Height above average terrain
HEIGHT BASED ON LARGE AREA SURROUNDING OBJECT; OFTEN USED IN U.S. FOR ANTENNA TOWERS
Antenna height above average terrain; HAAT; Height Above Average Terrain; EHAAT; Effective height above average terrain; Height of antenna above average terrain; Effective height of antenna above average terrain; Metres above average terrain
Height above average terrain (HAAT), or (less popularly) effective height above average terrain (EHAAT), is the vertical position of an antenna site is above the surrounding landscape. HAAT is used extensively in FM radio and television, as it is more important than effective radiated power (ERP) in determining the range of broadcasts (VHF and UHF in particular, as they are line of sight transmissions).