Christian Bornkessel

Mobile phone base stations and adverse health effects: phase 2 of a cross-sectional study with measured radio frequency electromagnetic fields

Objective: The aim of the cross-sectional study was to test the hypothesis that exposure to continuous low-level radio frequency electromagnetic fields (RF-EMFs) emitted from mobile phone base stations was related to various health disturbances. Methods: For the investigation people living mainly in urban regions were selected from a nationwide study in 2006. In total, 3526 persons responded to a questionnaire (response rate 85%). For the exposure assessment a dosimeter measuring different RF-EMF frequencies was used. Participants answered a postal questionnaire on how mobile phone base stations affected their health and they gave information on sleep disturbances, headaches, health complaints and mental and physical health using standardised health questionnaires. Information on stress was also collected. Multiple linear regression models were used with health outcomes as dependent variables (n = 1326). Results: For the five health scores used, no differences in their medians were observed for exposed versus non-exposed participants. People who attributed adverse health effects to mobile phone base stations reported significantly more sleep disturbances and health complaints, but they did not report more headaches or less mental and physical health. Individuals concerned about mobile phone base stations did not have different well-being scores compared with those who were not concerned. Conclusions: In this large population-based study, measured RF-EMFs emitted from mobile phone base stations were not associated with adverse health effects.

Quality control for exposure assessment in epidemiological studies.

In the framework of an epidemiological study, dosemeters were used for the assessment of radio frequency electromagnetic field exposure. To check the correct dosemeters performance in terms of consistency of recorded field values over the entire study period, a quality control strategy was developed. In this paper, the concept of quality control and its results is described. From the 20 dosemeters used, 19 were very stable and reproducible, with deviations of a maximum of +/-1 dB compared with their initial state. One device was found to be faulty and its measurement data had to be excluded from the analysis. As a result of continuous quality control procedures, the confidence in the measurements obtained during the field work was strengthened significantly.

Emulation of virtual radio environments for realistic end-to-end testing for intelligent traffic systems

We consider two approaches for real-time end-to-end over-the-air testing for intelligent traffic systems using virtual radio environments. One approach is based on coherent wavefield synthesis, while the other aims at emulating the essential features of a realistic radio channel in vehicular ad-hoc networks. Due to finite hardware resources, the former is limited to electrically small systems-under-test, while the latter is suited for typical vehicle-to-vehicle scenarios. Three major aspects of the emulation of radio environments in our facilities in Ilmenau, Germany, are described: 1. Emulation hardware, 2. Channel sounding, modeling, and feature extraction, 3. Emulation methods.

Measured impact of electromagnetic scattering off wind turbines on broadcast signal propagation

The electromagnetic scattering pattern of a wind turbine at DVB-T and DAB frequencies was studied by measurement on a scaled laboratory model, taking into account different yaw and pitch angles, and blade positions. The scattered energy peaks along backward directions, where it is stronger for vertical than for horizontal polarization, and is dominated by the mast. The variation of the yaw angle has greater effect compared to blade and pitch variations. Illuminating the wind turbine from the back results in stronger scattering compared to the front side due to the aerodynamic cross-sectional shape of the blades. The scattering becomes stronger for increasing electrical size of the wind turbine. The experimental approach proves reliable and helpful for the development of propagation models.