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BELL SYSTEM TECHNICAL JOURNAL 



height available (12 m.). This effect of the ground was therefore more 

 detrimental when the longer waves were used, since the antenna could 

 not then be raised to corresponding heights. Even taking this into 

 account, the over-land transmission paths of these tests favor the 

 shorter wave-lengths. A theoretical reason for this will be given 

 later. 



In one direction from Deal, S. 50° 46' W., measurements were made 

 on 69 mc. at numerous places along the beam of a directive antenna, 

 up to a distance of about 95 km. The profile of this path along the 

 straight line to the most distant point, Chesilhurst, is shown in Fig. 6-B. 

 Displacements of intermediate points from this line are negligible 



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10 20 



DISTANCE- KILOMETERS 



100 



Fig. 8 — Field strength as a function of distance for transmission over level country, 

 along the profile of Fig. 6-5. 



except in the case of New Egypt. Here a slight displacement was 

 made in order to use a favorable receiving site for more extensive 

 measurements. The profile in this neighborhood is superposed on the 

 main profile. The various receiving points are shown by small 

 arrows. 



The received field is plotted as a function of distance in Fig. 8. 

 For comparison purposes a straight line representing the inverse square 

 law is drawn. This represents the general trend very well. 



Transmission along this path is of particular interest since it repre- 

 sents conditions to be expected over flat land. The profile in Fig. 6-B 

 shows that if the immediate neighborhood of terminal points be left 

 out of consideration, the maximum difference in elevation along the 

 path is only 45 meters. This path probably represents a spherical 



