MAGNETRON AS GENERATOR OF CENTIMETER WAVES 



241 



determined as a function of frequency by a measurement of the impedance 

 Zc looking into a non-oscillating magnetron through its output circuit and 

 an independent measurement or calculation of one of the parameters such 

 as C or Foc . The impedance Zc in terms of the equivalent circuit is the 

 impedance across the terminals CD in Fig. 31 (a) looking to the left with 



CONTOURS OF CONSTANT POWER OUTPUT 



-■ CONTOURS OF CONSTANT FREQUENCY 



Fig. 33.— A typical experimental Rieke diagram for magnetrons in the centimeter 

 wavelength range. The p = 0.2 circle indicates a pulling figure of 0.02 /„ mc/s for this 

 example. Present practice is to couple long wavelength magnetrons more tightly to the 

 load and short wavelength magnetrons less tightly to the load than this. The rotation of 

 the diagram from the position of the contours of chart {b) of Fig. 32 is attributable to the 

 transformer action between the terminals of the ideal transformer of the circuit of Fig. 31 

 {b) and the point in the output line to which the exijerimental diagram is referred. 



the termmals AB open circuited. From the circuit of Fig. 31 (b) this is 

 seen to be 



^.--(-£)H0 



1 



Gc+i2Fo 



fa)0 



(39) 



