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Procedure
1. Start with the transmit power and the number of the channel to be used in dBm. Subtract the total loss of all transmission
elements between the antenna and the radio on one side of the link (dB).
2. Add the gain of the antenna you will be using. The total is the EIRP (Equivalent Isotropically Radiated Power).
3. Determine the path loss of the microwave link by using the mathematical formula of L
Budget.
4. Add the gain of the antenna on the second side of the link.
5. Subtract the total loss of all transmission elements between the antenna and the radio on the second side of the link. The
result is the Received Signal Level (RSL).
6. For details on the receive sensitivity and data rate values used for the wireless link, for details refer to ORiNOCO
AP-9200R Hardware Installation Guide.
7. Subtract this value from the Received Signal Level; this is the Fade Margin.
:
• The RSL must be higher than the Receiver Sensitivity plus the Fade Margin for a good link. The amount of Fade
Margin indicates the reliability of the link. The more the Fade Margin, the more reliable is the link.
The results of this link budget calculation are very important for determining any potential problems during installation. If you
have calculated the expected RSL, you can verify that it has been achieved during installation and troubleshooting.
Tabulated below is the relation between the Distance and Link Budget, for a selected frequency:
Link Budget
Distance
(dB)
(m)
61
4.8
62
5.4
63
6.0
64
6.8
65
7.6
66
8.5
67
9.5
68
11
69
12
Link Budget
Distance
(dB)
(m)
70
13
71
15
72
17
73
19
74
21
75
24
76
27
77
30
78
34
79
38
80
43
81
48
®
ORiNOCO
AP-9200R - Hardware Installation Guide
Reference Frequency: 5600 MHz Center Frequency for Europe
Fresnel
Link Budget
Zone (m)
(dB)
0.3
91
0.3
92
0.3
93
0.3
94
0.3
95
0.3
96
0.4
97
0.4
98
0.4
99
Fresnel
Link Budget
Zone (m)
(dB)
0.4
100
0.5
101
0.5
102
0.5
103
0.5
104
0.6
105
0.6
106
0.6
107
0.7
108
0.7
109
0.8
110
0.8
111
Distance
Fresnel
(m)
Zone (m)
151
1.4
170
1.5
190
1.6
214
1.7
240
1.8
269
1.9
302
2.0
339
2.1
380
2.3
Distance
Fresnel
(m)
Zone (m)
426
2.4
478
2.5
537
2.7
602
2.8
676
3.0
758
3.2
850
3.4
954
3.6
1071
3.8
1201
4.0
1348
4.2
1512
4.5
Measuring Signal Performance
Calculating Link
illustrated in
p,
Link Budget
Distance
(dB)
(m)
121
4.8
122
5.4
123
6.0
124
6.8
125
7.6
126
8.5
127
9.5
128
10.7
129
12.0
Link Budget
Distance
(dB)
(m)
130
13.5
131
15.1
132
17.0
133
19.0
134
21.4
135
24.0
136
26.9
137
30.2
138
33.9
139
38.0
140
42.6
141
47.8
®
Fresnel
Zone (m)
8.0
8.5
9.0
9.5
10.1
10.7
11.3
12.0
12.7
Fresnel
Zone (m)
13.4
14.2
15.1
16.0
16.9
17.9
19.0
20.1
21.3
22.6
23.9
25.3
58
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