File:Early vertical wire antennas.svg

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English: Drawing showing types of vertical wire antennas used for the first wireless telegrapy radio transmitters and receivers during the first two decades of the 20th century. Guglielmo Marconi invented the vertical or monopole antenna in 1895, he found he could transmit longer distances by connecting one side of his transmitter to a metal plate suspended above ground and the other side to ground. (A) shows the early type of antenna he used until about 1900. The metal plate, which he called a "capacity area", was to add capacitance to the antenna, since the power output of the early spark gap transmitters was proportional to the amount of electric charge stored in the antenna before each spark. (B) He found that the plate did not help and a simple vertical wire had almost as much capacity. (C-F) Later researchers found that multiple parallel wires were a more convenient way to increase the capacitance, and also decreased the ohmic resistance, improving the efficiency of the antenna. (E) and (F) were called "cage antennas"; the symmetrical geometry equalized the current in the wires, reducing resistance.
Français : Dessin montrant des types d'antennes à fil verticaux utilisées pour les premiers émetteurs et récepteurs radio au cours des deux premières décennies du XXe siècle. Guglielmo Marconi a inventé l'antenne verticale monopole en 1895, il a découvert qu'il pouvait transmettre sur une plus longues distances en connectant un côté de son émetteur à une plaque métallique suspendue au-dessus du sol en extrémité du fils d’antenne.
  • (A) montre le premier type d'antenne qu'il a utilisé jusqu'à environ 1900. La plaque métallique, qu'il a appelée une "zone de capacité", devait ajouter de la capacité à l'antenne, car la puissance de sortie des premiers émetteurs d'écart d'étincelle était proportionnelle à la quantité de charge électrique stockée dans l'antenne avant chaque étincelle.
  • (B) Il a constaté que la plaque n'aidait pas et qu'un simple fil vertical avait presque autant de capacité.
  • (C, D, E, F) Des chercheurs ultérieurs ont découvert que plusieurs fils parallèles étaient un moyen plus pratique d'augmenter la capacité, et de réduire également la résistance ohmique, améliorant ainsi l'efficacité de l'antenne.
  • (E) et (F) étaient appelés "antennes de la cage" ; la géométrie symétrique égalisait le courant dans les fils, réduisant ainsi la résistance.
Date
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Author Chetvorno

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Early vertical wire antennas

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12 February 2018

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Date/TimeThumbnailDimensionsUserComment
current23:55, 10 December 2018Thumbnail for version as of 23:55, 10 December 20181,627 × 951 (70 KB)ChetvornoAltered shape of metal plate in first (A) antenna to make it look more like pictures of Marconi's antennas
18:07, 12 February 2018Thumbnail for version as of 18:07, 12 February 20181,627 × 951 (80 KB)ChetvornoUser created page with UploadWizard
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