a. The receiver (fig. 1) is a high-performance, exceptionally stable, general-purpose receiver for use in both fixed and mobile service. The receiver provides reception of continuous wave (cw),modulated-continuous-wave (mew), amplitude-modulated (am), frequency-shift keyed (fsk) and single-sideband (ssb) signals within a frequency range of .5 to 32 megacycles (me). In this receiver, the radio-frequency (rf), intermediate-frequency (if), audio-frequency (af), oscillator and power-supply circuits are situated on individual removable sub chassis (fig. 56 through 72) mounted on a front panel and main frame assembly (fig. 74). These sub chassis can be removed readily for trouble shooting and repair in a minimum of time, by the use of ordinary hand tools. All the sub chassis can be interchanged between any receivers bearing the same model number. b. The receiver furnishes an output of 500 milliwatts (mw) of af power to a local 600-ohm load (loudspeaker and headset), and 10 mw of af power for application to a 600-ohm balanced line, Operation is possible from an alternating current (ac) input of either 115 or 230 volts ±10 per cent, 48 to 62 cycles per second (cps). c. Connectors and terminals are provided for use of the receiver with auxiliary equipment. A 50-ohm, if output connection is provided for carrier-shift teletypewriter, single-sideband, or other auxiliary equipment. Automatic gain control (age) and diode-detector load connections are available for use in diversity combining systems. When the receiver is used in a single sideband reception system, an external age circuit may be substituted for the internal control circuit. Connections are also provided for external manual rf gain control; however, when using only the receiver for single-sideband reception, manual gain control of the receiver should be used rather than automatic gain control. A break-in relay for disabling the receiver circuits is operated by grounding a terminal provided at the rear of the receiver. d. The calibration of the receiver is accurate to within 300 cycles per second, an accuracy that permits use of the receiver as an accurate frequency meter.