The 2. band is subdivided into up to 14 channels, spaced at 5 MHz intervals from 2412 MHz up to 2484 MHz.
Wi-Fi requires bandwidth of approximately 20 MHz, not 5 MHz. Consequently, a site designer needs to choose the channels that do not overlap. On a WLAN where only the first 11 channels are available, channels
1, 6, and 11 can be selected as non-overlapping. Note: In the Americas, regulations permit the use of channels
1-11 only, while in Europe, channels 1-13 are permitted. In Japan, all 14 channels are permitted.