MHX-920 Operating Manual:Glossary
9
Examples:
FCC and Industry Canada Regulations allow up to 36dBm effective
radiated power (ERP). Therefore, the sum of the transmitted power (in
dBm), the cabling loss and the antenna gain cannot exceed 36dBm with
respect to the isotropic radiator.
Example 1)
What is the maximum power the MHX920 can be set to comply with
FCC and IC given the following equipment given a Rubber Ducky Ant
Gain 2dBi and no cable or connectors in the system?
Max ERP 36dBm
Max TX power = ERP – Ant Gain(dBi) + Cable/Connector loss (dB)
Ant Gain dBi = 2dBi
Max TX power = 36dBm – 2dBi + 0dB = 34dBm
We can set the modem to the maximum power setting of 30dBm.
Example 2)
What is the maximum power the MHX920 can be set to comply with
FCC and IC given the following equipment given a Yagi Ant Gain
12dBd and cable and connector loss of 4.5 dB?
Max ERP 36dBm
Max TX power = ERP – Ant Gain(dBi) + Cable/Connector loss (dB)
Ant Gain dBi = Ant Gain dBd + 2.15 dB
Yagi Gain (dBi) = 12 + 2.15 = 14.15dBi
Max TX power = 36dBm – 14.15dB + 4.5dB = 26.35dBm
We must round down
Hence Max TX power = 26dBm
Example 3)
What is the maximum power the MHX920 can be set to comply with
FCC and IC given the following equipment given a Omni Ant Gain
6dBd and cable and connector loss of 2.5 dB?
Max ERP 36dBm
Max TX power = ERP – Ant Gain(dBi) + Cable/Connector loss (dB)
Ant Gain dBi = Ant Gain dBd + 2.15 dB
Omni Gain (dBi) = 6 + 2.15 = 8.15dBi
Max TX power = 36dBm – 8.15dB + 2.5dB = 30.35dBm
Hence Max TX power = 30dBm
