User`s guide

Radio Signal Propagation
C-7
Pl - Path loss in dB
Cr - Receiver cable attenuation in dB
Si - Received power level at receiver input in dBm
Ps - Receiver sensitivity in dBm
Si = P
out
- Ct + Gt - Pl + Gr - Cr
EIRP = P
out
- Ct + Gt
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
In conclusion, the received signal power is above the
sensitivity threshold, so the link should work. The problem is
that there is only a 2 dB difference between received signal
power and sensitivity. Normally, a higher margin is desirable
due to fluctuation in received power as a result of signal
fading.