RADIO RECEIVING SET AN/FRR-12X
Year 1952

Radio Receiving Set AN/FRR-12X consists of two Radio Receivers R-274/FRR and Terminal Box J-346/FRR-12X which are mounted in Rack MT-693/FRR-12X.
The two receivers are used to provide dual diversity reception for the purpose of minimizing the effects of fading r-f (radio-frequency) input signals.
Such a system is required to assure stable and consistent operation of radioteletype equipment with which the set maybe used
The receivers provide both r-f (audio-frequency) output, making the receiving set suitable for use with all models of Dual Diversity Converter CV-31(*)/TRA-7 or Radioteletype Terminal Equipment AN/FGC-1or AN/FGC-1X.
The receivers are capable of reception of carrier-shift, c-w (continuos-wave), icw (interupted continuos wave), mcw (modulated continuos wave), and a-m (amplitude-modulation) type of signals.
The receivers operate in the range of .54 mc (megacycle) to 54 mc, using six bands and manual tuning.
There are, in addiction,six crystal channels that may be chosen at any frequency in the range of 1.5 mc to 29.7 mc.
The receivers may be used independentlyof Radio Radio Receiving Set AN/FRR-12X
Terminal Box J-346/FRR-12X provides facilities for connecting balanced or unbalanced antennas to the radio receivers.
Either balanced or unbalanced doublets, rhombic, or a long-wire antenna and ground can be matched to the receiver imput circuit.

DEPARTMENT OF THE ARMY TECHNICAL MANUAL TM 11-896A

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