In simple terms, interference can be defined as the harmful effect of an unwanted signal on reception by a radio system which disturbs the correct transmission of information. This disturbance to reception ranges from a small degradation to total signal loss.

Interference can affect all radiocommunications services and applications: mobile, radio, television and radio broadcasting, amateur, radiodetermination, satellite services, as well as gate access remote controls, Wi-Fi networks and other equipment and short-range stations used by everyone on a day to day basis.

Within the scope of radiocommunications services, ANACOM investigates all reported situations of interference, giving priority to situations of interference which affect security and emergency services, in particular aeronautical services, where degradation might put the safety of people and infrastructure at risk.

However, most interference complaints that reach ANACOM, especially those related to the reception of Digital terrestrial television, are not in fact a question of interference but instead result from problems related to reception installation (e.g. malfunctioning reception equipment, poor installation or degradation of aerials and/or cables connecting aerials to the television receiver).

Therefore, before reporting interference to ANACOM, the reception installation should be checked to ensure that it is in good operating condition, if necessary by a specialist technician.

Once it has been confirmed that there is no fault in the installation, and if the interference persists, immediately contact the respective CMCE - Centro de Monitorização e Controlo do Espectro (Spectrum Monitoring and Control Centre), according to the operating area. If possible, contact should be made while the interference is occurring.

The complaint should include the contact details of the person making the complaint, the location and the characteristics of the interference (for example, whether it is permanent or intermittent).

ANACOM will analyse the situation and may contact the person reporting the complaint to obtain additional information or to schedule on-site verification.