Man-made noise measurements in indoor locations in Medium Wave band

This paper presents a study of man-made noise at frequencies below 2 MHz. In this study noise values are obtained from field measurements in different indoor environments in some cities in the north of Spain. The lowest frequencies of the Medium Wave band have been traditionally used for commercial AM transmission and in some countries there is hardly any transmission left. Recently new digital standards, such as DRM and IBOC, have been developed for audio broadcasting in this frequency band. However, there are very few references concerning noise levels in indoor locations at these frequencies. This study is necessary for radio service planning. These results could also complete the data noise values collected by the ITU. This paper also explains the difficulties in the process to obtain accurate results from the measurements, following the recommendations of the ITU and some other reports concerning noise measurements.