Propagation Effects Handbook for Satellite Systems - DESCANSO ...

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Washington, D.C. should on the average expect one maximum 5-minute fade each year, one maximum 10-minute fade every three years, etc. 6.3.5.2 Annual and Daily Temporal Distribution of Intense Rain Events. The temporal distribution of rain-induced fade events can be important to a designer since loss of a link during low utilization periods may be tolerable. Figure 6.3-16a shows the distribution, by season, of “record” rainfall events at 207 weather stations throughout the U.S. The events are measured in terms of depth-duration, which specifies the total number of inches of rain and the time over which it fell. The durations are shown in the figure, and range from 5 minutes to 24 hours. Figure 6.3-16b shows the distribution of the maximum events by the times when they start. It is clear that the short-duration events, having the most intense rain (and the deepest fades) occur predominantly in the summer months and during the afternoon hours. There are regional variations of course: throughout much of the west coast, summer rains are insignificant. In the xnidwest, nocturnal thunderstorms are common. The figure also shows that more than 40% of the record 24-hour rainfall events happen in the fall, when steady strati<strong>for</strong>m rains are the rule. The regional variations in the time distribution of heavy rains is clearly shown in Figure 6.3-17 (Rasmussen- 1971). It gives the time of day of the maximum thunderstorm frequency, based on 10 years’ observations. A phenomenon not indicated by the map is the existence of secondary peaks in thunderstorm frequency in many regions. 6.3.6 Rate of Change of Attenuation Experimental data related to the rate-of-change of attenuation is relatively sparse. Apparently experimenters have not analyzed their measurements to obtain this in<strong>for</strong>mation except during some extreme attenuation occurrences. Some measurements made at Rosman, NC of the CTS 11.7 GHz beacon showed a maximum rate-of-change of 2 dB/sec on April 24, 19-7 (Ippolito-1979). This translates to change of rain rate from 50 n nr to 57 mm/hr in ne second. Assuming this 6-56 -,
m I s 70 2(J I 10 0 a) BY SEASONS — — — I 1--1 1. SEASONS Dec., Jan., Feb. 2. Mar., Apr., May 3. Jun., Jul., Aug. 4. sep., Oct., Nov. 1234 7234 1234 7234 f234 1234 1234 7234 7234 1234 7234 5 1 0 1 5 3 0 1 2 3 6 1 2 1 8 2 4 MINUTES HOURS Figure 6.3-16. I b) BY pime of Beginning) I QUARTER DAYS 1. Midnight to6 A.M. 2. 6A. M. to Noon 3. Noon to 6 P.M. 4. 6 P.M. to Midnight L 60 I I I 50 ~ 1234 7234 1234 1234 1234 1234 5 1 0 1 5 3 0 1 MINUTES 1234 7234 1234 1234 1234 2 3 6 1 2 1 8 2 4 HOURS Distribution of Maximum Rainfall Occurrences at U.S. First-Order Stations (U.S. Dept. Comm.-l947) 70 ,. w
Page 1 and 2:
1 6.1 INTRODUCTION 6.1.1 purpose CH
Page 3 and 4:
,s Table 6.1-1. Guide to Sample Cal
Page 5 and 6: I . . 6.1.4 Other Propagation Effec
Page 7 and 8: . . collisions at normal atmospheri
Page 9 and 10: D 1000 100 10 1 U.S. Standard Atmos
Page 11 and 12: Frequency (GHz) 10 15 20 30 40 80 1
Page 13 and 14: If PW is not available from local w
Page 15 and 16: . . The equivalent heights for oxyg
Page 17 and 18: m t TEMPERATURE rC) o 5 10 15 20 25
Page 19 and 20: 6.3 PREDICTION OF CUMULATIVE STATIS
Page 21 and 22: LSTATION LOCATION AND ELEVATION STE
Page 23 and 24: The models require the following in
Page 25 and 26: I z za E 100 g w ~ z z K 50 a) ALL
Page 27 and 28: B . . . t- I I I I I 1 11/1 - . . .
Page 29 and 30: .- . 9 s@EQ - If Z S D, compute the
Page 31 and 32: 1 0.02 0.05 0.2 0.5 4. Compute D: U
Page 33 and 34: I . ,. . ~ q 8 H v ~ 1.0 0.8 0.6 0.
Page 35 and 36: Step 6 Calculate the attenuation ex
Page 37 and 38: m I : STEP 1 SELECT CLIMATE ZONE FR
Page 39 and 40: 9 10.OOOO 1.0000 0,1ooo 0.0100 0.00
Page 41 and 42: 1 6.3.3 Estimates of Attenuation Gi
Page 43 and 44: ● We now proceed exactly as in th
Page 45 and 46: 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: - GIVEN: STATION PARAMETERS OPERATI
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 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
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\ 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
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-. 50 40 30 20 10 0 . T(XPD < ABCIS
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9 electrostatic fields discharge ra
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, f w m I
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. XPD 2 = XPD1 - 20 lo91~ f ~ 1 0.4
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● 3.0 14 0.6 0.3 0,1 0.0s 0.03 0.
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where, for example, for the frequen
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L .- . ., not appear to be sufficie
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D ‘1 may be considered to be rece
Page 133 and 134:
D - 0 m a 80 60 40 20 0 -20 \ — i
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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
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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
Page 155 and 156:
I Strickland, J.I. (1974), “Radar
Page 157:
D Wulfsberg, K.N. (1964), “Appare
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