Calculating Eirp For Connectorized Units; Table 4-21 Maximum Permitted Antenna Gain (Allowing For Cable Loss) - Motorola PTP 250 User Manual

Compliance with radio regulations

Calculating EIRP for connectorized units

When operating with external antennas in countries that impose an EIRP limit, the
administrator has to set the maximum transmit power to ensure that EIRP does not
exceed the limit allowed by regulations.
To calculate the maximum EIRP that the unit can output, use this formula:
Maximum EIRP (dBm) =
Maximum Power Level (dBm) + Antenna Gain (dBi) – Cable Loss (dB)
To calculate the highest permissible setting of Maximum Power Level, use this
formula:
Maximum Power Level (dBm) =
Allowed EIRP (dBm) – Antenna Gain (dBi) + Cable Loss (dB)
Where:
NOTE

Table 4-21 Maximum permitted antenna gain (allowing for cable loss)

Allowed EIRP
30 dBm
36 dBm
4-30
Maximum Power
Level (dBm)
Allowed EIRP
(dBm)
Antenna Gain
(dBi)
Cable Loss (dB)
Choose an antenna and RF cable that will not cause the PTP 250 to exceed
Allowed EIRP. As PTP 250 does not support Maximum Power Level settings
below 4 dBm, the maximum antenna gain (allowing for cable loss) is limited
as follows (examples in
Maximum Antenna Gain (dBi) – Cable Loss (dB) = Allowed EIRP (dBm) – 4
Maximum (Antenna Gain - Cable Loss)
26 dBi
32 dBi
Is:
the highest permissible setting of the
Maximum Power Level attribute in the
Step 2: Wireless Configuration page
the EIRP limit allowed by the regulations
Antenna Gain as set in the Step 2:
Wireless Configuration page
Cable Loss as set in the Step 2: Wireless
Configuration page
Table 4-21):
Chapter 4 Reference information
phn-2182_002v000
May 2011