During an automatic scanning of an AM frequency band it is required that the scanning is only stopped when a usable audio signal is received. To achieve this normally the receiver checks the (RF) signal level and the IF frequency of the received signal. Because at night the propagation of AM signals is improved as a consequence of the weather conditions it is possible that a far away station having the same transmitting fequency interferes with a local station. To overcome this a detector and receiver are proposed whereby the detector detects interferences of two or more stations and supplies a detection signal resulting in resuming scanning for a next station.