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AN ATTEMPT TO EVALUATE THE EXPOSURE OF OPERATORS OF PORTABLE RADIOS AT 30 MHZ

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Q. Balzano, O. Garay, F.R. Steel · 1970

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1970 research examined EMF exposure from 30 MHz portable radios using phantom models, establishing early occupational safety protocols.

Plain English Summary

Summary written for general audiences

This 1970 technical report examined electromagnetic field exposure levels experienced by operators using portable radios at 30 MHz frequency. Researchers used phantom models and tissue simulation techniques to measure power density and assess potential exposure risks. This represents early scientific efforts to understand occupational EMF exposure from two-way radio equipment.

Why This Matters

This study represents pioneering work in occupational EMF exposure assessment, examining portable radios operating at 30 MHz during an era when such devices were becoming widespread in professional settings. The research focus on phantom models and tissue simulation demonstrates early recognition that proximity to transmitting devices creates significant exposure scenarios. What makes this particularly relevant today is that 30 MHz falls within the same general frequency range as many modern wireless technologies, and the fundamental physics of near-field exposure remain unchanged. The reality is that portable radio operators then faced similar exposure patterns to what we see with modern handheld devices, just at different frequencies and power levels. This early occupational health research laid groundwork for understanding how close-contact EMF sources affect the human body.

Finding

The temperature measurements show that a deposition rate substantially smaller than 1 mW/gr is caused by the radios used in the tests.

In their words

The temperature measurements show that a deposition rate substantially smaller than 1 mW/gr is caused by the radios used in the tests.

Figures from the Original Paper

Diagram extracted from the original research document.

graphPage 2 - AI-described figure: Figure 2 and Figure 3 show magnetic power density measurements for a Handi-Com MH10 device at different probing distances using telescopic and helical antennas, respectively.

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 30 MHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 30 MHzPower lines50/60 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Specific exposure levels were not quantified in this study. Duration: 1 minute

Study Details

To evaluate the exposure of operators of portable radios at 30 MHz by measuring energy deposition in simulated human tissue.

Simulated human tissue was used in the form of muscle and fat/bone phantoms. The muscle mixture had ...

No detectable temperature increase was found in the phantoms for a one-minute exposure, even when an...

The results indicate that there is no thermal hazard present for such low deposition rates. Even at maximum power density levels, the exposure from portable radios at 30 MHz does not cause appreciable temperature increments in simulated tissue.

Cite This Study
Q. Balzano, O. Garay, F.R. Steel (1970). AN ATTEMPT TO EVALUATE THE EXPOSURE OF OPERATORS OF PORTABLE RADIOS AT 30 MHZ.
Show BibTeX
@article{an_attempt_to_evaluate_the_exposure_of_operators_of_portable_radios_at_30_mhz_g5308,
  author = {Q. Balzano and O. Garay and F.R. Steel},
  title = {AN ATTEMPT TO EVALUATE THE EXPOSURE OF OPERATORS OF PORTABLE RADIOS AT 30 MHZ},
  year = {1970},
  
  
}
No DOI on file for this study.

Quick Questions About This Study

The portable radios studied operated at 30 MHz frequency. This frequency falls in the HF (high frequency) radio band, commonly used for two-way radio communication systems in professional and emergency service applications during that era.
Researchers used phantom models and tissue simulation techniques to evaluate exposure levels. These methods allowed scientists to measure power density and assess how electromagnetic fields from the radios would interact with human tissue in realistic usage scenarios.
Portable radio operators represented one of the first widespread occupational groups with regular close-proximity EMF exposure. As handheld two-way radios became common in police, fire, and other professional services, understanding potential health impacts became a workplace safety priority.
30 MHz operates at a lower frequency than most modern wireless devices, which typically use much higher frequencies like 900 MHz to 5 GHz. However, the fundamental near-field exposure principles remain similar when devices are held close to the body.
This early research established foundational methods for measuring occupational EMF exposure that are still relevant today. The phantom modeling and tissue simulation approaches developed then continue to inform how we assess exposure from modern handheld wireless devices and establish safety guidelines.