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A tuned radio frequency receiver (or TRF receiver) is a type of radio receiver that is composed of one or more tuned radio frequency (RF) amplifier stages followed by a detector (demodulator) circuit to extract the audio signal and usually an audio frequency amplifier. This type of receiver was popular in the 1920s.
Today's radios are usually uneconomical to repair because mass production and technological improvements in numerous areas have made them so inexpensive to buy, while the cost of human labor and workshop overheads have increased greatly in comparison. Typical insides of an antique radio, showing the vacuum tubes.
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.
A family listening to a crystal radio in the 1920s Greenleaf Whittier Pickard's US Patent 836,531 "Means for receiving intelligence communicated by electric waves" diagram US Bureau of Standards 1922 Circular 120 "A simple homemade radio receiving outfit" taught Americans how to build a crystal radio.
The sub-receiver tunes between 118 and 174 MHz, and from 220 to 512 MHz (VFO ranges). [28] The radio's main receiver uses DSP at the IF level, so a very flexible selection of bandwidths are available without the purchase of mechanical filters, as was necessary on past radios.
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 ...
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.
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.