There is still controversy about who invented radio.
In 1893, Nikola Tesla publicly demonstrated wireless communications for the first time in St. Louis, Missouri, USA. In lectures to the Franklin Institute in Philadelphia and to the National Electric Light Association, he described and demonstrated the basic principles of radio communications. The instrument he built contained all the basic elements of radio systems that preceded the invention of the vacuum tube.
Guglielmo Marconi holds what is generally regarded as the world's first patent for radio technology, British Patent No. 12039, "Improvements in the Technology of Electrical Pulses and Signal Transmission and All Equipment required”.
Nikola Tesla patented radio technology in the United States in 1897. However, the U.S. Patent Office revoked his patent in 1904 and instead granted Marconi a patent for his invention of radio. This move may have been the result of the influence of Marconi's financial backers in the United States, including Thomas Edison and Andrew Carnegie. In 1909, Marconi and Karl Ferdinand Braun received the Nobel Prize in Physics "for their contribution to the invention of wireless telegraphy".
In 1943, shortly after Tesla’s death, the U.S. Supreme Court reaffirmed that Tesla’s patents were valid. This decision recognized that his invention preceded Marconi's patent. Some believe the decision was made for obvious financial reasons. This way the U.S. government during World War II could avoid paying patent royalties to Marconi.
In 1898, Marconi opened the world's first radio factory in Hall Street, Chelmsford, England, employing about 50 people.