TRANSATLANTIC RADIO TELEPHONY 



363 



The ground constants may be determined from measurement of 

 the "quasi-tilt angle" as the following development shows: 

 Equation (302) may be written as two equations 



tan T 





fkp 



18 X W 



1 + 



8 = ^tan" 



fkp 



18 X IQii 



18 X 10^ 

 fkp 



(303) 



(304) 



0.8 



Tr/4 



ZlU 



§o 



Z^ 



UJl) 



ujuj 0.5 

 5,-1 



I" 



^O 



<o 

 Q--J 



Q002 .004 001 002 O04 0.1 02 

 QUASl-TlLT ANGLE — RADIANS 



0.002 004 0.01 002 0.04 01 0,2 

 OLJASl-TILT ANGLE —RADIANS 



Fig. 20 — Relation between quasi-tilt angle, ground resistivity, and phase angle 

 between horizontal and vertical components of an electric wave. (By Zenneck's 

 formula.) 



Solving equations (303) and (304) as simultaneous equations for b 

 in terms of k and T and for p in terms of/, k, and 2^ yields 



5 = ^cos~^ {k tan^ T), 



(305) 



P = 



18 X 10" 



tan2 T 



f -yll - k' tan^ T 



(306) 



