Adtran TRC4206 Manual Do Utilizador
Section 2, Microwave Path Engineering Basics
TRACER 4206 System Manual
14
© 2002 ADTRAN, Inc.
612804206L1-1A
1.
LINE-OF-SITE
The TRACER 4206 system is designed for operation in the 5725 MHz to 5850 MHz unlicensed Industrial,
Scientific, and Medical (ISM) frequency band. Radio wave propagation in this band exhibits microwave
characteristics, which are ideally suited for point-to-point, line-of-sight communications. Line-of-sight
essentially requires that the transmitting antenna and receiving antenna are able to “see” each other, and
that the straight-line path between the two antennas is free of any obstructions, such as buildings, trees,
mountains, and, in longer paths, even the curvature of the earth.
Scientific, and Medical (ISM) frequency band. Radio wave propagation in this band exhibits microwave
characteristics, which are ideally suited for point-to-point, line-of-sight communications. Line-of-sight
essentially requires that the transmitting antenna and receiving antenna are able to “see” each other, and
that the straight-line path between the two antennas is free of any obstructions, such as buildings, trees,
mountains, and, in longer paths, even the curvature of the earth.
2.
DECIBELS
The received signal power equation is often expressed in a decibel (dB) format, which turns the power
multiplication and division operations into addition and subtraction operations. In general, any quantity
can be expressed in decibels. If the quantity (x) is a power level, the decibel equivalent is defined as
multiplication and division operations into addition and subtraction operations. In general, any quantity
can be expressed in decibels. If the quantity (x) is a power level, the decibel equivalent is defined as
If the quantity x is referenced to a milliwatt (mW), then the decibel-milliwatt (dBm) is used instead of a
generic decibel.
generic decibel.
3.
RECEIVER POWER
The radio frequency (RF) signal power that is available at the input to the receiving TRACER 4206 system
is the next parameter of interest in analyzing a wireless path. The TRACER 4206 has a maximum output
power level of 100 mW, which is equivalent to 20 dBm. This output signal will be attenuated and distorted
by various factors, all of which will degrade the original signal and affect the signal strength and quality as
sensed by the receiving unit. A simplified power budget analysis is beneficial to perform after verifying a
suitable line-of-sight path to determine if the microwave path is suitable, even for ideal, non-distorted
signals.
is the next parameter of interest in analyzing a wireless path. The TRACER 4206 has a maximum output
power level of 100 mW, which is equivalent to 20 dBm. This output signal will be attenuated and distorted
by various factors, all of which will degrade the original signal and affect the signal strength and quality as
sensed by the receiving unit. A simplified power budget analysis is beneficial to perform after verifying a
suitable line-of-sight path to determine if the microwave path is suitable, even for ideal, non-distorted
signals.
The equation relating received signal power to the other microwave parameters is
Point-to-Point
Wireless communication from a single site to another
individual site. Contrast with point-to-multipoint
individual site. Contrast with point-to-multipoint
Line-of-Sight
An unobstructed, direct path exists between the
transmitting and the receiving antennas.
transmitting and the receiving antennas.
x
dB
10 log
10
x
( )
⋅
=
(dB)
x
dBm
10 log
10
x
1mW
-------------
⋅
=
(dBm)
P
R
P
T
G
T
G
R
λ
2
4
π
( )
2
d
2
L
---------------------------
=
(watts, W)