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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.
Audio reproduction quality of TRF sets was limited by the available loudspeakers. "High Fidelity" was not to become a radio marketing concept until the mid-1930s and was not realized until the advent of FM broadcasting. Reaction sets, also known as regenerative receivers, rely on positive feedback to achieve adequate gain. This approach ...
The RCA model R7 Superette superheterodyne table radio. This is a list of notable radios, which encompasses specific models and brands of radio transmitters, receivers and transceivers, both actively manufactured and defunct, including receivers, two-way radios, citizens band radios, shortwave radios, ham radios, scanners, weather radios and airband and marine VHF radios.
The Majestic Model #71 introduced in 1927, for example, was a tuned radio frequency receiver with a 9-inch (23 cm) speaker, powered from AC house current. [10] This was a considerable improvement over previous radios having typically poor selectivity and producing inferior sound from old-fashioned horn speakers or earphones.
The (American version) radio's main receiver covers 30 kHz through 60 MHz, 142 MHz through 152 MHz, and 420 through 450 MHz (plus 1240 through 1300 MHz with the "X" model). The sub-receiver tunes between 118 and 174 MHz, and from 220 to 512 MHz (VFO ranges).
The show featured top entertainment and became one of the most popular and acclaimed regular radio programs of the era. At its peak in 1929, the company employed over 12,000 workers manufacturing nearly one million radio sets. Its models included the metal-cabinet seven-tube Model 57 at US$105 and the wooden-cabinet eight-tube Model 60 at US$80 ...
The receiver functions as a tuned radio frequency (TRF) receiver. The radio frequency (RF) signal from the tuned circuit ( bandpass filter ) is amplified, then passes through the high pass filter to the demodulator , which extracts the audio frequency (AF) ( modulation ) signal from the carrier wave .
The Neutrodyne receiver, invented in 1922 by Louis Hazeltine, [133] [134] was a TRF receiver with a "neutralizing" circuit added to each radio amplification stage to cancel the feedback to prevent the oscillations which caused the annoying whistles in the TRF.