Radio Receiver R392/URR is capable of very high performance. It is mechanically very complex as is usual for many post war Collins military designs. The set uses many locally unobtainable tubes and has the potential to be a difficult piece of equipment to maintain. There are several removable modules including a precision PTO (Permeable Tuned Oscillator) as the main frequency tuning component. All other coils are tuned by ferrite slugs connected to a bar (slug rack) which simultaneously tunes all coils. The slugs are used to tune the inductors (instead of a tuning capacitor) to give a linear frequency response. The two main frequency tuning knobs are connected to mechanical digital counters to indicate megacycles and kilocycles, each separately controllable.
The R392 to the best of my knowledge has never been used by our armed services. The display set was brought into the country by a visiting American. The set does not have provision for SSB, although riding the RF/AF controls enable SSB to be decoded on CW. The set would be suitable for short wave listeners equipped with heavy duty tables! Audio output is at 600 ohms and quite adequately drives a speaker. There is also headphone output available. Power input is 28 vdc at 4 amps.
© Ian O'Toole, 2009. Page created: 28/04/03 Last updated: 4/12/2009