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Repair and restoration of vintage amateur radio equipment may involve replacing vacuum tubes, reforming electrolytic capacitors if needed, replacing any faulty resistors, replacing two-wire power cords with three-wire cords except on transformerless AC/DC radios, and receiver alignment as necessary. [37]
The company was founded in 1943 by radio design engineer Robert L. Drake. The company began as a manufacturer of low pass and high pass filters for the government and amateur radio market, and after World War II, produced amateur radio transmitters and receivers and communications receivers for maritime mobile service.
A radio-frequency power amplifier (RF power amplifier) is a type of electronic amplifier that converts a low-power radio-frequency (RF) signal into a higher-power signal. [1] Typically, RF power amplifiers are used in the final stage of a radio transmitter , their output driving the antenna .
A valve RF amplifier (UK and Aus.) or tube amplifier is a device for electrically amplifying the power of an electrical radio frequency signal. Low to medium power valve amplifiers for frequencies below the microwaves were largely replaced by solid state amplifiers during the 1960s and 1970s, initially for receivers and low power stages of ...
Swan merged with Cubic Corporation in 1967, and Johnson managed Swan as its subsidiary until 1973. Johnson founded Atlas Radio in 1974. Atlas produced smaller solid state radios for mobile communications from vehicles of all types. [3] Many Swan radios remain in service today, restored and operated by vintage amateur radio enthusiasts. [2]
Some commercially manufactured one to two kilowatt linear amplifiers used in amateur radio still use vacuum tubes (valves) and can provide 10 to 20 times RF power amplification (10 to 13 dB). For example, a transmitter driving the input with 100 watts will be amplified to 2,000 watts (2 kW) output to the antenna.
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VOACAP simulation of propagation against distance, comparing effective radiations of 1 watt (top) and 99 Watts (bottom).. The practice of operating with low power was popularized as early as 1924, with a variety of reports, editorials and articles published in U.S. amateur radio magazines and journals that encouraged amateurs to lower power output, both for purposes of experimentation, and for ...