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A SYSTEM FOR DETERMINING THE RADIOFREQUENCY ABSORPTION COEFFICIENT OF THE HUMAN BODY IN THE HIGH FREQUENCY BAND

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Douglas A. Hill, Harry M. Assenheim, George W. Hartsgrove, George A. Grant · 1977

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Human RF absorption at 23.25 MHz varied dramatically between individuals, absorbing 0-2 watts from 400-watt exposure.

Plain English Summary

Summary written for general audiences

This 1977 study developed a highly precise system to measure how much radiofrequency energy the human body absorbs from 10-26 MHz electromagnetic radiation. Testing three volunteers at 23.25 MHz, researchers found people absorbed only 0-2 watts from 400 watts of incident power, but absorption varied significantly between individuals and body positions.

Why This Matters

This pioneering research from 1977 represents one of the earliest systematic attempts to measure RF absorption in humans, establishing measurement techniques still relevant today. The finding that human bodies absorbed only 0.5% of incident RF power at these frequencies might seem reassuring, but the significant individual variation and position-dependent absorption patterns reveal the complexity of EMF interactions with human biology. What's particularly noteworthy is that even at these relatively low frequencies (23.25 MHz), researchers observed measurable biological absorption that differed markedly between test subjects. This variability suggests that standard exposure guidelines based on average responses may not adequately protect all individuals, a concern that remains relevant as we're exposed to increasingly complex RF environments from modern wireless devices operating at much higher frequencies.

Exposure Information

Specific exposure levels were not quantified in this study.

Cite This Study
Douglas A. Hill, Harry M. Assenheim, George W. Hartsgrove, George A. Grant (1977). A SYSTEM FOR DETERMINING THE RADIOFREQUENCY ABSORPTION COEFFICIENT OF THE HUMAN BODY IN THE HIGH FREQUENCY BAND.
Show BibTeX
@article{a_system_for_determining_the_radiofrequency_absorption_coefficient_of_the_human__g5279,
  author = {Douglas A. Hill and Harry M. Assenheim and George W. Hartsgrove and George A. Grant},
  title = {A SYSTEM FOR DETERMINING THE RADIOFREQUENCY ABSORPTION COEFFICIENT OF THE HUMAN BODY IN THE HIGH FREQUENCY BAND},
  year = {1977},
  
  
}

Quick Questions About This Study

Researchers tested human radiofrequency absorption at 23.25 MHz, within the 10-26 MHz range their measurement system was designed to evaluate. This frequency falls in the shortwave radio band.
Test subjects absorbed only 0-2 watts from 400 watts of incident 23.25 MHz radiation, representing just 0.5% absorption efficiency. This low absorption rate surprised researchers at the time.
Yes, volunteers in the EKH orientation (lying with electric field parallel to body length) absorbed significantly more 23.25 MHz energy than in the KEH orientation (perpendicular positioning).
The system achieved exceptional precision of ±0.05% of incident power (±0.002 dB) after computer averaging, making it one of the most accurate RF absorption measurement systems of its era.
Individual differences in body composition, size, and tissue properties caused significant variation in 23.25 MHz absorption between the three volunteers, though results were reproducible for each individual person.