History of Radio Transmitters
The development of the radio transmitter created the modern communications age. Without the radio transmitter, television, cell phones, computers, the Internet and the radio would have developed in considerably different ways, if at all. The technologies developed to make and improve radio transmitters and receivers led to all of these innovations.
Other People Are Reading
-
History
-
In 1888, Heinrich Hertz discovered that energy generated by a transmitting oscillator could be detected from across his laboratory by using a gapped metal loop. Guglielmo Marconi seized on this idea to build a wireless telegraph and started experiments in 1894. When the Italian Ministry of Post and Telegraphs said it was not interested in his inventions, Marconi moved to England in 1896. The British were extremely interested and gave him all the support he needed. Marconi obtained a patent and set up the Wireless Telegraph and Signal Company. Ships communications were greatly improved by his inventions, and many lives were saved using his wireless telegraph system, including survivors of the Titanic, which had a Marconi wireless on board. He succeeded in transmitting a transatlantic signal on Dec. 12, 1901, from Ireland to Canada. A year before, Canadian inventor Reginald Fessenden succeeded in transmitting the first voice over radio waves. With these two technologies in place, development of the radio as we know it today began.
Function
-
The radio transmitter encodes the sound into a sine wave. The sine wave is modulated to carry information using either pulse modulation (PM), amplitude modulation (AM), or frequency modulation (FM). This sine wave is then transmitted through an antenna.
-
Features
-
Radio transmitters allow communication of information over any distance without wires. They also use many frequencies allowing multiple communications simultaneously. They allow encoding and decoding that result in high quality sound for the communications being sent.
Types
-
Spark gap transmitters were the earliest form of radio transmitter, but were limited in range and could not transmit voice or music successfully. The Poulson arc generator, patented in 1903, and the Alexanderson alternator, patented in 1911, superseded the spark gap transmitter in the early 1900s as they had much greater control and range. Vacuum tube transmitters took over in the 1920s and '30s. Modern radio uses integrated circuits.
Benefits
-
Radio transmitters have a range of benefits, including their life-saving capabilities, which have been employed by ships since the early 1900s. With technologies developed for the radio transmitter, we now have television, cell phones and the Internet.
-
