User Manual

AirLink T1/E1 Installer’s Guide

Supplement - U.S./Canada Installation Rules

Rev. A - 4/95 3

It is imperative that the installer calculate the EIRP of this installation with

non-Cylink antennas and adjust the transmit output power so that the

maximum allowable EIRP is not exceeded.

NOTE Exceeding specified levels may create an installation that violates United States FCC

Rules and Regulations.

The EIRP depends on the transmit output power, the antenna feedline and

connector losses, and the antenna gain. The transmit output power must be

reduced by the amount in dB required to limit the EIRP to no more than 36 dBm.

Calculating the Maximum Transmit Output Power

with Non-Cylink Antennas

The transmit output power of the AirLink T1/E1 is adjustable in discrete

increments according to the levels described in the AirLink T1 Installer’s Guide

or AirLink E1 Installer’s Guide.

To determine the maximum allowable transmit output power, start with the

maximum EIRP (36 dBm). Add the calculated antenna feedline loss and the

specified connector loss. Next, refer to the antenna manufacturer’s specifications

to determine the antenna gain value. If the antenna gain is expressed in dB

relative to a reference dipole (that is, in dBd), add 2 dB to the specified gain

value to get the antenna gain relative to an isotropic radiator (that is, in dBi).

Subtract this value from the earlier numbers to get the resultant transmit output

power level. Compare the resultant transmit output power level to the 36 dBm

maximum allowed by the FCC specifications. Take the lesser of the resultant

transmit output power level or 36 dBm as the maximum AirLink T1/E1 transmit

output power. Adjust the AirLink T1/E1 RF power to this level.

Use the following format to calculate the maximum transmit output power

level:

(a) Maximum allowable EIRP: + 36 dBm

(b) Plus feedline loss: + ____ dB

(d) Minus antenna gain: - ____ dB

(1) Resultant AirLink T1/E1 transmit output

power (sum of a through d): _______dBm

(2) U.S. Specifications—FCC power limit: 36 dBm

(3) Maximum AirLink T1/E1 transmit output

power (the lesser of (1) and (2): _______dBm