GAS-DISCHARGE TRANSMIT-RECEIVE SWITCH 



79 



appendix C the loss chargeable to the ATR and the associated transmitting 

 arm can be expressed as a factor F given by 



F = - m 



(2 + Cy + B' 



where G and B are respectively the conductance and susceptance of this 

 branch in units of the surge admittance of the transmission line. Since 



Fig. 31— Curves for constant ATR loss in db as a function of the impedance of the trans- 

 mitting branch 



curves for constant values of F appear on the reflection coefficient plane 

 (Smith transmission line chart) as circles this presentation is very con- 

 venient. Fig. 31 is such a plot (impedance circles rather than admittance 

 circles are shown). 



If now an ATR is introduced having a resistive component of impedance 

 the range of values of G and B is restricted so that a minimum value of F 

 exists for any random value of the magnetron impedance. With variations 

 in the magnetron cold impedance or in the effective length of line between 

 the magnetron and the ATR junction the value of F will vary between this 



