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Updated: May 21, 2026
06:43
Effective Analysis of Human Exposure Conditions with Body-worn Dosimeters in the 2.4 GHz Band
Published on: May 2, 2018
Simultaneous occupational exposure to FM and UHF transmitters
Blaž Valič1, Bor Kos, Peter Gajšek
1Institute of Non-Ionizing Radiation, Ljubljana, Slovenia. blaz.valic@inis.si
Summary
Occupational exposure from combined radio and TV transmitters can exceed reference levels. While electric field strength was high, specific absorption rate (SAR) values indicate safety for FM, but UHF exposure requires careful monitoring.
Area of Science:
- Electromagnetic field (EMF) measurements and analysis
- Occupational health and safety in broadcasting environments
Background:
- Broadcasting transmitters, including Frequency Modulation (FM) and Ultra-High Frequency (UHF), often co-locate on shared masts.
- Previous studies indicate potential for occupational exposure to exceed established reference levels due to combined sources.
Purpose of the Study:
- To analyze combined electromagnetic field (EMF) exposure from co-located FM and UHF transmitters.
- To evaluate the conservativeness of current reference levels for occupational exposure in such scenarios.
Main Methods:
- Measurements and calculations of electric field strength were performed on a 40-m mast hosting a 25 kW FM transmitter and a 5 kW UHF transmitter.
- Specific Absorption Rate (SAR) values were assessed to determine compliance with basic restrictions.
Main Results:
- Measured and calculated electric field strength values exceeded reference levels by up to 10 times.
- Specific Absorption Rate (SAR) values remained below basic restrictions for FM exposure, even when electric fields exceeded levels tenfold.
- For UHF exposure, reference levels were found to be non-conservative, accurately predicting actual exposure.
Conclusions:
- Current reference levels for FM exposure are highly conservative, allowing for significant electric field exceedances without biological risk.
- Reference levels for UHF exposure are less conservative and provide a reliable indicator of actual biological exposure.
- Combined EMF exposure from co-located transmitters necessitates careful assessment, particularly for UHF frequencies, to ensure occupational safety.
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