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The 807 is fully rated to 60 MHz, derated to 55% at 125 MHz in Class C, Plate-modulated operation, thus they were popular with amateur radio operators (radio hams). In this application a single 807 could be run in class-C as an oscillator or amplifier which could be keyed on and off to transmit Morse Code in CW mode.
The term usually refers to a type of radio-frequency (RF) power amplifier, some of which have output power measured in kilowatts, and are used in amateur radio. Other types of linear amplifier are used in audio and laboratory equipment. Linearity refers to the ability of the amplifier to produce signals that are accurate copies of the input.
Improved models of the two transceivers were periodically introduced well into the 1970s along with accessories, including a remote VFO (for separate control of receiver and transmitter frequency) and the Mark-I and Mark-II linear amplifiers. Magazine ad circa 1970s featuring Swan 600T/600R
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.
The receiver is filtered by a 22 pole crystal filter with switchable extra 8 and 6 pole narrow band CW filters, a 14 pole SSB filter and a separate 14 pole CW filter. The RF circuit is based on a – manually or automatically – microprocessor controlled PIN diode attenuator with 2 bipolar power transistors used as a high level RF amplifier in the receive mode and as a double RF output pre ...
K.W. Electronics was a British manufacturer of amateur radio equipment founded in the mid-1950s by the late Rowley Shears G8KW. It was based in Dartford, Kent, and manufactured a wide range of high frequency band receivers, transmitters and accessory equipment. The company was taken over by DECCA and subsequently ceased production during the 1970s.
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). [28]
Following World War II came the HRO-7 (1947–1949, 12 tubes, including 2 miniature tubes), HRO-50 (1949–1950, built-in tuning dials and power supply, push-pull audio amplifier, improved styling and performance), HRO-50-1 (1951, increased IF selectivity), and HRO-60 (1952–1964, dual conversion for coils B (7–14.4 MHz) and A (14-30 MHz ...