REFLEX OSCILLATORS 



591 



room temperature and r,„ shall not exceed the initial gap spacing. From 

 our previous analysis we know that to provide maximum tuning speed we 

 desire to make the temperature intervals Tc — To and T,,, — Tk as large as 

 possible. For any given tuning characteristic these intervals may be ad- 

 justed by a variation of the initial gap spacing subject to the limitation just 



10 



6 ■ - 



420 440 



DEGREES CENTIGRADE 



Fig. 85. — The cycling time of the W.E. 2K45 as a function of the temperature of the 

 channel at the band frequency limit requiring the smaller tuner power. The solid lines 

 are the experimental curves, the dashed lines are theoretical results. One point on the 

 heating time is fitted in order to determine the heat capacity of the tuner. 



imposed. Since Tc and Th are interrelated for a given bow characteristic 

 by the fact that they correspond to a specific increment of motion 8 deter- 

 mined by the cavity design, we may study the effect of shifting the interval 

 8 along the tuner characteristic by varying the initial gap offset. We may 

 specify this in terms of value of Tc . The result of such a study is shown in 

 Fig. 85. The optimum offset corresponds to the temperature at which the 



