Indoor Radio Noise Long-Term Measurements in Medium Wave Band in Buildings of City Areas in the North of Spain

This letter presents a study of indoor radio noise levels in the Medium Wave band up to 2 MHz, based on field trials. The work is based on long-term measurements carried out in buildings located in the areas of Bilbao and Vitoria in the north of Spain. The studied channels are centered in 630, 675, 1035, 1242, 1359, 1620, 1720, and 1910 kHz. The noise variation between daytime and nighttime and the variation depending on the type of building, office or household, have been analyzed. The obtained values, compared to the values predicted in ITU-R P-372 for outdoor locations in city environments, are higher. Reference values for radio planning are given for these frequency bands.