430 
PROPAGATION THROUGH THE STANDARD ATMOSPHERE 
‘TasBLé 12. Quantities dependent on polarization. 
Earth, Very Dry Soil. 
of 6 
0.916 X 107 
3,000. 1.98 X10° | 
oH 
300. 0.426 X 10° 3 
ay 
30. 0.933 X 105 = 
oO 
ao 
3. 0.444 x 105 A 
0.3 0.854 X 105 
1.835 X 105 
HorizontaL PoLarizaTION 
degrees 
5] = (42)e —1| 
my lecl? Hare S(6) 
ae _ 14.2 xX 104 |e, — 1] degrees a 
Xa Je,|? Fig. 54 Fig. 57 
Fig. 53 
30.000. 0.01] 5.72x10° | 2 | 
3.000. 01 | 1.2 x 105 E | 
300. 18 2.6 X 104 E 
30. 10. 57x10 | 3 | 
3. 100. 850. 
0.3 1,000. 23. 
for the receiver (Figure 60). This process, however, is 
subject to the restriction mentioned in the next 
paragraphs. 
The addition of the factors given in the preceding 
paragraph is valid all the way up to the maximum of 
the first lobe, where the field is given by the sum of the 
direct and reflected rays, provided that the antennas 
have comparable heights. 
The radio gain can therefore never be more than 
6 db greater than the free-space gain with the same 
antennas. 
If, however, one antenna is low, h < h,, and the 
other is very high, h > 40h,, the method discussed 
fails since the height-gain factors are based on the 
first mode only. In this event, either the methods 
outlined on pp- 419-420 must be employed or the 
1 (0) 
1 (0) 
1 (0) 
0.118 0.99 (0) 
0.81 X 10+ } 0.96 (— 1) 
1.044 X 10> | 0.77 (— 5) 
1.047 < 10-8 | 0.55 (+10) 
radio gain at low elevations must be connected 
graphically with the value obtained in the optical 
region for the first maximum. 
As an aid to the computer in checking his results, 
four tables of computations are given. Table 11 
gives the values of certain quantities, for a wide 
range of frequencies and for very dry soil, which are 
independent of polarization. Those quantities which 
are dependent on polarization are given in Table 12. 
Table 13 gives detailed calculations for ground level 
radio gain for doublets for a wavelength of \ = 1.0 
meter, while Table 14 gives the first mode height- 
gain factors for the same wavelength. 
Similar charts and tables may be prepared easily 
for transmission over other types of earth for a 
similar range of frequencies. 
