User's Guide

10 Connectorized PTP 500 Series Bridge
180
10.5 Regulatory Issues with Connectorized Units
10.5.1 Normal EIRP limits
In most regions (including USA, Canada, Europe and Australia) operation of products in the
band 5470 MHz to 5725 MHz is constrained by an EIRP limit. The constraint is that the EIRP
must not exceed (17 + 10 x Log Bandwidth) dBm.
In some regions (including Europe) operation of products in the band 5725 MHz to 5850/5875
MHz is constrained by an EIRP limit. The constraint is that the EIRP must not exceed (23 +
10 x Log Bandwidth) dBm.
As the PTP 54500 and PTP 58500 have an operating bandwidth from approximately 5 MHz
to approximately 15 MHz, then the maximum allowed EIRP depends on the operating
bandwidth of the radio as shown in Table 18.
Table 18 -
Normal EIRP limits with operating channel bandwidth
Operating bandwidth
(MHz)
Allowed EIRP (dBm) at
5.4 GHz
Allowed EIRP (dBm) at
5.8 GHz
5 24 30
10 27 33
15 28.8 34.8
10.5.2 Calculating EIRP
When operating with external antennas, the installer or operator has to set the maximum
transmit power to ensure that the EIRP limit is not exceeded. The EIRP may be calculated
from:
Allowed EIRP(dBm) = Max_Transmit_Power (dBm) + Antenna Gain (dBi) – Feeder
Losses (dB)
and hence:
Max_Transmit_Power (dBm) = Allowed EIRP(dBm) – Antenna Gain (dBi) + Feeder
Losses (dB)