Propagation Effects Handbook for Satellite Systems - DESCANSO ...

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70 60 60 40 ELEVATION ANGLE = 4S 0 ~ DATA OF NOWLAND, et 81 HORIZONTAL POLARIZATION x----x USING La= 12082R+”3 CANTING ANGLE = 10° D . . . ..~ CCIR (PROPOSED, r = 10°) CANTING ANGLE DISTRIBUTION, .m.o~ . 0 VERT, VA 1977 O“”x RHCP, 0 VA, , 0770 VERT, VA 1978 O EXPERIMENTAL DATA Tx = AUSTIN, TX 0 RHCP, TX, 1977 . () VERT, VA, 1977 0 RHCP, VA, 1978 () HORIZ, VA, 1977 () VERT, VA, 1978 30 0 10 20 30 40 26 24 RHCP, VA, 1077 FREQUENCY (tiHz) ,x@ ox@#~ O VERT, VA, 1977 ~ e - - - - - 22 so RHCP, TX, 197~~ HORIZ, VA, 1977 ● ******** 0 , ● **.***,********* ● ****** O VERT, VA, 1978 1=’ 16 0 RHCP, VA, 1978 0 VERT, VA, 1077 (SAME AS ABOVE) 14 t ? ~ = 7, VERT, VA, 1078 ,s~ o 10 20 30 40 FREOUENCY (GHz) Figure 6.6-3. Frequency Dependence of the Coefficients in the Cross-Polarization Discrimination Relation 6-112 -
● these do not correlate well with the theory (possibly because of the polarization dependence of ~). The important results of these figures are that & increases with increasing frequency, while ~ appears to be relatively constant. In the relation XPD = s - ~ loglO(A) this would imply that the XPD increases with increasing frequency, but because of the rapid increase in A with frequency, XPD will actually decrease for increasing frequency and moderate rain rates. Chu (1980) has found linear relations between the XPD and frequency throughout the 10 to 30 GHz frequency range. Specifically, XPD (expressed as a numerical ratio) is directly proportional to frequency for a fixed rain rate, and is inversely proportional to frequency for a fixed value of rain attenuation. Bostian (1979b) confirms this linear relation between the XPD (fl) and XPD(fz) from his monthly COMSTAR data for 1978, but~ the value XPD(fz)/XPD(fl) varies from month to month. 6.6.2.3 Elevation Anqle Dependence of Depolarization. In the U.S. and Canada depolarization measurements have been obtained at elevation angles from 10.7° in Blacksburg, VA (Bostian, et al-1986) to 49° at Austin, Texas (Vogel-1978). The general dependence of XPD versus A on elevation angle 6 can be obtained from the theoretical results of Nowland, et al (1977a). Note that both the coefficient a and the total attenuation A depend on elevation angle. The elevation angle dependent results of Nowland, et al (1977b) 11.7 GHz (experimental data) are shown in Figure 6.6-4. Clearly the a coefficient is elevation angle dependent, however the experimental data does not confirm this fact. The b coefficient appears to be nearly independent of elevation angle and does appear to agree with the limited data base. Chu (1980) has observed that the differential propagation constant for depolarization is governed by a COSZ8 relation. 6-113
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1 6.1 INTRODUCTION 6.1.1 purpose CH
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,s Table 6.1-1. Guide to Sample Cal
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I . . 6.1.4 Other Propagation Effec
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. . collisions at normal atmospheri
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D 1000 100 10 1 U.S. Standard Atmos
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Frequency (GHz) 10 15 20 30 40 80 1
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If PW is not available from local w
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. . The equivalent heights for oxyg
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m t TEMPERATURE rC) o 5 10 15 20 25
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6.3 PREDICTION OF CUMULATIVE STATIS
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LSTATION LOCATION AND ELEVATION STE
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The models require the following in
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I z za E 100 g w ~ z z K 50 a) ALL
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B . . . t- I I I I I 1 11/1 - . . .
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.- . 9 s@EQ - If Z S D, compute the
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1 0.02 0.05 0.2 0.5 4. Compute D: U
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I . ,. . ~ q 8 H v ~ 1.0 0.8 0.6 0.
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Step 6 Calculate the attenuation ex
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m I : STEP 1 SELECT CLIMATE ZONE FR
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9 10.OOOO 1.0000 0,1ooo 0.0100 0.00
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1 6.3.3 Estimates of Attenuation Gi
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● We now proceed exactly as in th
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STEP 1 GIVEN: STATION PARAMETERS SA
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. B . . . 4. Repeat the process for
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. . ● 100 10 1.0 .1 .01 . . RAIN
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not normally available~ but empiric
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● The intensity-duration-frequenc
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- GIVEN: STATION PARAMETERS OPERATI
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m I s 70 2(J I 10 0 a) BY SEASONS
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.“ ● change in rain rater the r
Page 61 and 62: m To x o 6 x(n wux!- (5 zawwvxw x 1
Page 63 and 64: ● ✎ ✎ ✎ 10 1 0.1 0.01 0 . -
Page 65 and 66: ● ✎ ✎ ✎ appears to be gener
Page 67 and 68: 6.4.2.3 Statistics of Microwave Eff
Page 69 and 70: ● For each hour’s observations,
Page 71 and 72: Plots of noise temperature and atte
Page 73 and 74: .- I where Lf is the fog extent~ in
Page 75 and 76: than a minute and on spatial scales
Page 77 and 78: . . . 022 = angle-of-arrival varian
Page 79 and 80: B . . Figure 6.5-2 represents the a
Page 81 and 82: - . . , 1 I t , 3 , I 1 # 1 1 aJ 0a
Page 83 and 84: I . . -. % i ! ~ * 76.00 I h 60.00
Page 85 and 86: I where the constants are the same
Page 87 and 88: .U . . \ Table 6.5-1. Fading Data P
Page 89 and 90: o -5C \ A — . \ \ \ \ N- ● ●
Page 91 and 92: I 1 \ 0,, FADE DEPTHS I 1 l.d 0.1 1
Page 93 and 94: 9 m ELEVATION ANGLE [DEGREESI ELEVA
Page 95 and 96: Figure 6.5-12 is an example for thi
Page 97 and 98: equal. The fade distributions resul
Page 99 and 100: m . ANTENNA BEAMVVID~ (DEG) d o 0 w
Page 101 and 102: . . 6.5.5.2.2 Spatial Diversity. Pa
Page 103 and 104: fluctuation power at 1 Hz is on the
Page 105 and 106: develops (Pruppacher and Pitter-197
Page 107 and 108: .8 where: f = frequency, in GHz r =
Page 109 and 110: B . k 11.7 26 \ QHz DATA, CTS A VPl
Page 111: \ for the 11.7 GHz CTS beacon at 50
Page 115 and 116: . However the XPD dependence on ele
Page 117 and 118: -. 50 40 30 20 10 0 . T(XPD < ABCIS
Page 119 and 120: 9 electrostatic fields discharge ra
Page 121 and 122: , f w m I
Page 123 and 124: . XPD 2 = XPD1 - 20 lo91~ f ~ 1 0.4
Page 125 and 126: ● 3.0 14 0.6 0.3 0,1 0.0s 0.03 0.
Page 127 and 128: where, for example, for the frequen
Page 129 and 130: L .- . ., not appear to be sufficie
Page 131 and 132: D ‘1 may be considered to be rece
Page 133 and 134: D - 0 m a 80 60 40 20 0 -20 \ — i
Page 135 and 136: m I s 1 \\ I , t Frequency (GHz) Fi
Page 137 and 138: -. Table 6.8-1. Cumulative Statisti
Page 139 and 140: D - The propagation margin is then
Page 141 and 142: 1- * w -180 -190 -m -21 / ---+---4~
Page 143 and 144: - . . 6.9 UPLINK NOISE IN SATELLITE
Page 145 and 146: 280 260 240 220 200 180 160 140 120
Page 147 and 148: 6.10 REFERENCES Ahmed, I.Y. and L.J
Page 149 and 150: ● International Telecommunication
Page 151 and 152: Atmospheric Emission observations,
Page 153 and 154: 8.6 and 3.2 mm Radio Waves by Cloud
Page 155 and 156: I Strickland, J.I. (1974), “Radar
Page 157: D Wulfsberg, K.N. (1964), “Appare
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