ABB Tropos 4310-XA Installation Manual page 18

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:
Tx Antenna Setting (dB) =
802.11a:
Tx Antenna Setting (dB) =
Tropos Mobile Mesh Router Installation Guide Models 4310-XA and 4319-XA
0 if Gain' < 7 dBi
Gain' - 7 if Gain' > 7dBi
4 if Gain' < 9 dBi
Gain' - 5 if Gain' > 9 dBi
Chapter 3
18