Superheterodyne receiver
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The superheterodyne receiver, commonly called the superhet, is a radio receiver that uses heterodyning to convert incoming radio-frequency signals to a fixed intermediate frequency. The signal is then
A five-tube superheterodyne receiver manufactured by Toshiba circa 1955
Superheterodyne transistor radio circuit circa 1975
The first commercial superheterodyne receiver was the RCA Radiola AR-812. It was released on 4 March 1924 priced at $286 (equivalent to $5,370 in 2025). It used six triodes: a mixer, a local oscillator, two IF and two audio amplifier stages, with an IF of 45 kHz. It was a commercial success, offering better performance than competing receivers.
Philco radio model PT44 front
Edwin Howard Armstrong
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Edwin Howard Armstrong was an American radio-frequency engineer and inventor who developed FM radio and the superheterodyne receiver system.
Superheterodyne receiver
…amplifiers by canceling unwanted feedback, allowing more gain per tube. Superregenerative receivers, which achieve very high gain, were developed by Edwin H. Armstrong in 1922 while studying the regenerative receiver. The circuit did not become widely used in broadcast or television reception. Broadcasting expanded…
Sketch of Armstrong, c. 1954
Armstrong's boyhood home, overlooking the Hudson River in Yonkers, New York, c. 1975
Armstrong explaining the superregenerative circuit, New York, 1922
Armstrong arranged for the construction of a transmission tower in Alpine, New Jersey, near New York City, and financed demonstration operation of W2XMN, the first FM radio station. W2XMN's antenna is mounted between the top two tiers, visible as a vertical line at the far upper right.