ih:h:iu:ri..ii<iiifis in loadi-.d ir.i.r.riioxii circi'its 57.? 



ill which iMch irrin ilcpriids upon only oiii' iiKh'pcnilrnl \.iri.il)k- 

 .mil in whicli I hi' syinliols \\ii\v llu- following mt-anings: 



^u = Irregularit\- fiinriion =20 logio^^ (4'S) 



7/ 

 51,. = Frequcn( > limrti(>n=2() logio^ 



(44) 



5f = Distribution funrtion = 10 logio, 1 (45) 



log.^ 



Sa = Attenuation function = 10 logui, t^ (46) 



Meaning ok EguATioN (42) 



To inulerstand more clearly the meaning of equation (42) imagint- 

 that a large number of circuits of the same type and gauge are to be 

 built in accordance with the same specifications so that the repre- 

 sentative (r.m.s.) deviation including all causes has the same value 

 // for each circuit. Further, imagine that the value of S has been 

 calculated by formula (42) using a particular frequency / and a con- 

 venient fraction F. It is to be e.\pected that when the circuits have 

 been built and their return losses measured at the given frequency / 

 the fraction F of the whole group will have return losses lower than 

 5 and the rest will have higher return losses. 



In discussing expected results it is sometimes preferable to state 

 the fraction 1 — F of the circuits whose return losses will be greater 

 than the assigned value rather than the fraction F whose return 

 losses will be lower. This is done in Figs. 9 to 14 described below. 



Location of rnii First Ikkkgli-akitv 



In equations (14), (15) and (16) and all the equations which depend 

 upon them it was assumed that the first irregularity occurs at the 

 sending end of the line. Two other assumptions are equally plausi- 

 ble and might under some circumstances be preferable. These are 

 that the first irregularity occurs (a) at one-half section from the 

 end or (b) at a full section. In the first case (a) the current returned 

 to the sending end from each irregularity will be reduced by the 

 factor A and in the second (b) by the factor A-, that is the return 

 loss given by equation (42) should be increased by (a) the amount 

 of the transmission loss in one loading section or (b) twice the amount 

 of the transmission loss in one loading section respectively. 



