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DEVELOPMENT OF MAGNETIC NEAR-FIELD PROBES

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Frank M. Greene · 1975

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Accurate magnetic field measurement requires specialized probes, foundational research that enables modern EMF health studies.

Plain English Summary

Summary written for general audiences

This 1975 technical report by Frank M. Greene focused on developing specialized probes to measure magnetic near-fields around electromagnetic sources. The research addressed fundamental measurement challenges in electromagnetics, establishing methods for accurately detecting and quantifying magnetic field exposure in close proximity to EMF-generating devices.

Why This Matters

This foundational research represents a critical piece of the EMF measurement puzzle that often gets overlooked. The science demonstrates that accurate magnetic field measurement has been a recognized challenge since the 1970s, when researchers like Greene were developing the very tools we rely on today to assess exposure levels. What this means for you is that the magnetic fields from your household appliances, power lines, and electronic devices require specialized measurement techniques to properly quantify. The reality is that without reliable measurement methods, we cannot establish meaningful exposure standards or conduct credible health research. This technical groundwork laid the foundation for modern EMF assessment, making it possible to distinguish between safe and potentially harmful exposure levels in our daily environment.

Exposure Information

A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 10 MHz to 40 MHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 10 MHz to 40 MHzPower lines50/60 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Specific exposure levels were not quantified in this study.

Study Details

To develop two portable magnetic-field-strength probes for assessing occupational exposure from industrial RF power sources operating within the frequency range 10 MHz to 40 MHz.

The probes consist of small, single-turn, balanced loop antennas 10-cm and 3.16-cm in diameter. Each...

The probes consist of small, single-turn, balanced loop antennas 10-cm and 3.16-cm in diameter. Thei...

The NBS magnetic-field probes respond essentially to only the magnetic-field component of an E-M radiation field. Commercially available E-M survey meters have virtually no magnetic-field response. Consequently, a substantial magnetic-field could be present in an E-M radiation field and the commercially manufactured meters would indicate a negligible hazard. Specialized magnetic-field-strength probes are mandatory to characterize the magnetic-field component of RF radiation sources operable from approximately 10 MHz to 300 MHz. The probes can be used to accurately measure magnetic near fields which exist within a few centimeters of an RF radiation source. Precision magnetic near field measurements are possible because of proper antenna and probe design, a thorough knowledge of measurement errors, and a detailed outline of procedures to virtually eliminate measurement errors.

Cite This Study
Frank M. Greene (1975). DEVELOPMENT OF MAGNETIC NEAR-FIELD PROBES.
Show BibTeX
@article{development_of_magnetic_near_field_probes_g4642,
  author = {Frank M. Greene},
  title = {DEVELOPMENT OF MAGNETIC NEAR-FIELD PROBES},
  year = {1975},
  
  
}
No DOI on file for this study.

Quick Questions About This Study

Magnetic near-field probes are specialized instruments designed to measure magnetic field strength and characteristics in close proximity to electromagnetic sources like power lines, appliances, and electronic devices.
The 1970s marked growing awareness of EMF exposure concerns, making accurate measurement essential for establishing safety standards and conducting meaningful health research on electromagnetic field effects.
Near-field measurements capture magnetic field characteristics very close to the source, where field behavior is more complex and potentially more intense than far-field measurements taken at greater distances.
Early magnetic field measurement faced technical challenges including probe sensitivity, interference from other sources, and accurately capturing the complex behavior of electromagnetic fields near their sources.
This foundational measurement research enabled the accurate EMF exposure assessments used in today's health studies, providing the technical foundation for understanding electromagnetic field effects on human biology.