User manual

AP User Manual January 2004
Software Release 4.1
Canopy
™ System
Calculator
Automatically calculate
Fresnel Zone (vertical dimension)
from known
Distance from Transmitter to Receiver
Distance from High-elevation Object to Receiver
Frequency
Distance from transmitter to receiver (kilometers)
Distance from high-elevation object to receiver (kilometers)
Distance from transmitter to receiver (miles)
Distance from high-elevation object to receiver (miles)
Frequency (GHz)
Maximum Fresnel zone radius, midway between Tx and Rx (meters)
Fresnel zone radius at object (meters)
Minimum clearance required beween line of sight and top of object (meters)
Maximum Fresnel zone radius, midway between Tx and Rx (feet)
Fresnel zone radius at object (feet)
Minimum clearance required beween line of sight and top of object (feet)
Determinants
Results
Enter Values
Read Values
Figure 16: Canopy System Calculator page for Fresnel zone dimensions
5.2.5 Free Space Path Loss
An RF signal in space is attenuated by atmospheric and other effects as a function of the distance
from the initial transmission point. The further a reception point is placed from the transmission
point, the weaker is the received RF signal.
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 = Rx signal level − Rx sensitivity
The Rx sensitivity of the AP is stated under AP MODULE SPECIFICATIONS on Page 100. The
determinants in Rx signal level are illustrated in Figure 17.
Issue 5 Page 45 of 102