User's Manual

Radio Site Planning Hardware Installation Guide
5-6 Airspan Networks Inc. 02030311-10
Note: Free space propagation loss is valid only when the first Fresnel Zone is
clear.
 Receive (dBm): Rx antenna gain (dBi) - cable loss (dB)
The formula to calculate receive signal strength:
RSS = Tx EIRP – Path Loss + Receive (i.e. Tx gain – Tx cable loss)
The RSS value must be greater than radio's receiver sensitivity for communication
link to succeed.
Example:
 Given: frequency is 2.4 GHz; Tx power output is 27 dBm; Tx and Rx cable loss
is 0 dB; Tx antenna gain is 11 dBi; Rx antenna gain is 15 dBi; distance between
sites is 6 km; receiver sensitivity at 8-level FSK is -75 dBm.
 Calculation: RSS = Tx + Tx gain – cable loss – path loss (fade margin + 32.44
+ 20logf + 20logf) + Rx gain – cable loss
Therefore, RSS = 27 + 11 – 116 + 15 = -63 dBi
 Conclusion: calculated link budget received signal strength (-63) is above the
device's receive sensitivity threshold (-75); thus a communication link should
succeed.