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A transistor radio is a small portable radio receiver that uses transistor-based circuitry. Following their development in 1954, made possible by the invention of the transistor in 1947, they became the most popular electronic communication device in history, with billions manufactured during the 1960s and 1970s.
Ham Radio History. In 1873, James Clerk Maxwell presented his theory of the electromagnetic field. In 1901 Guglielmo Marconi communicated across the Atlantic with a radio device using high power and giant antennas. To curb interference, Congress approved the Radio Act of 1912, which required amateurs to be licensed and restricted to the single wavelength of 200 meters.