DescriptionMarconi radio lighthouse on Inchkeith Island 1925.jpg
English: An experimental rotating radio beacon for ships built by Guglielmo Marconi 1922 on Inchkeith Island in the Firth of Forth, UK. It consisted of two cylindrical parabolic antennas of tuned wires, back-to-back, 32 feet in height with a horizontal aperture of 43 feet, mounted on a rotating platform which turned at a constant rate. The concept was to create a radio version of a lighthouse, which emitted two beams 180° apart which slowly rotated. Vertical feed antennas at the focus of each paraboloid are driven by two 500 watt spark transmitters in a separate building. A contact system on the rotating platform switched the beams on and off to transmit numbers in Morse code indicating the bearing of the ship from the beacon. It was operated at various wavelengths between 4.25 and 6.25 meters (48 - 70.6 MHz). (more information in Marconi constant speed rotating beam beacons, nonstopsystems.com
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Uploaded a work by N. Wells from Retrieved from [https://archive.org/details/sim_engineering_1925-03-13_119_3089/page/n3/mode/2up Wells, N. The Marconi Wireless Beam Reflector on Inchkeith in ''Engineering'' magazine, London, Engineering Ltd, Vol. 119, No. 3089, March 13, 1925, p.319, fig.1] on archive.org with UploadWizard