User Manual

TRACER 4205 System Manual Section 2, Microwave Path Engineering Basics
612804205L1-1A © 2002 ADTRAN, Inc. 17
When using decibel notation, the received power equation becomes
or
Where, in the second equation the path loss has been lumped into a single quantity, L
P
, as discussed
previously. When using decibel notation, it is necessary that all quantities are individually converted to
decibels prior to performing addition and subtraction.
When d is expressed in miles and f in GHz, the path loss expression in decibels becomes
Figure 1 illustrates a wireless link containing all of the parameters previously discussed.
20 138
21 138
22 139
23 139
24 139
25 140
Table 2. Path Loss for Given Path Lengths
Path Length
(miles)
Path Loss
(dB)
P
R
P
T
G
T
G
R
L– 20 · log
10
–++
4πdf
c
------------


=
(dBm)
P
R
P
T
G
T
G
R
L– L
P
–++=
(dBm)
L
P
96.6 20 log
10
d() 20·log+
10
f()⋅+=
(dB)