GE MDS entraNET 900, Техническое руководство

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158 MDS entraNET Technical Manual 05-4055A01, Rev. E
2. Subtract the antenna system gain from 27 dBm (the maximum
allowable EIRP). The result indicates the maximum transmitter
power (in dBm) allowed under the rules. In the example above, this
is 19 dBm.
3. If the maximum transmitter power allowed is less than 27 dBm,
reduce the transmit power accordingly using the radio menu system
(
Main Menu>Radio Configuration>RF Output Power Setpoint
), or introduce
additional feedline loss. The EIRP of the antenna system should
never exceed 27 dBi.
For convenience, Table 6-5 lists several antenna system gains, and
shows the maximum allowable power setting. Note that a gain of 0 dB
entitles you to operate the radio at the full power output of27 dBm
(0.5 W). To convert dBm to Watts, refer to
Table 8-4 on Page 193 .
* Most antenna manufacturers rate antenna gain in dBd in their
literature. To convert to dBi, add 2.15 dB.
† Feedline loss varies by cable type and length. To determine the loss
for common lengths of feedline, see Table 6-1 on Page 155 .
6.4 HOW MUCH OUTPUT POWER CAN
BE USED?
(ETSI 2400 MHz systems)
In regions where ETSI requirements apply, 2400 MHz transceivers are
supplied from the factory with a +20 dBm (100 mW) RF power setting.
This is the maximum EIRP transmitter output power allowed under
ETSI standards. The power must be
decreased from this level if the
antenna system gain exceeds 0 dBi. The allowable level is dependent on
the antenna gain, feedline loss, and the transmitter output power setting.
Table 6-5. Antenna System Gain versus Power Output Setting
(U.S.A. and Canada only)
Antenna System Gain
(Antenna Gain in dBi*
minus Feedline Loss in dB†)
Maximum Power
Setting
(in dBm)
EIRP
(in dBm)
0 27 27
5 22 27
7 20 27
9 18 27
12 15 27
15 12 27