As the majority of the vintage radio enthusiasts are city-based, many have not had the opportunity of seeing and being involved with sets specifically designed to operate in remote rural locations. They are quite different, as can be appreciated when all of the conditions that these sets had to work under are taken into consideration.

In the 1950s, commercial AM broadcast stations had an aerial power of 2kW in country areas and 5kW in the city. Nation-al stations were up to 10kW and many are now 50kW. In most country areas, there were usually only two or three stations within a radius of perhaps 160km. If you wanted to hear more, it was necessary to have a large outside aerial and an earth – and a set that was quite sensitive.

I lived near Bordertown in South Australia and the only stations of good strength were 3WV with 10kW 110km away at Dooen, 3LK (3WM) with 2kW 130km away at Lubeck, and 3SH with 2kW 250km away at Swan Hill.

The typical mains-operated 4-valve set was totally inade-quate and the average 5-valve (including rectifier) mains receiv-er was still struggling to do a satisfactory job. To get the necessary sensitivity, 5-valve sets were used in

The 32V Operatic Mignon, made in South Australia, was really equivalent to a 6-valve mains receiver since it did not use a rectifier. Its RF stage was highly desirable since it was often used in remote rural areas.

Typically, these sets had an RF stage, converter, an IF stage, detector and first audio amplifier, and an audio output stage.

In normal sets, AC mains operation was quite easily achieved using a trans-former with windings to supply the various voltages required for the valves and a vacuum tube rectifier to convert the AC to DC.

On 32V DC sets, things were nowhere this easy. Nominally, the receiv-er could be like its AC mains brother but to supply the high voltage (HT) for the valves, it was necessary to use a vibrator power supply.