Effective radiated power (ERP) is the product of antenna input power and antenna power gain, expressed in kilowatts. In other words, ERP is the power supplied to an antenna multiplied by the antenna gain in a given direction. If the direction is not specified, the direction of maximum gain is assumed. The type of reference antenna must be specified. The product of the power supplied to the antenna and its gain relative to a half-wave dipole in a given direction. If the direction is not specified, the direction of maximum gain is assumed.
Effective radiated power takes into consideration transmitter power output (TPO), transmission line attenuation (electrical resistance and RF radiation), RF connector insertion losses, and antenna directivity, but not height above average terrain (HAAT). ERP is typically applied to antenna systems.