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6 |
For convenience, the table below lists several antenna system gains and shows the maximum allowable power setting of the radio. Note that a gain of 6 dB or less entitles you to operate the radio at full power output 30 dBm (1 Watt).
Antenna System Gain | Maximum Power | |
(Antenna Gain in dBi* | Setting | EIRP minus |
Feedline Loss in dB†) | (in dBm) | (in dBm) |
6 (or less) | 30 | 36 |
8 | 28 | 36 |
10 | 26 | 36 |
12 | 24 | 36 |
14 | 22 | 36 |
16 | 20 | 36 |
*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, as shown previously.
How Much Output Power Can Be Used? (U.S.A. and Canada, 2400 MHz systems)
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.
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.
| Chapter 6 Installation |