The calibration and use of EMC antennas, 30 MHz to 1000 MHz

The coupling of two horizontally polarised resonant dipole antennas measured on the NPL open-field site is in agreement with theoretical prediction to better than ±0.2 dB. The antenna design and qualities of the site and the measurement are thereby validated. Antenna factor potentially can be measured to an uncertainty of 0.2 dB by the standard antenna method. The quality of the site enables accurate swept frequency calibrations of broadband antennas using the standard site method. Emission tests require that the antenna is scanned in height: the variation of antenna factor with height of a tuneable dipole antenna fed by a Roberts balun has been calculated. The operation of broadband EMC antennas as used by test houses has been experimentally examined and measurement uncertainties have been quantified for antenna factor variation with height, input match, directivity, separation from the emitter, reflection from the feed cable and variation of phase centre with frequency of log antennas