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BELL SYSTEM TECHNICAL JOURNAL 



These data are for two tubes operated in the push-pull circuit shown 

 in Fig. 9. The output shown represents only useful power, since it is 

 the photometrically measured power consumed in a lamp load. It will 

 be noted that, whereas the maximum output at 100 megacycles is 55 



tig. 9 — A lypiial push-pull circuit lor use at ultra-high frequencies. .\ circuit of 

 this type was used to obtain the data shown in Figs. 8 and 11. 



watts per tube and the efficiency 50 per cent, corresponding roughly 

 to the 86 watts output at 47 per cent efficiency for the tube of Fig. 5, 

 the output at 200 megacycles is 34 watts at 2>2) per cent efficiency as 

 compared to less than 10 watts at an efficiency of only a few per cent 



