The TMC Model MSR, Single Sideband Converter will, in a number of ways, improve operation of certain radio receivers for various modes of operation. The overall skirt selectivity of most receiving systems is greatly sharpened, rejecting unwanted adjacent signals or interference with no detrimental effect to the desired signal. The tuning of single sideband signals is greatly simplified since the final tuning is done at the MSR, not the receiver. A mechanical and electrical bandspread tunes over the I. F. bandpass. This effective vernier easily tunes SSB or exalted carrier AM signals within cycles of correct tone. Either sideband is selectable, either with the bandpass tuning feature or by inverting the osc. separation. CW, MCW and FS signals are easily tunable with the bandspread feature. For extreme stability, the first oscillator is switched to crystal control for both upper and lower sideband positions. The local or remote tuned VFO feature of the MSR permits operation with any receiver having an I. F. nominally centered at 455 kc. > However, when the oscillator is switched to crystal control and the proper crystals inserted, most any receiver I. F. may be accommodated. The required I. F. connection between the receiver and MSR through a low loss coaxial cable is as follows: AN/FRR-49(v) to MSR, BNC connector to BNC. R-840/URR to MSR, Phono connector to BNC. R-390/URR to MSR, BNC connector to BNC. R-274B/URR to MSR, UHF connector to BNC. The audio output is available in three levels: 1. 2 watts for 600 ohm line or 8 ohm loudspeaker. 2. 150 milliwatts for 600 ohm line or 8 ohm loudspeaker. 3. 0 dbm/1 milliwatt for 600 ohm telephone line. 'Terminals at the rear panel provide the simple connections fbr remote control of the main features of the MSR without modifications or the use of additional lines or tones when used in the TMC RCR system. By this means it is possible to remotely or locally tune the MSR across the receiver I. F. passband, select sidebands with a remote indication of which sideband is in use, and still retain all of the remote control features of the RCR system.