REFLECTION COEFFICIENTS 
Tasie 6. Reflection coefficient of rough ground. 
265 
A = 9 cm.1? 
Grazing Vertical polarization 
angle, Level Long Short 
degrees estimated grass grass Bare 
22 0.20 0.08 0.20 0.23 
36.5 0.40 0.06 0.17 0.27 
4605 0.48 0.06 0.16 0.26 
Horizontal polarization 
Level Long Short 
estimated grass grass Bare 
0.82 0.12 0.74 0.81 
0.73 0.12 0.43 0.50 
0.68 0.03 0.36 0.46 
face so prepared was measured again. The results of 
these measurements are to be found in Table 6. The 
estimated reflection coefficient of level ground of the 
same moisture content is also included here. 
Finally, the results on the electrical constants of 
different kinds of grounds for 9-cm waves have been 
collected in Table 7. 
Tas. 7. Electrical constants of the ground. \ = 9 cm.1,2 
Attenuation 
Medium €, omhos/m 4 factor db/m 
Very drysandyloam 2 0.033 0.178 36 
Saturated sandy loam 24 0.666 3.54 220 
Tap water 80 2.22 12.0 380 
4%, solution of coarse 
salt 80 6.11 33.0 1100 
Dry turf 3 0.055 0.30 50 (calc) 
(est) 
Wet turf 6 0.11 0.60 80 (cale) 
(est) 
Tt is seen that in the previous experiments’? no 
attempt was made at finding the phase angle shift at 
Teflection. At 10 cm® such an attempt was made. How- 
GRAZING ANGLE IN DEGREES 
Ficure 16. Sea reflection coefficient p, versus grazing 
angle y at 10 cm. Vertical polarization. 
ever, the distances involved here could not be meas- 
ured more accurately than a small fraction of a half 
wavelength, or 5 cm. Therefore, these experiments 
are not to be considered, as the author himself points 
out, as giving quantitative information on the phase 
angle shift at reflection and they will not be dis-, 
cussed here. 
Summary of Experimental 
Investigations on Reflection 
Here the results of certain additional reports of 
experiments on microwave reflection by either sea or 
land performed under more nearly operational con- 
ditions are summarized.*” 
In one series of experiments* performed by British 
workers, at 9.3 cm, the transmitter was located on the 
shore and could be placed at two heights, 35 and 130 
ft. The receiver was placed on a ship at a constant 
height of about 33 ft. The field strength of the radia- 
0.9 
0.7 
sd 
Ficurs 17. Sea reflection coefficient , versus grazing 
angle y at 10 cm. Horizontal polarization. 
