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BELL SYSTEM TECHNICAL JOURNAL 



wave-antenna, and a measured directional diagram, yields information 

 on the direction of arrival of static. 



Data on wave-antenna characteristics have been taken at several 

 widely separated locations. Two antenna systems have been con- 

 structed by the British General Post Office — one at Wroughton, Wilt- 

 shire, in southern England, and one at Cupar, Fifeshire, in southeastern 

 Scotland. We likewise have data on our antenna system at Houlton, 

 Maine. The character of the earth under each of these antenna 

 systems is different, resulting in widely different quasi-tilt angles and 

 antenna directional characteristics. 



The probable geological formations under individual antennas at 

 each of the three antenna sites mentioned in the preceding paragraph 

 are shown in Fig. 7. The data for the British locations were compiled 

 from the published reports of geological surveys conducted by the 

 British Government, and the data for the Houlton location were 

 taken from the "Soil Survey of the Aroostook Area, Maine," published 

 by the U. S. Department of Agriculture. In Table I, the ground con- 

 stants are given for these three locations, determined by the method 

 given in Section 4, "Quasi-tilt Angle and Ground Resistivity": 



TABLE I 



Fig. 8 shows the directional characteristics, calculated by the method 

 given in Appendix 1, of wave-antennas erected over the geological 

 formations shown in Fig. 7. In these directional characteristics, it 

 is important to notice that a decrease in quasi-tilt angle increases the 

 relative importance of the component of the received current due to 

 the vertical component of the impressed field (abbreviated to the 

 "vertical effect"). It is evident from Fig. 8 that the relative direc- 

 tional receptivity for the arc between 9 = 90 degrees and 6 = 270 

 degrees is smaller and that the effective height is much greater for the 

 antenna at Houlton, for which the ground resistivity is higher than for 

 the other two antennas. 



Measured relative directional receptivities are also shown in Fig. 8. 

 The values for the Cupar antenna were determined by using trans- 



