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| 1895 | Guglielmo Marconi (Italy) demonstrated the use of electromagnetic waves for long distance communication, resulting in the first practical wireless telegraph system. He also discovered that the range of wireless communication improved substantially with increased antenna elevation and the use of a grounded connection to the antenna. |
| 1899 | Marconi sends the first wireless telegraph message across the English Channel. |
| 1900 | Invention of crystal detector. The first model was a steel needle resting on a carbon block. Subsequent designs used a thin metal probe, or whisker in contact with a crystal of lead sulfide or carborundum. |
| 1901 | Marconi sends a wireless signal (the letter "s") between Cornwall, England and St. John's, Newfoundland |
| 1903 | Valdemar Poulsen (Denmark) develops the arc transmitter, capable of generating a relatively clean radiofrequency signal. The Poulsen transmitter was widely used until the 1920s, when it was displaced by vacuum tube designs. |
| 1904 | Sir John Fleming (England) develops the vacuum diode based on the Edison effect. The device serves as a radio wave detector and is the first practical vacuum tube. |
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