MOBILE RADIO TRANSMISSION 



107' 



tea miles the data are the result of tests in Manhattan and the Bronx. 

 For each distance a test course was laid out approxiniatoly following a 

 circle with that distance as a radius. The data for ten miles atid greater 

 distances were obtained on two series of tests along ladials from the 

 land transmitter, one of which followed Route 1 through New Rochelle, 

 N. Y., and the other followed Route 10 toward Dover, N. J. For refer- 

 ence, a cur\'e has been gi\'en on each of these figures which shows the 

 computed loss based upon the assumption of smooth earth. 



A curve labeled "1 per cent" means that in one per cent of the sample 

 measurements the loss was less than that indicated on the ordinate. 

 The meaning of the labels on the other curves is similar. The curve 

 labeled "50 per cent" is, of course, the median. 



It will be apparent that the assumption of smooth earth is not applica- 

 ble to the area tested. The data for median losses are in the order of 30 db 

 greater than the ^'alue computed over smooth earth. This additional loss 

 may be thought of as a "shadow" loss arising from the presence of manj^ 

 buildings and structures. 



The disti-ibution of losses given in these three curves is wider than 

 the Ravleigh distribution of Fig. 5. This is because the data for each 



0.3 0.4 0.6 0.8 1.0 2 3 4 5 6 



DISTANCE FROM TRANSMITTER IN MILES 



Fig. 6 — Measured path loss at 150 mc in Manhattan and the Bronx and suburbs. 

 (Note: Data for 10 miles and greater were taken on Route 1 toward New Rochelle 

 and on Route 10 toward Dover.) 



