Also, the thing is that regulations specify EIRP, in terms of power density, meaning that an AP may not transmit more than a certain level of milliwatts per MHz BW. So if a station is bound by regulations to not transmit more than 1 W per MHz BW, for a 20 MHz channel you are transmitting at maximum 50 mW. And as the channel become wider, the station will transmit even less.    So using a wider channel versus a narrow, really comes with a trade off, on what you want/need. A narrow channel means more channels, higher transmit power, but a "smaller highway", whereas a wider channel means less channels to work with, less transmit power, but more room on the "highway" to move data.    If you reference https://mcsindex.com/, you can see what theorethical speeds you may achieve, depending on channel widths and available SNR.  ... View more