Transmitter power output
In radio transmission, transmitter power output (TPO) is the actual amount of power (in watts) of radio frequency (RF) energy that a transmitter produces at its output.[1]
TPO is a concept related to effective radiated power (ERP), but refers to the power output of a transmitter, without accounting for antenna gain. The ERP for VHF/UHF transmitters is normally more than the TPO, for LF/MF transmitters it has nearly the same value, while for VLF transmitters it may be less.