User's Guide

Appendix A. Radio Signal Propagation
User's Guide A-6 BreezeNET BU-DS.11/RB-DS.11
System Characteristics
Receiver Sensitivity
The minimum RF signal power level required at the input of a receiver for certain performance (e.g.
BER).
EIRP (Effective Isotropic Radiated Power)
The antenna transmitted power. Equal to the transmitted output power minus cable loss plus the
transmitting antenna gain.
P
out
Output power of transmitted in dBm
CtTransmitter cable attenuation in dB
GtTransmitting antenna gain in dBi
GrReceiving antenna gain in dBi
PlPath loss in dB
CrReceiver cable attenuation is dB
SiReceived power level at receiver input in dBm
PsReceiver sensitivity is dBm
Si = P
out
- Ct + Gt - Pl + Gr - Cr
EIRP = P
out
- Ct + Gt
Example:
Link Parameters:
Frequency: 2.4 Ghz
P
out
= 4 dBm (2.5 mW)
Tx and Rx cable length (Ct and Cr) = 10 m. cable type RG214 (0.6 dB/meter)
Tx and Rx antenna gain (Gt and Gr) = 18 dBi
Distance between sites = 3 Km
Receiver sensitivity (Ps) = -84 dBm
Link Budget Calculation
EIRP = P
out
- Ct + Gt = 16 dBm
Pl = 32.4 + 20xLog(FMhz) + 20xLog(RKm) ≅ 110 dB
Si = EIRP - Pl + Gr - Cr = -82 dBm