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BELL SYSTEM TECHNICAL JOURNAL 



Preliminary experiments with diode no. 24 had shown that when 

 wave power issuing from the tube was allowed to radiate into free 

 space, a space current of 500 milliamperes with anode voltage of about 

 300 volts was required to maintain oscillations. An interesting and 

 instructive experiment is then to determine by how much this current 



^^ZZ^^^^ZZZ 



Fig. 3 — Hollow wave guide mounting for diodes. 



is reduced when radiation is held to as low a value as possible. For 

 this purpose an assemblage as in Fig. 4 was used. Here a wave guide 

 mounting of form comparable to Fig. 3 is clamped into sections of wave 

 guide closed at the two ends by closely fitting but longitudinally ad- 



