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
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
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.