TRACER 4102/4202 System Manual
Section 2 Microwave Path Engineering Basics
612804202L1-1A
© 2004 ADTRAN, Inc.
19
Table 2 gives typical loss figures for some of the more common coaxial cable types (per 100 feet).
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:
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.
Table 2. Typical Coaxial Loss for Common Cable Types
Cable Type
2.4 GHz Loss/100 ft.
(in dB)
5.8 GHz Loss/100 ft.
(in dB)
RG58
80
N/A
RG8 (air)
20
N/A
RG8 (foam)
9
N/A
1/4” Coax
5.91
11.36
3/8” Coax
5.76
9.65
1/2” Coax
3.83
6.49
5/8” Coax
2.98
4.90
7/8” Coax
2.2
N/A
1 1/4” Coax
1.62
N/A
1 5/8” Coax
1.41
N/A
5.8 GHz Elliptical Waveguide
N/A
1.23
L
P
4
π
d
λ
----------
2
4
π
df
c
------------
2
=
=
(dB)
L
P
96.6
20 log
10
d
( )
20·log
+
10
f
( )
⋅
+
=
(dB)
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Страница 14: ...Section 2 Microwave Path Engineering Basics TRACER 4102 4202 System Manual 14 2004 ADTRAN Inc 612804202L1 1A...
Страница 34: ...Section 3 Engineering Guidelines TRACER 4102 4202 System Manual 34 2004 ADTRAN Inc 612804202L1 1A...
