DEVELOPMENT OF AN RF NEAR-FIELD EXPOSURE SYNTHESIZER (10 to 40MHz)
Frank M. Greene · 1976
Government agencies were developing specialized RF exposure equipment by 1976, showing early recognition of EMF health research needs.
Plain English Summary
This 1976 NIOSH technical report describes the development of equipment to artificially create radiofrequency electromagnetic fields in the 10-40 MHz range for research purposes. The synthesizer was designed to generate controlled near-field RF exposures, allowing researchers to study how these specific frequencies affect biological systems. This represents early government recognition of the need for standardized tools to investigate RF health effects.
Why This Matters
This technical report represents a pivotal moment in EMF research history. In 1976, the National Institute for Occupational Safety and Health recognized that studying RF health effects required sophisticated equipment capable of generating controlled electromagnetic exposures. The 10-40 MHz frequency range covered by this synthesizer includes bands used for CB radio, amateur radio, and industrial heating applications that workers and the public encounter regularly. What makes this significant is the timing. This was developed during an era when RF exposure standards were still being established, and government agencies were beginning to grapple with the biological implications of our increasingly electromagnetic world. The fact that NIOSH invested in developing specialized exposure equipment demonstrates early institutional awareness that RF fields warranted serious health investigation, not just engineering consideration.
Exposure Information
Specific exposure levels were not quantified in this study.
Study Details
To provide a means of independently generating high-level electric and magnetic near fields in the frequency range 10 to 40 MHz for use in evaluating occupational hazards resulting from exposure of industrial personnel to strong, non-ionizing, RF radiation
The synthesizer consists of a balanced, parallel-plate strip line to generate the "desired" electric...
The synthesizer can produce a fairly pure (high-impedance) E field of up to 5,000 volts per meter ov...
The RF radiation-exposure facility described in this report will enable researchers to independently generate hazard-level electric and magnetic fields for use in conjunction with their non-ionizing RF radiation-exposure programs being carried out in the frequency range 10 to 40 MHz. This RF near-field synthesizer, in conjunction with the electric, and magnetic near-field probes recently developed at NBS, will also enable researchers to evaluate any near-field effects encountered in connection with their studies of RF biological hazards. The synthesizer can be used to generate a fairly pure (high-impedance) electric field and a fairly pure (low-impedance) magnetic field over the above frequency range. These two fields can be adjusted essentially independently over wide ranges of magnitude, phase difference and relative spatial orientation in order to simulate various near-field configurations. The maximum RF driving power required is one kilowatt for each field system, depending upon the frequency and field level used. The recent discovery at NBS and elsewhere of the major roll played by the magnetic component of the field in the area of RF biological hazards to humans in this frequency range points up the need for suitable instrumentation for further evaluating this effect.
Show BibTeX
@article{development_of_an_rf_near_field_exposure_synthesizer_10_to_40mhz__g7292,
author = {Frank M. Greene},
title = {DEVELOPMENT OF AN RF NEAR-FIELD EXPOSURE SYNTHESIZER (10 to 40MHz)},
year = {1976},
}