A Two Valve Battery “Straight” For Local Station Reception

A two valve battery portable intended for local station reception. The circuit was found in 1958 Radio and TV servicing and was known as Every Ready model H. The circuit originally used DK92 and DL92 valves, this version runs satisfactorily with DK96 and DL96 newer generation valves. A simple TRF design with grid leak detector, the reaction coupling capacitor is fixed rather than variable, instead the volume control potentiometer dampens the circuit  as it is connected directly across the tuned aerial circuit. The tuning coil employed was a N.O.S. Repanco DRR type ideally suited to the original design. An audio choke may be formed by using the secondary winding only of a OEP (Oxford Electrical Products) model A262A3E audio impedance matching transformer. The audio output transformer is of type OEP N35A002F 3W valve output transformer.

This set requires an external throw out long-wire aerial, care is needed to ensure the set is not overloaded by strong local stations and so some experimentation may be required. In North Bristol, Radio Bristol from the Mangotsfeild transmitter can be easily heard but also more distant stations such as Radio 5 live may also be heard.

Whilst not as sophisticated as a superhet, this simple design produces remarkable results from just two valves.