Tubes for High-Power Short-Wave Broadcast Stations-Their Characteristics and Use

This paper outlines the vacuum-tube requirements necessary because of the increasing power of short-wave broadcast transmitters. Different ways of meeting the requirements are discussed: use of a large number of tubes in parallel; of demountable structures; or of sealed tubes. The development of a sealed tube capable of 200 kilowatts carrier output for two tubes in parallel is described. The main features of the different parts of the tube are indicated together with its characteristics. A description is also given of some of the tools and machines specially developed for the manufacture of these tubes. A broadcast center in which the tubes are used is briefly described. The salient points of the transmitting circuit and equipment are shown. A short description of high-power grid-controlled rectifiers is also given.