Effective radiated power

In radio telecommunications, effective radiated power (ERP) is determined by subtracting system losses and adding system gains to the actual electrical power output of a transmitter. ERP is not equivalent to the power that is radiated, but is a quantity that takes into consideration transmitter power and antenna directivity. ERP is typically applied to antenna systems. For example, if an antenna system has 9 dB gain and 6 dB loss, its ERP is 3 dB over the transmitter power output (TPO).
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1. The power supplied to an antenna multiplied by the antenna gain in a given direction. (188 ) Note 1: If the direction is not specified, the direction of maximum gain is assumed. Note 2: The type of reference antenna must be specified. 2. The product of the power supplied to the antenna and its gain relative to a half-wave dipole in a given direction. [NTIA ] [RR ] Note: If the direction is not specified, the direction of maximum gain is assumed.