{"id":61,"date":"2021-08-13T16:17:20","date_gmt":"2021-08-13T16:17:20","guid":{"rendered":"http:\/\/1bcg.org\/1BCG\/?page_id=61"},"modified":"2021-08-20T00:42:37","modified_gmt":"2021-08-20T00:42:37","slug":"the-original-1bcg-transmitter","status":"publish","type":"page","link":"http:\/\/1bcg.org\/1BCG\/the-original-1bcg-transmitter\/","title":{"rendered":"The 1921 Transmitter"},"content":{"rendered":"\n
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1BCG Transmitter in 1921<\/figcaption><\/figure><\/div>\n\n\n\n

<\/p>\n\n\n\n

The 1BCG transmitter, as originally built, used two UV-204 Radiotron tubes in a self-excited, self-rectifying Colpitts oscillating circuit. It was rebuilt in the field into a master-oscillator, power-amplifier (MOPA) arrangement, to avoid the disadvantages of a self-excited oscillator and to produce a pure, steady CW signal. The single-204 oscillator was direct coupled to three more 204s in parallel in the amplifier. A motor-generator set supplied 2000 V dc for the plate voltage. <\/p>\n\n\n\n

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1BCG Circuit in 1921<\/figcaption><\/figure><\/div>\n\n\n\n
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A type UV-204 triode<\/figcaption><\/figure><\/div>\n\n\n\n

After the successful completion of the tests, the 1921 1BCG transmitter was removed to Columbia University for exhibition at a reading of a paper by the Radio Club of America. It is unknown what happened to the transmitter after that event.<\/p>\n\n\n\n

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1BCG Antenna in 1921<\/figcaption><\/figure><\/div>\n\n\n\n

The antenna was a 100-foot horizontal cage flattop, made up in two sections each 50 feet long with eight #14 stranded phosphor-bronze wires that were equally spaced around 18-inch-diameter metal hoops and connected from the center point with a 70-foot cage downlead.
There was also a counterpoise consisting of 30 radial wires, each 60 feet long. The radials extended from a common central point, at a height of seven feet above the ground. To reduce resonance effects, the counterpoise had two equal fan-shaped halves, each with 15 wires.<\/p>\n\n\n\n

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The 1BCG Antenna in 1921<\/figcaption><\/figure><\/div>\n\n\n\n
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The 1BCG Antenna Counterpoise in 1921<\/figcaption><\/figure><\/div>\n\n\n\n
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1BCG Crew in 1921<\/figcaption><\/figure><\/div>\n\n\n\n

The 1BCG crew assembled at the shack. Left to right: Ernest V. Amy, John F. Grinan, George E. Burghard, Edwin H. Armstrong and Minton Cronkhite. Missing is Walker P. Inman.<\/p>\n\n\n\n

\n","protected":false},"excerpt":{"rendered":"

The 1BCG transmitter, as originally built, used two UV-204 Radiotron tubes in a self-excited, self-rectifying Colpitts oscillating circuit. It was rebuilt in the field into a master-oscillator, power-amplifier (MOPA) arrangement, to avoid the disadvantages of a self-excited oscillator and to produce a pure, steady CW signal. The single-204 oscillator was direct coupled to three more […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":1,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"http:\/\/1bcg.org\/1BCG\/wp-json\/wp\/v2\/pages\/61"}],"collection":[{"href":"http:\/\/1bcg.org\/1BCG\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/1bcg.org\/1BCG\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/1bcg.org\/1BCG\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/1bcg.org\/1BCG\/wp-json\/wp\/v2\/comments?post=61"}],"version-history":[{"count":24,"href":"http:\/\/1bcg.org\/1BCG\/wp-json\/wp\/v2\/pages\/61\/revisions"}],"predecessor-version":[{"id":209,"href":"http:\/\/1bcg.org\/1BCG\/wp-json\/wp\/v2\/pages\/61\/revisions\/209"}],"wp:attachment":[{"href":"http:\/\/1bcg.org\/1BCG\/wp-json\/wp\/v2\/media?parent=61"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}