User guide

Designing Your Canopy Network March 2005
Through Software Release 6.1
Issue 1 Page 97 of 425
Canopy System User Guide
Tx
power
T
x antenna
loss
Tx
cable
loss
Rx antenna
gain
Rx
cable
loss
Rx
signal
level
Transmitter
or Amplifier
receiver
or amplifier
distance
free space signal
transmitter
or amplifier
Figure 37: Determinants in Rx signal level
Rx signal level is calculated as follows:
Rx signal level dB =
Tx power − Tx cable loss + Tx antenna gain
−
free space path loss + Rx antenna gain − Rx cable loss

NOTE:
This Rx signal level calculation presumes that a clear line of sight is
established between the transmitter and receiver and that no objects
encroach in the Fresnel zone.
12.1.4 Calculating Fade Margin
Free space path loss is a major determinant in Rx (received) signal level. Rx signal level,
in turn, is a major factor in the system operating margin (fade margin), which is calculated
as follows:
system operating margin (fade margin) dB = Rx signal level dB − Rx sensitivity dB