The term (AF) is used to define the antenna calibration relationship required for making accurate radiated emission measurements. The unknown electric field strength (E in V/m) is obtained by multiplying the voltage (V in Volts or uVolts) at the measuring receiver by the (AF), allowing for attenuation (A) in the connecting cable. AF = E/V, the conversion can be expressed in dB by: E(dBµV/m) = V(dBµV) + AF(dB/m) + A(dB)