Communications receiver
From Wikipedia, the free encyclopedia
A communications receiver is a type of radio receiver characterised by its frequency coverage, frequency selection, and range of adjustments to the radio signal. They are more sensitive and more selective than normal shortwave radios. Although they are available as commercial products for ham use, traditionally, it was government or the military that drove the technological advances in this type of set.
Typically, a communications receiver will be of the superheterodyne type in double, triple or, more rarely, quad conversion. It will feature multiple RF and IF amplification stages and may have at least one IF stage that is crystal controlled. It will usually have an additional BFO product detctor for SSB and CW reception capabilities. The frequency coverage of receivers of this type is typically in the range of 500 kHz to 30 MHz.
The front panel controls are typically more comprehensive than an ordinary shortwave radio. Usual features include: signal strength meter; RF gain control; AVC/AGC adjustments; antenna tuner; bandwidth filters; BFO tuning; audio limiters or attenuators. Frequency display dials may either be analog (typically marked to fine increments for accuracy) or digital.
The older generation of tube-based communications receivers are affectionately known as boatanchors for their large size and weight. Such receivers include the Collins R-390 and R-390A, the RCA AR-88, the Racal RA-17L and the Marconi Electra. However, even modern solid-state receivers can be very large and heavy, such as the Plessey PR2250, the Redifon R551 or the Rohde & Schwarz EK070.
[edit] See also
Osterman, Fred (1998). Shortwave Receivers Past & Present: Communications Receivers 1942-1997. Universal Radio Research, Reynoldsburg (USA).
