What speed and frequency range are used by 802.11ac?

802.11ac operates in the 5 GHz range. The 900 MHz range has frequently been used for phones and non-Wi-Fi wireless networks as well as other amateur radio uses, and 2.4 GHz is used by 802.11n and other protocols. Knowing that multiple ranges are available and that they may behave differently based on how many access points are in use and whether other devices that may cause interference on that band are in the area can be important for wireless network deployments.