RADIO DEVELOPMENT

New Zealand Herald, Volume LXX, Issue 21469, 18 April 1933, Page 9

RADIO DEVELOPMENT

ASTONISHING DISCOVERIES IMPROVED BATTERY SETS LONDON, Ar>ril 10 So many astonishing wireless developments have occurred in the last fewmonths that the technical journals complain of the difficulty of keeping abreast of them. The discovery of a quiescent pushpull which gives an output from battery sets equal to that obtained from electric sets, recently bailed as revolutionary, is already superseded by the invention of a "Class B" valve that costs 14s. This, with a 120-volt battery current, gives fully two watts of undistorted output, sufficient to fill a concert hall, whereas even the largest sets operated from electric mains are capable of only 11 watts. The new valve, in spite of its power, uses less current than ordinary valves. New ferrocart coils, with a coil of finely-divided iron, give astonishing selectivity equal to the superheterodyne. . Another important development is the Westector rectifier, composed of discs treated with copper. This gives fine selectivity, combined with considerable distortionless amplification. Experts consider that the combination of these three developments will make existing sets obsolete.