The HT-37 is the 6th generation of AM, CW and SSB exciter/transmitters produced by Hallicrafters. It is normally pared with the HT-41 linear amp and the SX-111 receiver.
HT 37 FIRST RUN TEST SPECIFICATIONS
HR MAG FEB 1979 “IMPROVING THE HT-37
HR MAG NOV 1969 “IMPROVED SIDEBAND REJECTION”