Communications receiver
From Wikipedia, the free encyclopedia
A communications receiver is a type of radio receiver used as a component of radio communication link. Commercial communications receivers are characterised by high stability and reliability of performance, and are generally adapted for remote control and monitoring.
For marketing purposes, almost any hobby-type receiver is advertised as a "communications receiver" although none are suited for heavy-duty, reliable 24-hour use as the primary form of communication for an isolated station.
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 detector 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. Communication receivers are suited for operation near powerful transmitting facilities and so must have good internal shielding, filtering, and other design features to provide high selectivity and stability. Rejection of interfering signals will typically be much greater than a consumer-type general coverage or broadcast receiver.
The front panel controls are typically more comprehensive than those on a broadcasting receiver. 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.
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Osterman, Fred (1998). Shortwave Receivers Past & Present: Communications Receivers 1942-1997. Universal Radio Research, Reynoldsburg (USA).
