File:Drawing of Heinrich Hertz spark radio transmitter and parabolic antenna 1888.jpg
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Drawing_of_Heinrich_Hertz_spark_radio_transmitter_and_parabolic_antenna_1888.jpg (413 × 376 pixels, file size: 47 KB, MIME type: image/jpeg)
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[edit]DescriptionDrawing of Heinrich Hertz spark radio transmitter and parabolic antenna 1888.jpg |
English: Drawing of experimental 450 MHz spark radio transmitter and parabolic antenna built by German physicist Heinrich Hertz in 1888 and used in his historic first researches on radio waves (Hertzian waves). This is the earliest example of a parabolic antenna. The antenna is described in Heinrich Hertz, Daniel Evan Jones (1893) Electric Waves, 2nd Ed., McGraw-Hill, New York, p. 175 as a 2 m x 2 m sheet of zinc attached to a wooden frame to make a cylindrical parabolic reflector with aperture 2 m high by 1.2 m wide, with focal length of 12.5 cm. A section of the reflector is shown cutaway to reveal the antenna. Along the focal line is suspended a Hertzian dipole antenna consisting of two 1 cm dia. brass rods about 13 cm long, with metal balls attached to its adjacent ends to make a spark gap about 3 mm wide. The dipole elements are attached to an induction coil powered by a battery on a table behind the antenna, which applied high voltage pulses which caused sparks in the spark gap, exciting high frequency oscillations in the dipole. The wavelength of the waves produced was measured by Hertz at 66 cm, making the corresponding frequency 454 MHz. |
Date | |
Source | Retrieved 4 September 2024 from Morse, A. H. "The Short Wave" in Wireless World magazine, London, Vol.17, No.13, 23 September 1925, p.389, fig.1 on https://www.worldradiohistory.com |
Author | A. H. Morse |
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[edit]Public domainPublic domainfalsefalse |
This work is in the public domain in the United States because it was published (or registered with the U.S. Copyright Office) before January 1, 1929.
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Note: This tag should not be used for sound recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:Drawing_of_Heinrich_Hertz_spark_radio_transmitter_and_parabolic_antenna_1888.jpg |
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 19:49, 5 September 2024 | 413 × 376 (47 KB) | Chetvorno (talk | contribs) | Uploaded a work by A. H. Morse from Retrieved 4 September 2024 from [https://www.worldradiohistory.com/UK/Wireless-World/20s/Wireless-World-1925-09.pdf Morse, A. H. "The Short Wave" in ''Wireless World'' magazine Vol.17, No.13, 23 September 1925, p.389, fig.1] on https://www.worldradiohistory.com with UploadWizard |
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Author | Chris Burks |
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Date and time of data generation | 06:10, 4 September 2024 |
Horizontal resolution | 96 dpi |
Vertical resolution | 96 dpi |
Software used | GIMP 2.10.12 |
File change date and time | 12:23, 4 September 2024 |
Date and time of digitizing | 06:10, 4 September 2024 |
DateTimeOriginal subseconds | 93 |
DateTimeDigitized subseconds | 93 |
Unique ID of original document | xmp.did:e83ea8f9-6a04-426c-a7a6-3899622c3c86 |