Adtran TRC6410L2X ユーザーズマニュアル
Section 2 Microwave Path Engineering Basics
TRACER 6000 Series Integrated System Manual
22
Copyright © 2005 ADTRAN, Inc.
612806420L1-1D
Path Loss (L
P
)
Path loss is the estimated attenuation between the transmit and receive antennas caused by signal
separation and scattering. The path loss is considered basic transmission loss over the microwave link. The
following expression calculates path loss:
separation and scattering. The path loss is considered basic transmission loss over the microwave link. The
following expression calculates path loss:
where
f
carrier frequency (Hz)
λ
carrier wavelength (c / f) (meters)
d
path distance (meters)
c
speed of light, free-space (meters)
or
where d is expressed in miles and f in GHz.
Path loss, as shown here, increases rapidly as either the path length increases or the carrier wavelength
decreases (which happens as the carrier frequency increases). Therefore, longer microwave paths naturally
experience more path loss than shorter paths. Likewise, higher frequency microwave communication
experiences more path loss than lower frequency microwave communication.
decreases (which happens as the carrier frequency increases). Therefore, longer microwave paths naturally
experience more path loss than shorter paths. Likewise, higher frequency microwave communication
experiences more path loss than lower frequency microwave communication.
The path loss values for various path lengths for the TRACER 64x0 2.4 and 5.8 GHz systems are listed in
Table 7 (miles) and Table 8 on page 23 (kilometers).Values not listed in the tables can be interpolated from
those listed.
those listed.
Table 7. Path Loss for Given Path Lengths (miles)
Path Length
(miles)
Path Loss (dB)
at 2.4 GHz
Path Loss (dB)
at 5.8 GHz
1
104
112
2
110
118
3
114
121
4
116
124
5
118
126
10
124
132
15
128
135
20
130
138
25
132
140
30
134
141
35
135
143
L
P
20 log
4
πd
λ
----------
⎝
⎠
⎛
⎞
⋅
=
(dB)
L
P
96.6
20 log
10
d
( ) 20·log
+
10
f
( )
⋅
+
=
(dB)