 1933, FM radio was patented by inventor Edwin H. Armstrong. FM uses frequency modulation of the radio wave to minimize static and interference from electrical equipment and theatmosphere, in the audio program. In 1937, W1XOJ, the first experimental FM radio station, was granted a construction permit by the U.S. Federal Communications Commission (FCC). In the 1930s, standard analog television transmissions started in Europe, and then in the 1940s in North America. Armstrong's FM system was designated by the FCC to transmit and receive television sound.
Marconi's prioritydispute
Main article: Invention of radio
In 1943, the United States Supreme Court ruled one Marconi patent invalid on the basis of prior art by John Stone Stone and Tesla. This decision was based on the fact that prior art existed before the establishment of Marconi's patent. Ignoring Tesla's prior art, the decision may have enabled the U.S. government to avoid having to pay damages that werebeing claimed by the Marconi Company for use of its patents during World War I (as, it is speculated, the government's initial reversal to grant Marconi the patent right in order to nullify any claims Tesla had for compensation).
FM in Europe
After World War II, the FM radio broadcast was introduced in Germany. In 1948, a new wavelength plan was set up for Europe at a meeting in Copenhagen....