Black Box LW0050A Manual page 124

PRO 11 SERIES WIRELESS ETHERNET
Antenna Beamwidth
The directiveness of a directional antenna. Defined as the angle between two half-
power (-3 dB) points on either side of the main lobe of radiation.
S C
YSTEM HARACTERISTICS
Receiver Sensitivity
The minimum RF signal power level required at the input of a receiver for certain
performance.
EIRP (Effective Isotropic Radiated Power)
The power transmitted by an antenna. Equal to the transmitted output power
minus cable loss plus the transmitting antenna gain.
P out Output power of transmitted in dBm
Ct Transmitter cable attenuation in dB
Gt Transmitting antenna gain in dBi
Gr Receiving antenna gain in dBi
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
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 + 20 × Log(F MHz ) + 20 × Log(R km ) @ 110 dB
Si = EIRP - Pl + Gr - Cr = -82 dBm
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