GE MDS entraNET 900, Техническое руководство

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05-4055A01, Rev. E MDS entraNET Technical Manual 157
Note that a gain of 6 dB or less entitles you to operate the radio at full
power output of 30 dBm (1 W).
* Most antenna manufacturers rate antenna gain in dBd in their litera-
ture. 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 .
To convert dBm to Watts, refer to the chart shown on Page 193.
6.3 HOW MUCH OUTPUT POWER CAN
BE USED?
(U.S.A. and Canada, 2400 MHz systems)
Non-ETSI 2400 MHz transceivers are normally supplied from the
factory set for +27 dBm (0.5 Watt) RF power output; this is the
maximum transmitter output power allowed under FCC and Industry
Canada rules. The power must be
decreased from this level if the
antenna system gain exceeds 0 dBi. The allowable level depends on the
antenna gain, feedline loss, and the transmitter output power setting.
NOTE: In regions where ETSI requirements apply, the maximum
allowable RF output is generally limited to 100 mW (+20
dBm) on 2400 MHz. License-free operation on 900 MHz is not
permitted. For more information, see
HOW MUCH OUTPUT
POWER CAN BE USED? (ETSI 2400 MHz systems) on
Page 158.
6.3.1 Calculating System Gain
To determine the maximum allowable power setting of the radio,
perform the following steps:
1. Determine the antenna system gain by subtracting the feedline loss
(in dB) from the antenna gain (in dBi). For example, if the antenna
gain is 10 dBi, and the feedline loss is 2 dB, the antenna system gain
is 8 dB.
Table 6-4. 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)
6 (or less) 30 36
8 28 36
10 26 36
12 24 36
14 22 36
16 20 36