User Manual

13 PTP 500 Series Bridge – Connectorized Model
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The external antennas can be either dual-polarization (as the integrated antenna) or two
single polarized antennas can be used in a spatially diverse configuration. It is expected that
the dual-polarization antennas would normally be used to simplify the installation process;
spatially diverse antennas may provide additional fade margin on very long LOS links where
there is evidence of correlation of the fading characteristics on Vertical and Horizontal
polarizations.
Dual polarization antennas (with a gain greater than the integrated antenna) are currently only
available in parabolic dish form.
13.5 Link Budget
An estimate of the link budget for a specific application can be obtained by using the Motorola
Systems link estimation tools. For more information see the Motorola web site.
13.6 Regulatory Issues
Installations must conform to any applicable local regulations for the Equivalent Isotropic
Radiated Power (EIRP).
Ensuring compliance becomes more complex when the connectorized unit is used with
external antennas which may be locally sourced. With higher gain external antennas fitted,
the Maximum Transmit power may need to be reduced for operation in specific countries.
See Section 5.2 “Licenses and Region Codes” for any EIRP restrictions that may apply in
your region.
In some regions, operation of the PTP 54500 products is constrained by an EIRP limit. The
normal constraint is that the EIRP does not exceed 30 dBm (36 dBm for PTP 58500) for radio
signals with a bandwidth of >=20 MHz. As the PTP 54500 operating bandwidth is
approximately 15 MHz, then the limit is 34.8 dBm EIRP (28.8 dBm for PTP 58500).
When operating with external antennas, the installer/operator has to set the maximum
transmit power to ensure that the EIRP limit is not exceeded. The Set_Max_Transmit_Power
is calculated as below:
Set_Max_Transmit_Power = [Max_Transmit_Power] rounded down to nearest lower dB.