The Ambient Noise (AN) measurement is done in accordance with CISPR 22 and EN 50022.
Broadband antennas are set up in the receive position in one height and in both polarisations. The received field strength is recorded in the range from 30 MHz to 18 GHz with a measurement bandwidth of 120 kHz. The span of the spectrum analyser is set related to the frequency steps so that the whole spectrum is scanned continuously. From each span the peak value is taken as measurement value.
We need a calibrated test receiver or spectrum analyser with GPIB interface, calibrated antenna(s) and cabling.