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Replica Of Parabolic Transmitter For Marconi's Original Beam System, by Marconi Company, England, 1920s/1930s
Inventory Number: 59943
Number of documents: 2
Document Type: Label
Document Heading: Celluloid Plaque
Text:
The circular celluloid plaque seems to refer to an early display (late 1920s-1930s) of historic Marconi equipment. The two instruments that make up Marconi's Original Beam System (Inv. Num.s 59943 & 40344) have long been described as replicas, and were presumably constructed for this display, probably using original components.
Document Type: Label
Document Heading: Museum Label
Text:
The beam system is described thus in an associated museum label: "These are replicas of Marconi's first experimental apparatus using parabolic reflectors for the transmission and reception of wireless telegraphy. With such apparatus he demonstrated in Italy the possibilities of 'beam' transmission and reception. He confirmed his results officially before representatives of the British Post Office, the Navy and the Army at Salisbury Plain, in September 1896 when he communicated over 1¾ miles."
The transmitter of the beam system is described thus in an associated museum label:
"This consisted of a Righi Oscillator, producing very short waves of the order of 25 centimetres length, placed in the focal line of a parabolic cylindrical copper mirror. The outside balls are connected to a Ruhmkorff coil, and sparks controlled by a Morse key feed the oscillator. The two large balls form a Hertz oscillator and their dimensions control the length of the wave emitted. The focal length of the parabolic copper mirror employed may be either ¼ or ¾ of the wavelength emitted."
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