User Manual

AirLink T1/E1 Installer’s Guide
Supplement - U.S./Canada Installation Rules
6 Rev. A - 4/95
NOTE Exceeding specified levels may create an installation that violates Industry Canada’s
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
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 applicable Industry Canada Specifications and
Guidelines. Take the lesser of the resultant transmit output power level or 36
dBm as the maximum AirLink T1 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
(c) Plus connector loss: + ____ dB
(d) Minus antenna gain: - _____ dB
(1) Resultant AirLink T1/E1 transmit output
power (sum of a through d): _______dBm
(2) Industry Canada Specifications and
Guidelines—IC power limit: 36 dBm
(3) Maximum AirLink T1/E1 transmit output
power (the lesser of (1) and (2): _______dBm
In the following example, given antenna gain of 25 dBi, feedline loss of 3 dB,
and connector loss of 1 dB, the transmit output power cannot be adjusted to more
than 32 milliwatts (15 dBm).