The EMC community uses an antenna connected to a receiver such as a spectrum analyzer, a network analyzer, or an RF voltmeter to measure field strength E. Most of the time these devices have a load resistor  that matches the antenna impedance. The incident field strength  equals antenna factor AF times the received voltage . We relate this to the antenna effective height:

  (6)

AF has units  but is often given as . Sometimes, antenna factor is referred to the open-circuit voltage and it would be one-half the value given by Eq. (6). We assume that the antenna is aligned with the electric field; in other words, the antenna polarization is the electric field component measured:

This measurement may be corrupted by a poor impedance match to the receiver and any cable loss between the antenna and receiver that reduces the voltage and reduces the calculated field strength.