Adtran TRC3202 用户手册
Section 2, Microwave Path Engineering Basics
TRACER 2210/3202 System Manual
18
© 2002 ADTRAN, Inc.
61280012L1-1A
4.
PATH LOSS
The expression
where
f
carrier frequency (Hz)
λ
carrier wavelength ( c / f ) (meters)
d
path distance (meters)
c
speed of light, free-space (meters)
is called the path loss, and increases rapidly as either path length increases or carrier wavelength decreases
(which happens as the carrier frequency increases). So, longer microwave paths will naturally experience
more path loss than shorter paths. Likewise, higher frequency microwave communication will experience
more path loss than lower frequency microwave communication.
(which happens as the carrier frequency increases). So, longer microwave paths will naturally experience
more path loss than shorter paths. Likewise, higher frequency microwave communication will experience
more path loss than lower frequency microwave communication.
Table 1 tabulates path loss values for various path lengths for the TRACER 2210/3202 system. Values not
listed in the table can be interpolated from those listed.
listed in the table can be interpolated from those listed.
Table 1. Path Loss for Given Path Lengths
Path Length
(miles)
Path Loss
(dB)
1
112
2
118
3
121
4
124
5
126
10
132
15
135
20
138
25
140
30
141
35
143
L
P
4
π
d
λ
----------
2
4
π
df
c
------------
2
=
=
(watts, W)