A communications receiver is a type of radio receiver

Receiver (radio)

A radio receiver converts signals from a radio antenna to a usable form. It uses electronic filters to separate a wanted radio frequency signal from all other signals, the electronic amplifier increases the level suitable for further processing, and finally recovers the desired information through...

 used as a component of a radio communication link.

Features

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 is of the superheterodyne type in double, triple or, more rarely, quad conversion. It features multiple RF

Radio frequency

Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...

 and IF

Intermediate frequency

In communications and electronic engineering, an intermediate frequency is a frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception. The intermediate frequency is created by mixing the carrier signal with a local oscillator signal in a process called...

 amplification stages and may have at least one IF stage that is crystal controlled. It usually has a BFO and a product detector

Product detector

A product detector is a type of demodulator used for AM and SSB signals. Rather than converting the envelope of the signal into the decoded waveform like an envelope detector, the product detector takes the product of the modulated signal and a local oscillator, hence the name...

 for SSB

Single-sideband modulation

Single-sideband modulation or Single-sideband suppressed-carrier is a refinement of amplitude modulation that more efficiently uses electrical power and bandwidth....

 and CW

Morse code

Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...

 reception. 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

S meter

An S meter is an indicator often provided on communications receivers, such as amateur radio receivers or shortwave broadcast receivers. The scale markings are derived from a subjective system of reporting signal strength from S1 to S9 as part of the RST code...

; RF gain control; AVC/AGC

Automatic gain control

Automatic gain control is an adaptive system found in many electronic devices. The average output signal level is fed back to adjust the gain to an appropriate level for a range of input signal levels...

 adjustments; antenna tuner

Antenna tuner

An antenna tuner, transmatch or antenna tuning unit is a device connected between a radio transmitter or receiver and its antenna to improve the efficiency of the power transfer between them by matching the impedance of the equipment to the antenna...

; 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

Boat anchor

In amateur radio and computing, boat anchor is a slang term used to describe something obsolete, useless, and cumbersome - so-called because metaphorically its only productive use is to be thrown into the water as a boat mooring.-Hardware:...

 for their large size and weight. Such receivers include the Collins R-390 and R-390A

R-390A

The R-390A /URR is a general coverage HF radio communications receiver designed by Collins Radio Company for the US military.-History:The R-390A military shortwave radio receiver was the result of a project undertaken by the U. S. Army Signal Corps in 1954 to replace the existing R-390 receiver...

, the RCA

RCA

RCA Corporation, founded as the Radio Corporation of America, was an American electronics company in existence from 1919 to 1986. The RCA trademark is currently owned by the French conglomerate Technicolor SA through RCA Trademark Management S.A., a company owned by Technicolor...

 AR-88, the Racal

Racal

Racal Electronics plc was once the third-largest British electronics firm. Listed on the London Stock Exchange and once a constituent of the FTSE 100 Index, Racal was a diversified company, offering products including: as voice and data recorders; point of sale terminals; laboratory instruments;...

 RA-17L and the Marconi

Marconi Company

The Marconi Company Ltd. was founded by Guglielmo Marconi in 1897 as The Wireless Telegraph & Signal Company...

 Electra. However, even modern solid-state receivers can be very large and heavy, such as the Plessey

Plessey

The Plessey Company plc was a British-based international electronics, defence and telecommunications company. It originated in 1917, growing and diversifying into electronics. It expanded after the second world war by acquisition of companies and formed overseas companies...

 PR2250, the Redifon R551 or the Rohde & Schwarz

Rohde & Schwarz

Rohde & Schwarz is an independent group of companies specializing in electronics. Well known as a manufacturer of electronic test equipment, they also manufacture equipment used for broadcasting, radiolocation, and radio communications...

 EK070/D2-80.

See also

• Amateur radio
  Amateur radio
  Amateur radio is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication...
  
  
• Scanner
  Scanner (radio)
  A scanner is a radio receiver that can automatically tune, or scan, two or more discrete frequencies, stopping when it finds a signal on one of them and then continuing to scan other frequencies when the initial transmission ceases....
  
  
• Shortwave listening
  Shortwave listening
  Shortwave listening is the hobby of listening to shortwave radio broadcasts located on frequencies between 1700 kHz and 30 MHz. Listeners range from casual users seeking international news and entertainment programming to hobbyists immersed in the technical aspects of radio reception and DXing...
  
  
• Shortwave radio
• Traffic analysis
  Traffic analysis
  Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in communication. It can be performed even when the messages are encrypted and cannot be decrypted. In general, the greater the number of messages observed, or even intercepted and...
  
  
• Wadley Loop
  Wadley Loop
  The Wadley Loop circuit was designed by Dr. Trevor Wadley in the 1940s and was first used for a stable Wavemeter.- Overview :In a traditional superheterodyne radio receiver, most oscillator drift and instability occurs in the first frequency converter stage, because it is tunable and operating at a...
  
  

Further reading