1198 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER, 1953 



4 8 12 16 20 24 28 32 36 40 44 



PATH LOSS IN DECIBELS (RELATIVE TO MIDDAY NORMAL) 



Fig. 7 — statistical distributions of fading measured on Lowden-Princeton, 

 fk^^'^irJ'^ during July and August, 1950. These curves are useful in predicting 

 the efficacy of specific frequency-diversity systems as described in the text. 



siderably more severe than is shown by the curves on Fig. 8. This is 

 because the latter curves include all the time within the months under 

 consideration. Therefore, they include much time when the fading 

 mechanism was not present in the path, and the path loss remained 

 steady near mid-day normal. 



There is evident similarity between the shapes of Curves A through F 

 (on Fig. 7) with the shape of the curve which is based upon the Rayleigh 

 distribution. This is consistent with the theory that deep fading asso- 

 ciated with multipath transmission is caused by random phasing of a 

 large number of vectorial components. 



