Microhard Systems MHX-910A, Operating Manual

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MHX 910A Operating Manual: Chapter3 Installation
13
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 MHX-910A can be set to comply with
FCC and IC given the following equipment given a Rubber Ducky
Antenna 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 MHX-910A can be set to comply with
FCC and IC given the following equipment given a Yagi Antenna 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 MHX-910A can be set to comply with
FCC and IC given the following equipment given a Omni Antenna 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