CALCULATION OF RADIO GAIN 407 
DIELECTRIC EARTH 
AS |, SEA=WATER, V P 
\< 10, OVER-LAND, V P 
LAND anp SEA,H P 
FOR SE A-WATER, V P USE 
CURVE WITH APPROPRIATE 
\ VENTER 
aN 
-100 
rH RNMAELEEEE 
EEE eee 
UE PERSE GRU ROREER 
a Bi Ie [| 
eae 
=110 
-120) 
ala 
ie ea es at i Ut} 
Figure 32. Shadow factor Fz, 20 log F, (evaluating all modes), or 20 log F,/(sd)? versus sd. Curve for dielectric earth, 
20 log F, , is the same as curve O in Figure 58. 
For the case of sea water, vertical polarization and FORMULA FOR THE DIELECTRIC MARTH. 
wavelength in the VHF (1 to 10 meters) range, 6>>1. 
g requires a correction factor g’ which depends on X. 
p A table of g’ is given with the graph of g in Figure 36. The first mode has the form #(d) - f(hi) - f(ha). 
The change of f with height h is represented If the value of the gain is given substantially by the 
schematically in Figure 29 (also Figures 7, 25,47). first mode, and substitution from equation (148) is 
