Adtran TRC4206L1 Manual Do Utilizador
Section 2, Microwave Path Engineering Basics
TRACER 4206 System Manual
20
© 2002 ADTRAN, Inc.
612804206L1-1A
Table 4. Typical Coaxial Loss for Common Cable Types, per 100 ft
In certain areas where lightning strikes are frequent, a lightning arrestor should be installed directly on the
antenna coax. This will help protect the RF electronics in the downstream path from damaging voltages
and currents, including the TRACER 4206 unit.
antenna coax. This will help protect the RF electronics in the downstream path from damaging voltages
and currents, including the TRACER 4206 unit.
8.
RECEIVER SENSITIVITY
Receiver sensitivity is a value expressed in decibels referenced to one milliwatt (dBm) that corresponds to
the minimum amount of signal power needed at the receiver to achieve a given bit error rate (BER).
Receiver sensitivity is usually a negative number of decibels, and as such smaller receiver sensitivity is
better for a given BER. Several factors affect receiver sensitivity, including the data bandwidth of the
wireless link, and the amount of additional signal degradation introduced in the receiver electronics. The
receiver sensitivity of the TRACER 4206 is -89 dBm at 10
the minimum amount of signal power needed at the receiver to achieve a given bit error rate (BER).
Receiver sensitivity is usually a negative number of decibels, and as such smaller receiver sensitivity is
better for a given BER. Several factors affect receiver sensitivity, including the data bandwidth of the
wireless link, and the amount of additional signal degradation introduced in the receiver electronics. The
receiver sensitivity of the TRACER 4206 is -89 dBm at 10
-6
bit error rate. Three band plans are provided
for frequency agility, should an interferer be nearby.
9.
FADE MARGIN
Fade margin is a value indicating the amount of extra signal power available to the receiver to operate at a
maximum bit error rate (BER). Higher levels of fade margin are better, and will protect the viability of the
microwave link against signal fading. For most applications, 20 to 30 dB of fade margin should ensure a
reliable link. Fade margin is simply the difference between the available signal power at the receiver and
the receiver sensitivity, discussed previously:
maximum bit error rate (BER). Higher levels of fade margin are better, and will protect the viability of the
microwave link against signal fading. For most applications, 20 to 30 dB of fade margin should ensure a
reliable link. Fade margin is simply the difference between the available signal power at the receiver and
the receiver sensitivity, discussed previously:
10. PATH AVAILABILITY
The path availability of a wireless link is a metric that expresses the fractional amount of time a link is
available over some fixed amount of time, and depends on several factors. Path availability is expressed as
available over some fixed amount of time, and depends on several factors. Path availability is expressed as
Cable Type
Cable Loss (dB/ft)
RG-213, RG-214, RG-293
20
1/4” Coax
11.36
3/8” Coax
9.65
1/2” Coax
6.49
5/8” Coax
4.90
5.8 GHz Elliptical Waveguide
1.23
F
P
R
P
sens
–
P
R
G
T
G
R
L
–
L
P
–
P
sens
–
+
+
=
=
(dB)
A
1
2.5
10
6
–
×
(
)abfd
3
10
F 10
⁄
–
(
)
–
[
] 100%
×
=
(dB)