ULTRA-SHORT WAVE PROPAGATION 



141 



ANGLE OF ELEVATION — DEGREES 



Fig. U-yl— Field strength as a function of the angle of elevation of the receiver, 

 for transmission over salt water at 80 mc. The two experimental curves are from 

 data taken with the receiver in an airplane flying at two constant altitudes. The 

 smooth curve is theoretical. 



ANGLE OF ELEVATION— DEGREES 



Fig. 11-5 — Theoretical angles of elevation of maximum and minimum, and 

 magnitude of their ratio, as functions of the conductivity of the water for a dielectric 

 constant of 80, and a frequency of 80 mc. The experimental points shown (from 

 Fig. 11-^4) indicate a conductivity of about 17 X 10"^^ e.m.u. 



