English: Multiwire T aerial of radio station WBZ in Springfield, Massachusetts, USA, in 1925. Licensed on September 15, 1921, it is claimed to be the first commercially licensed broadcast station in the US (although other stations like WWJ and KDKA had been broadcasting under other licenses for several years). Located at the Westinghouse plant in East Springfield, it broadcast on a wavelength of 360 meters (833 kHz) with a power of 2000 W. The antenna is typical of the wire antennas used for mediumwave broadcasting in the 1920s. The vertical wire connecting to the middle of the antenna is the radiating element, and the multiwire horizontal part is the capacitive "top load"; its function is to increase the oscillating currents in the vertical wire to increase the radiated power.
Français : Antenne multifilaire de la station de radio WBZ à Springfield, Massachusetts, États-Unis, en 1925. Concédée sous licence le 15 septembre 1921, elle est censée être la première station de radiodiffusion sous licence commerciale aux États-Unis (bien que d'autres stations comme WWJ et KDKA diffusent sous d'autres licences depuis plusieurs années). Situé à l'usine de Westinghouse à East Springfield, il a diffusé sur une longueur d'onde de 360 mètres (833 kHz) avec une puissance de 2000 W. L'antenne est typique des antennes filaires utilisées pour la diffusion à ondes moyennes dans les années 1920. Le fil vertical qui se connecte au milieu de l'antenne est l'élément rayonnant, et la partie horizontale multifilaire est la "charge supérieure" capacitive ; sa fonction est d'augmenter les courants oscillants dans le fil vertical pour augmenter la puissance rayonnée.
This 1925 issue of Popular Radio magazine would have the copyright renewed in 1953. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. [1] Search of the Renewals for Periodicals for 1952, 1953 and 1954 show no renewal entries for Radio World. Therefore the magazine's copyright was not renewed and it is in the public domain.
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