The following lines were added (+) and removed (-):
Watts and dBm are both units of measure of power; either can be used. 0.001W = 0dBm; 3dBm = 0.002mW; 10dBm = 0.01W for example.In the US, the FCC limits the radiated power in 2.4GHz. The limit is a function of antenna horizontal beamwidth. More power with narrow beamwidth. This tends to reduce interference and benefit spectrum sharing.The 802.11g specs for OFDM require linearity in the standard and add-on amplifiers such that antenna gain is far more prudent than transmitter power. Most WiFi chipsets cannot produce an honest, high quality signal at more than about 36mw. The same chipsets can produce about 100mW in the lowest speeds of 11g and all 11b speeds, since 11b is not OFDM.Increasing antenna gain is a lot more cost effective than increasing transmit power.