STEP 1
Determine the conditions for putting up a microwave link. Establish the
purpose of a microwave link and what kind of information should be transmitted at the
general transmission path.
Path Length
Reliability Requirement
Configuration
Traffic Capacity
STEP 3
32.50 kilometers
99.999%
Non-protected
8xE1 (4xE1 main plus, 4xE1 spare)
Obtain a topographical map in which both sites are contained.
Topographic image of Site A to Site B
Site A
Clark
Latitude: 1511'17.61"N
Longitude: 12032'58.81"E
Tarlac
Site B
Latitude: 15 28'33.20"N
Longitude: 120 35'47.01"E
STEP 4
Determine the frequency band required. Once the path length has been
identified, select a preliminary band which to select a specific microwave frequency
form.
2Ghz
5Ghz
8Ghz
85Km 75Km 60Km
10Ghz
13Gh
15GHz 18Ghz 23Ghz 26Ghz
45Km
z
35Km
15Km
10Km
5Km
3Km
STEP 5
Determine the channel plans available. The channel plans are based on
the frequency band and the bandwidth (multiplexed digital rate) of the traffic being
carried. These can be taken from the technical specifications set by CCIR or
sometimes, the equipment specifications themselves.
Band
Frequency Plan
13 GHz
Frequency Band
Low band range: 12.751-12.98 GHz
12.751 G
Hz- 13.248 GHz
High band range: 13.01 13.248 GHz
Duplex Spacing
266 MHz
Channel Spacing
14 MHz
STEP 6
From the channel plans or specifications available, select a frequency pair
which would be used for the actual computation of the hop.
FH FL
No. of Duplex Channels = C h annel Spacing
13.248 GHz12.751 GHz
=35.5 c h annels
No. of Duplex Channels =
14 MHz
Arbitrary Channels = 5
Bandwidth = Channel Spacing multiplied by the chosen Arbitrary Channel
Bandwidth =
Computation for the low band and high band frequencies:
Low Band Frequency (
FLB)
High Band Frequency (
FHB)
12.821 GHz
13.080 GHz
STEP 7
Using the formula below, compute for the minimum elevation at site A and
site B that would clear earth curvature
h=
16.252
=132.03125 m
4
1.5( )
3
STEP 8
Create a table plotting points along the path and identifying the possible
sources of reflections and obstruction.
Distance A
Distance B
Path
Elevation
Terrain
Earth
Curvature
Ground
Elevation
32.50
50
Urban
0.00
50.0000
0.50
32.00
51
Urban
1.25
52.2549
1.00
31.50
51
Urban
2.47
53.4706
1.50
31.00
52
Urban
3.65
55.6471
2.00
30.50
52
Rice field
4.78
56.7843
2.50
30.00
53
Urban
5.88
58.8824
3.00
29.50
54
Woods
6.94
60.9412
3.50
29.00
55
Woods
7.96
62.9608
4.00
28.50
56
Woods
8.94
64.9412
4.50
28.00
57
Rice field
9.88
66.8824
5.00
27.50
58
Rice field
10.78
68.7843
5.50
27.00
59
Rice field
11.65
70.6471
6.00
26.50
60
Rice field
12.47
72.4706
6.50
26.00
61
Rice field
13.25
74.2549
7.00
25.50
61
Rice field
14.00
75.0000
7.50
25.00
62
Rice field
14.71
76.7059
8.00
24.50
62
Rice field
15.37
77.3725
8.50
24.00
63
Rice field
16.00
79.0000
9.00
23.50
63
Rice field
16.59
79.5882
9.50
23.00
64
Rice field
17.14
81.1373
10.00
22.50
64
Rice field
17.65
81.6471
10.50
22.00
65
Rice field
18.12
83.1176
11.00
21.50
65
Woods
18.55
83.5490
11.50
21.00
63
Urban
18.94
81.9412
12.00
20.50
63
Rice field
19.29
82.2941
12.50
20.00
62
Rice field
19.61
81.6078
13.00
19.50
61
Rice field
19.88
80.8824
13.50
19.00
60
Rice field
20.12
80.1176
14.00
18.50
60
Rice field
20.31
80.3137
14.50
18.00
59
Urban
20.47
79.4706
15.00
17.50
58
Rice field
20.59
78.5882
15.50
17.00
57
Woods
20.67
77.6667
16.00
16.50
58
Woods
20.71
78.7059
16.50
16.00
62
Woods
20.71
82.7059
17.00
15.50
66
Rice field
20.67
86.6667
17.50
15.00
69
Woods
20.59
89.5882
18.00
14.50
71
Rice field
20.47
91.4706
18.50
14.00
72
Rice field
20.31
92.3137
19.00
13.50
74
Rice field
20.12
94.1176
19.50
13.00
76
Urban
19.88
95.8824
20.00
12.50
78
Woods
19.61
97.6078
20.50
12.00
80
Flat
19.29
99.2941
21.00
11.50
81
Woods
18.94
99.9412
21.50
11.00
81
Urban
18.55
99.5490
22.00
10.50
80
Flat
18.12
98.1176
22.50
10.00
80
Flat
17.65
97.6471
23.00
9.50
80
Urban
17.14
97.1373
23.50
9.00
80
Woods
16.59
96.5882
24.00
8.50
82
Woods
16.00
98.0000
24.50
8.00
85
Flat
15.37
100.3725
25.00
7.50
87
Flat
14.71
101.7059
25.50
7.00
89
Urban
14.00
103.0000
26.00
6.50
91
Urban
13.25
104.2549
26.50
6.00
93
Urban
12.47
105.4706
27.00
5.50
95
Urban
11.65
106.6471
27.50
5.00
97
Urban
10.78
107.7843
28.00
4.50
104
Urban
9.88
113.8824
28.50
4.00
110
Urban
8.94
118.9412
29.00
3.50
118
Rice field
7.96
125.9608
29.50
3.00
123
Rice field
6.94
129.9412
30.00
2.50
129
Rice field
5.88
134.8824
30.50
31.00
31.50
32.00
32.50
2.00
1.50
1.00
0.50
0.00
135
139
141
142
144
Flat
Rice field
Rice field
Urban
Urban
4.78
3.65
2.47
1.25
0.00
139.7843
142.6471
143.4706
143.2549
144.0000
STEP 9
From the table construct the figure which shows the path profile including
the earth curvature and elevation along the path.
160
140
120
100
80
60
40
20
0
0
10
15
20
Path Profile
Ground Elevation ___
Path Elevation ___
25
30
35
Earth Curvature ___
STEP 10
Compute for the minimum tower height
Tower Height @ Point A = LOS Obstruction Height @ distance A
= 184m 144m = 40m
Tower Height @ Point B = LOS Obstruction Height @ distance B
= 90m 50m = 40m
STEP 12
Determine the clearance of line of sight path
200.0000
180.0000
160.0000
140.0000
120.0000
100.0000
80.0000
60.0000
40.0000
20.0000
0.0000
0
10
15
20
Graph of Line of Sight
25
30
35
STEP 13
Using the figure and table as reference, determine the following
1) Point along the path terrain that is closest to the line of sight propagation
2) Possible reflection points
Distance
A
Distance
B
Path
Elevation
Terrain
Earth
Curvature
LOS
Reflections
32.50
50
Urban
0.00
90.0000
0.50
32.00
51
Urban
1.25
91.4462
4480.0000
1.00
31.50
51
Urban
2.47
92.8923
2205.0000
1.50
31.00
52
Urban
3.65
94.3385
1446.6667
2.00
30.50
52
Rice field
4.78
95.7846
1067.5000
2.50
30.00
53
Urban
5.88
97.2308
840.0000
3.00
29.50
54
Woods
6.94
98.6769
0.0000
3.50
29.00
55
Woods
7.96
100.1231
0.0000
4.00
28.50
56
Woods
8.94
101.5692
0.0000
4.50
28.00
57
Rice field
9.88
103.0154
435.5556
5.00
27.50
58
Rice field
10.78
104.4615
385.0000
5.50
27.00
59
Rice field
11.65
105.9077
343.6364
6.00
26.50
60
Rice field
12.47
107.3538
309.1667
6.50
26.00
61
Rice field
13.25
108.8000
280.0000
7.00
25.50
61
Rice field
14.00
110.2462
255.0000
7.50
25.00
62
Rice field
14.71
111.6923
233.3333
8.00
24.50
62
Rice field
15.37
113.1385
214.3750
8.50
24.00
63
Rice field
16.00
114.5846
197.6471
9.00
23.50
63
Rice field
16.59
116.0308
182.7778
9.50
23.00
64
Rice field
17.14
117.4769
169.4737
10.00
22.50
64
Rice field
17.65
118.9231
157.5000
10.50
22.00
65
Rice field
18.12
120.3692
146.6667
11.00
21.50
65
Woods
18.55
121.8154
0.0000
11.50
21.00
63
Urban
18.94
123.2615
127.8261
12.00
20.50
63
Rice field
19.29
124.7077
119.5833
12.50
20.00
62
Rice field
19.61
126.1538
112.0000
13.00
19.50
61
Rice field
19.88
127.6000
105.0000
13.50
19.00
60
Rice field
20.12
129.0462
98.5185
14.00
18.50
60
Rice field
20.31
130.4923
92.5000
14.50
18.00
59
Urban
20.47
131.9385
86.8966
15.00
17.50
58
Rice field
20.59
133.3846
81.6667
15.50
17.00
57
Woods
20.67
134.8308
0.0000
16.00
16.50
58
Woods
20.71
136.2769
0.0000
16.50
16.00
62
Woods
20.71
137.7231
0.0000
17.00
15.50
66
Rice field
20.67
139.1692
63.8235
17.50
15.00
69
Woods
20.59
140.6154
0.0000
18.00
14.50
71
Rice field
20.47
142.0615
56.3889
18.50
14.00
72
Rice field
20.31
143.5077
52.9730
19.00
13.50
74
Rice field
20.12
144.9538
49.7368
19.50
13.00
76
Urban
19.88
146.4000
46.6667
20.00
12.50
78
Woods
19.61
147.8462
0.0000
20.50
12.00
80
Flat
19.29
149.2923
40.9756
21.00
11.50
81
Woods
18.94
150.7385
0.0000
21.50
11.00
81
Urban
18.55
152.1846
35.8140
22.00
10.50
80
Flat
18.12
153.6308
33.4091
22.50
10.00
80
Flat
17.65
155.0769
31.1111
23.00
9.50
80
Urban
17.14
156.5231
28.9130
23.50
9.00
80
Woods
16.59
157.9692
0.0000
24.00
8.50
82
Woods
16.00
159.4154
0.0000
24.50
8.00
85
Flat
15.37
160.8615
22.8571
25.00
7.50
87
Flat
14.71
162.3077
21.0000
25.50
7.00
89
Urban
14.00
163.7538
19.2157
26.00
6.50
91
Urban
13.25
165.2000
17.5000
26.50
6.00
93
Urban
12.47
166.6462
15.8491
27.00
5.50
95
Urban
11.65
168.0923
14.2593
27.50
5.00
97
Urban
10.78
169.5385
12.7273
28.00
4.50
104
Urban
9.88
170.9846
11.2500
28.50
4.00
110
Urban
8.94
172.4308
9.8246
29.00
3.50
118
Rice field
7.96
173.8769
8.4483
29.50
3.00
123
Rice field
6.94
175.3231
7.1186
30.00
2.50
129
Rice field
5.88
176.7692
5.8333
30.50
31.00
31.50
32.00
2.00
1.50
1.00
0.50
135
139
141
142
Flat
Rice field
Rice field
Urban
4.78
3.65
2.47
1.25
178.2154
179.6615
181.1077
182.5538
4.5902
3.3871
2.2222
1.0938
32.50
STEP 14
0.00
144
Urban
0.00
184.0000
0.0000
Compute for the Thermal Fade Margin
In general, if the path is line-of-sight with adequate clearance, the loss in RF
signal between one end's transmitter and the other end's receiver will merely be that of
free space, as described by the equation:
Together with other losses and some gains, the Free Space Path Loss is classified as
follows:
Classification of Losses and Gains
Parameter
Microwave Radio Output
Power
Function
Value
Given
Unit
Type
dB
Variable
Connector Loss
Subtracte
d
dB
Variable
Waveguide Loss
Subtracte
d
dB
Variable
Connector Loss
Subtracte
d
dB
Variable
Antenna Gain
Added
dB
Variable
Free Space Path Loss
Subtracte
d
dB
Variable
Description
Taken from
Radio
Specification
s
Taken from
Waveguide
Specification
s
Taken from
Waveguide
Specification
s
Taken from
Waveguide
Specification
s
Taken from
Antenna
Specification
s
Computed
from formula
Antenna Gain
Added
dB
Variable
Connector Loss
Subtracte
d
dB
Variable
Waveguide Loss
Subtracte
d
dB
Variable
Connector Loss
Subtracte
d
dB
Variable
Microwave Radio Output
Power
Given
dB
Variable
Power Input to Receiver
(RSL)
Minimum Receiver
Threshold
Computed
dB
Variable
Given
dB
Variable
THERMAL FADE MARGIN
Computed
dB
Variable
Taken from
Antenna
Specification
s
Taken from
Waveguide
Specification
s
Taken from
Waveguide
Specification
s
Taken from
Waveguide
Specification
s
Taken from
Radio
Specification
s
Computed
from Formula
Taken from
Radio
Specification
s
Computed
from Formula
Note: Most computations assume a connector loss value set to 0.5 dB, in our design however we opted
to use connector losses that are much lower. This is taken from the connectors and adapters specification
sheet.
For Low Band Frequency
FLB = 12.821 GHz
FREE SPACE LOSS (FSL) = 92.4 + 20 log fGHz + 20 log Dkm
FSL = 92.4 + 20 log (12.821) + 20 log (32.5)
FSL = 144.7961052 dB
Waveguide loss = waveguide unit loss x waveguide length at Tower A
0.12
dB
x 40 m
m
= 4.8dB
Waveguide loss = waveguide unit loss x waveguide length at Tower B
0.12
dB
x 40 m
m
= 4.8dB
Received Signal Level (RSL)
RSL = Tx Output Waveguide loss Tx + Antenna Gain Tx FSL + Antenna Gain Rx
Waveguide loss Rx
First Link Budget Calculation for Low Band Frequency
LINK BUDGET FOR LOW BAND FREQUENCY
Microwave Radio Output Power
24 dB
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
0.20 dB
Antenna Gain
Free Space Path Loss
144.7961052 dB
Antenna Gain
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
0.20 dB
Received Signal Level
Minimum Receiver Threshold
-116 dB
Thermal Fade Margin
For High Band Frequency
FHB = 13.080 GHz
FREE SPACE LOSS (FSL) = 92.4 + 20 log fGHz + 20 log Dkm
FSL = 92.4 + 20 log (13.080) + 20 log (32.5)
FSL = 144.9698221 dB
First Link Budget Calculation for High Band Frequency
LINK BUDGET FOR HIGH BAND FREQUENCY
Microwave Radio Output Power
24 dB
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
0.20 dB
Antenna Gain
Free Space Path Loss
144.9698221 dB
Antenna Gain
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
0.20 dB
Received Signal Level
Minimum Receiver Threshold
-116 dB
Thermal Fade Margin
STEP 15
Determine Dispersive Fade Margin
Dispersive Fade Margin = 70 dB
DFM is acquired from the specification of the TRuepoint 4400 microwave radio.
STEP 17
Compute for Rain Attenuation
Coefficients for the Interpolation Method
Frequency
kh
kv
GHz
1
2
4
6
7
0.0000387
0.0001540
0.0006300
0.0017500
0.0030100
0.000352
0.0001380
0.0005910
0.0015500
0.0026500
0.912
0.963
1.121
1.308
1.332
0.880
0.923
1.075
1.265
1.312
8
10
12
15
20
25
30
35
40
0.0045400
0.0101000
0.0188000
0.0367000
0.0751
0.124
0.187
0.263
0.350
0.0039500
0.0088700
0.016800
0.0335000
0.0691
0.113
0.167
0.233
0.310
For Low Band Frequency
FLB = 12.821 GHz
M=
log 12log 12.821
log 12log 15
M =0.2965705323
1.327
1.276
1.217
1.154
1.099
1.061
1.021
0.979
0.939
1.310
1.264
1.200
1.128
1.065
1.030
1.000
0.963
0.929
x 1.217[0.2965705323 x ( 1.2171.154 ) ]
x 1.198316056
CCIR Rainfall attenuation can be computed by determining the rainfall
rate based on the location and design availability requirement. This
rainfall rate can be obtained from the climatic zone table. The rainfall
rate for Luzon Island, Philippines falls under Area N or 180 mm/h with
an unavailability of 0.001%
DE
32.5
32.5
1+
2.352192946
DE = 2.193442199
Since the industry minimum standard is 99.99%, we will use
from the CCIR Climatic Zones Table (see appendix E) that
is equal to 180 mm/h.
ARAIN = 2.193442199 x 10.21416212
ARAIN = 22.40417422 dB
Link Budget Calculation for
with Rain Attenuation
LINK BUDGET FOR LOW BAND FREQUENCY
Microwave Radio Output Power
24 dB
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
0.20 dB
Antenna Gain
Free Space Path Loss
144.7961052 dB
Attenuation due to rain
22.40417422 dB
Antenna Gain
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
0.20 dB
Received Signal Level
Minimum Receiver Threshold
-116 dB
Rain Fade Margin
For High Band Frequency
FHB = 13.080 GHz
M=
log 12log 13.080
log 12log 15
M =0.3861984616
x 1.217[0.3861984616 x ( 1.2171.154 ) ]
x 1.192669497
DE
32.5
32.5
1+
2.352192946
DE = 2.193442199
ARAIN
2.193442199 x 11.05594664
ARAIN
24.25057991 dB
Link Budget Calculation for
LINK BUDGET FOR HIGH
with Rain Attenuation
BAND FREQUENCY
Microwave Radio Output Power
Connector Loss
Waveguide Loss
Connector Loss
Antenna Gain
Free Space Path Loss
Attenuation due to Rain
Antenna Gain
Connector Loss
Waveguide Loss
Connector Loss
Received Signal Level
Minimum Receiver Threshold
Rain Fade Margin
STEP 18
24 dB
0.20 dB
0.20 dB
144.9698221 dB
24.11495234 dB
0.20 dB
0.20 dB
-116 dB
Include Antenna Misalignment to Fade Margin
Second Link Budget Calculation for Low Band Frequency
LINK BUDGET FOR LOW BAND FREQUENCY
Microwave Radio Output Power
24 dB
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
0.20 dB
Antenna Gain
Free Space Path Loss
144.7961052 dB
Antenna Misalignment loss
0.5 dB
Antenna Gain
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
0.20 dB
Received Signal Level
Minimum Receiver Threshold
-116 dB
Thermal Fade Margin
Second Link Budget Calculation for High Band Frequency
LINK BUDGET FOR HIGH BAND FREQUENCY
Microwave Radio Output Power
24 dB
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
0.20 dB
Antenna Gain
Free Space Path Loss
144.9698221 dB
Antenna Misalignment Loss
0.5 dB
Antenna Gain
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
0.20 dB
Received Signal Level
Minimum Receiver Threshold
-116 dB
Rain Fade Margin
STEP 19
Determine the possibility of Diffraction Loss
Diffraction Loss is also referred to as Obstacle Loss or Diffraction Attenuation. One
method of calculation is based on knife edge approximation. Having an obstacle free
60% of the Fresnel zone gives 0 dB loss.
STEP 21
Compute for Atmospheric Losses
21.1 Oxygen Absorption Loss
For Low Band Frequency
FLB = 12.821 GHz
A0 =
7.19 x 103+
6.09
4.81
dB
+
x 12.8212 x 103
2
2
km
12.821 +0.227 ( 12.82157 ) + 1.5
A0 = 7.668263776 x 10-3
dB
km
A0 per unit = 7.668263776 x 10-3
dB
km x 32.5 km
A0 = 0.2492185727 dB
For High Band Frequency
FHB = 13.080 GHz
A0 =
7.19 x 103+
6.09
4.81
dB
+
x 13.0102 x 103
2
2
km
13.010 +0.227 ( 13.01057 ) +1.5
A0 = 7.738324918 x 10
-3
dB
km
A0 per unit = 7.738324918 x 10-3
A0 = 0.2514955598 dB
21.2
Water Vapor Loss
For Low Band Frequency
FLB = 12.821 GHz
dB
km x 32.5 km
AH20 =
[
3
9
4.3
dB
+
+
] x 12.8212 x 12 x 104
2
2
2
km
( 12.82122.3 ) +7.3 (12.821183.3 ) + 6 ( 12.821323.8 ) +10
AH20 = 6.160959472 x 10
dB
km
-3
AH20 per unit = 6.160959472 x 10-3
dB
km x 32.5 km
AH20 = 0.2002311828 dB
For High Band Frequency
FHB = 13.080 GHz
AH20 =
[
3
9
4.3
dB
+
+
]x 13.0802 x 12 x 104
2
2
2
km
( 13.08022.3 ) +7.3 ( 13.080183.3 ) +6 (13.080323.8 ) +10
AH20 = 6.74521834 x 10
-3
dB
km
AH20 per unit = 6.74521834 x 10-3
dB
km x 32.5 km
AH20 = 0.2192195961 dB
STEP 22
Determine detailed Thermal Fade Margin
Detailed Thermal Fade Margin Calculation for Low Band Frequency
LINK BUDGET FOR LOW BAND FREQUENCY
Microwave Radio Output Power
24 dB
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
Antenna Gain
Free Space Path Loss
Oxygen Absorption Loss
Water Vapor Loss
Antenna Gain
Antenna Misalignment loss
Connector Loss
Waveguide Loss
Connector Loss
Received Signal Level
Minimum Receiver Threshold
Thermal Fade Margin
0.20 dB
144.7961052 dB
0.2492185727 dB
0.2002311828 dB
0.5 dB
0.20 dB
0.20 dB
-116 dB
Detailed Thermal Fade Margin Calculation for High Band Frequency
LINK BUDGET FOR HIGH BAND FREQUENCY
Microwave Radio Output Power
24 dB
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
0.20 dB
Antenna Gain
Antenna Misalignment loss
0.5 dB
Free Space Path Loss
144.9698221 dB
Oxygen Absorption Loss
0.2514955598 dB
Water Vapor Loss
0.2192195961 dB
Antenna Gain
Connector Loss
0.20 dB
Waveguide Loss
Connector Loss
0.20 dB
Received Signal Level
Minimum Receiver Threshold
-116 dB
Thermal Fade Margin
STEP 23
Compute for Flat Fade Margin
For Low Band Frequency
FLB = 12.821 GHz
10
87.75444504
(
)
87.75444504
10
FM FLAT =10 log[ (
]
)+10
10
FM FLAT =84.74414508 dB
FM FLAT =93.89714513 dB
For High Band Frequency
FHB = 13.080 GHz
10
87.55946384
(
)
87.55946384
10
FM FLAT =10 log[ (
]
)+10
10
FM FLAT =84.54916388 dB
FM FLAT =93.74234844 dB
STEP 24
Compute for the Composite Fade Margin
Composite Fade Margin is the fade margin applied to multipath
fade outage equations for a digital microwave radio.
For Low Band Frequency
FLB = 12.851 GHz
10
70
(
)
84.74414508
FM EFF=10 log[ (
)+( 3) 10 10 ]
10
FM EFF= 65.18050026 dB
65.22289015
For High Band Frequency
FHB = 13.080 GHz
10
70
(
)
84.54916388
FM EFF=10 log[ (
)+( 3) 10 10 ]
10
FM EFF= 65.17829579 dB
65.22267631
STEP 25
Compute for Path Reliability
NOTE: Calculations are done in radians
Using CCIR Recommendation 530
A. Pat
h Inclination
1000 x 32.5
90184
= 1000 x tan-1
= 2.892299627 milliRadians
B. Average Grazing Angle
m=
32.5
[3400 x ( 0.090+0.184 ) ]
m=1.133802061
0.090+0.184
c=
0.0900.184
c=0.3430656934
b 2
3 ( 0.3430656934 ) 3 ( 1.133802061 )
1.133802061+1
1
x cos
+ x cos1
3
1.133802061 x 3
3 3
2
( 1.1338 02061+ 1 )
))]
b 1.434048272
90+184
2
x (11.133802061)(1+1.434048272 )
32.5
=3.448917 milliRaidians
C. Geoclimatic Factor
This is the percent of time when the refractivity gradient of a specific place goes below
100 N units per kilometer. This value changes from month to month. In path
calculations, the worst fading month is taken from refractivity map while K is computed
as follows
(used for calculations over land paths)
5.4
1.5
K 10 x 32.5
K 7.376070202 x 10
Reliability for Low band frequency
1.1
ULB 7.376070202 x 10 (1+2.892299627 )
( 3.448917 )
8
ULB 1.287137627 x 10
Path Reliability:
Reliability for High Band frequency
1.2
( 12.821 )
0.93
( 32.5 )
3.3
(10
65.16663669
10
Path Reliability:
Using K-Q Reliability Calculation
For temperate climate, coastal regions with fairly flat region:
b = 1.2 (Asia)
c = 3.5
K Q value = 1 x 10-9
For Low band frequency
Path Reliability
For High Band frequency
Path Reliability
