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This 1920s TRF radio manufactured by Signal is constructed on a breadboard Tuning a TRF receiver, like this 5 tube Neutrodyne set from 1924 with two stages of RF amplification, was a complicated process. The three tuned circuits, controlled by the 3 large knobs, had to be tuned in unison to the new station.
Collins S-Line, featuring separate power supply, receiver, transmitter, and speaker console, c. 1960s. Amateur radio equipment of past eras like the 1940s, 50s, and 60s that are separate vacuum tube transmitters and receivers (unlike modern transceivers) are an object of nostalgia, and many see rehabilitation and on-air use by enthusiasts. [18 ...
E.H. Scott Radio Laboratories is sometimes confused with H.H. Scott. E.H. Scott was founded in 1925 by Chicago resident Ernest H. Scott. Its first product was the World's Record Super 8, a TRF (tuned radio frequency) design with typical harness wiring with 16 gauge silvered solid core copper wire employed in an array configuration that was typical to radios at the time. This construction ...
Area codes 210 and 726 are telephone area codes in the North American Numbering Plan (NANP) for San Antonio and most of its innermost suburbs in Bexar County in the U.S. state of Texas. The original area code, 210, was created in an area code split from area code 512 in 1992. After only a few years, the threat of number exhaustion forced a ...
The Neutrodyne radio receiver, invented in 1922 by Louis Hazeltine, was a particular type of tuned radio frequency (TRF) receiver, in which the instability-causing inter-electrode capacitance of the triode RF tubes is cancelled out or "neutralized" [1] [2] to prevent parasitic oscillations which caused "squealing" or "howling" noises in the speakers of early radio sets.
This is a list of area codes in the U.S. state of Texas. The date of establishment of each area code is indicated in parentheses: [1] 210: San Antonio area; overlays with 726 (November 1, 1992) 214: Dallas area, overlays with 469, 972, and 945 (October 1947) 254: Waco, Killeen, Temple, Belton, Stephenville and North Texas (May 25, 1997) 281 ...
0–9. Area codes 210 and 726; Area codes 214, 469, 972, and 945; Area code 254; Area codes 713, 281, 832, and 346; Area code 325; Area code 361; Area code 409
Hallicrafters founder Bill Halligan and his personal SX-28 depicted in a 1944 magazine ad. In July 1940, the Hallicrafters Company announced the SX-28 "Super Skyrider", the result of a development effort by 12 staff engineers and analysis of more than 600 reports that included input from U.S. government engineers, commercial users, and amateur radio operators.