Heinrich Rudolf Hertz February 22, 1857 - January 1, 1894 was the German physicist and mechanic for whom the hertz, an SI unit, was named after. In 1886, Hertz developed a dipole antenna. This antenna is a center-fed driven element for transmitting or receiving radio frequency energy. These antennas are the simplest practical antennas. Through experimentation, he proved that transverse free space electromagnetic waves can travel over some distance. With his apparatus configuration, the electric and magnetic fields would radiate away from the wires as traverse waves. Hertz had positioned the oscillator about 12 meters from a zinc reflecting plate to produce standing waves. Each wave was about four meters. Using the ring detector, he recorded how the magnitude and wave's component direction vary. Hertz measured Maxwell's waves and demonstrated that the velocity of radio waves was equal to the velocity of light. The electric field intensity and polarity was also measured by Hertz.
The Hertzian cone was first described by Hertz as a type of wave-front propagation through various media. His experiments help expand the field of electromagnetism transmission and his apparatus was developed further by others in the history of radio. Hertz also found that radio waves could be transmitted through different types of materials, and were reflected by others. This was key to radar and was investigated and exploited later by others. Hertz did not understand the practical importance of his experiments.
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