k
h,v
, α
h,v
constants for horizontal and vertical polarization. Constants are slightly different for each
polarization, see next table according to ITU-R P.838
Tab. 2.2: Constants k, α for horizontal and vertical polarization at 10, 11, 17 and 24 GHz
α
v
k
v
α
h
k
h
1.22
0.01
1.26
0.01
10 GHz
1.16
0.02
1.21
0.02
11 GHz
1.01
0.07
1.09
0.06
17 GHz
0.96
0.14
1.01
0.14
24 GHz
Fig. 2.2: Attenuation for 10 GHz,
polarization H, V
Fig. 2.3: Attenuation for 11 GHz,
polarization H, V
Fig. 2.4: Attenuation for 17 GHz,
polarization H, V
Fig. 2.5: Attenuation for 24 GHz,
polarization H, V
Fig. 2.2 shows that rain attenuation is greater for horizontal polarization. In regions with higher precip-
itation the difference in attenuation is more marked. The microwave links RAy17 and RAy24 uses both
polarizations, hence the need to consider worse of the two, i.e. horizontal polarization. When ACM is
13
© RACOM s.r.o. – RAy Microwave Link
Implementation Notes
