The aim of this study is to investigate whether placement of a 3G dialing mobile phone causes direct changes in EEG activity compared to the placement of a sham phone. Furthermore, it is investigated whether placement of the mobile phone on the ear or the heart results in different outcomes. The subjects are measured twice: on one of the two days the mobile phone is attached to the ear, the other day to the chest. In this single-blind, cross-over design, assessments in the sham phone conditions are conducted directly preceding and following the mobile phone exposure. During each assessment, EEG activity and radiofrequency radiation are recorded jointly. Delta, theta, alpha, slowbeta, fastbeta, and gamma activity are computed. The association between radiation exposure and the EEG is tested using multilevel random regression analyses with radiation as predictor of main interest.