Chapter 4
Tropos 7320 Router Installation Guide
55
Attenuation with External Antennas
If external antennas are used, it is necessary to adjust the transmit power attenuation to provide
the correct power level for the router. Use the following formulas to compute the required
attenuation level:
Gain’ (dBi) = Antenna Gain (dBi) - Cable Loss (dB)
802.11b/g/n:
802.11a/n point-to-multipoint:
TABLE 14
802.11b/g/n Antenna Configurations (2400-2483 MHz)
Antenna
Ordering Number
Measured
Cond. Avg.
Power (dBm)
Tx
Attenuation
Software
Setting (dB)
Approximate
EIRP (dBm)
7.4dBi omni, unit mounted
AN074077
28.6
0
36.0
10.0dBi omni, unit mounted
AN100022
26.0
3
36.0
12.0dBi sector, external bracket
mounted
AN120044
24.0
5
36.0
TABLE 15
802.11a/n Radio (5725-5850 MHz) - Antenna Configurations
Description
Part
Number
Measured Cond.
Avg. Power
(dBm)
Tx Attenuation
Software
Setting (dB)
Approximate
EIRP (dBm)
9.1dBi omni, unit mounted, point-to-
multipoint operation
AN091058 24
0
33
17dBi 90° sector, external bracket
mounted, point-to-point operation
a
a.
All external antennas include pole mounting bracketry and sealing materials. RF cables are not included.
AN170058 24
0
41
17dBi 90° sector, external bracket
mounted, point-to-multipoint opera-
tion
a
AN170058 19
5
36
19dBi patch antenna, external
bracket mounted, point-to-point oper-
ation
a
AN190058 24
0
43
Tx Antenna Setting (dB) =
0
Gain’ - 7
if Gain’ < 7 dBi
if Gain’ > 7dBi
