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Simultaneous Occupational Exposure to FM and UHF Transmitters

Valic B., Kos B., Gajsek P.

International Journal of Occupational Safety and Ergonomics

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2012

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Vol. 18, No. 2

161--170

EN

Occupational exposure caused by large broadcasting transmitters exceeds current reference levels. As it is common for different radio and TV transmitters to share the location, we analysed combined exposure on a 40-m high mast. The frequency modulation (FM) transmitter, located between the 10th and 30th metre, had the power of 25 kW, whereas an ultra-high frequency (UHF) transmitter of 5 kW occupied the top 8 m of the mast. Measured and calculated values of the electric field strength exceeded the reference levels up to 10 times; however, the results for the specific absorption rate (SAR) values show that the reference levels are very conservative for FM exposure, i.e., basic restrictions are not exceeded even when the reference levels are exceeded 10 times. However, for UHF exposure the reference levels are not conservative; they give a good prediction of real exposure.

2

Occupational Exposure Assessment on an FM Mast: Electric Field and SAR Values

Valic B., Kos B., Gajsek P.

International Journal of Occupational Safety and Ergonomics

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2012

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Vol. 18, No. 2

149--159

EN

Electric field strengths normally exceed the reference levels for occupational exposure in close vicinity to large frequency modulation (FM) transmitters. Thus, a detailed investigation on compliance with basic restrictions is needed before any administrative protection measures are applied. We prepared a detailed numerical model of a 20-kW FM transmitter on a 32-m mast. An electrically isolated anatomical human model was placed in 3 different positions inside the mast in the region where the values of the electric field were highest. The electric field strengths in this region were up to 700 V/m. The highest calculated whole-body specific absorption rate (SAR) was 0.48 W/kg, whereas the maximum 10-g average SAR in the head and trunk was 1.66 W/kg. The results show that the reference levels in the FM frequency range are very conservative for near field exposure. SAR values are not exceeded even for fields 10 times stronger than the reference levels.

3

Occupational Exposure to Base Stations—Compliance With EU Directive 2004/40/EC

Gajsek P., Simunic D.

International Journal of Occupational Safety and Ergonomics

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2006

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Vol. 12, No. 2

187--194

EN

The rapid growth of mobile communications has not only led to a rising number of mobile telephones. It has also made base stations essential for services widespread on many roofs. However, not everyone is aware that working close to sources of high frequency electromagnetic fields (EMF), such as transmitter antennas for mobile phones, pagers and police, fire and other emergency services, can result in high EMF exposure. This paper deals with measurements and calculations of the compliance boundary for workers in one typical roof top base station setting according to EU Directive and other relevant EN standards.

4

Application of EMF Emission Measurement Techniques to Wireless Communications Systems for Compliance With Directive 2004/40/EC

Simunic D., Gajsek P.

International Journal of Occupational Safety and Ergonomics

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2006

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Vol. 12, No. 2

177--186

EN

Europe is the only region in the world with common legislative acts regulating exposure to electromagnetic fields (EMF) for both the general public and workers. Council Recommendation 1999/519/EC deals with the limitation of exposure of the general public to EMF (0 Hz—300 GHz). Directive 2004/40/EC regulates the minimum health and safety requirements regarding the exposure of workers to the risks arising from EMF. This paper discusses the general application of existing standards and recommendations in measurement techniques for determining compliance of measured exposure limit values and action values with those defined in 2004/40/EC.