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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.
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 reflex receiver should not be confused with a regenerative receiver, in which the same signal is fed back from the output of the amplifier to its input. In the reflex circuit it is only the audio extracted by the demodulator which is added to the amplifier input, so there are two separate signals at different frequencies passing through the ...
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.
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.
English: Block diagram of a tuned radio frequency (TRF) receiver, the simplest type of amplifying radio receiver circuit. It consists of one or more tuned RF amplifiers, each consisting of a tuned circuit which functioned as a bandpass filter followed by a radio frequency (RF) amplifier; a detector (demodulator) to extract the audio waveform from the radio carrier wave; followed by an audio ...
Hallicrafters founder William J. Halligan depicted in a 1944 magazine ad. William J. Halligan (1898–1992), founded Hallicrafters Company in Chicago in late 1932. Prior to this, he had been involved in radio parts sales for some years but decided the time was right for a handcrafted amateur radio receiver - the company name being a combination of Halli(gan) and (hand)crafters.
A receiver circuit that used larger amounts of regeneration in a more complicated way to achieve even higher amplification, the superregenerative receiver, was also invented by Armstrong in 1922. [ 11 ] [ 5 ] : p.190 It was never widely used in general commercial receivers, but due to its small parts count it was used in specialized applications.