REFLEX OSCILLATORS 



535 



positive value tending to increase characteristic admittance and hence 

 decrease electronic tuning. Over a very restricted range in the high admit- 

 tance region Mm has large negative values and over a restricted range 

 outside of this region Mm has large positive values. 



Fig. 49. — Lines of constant value of a parameter. Mm shown on a chart giving the con- 

 ductance and susceptance of the terminating admittance of a short line. The parameter 

 plotted multiplied by the number of wave lengths in the line gives the additional charac- 

 teristic admittance due to the resonant effects of the line. The parameter Mm is of course 

 for terminated lines (center of chart). 



This is an appropriate point at which to settle the issue: what do we mean 

 by a "short line" as opposed to a "long line." For our present purposes, 

 a short line is one short enough so that Mm does not change substantially 

 over the frequency range involved. Thus whether a line is short or not 

 depends on the phase of the standing wave at the resonator (the position 



