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Show FOREFATHERS I OF RADIO By GEORGE LEWIS of The Crosley Kjidio Corporation. No one had succeeded in demonstrating demon-strating how IIert7' discoveries could be made the basis of a practical sys-lem. sys-lem. The waves created by Hertz' conl devoted his attention to the problem. prob-lem. The waves created by Hertz's crude apparatus could only be detected detect-ed at short distances from the apparatus. appa-ratus. It was necessary that two things be done before Hertz' methods could be adapted to practical wireless telegraphy: First, it was essential to devise some more powerful means of propagating the waves, and, second, a better detecting device than the simple wire loop and spark gap that he had used had to be worked out. Marconi solved both of these problems. prob-lems. G. Marconi. Very early In his experiments, Marconi Mar-coni made the discovery that if one i electrical terminal of the transmitting of receiving apparatus were connected connect-ed to the earth and the other end con nected to a metal plate or wire suspended sus-pended high in the air, the range over which transmission and reception could be accomplished would he mulli-PlPd mulli-PlPd many times. Marconi's earth connection is known today as the "ground," and his suspended wire or Plate Is what we know as an "aerial" or "antenna." Jn the line of detecting devices he improved an Instrument first thought f by Branly, and known as the "coherer." This instrument is a re-laT, re-laT, enabling the feeble vibrating electric elec-tric current set up In the receiving circuit by the radio waves' to release current from a local batlerv. means of these improvements. J Marconi was able to conduct many successful suc-cessful demonstrations of practical wireless telegraphy in England. In 1S9S, permanent stations were established estab-lished for communication between Alum bay and Bournemouth, England, a distance of 14 miles. A year later communication was maintained between be-tween England and France. |