Propagation Effects Handbook for Satellite Systems - DESCANSO ...

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6.5.5.2 Gain Degradation Desiqn Information. 6.5.5.2.1 Estimation of Domains. The effects of amplitude and angle-of-arrival fluctuations are? of course~ most prominent for very long path lengths and/or very narrow beamwidths. One may estimate whether or not gain degradation need be considered in a path design if elevation angle (or equivalent path length) and antenna beamwidth are known. Figure 6.5-14 presents regimes of average gain degradation between 0.5 and 3 dB and where they must be considered as a function of elevation angle and antenna beamwidth. Realized gain, or expected gain less gain degradation, is plotted as a function of antenna beamwidth (for any frequency) or equivalent aperture diameter at 30 GHz in Figure 6.5-15. All equivalent aperture diameters are presented for an antenna aperture efficiency of 0.6. The curve representing zero path length Lt is simply the common gain approximation G = 41253/Bz where B is the half power beamwidth in &~rees. Realized gain curves for path lengths of 50 to 300 km are plotted using the model. Equivalent” earth-space path elevation angles assuming a 6 km high homogeneous atmosphere are presented in parentheses. Notice that gain degradation due to turbulence-induced fluctuation is negligible for beamwidths wider than about 0.7° for all path lengths. Degradation effects then gradually increase as beamwidth narrows from 0.7° to 0.05° and at any particular beamwidth are approximately directly proportional, in dBr to path length. As beamwidth narrows beyond 0.05°, a saturation effect occurs and the degradation becomes constant for any one path length. All design figures of Section 6.5.5 represent estimates for clear air effects in a temperate climate during daytime and in the warmer months of the year. If a local value of Czn is known, more accurate values of R and Sz may be obtained. If local statistics of C2n are known, statistics of R and Sz may be obtained. 6-98
m . ANTENNA BEAMVVID~ (DEG) d o 0 w “o w “d L) “o “o I I I I . -?J > z-1m w A0Cn z > m w \ \ \ \ \ \ \ \ m l-w < > ~ o ZN imo C3 > zorm \ \ I m v w0 0 m
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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
Page 47 and 48: . B . . . 4. Repeat the process for
Page 49 and 50: . . ● 100 10 1.0 .1 .01 . . RAIN
Page 51 and 52: not normally available~ but empiric
Page 53 and 54: ● The intensity-duration-frequenc
Page 55 and 56: - GIVEN: STATION PARAMETERS OPERATI
Page 57 and 58: m I s 70 2(J I 10 0 a) BY SEASONS
Page 59 and 60: .“ ● 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: equal. The fade distributions resul
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 and 112: \ for the 11.7 GHz CTS beacon at 50
Page 113 and 114: ● these do not correlate well wit
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
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● International Telecommunication
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Atmospheric Emission observations,
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8.6 and 3.2 mm Radio Waves by Cloud
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I Strickland, J.I. (1974), “Radar
Page 157:
D Wulfsberg, K.N. (1964), “Appare
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