Adtran TRC4205 Manual Do Utilizador
Section 2, Microwave Path Engineering Basics
TRACER 4205 System Manual
16
© 2002 ADTRAN, Inc.
612804205L1-1A
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 4205 system. Values not listed
in the table can be interpolated from those 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
6
127
7
129
8
130
9
131
10
132
11
133
12
133
13
134
14
135
15
135
16
136
17
136
18
137
19
137
L
P
4
πd
λ
----------
2
4
πdf
c
------------
2
=
=
(dB)