This Receiver is of the superheterodyne type, specially designed for consistent and reliable reception of telegraphy and telephony signals even under bad conditions. It has a tuning range of 31 Mc/s. to 40 Kc/s by the use of interchangeable plug-in coil units and the output is arranged for either high or low resistance telephones or loud speaker. The Receiver operates from an input of 6 volts at I-4 amps, and 175/180 volts 65 milliamperes high tension, which is supplied by a special power unit when operating from A.C. Mains. For operation from a six volt accumulator a special Rotary Transformer Unit can be supplied to provide the necessary H.T. Voltage. This unit is free from interference and allows the same degree of performance to be obtained as when the Receiver is operated from the standard A.C. mains driven supply unit. Controls have been kept to a minimum consistent with full operational manual adjustment, and have their function marked for ease of identification. The tuning dial is illuminated and has four ranges directly calibrated, other ranges being referred by graph to an outer scale. A spring loaded Tufnol geared condenser drive mechanism, having a ratio of 70-1 and fitted with a flywheel, permits smooth and rapid operation of the tuning control, free from backlash and noiseless mechanically and electrically. The Receiver is now normally supplied with a band-pass crystal filter unit and known as type 358X. Triode output is available if desired, giving a reduced audio output .which, however, is more than adequate for all reception purposes.