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RF Radiation and Electromagnetic Field Safety

Preprinted from the Chapter 9 of the 1997 ARRL Handbook for Radio Amateurs, Copyright © 1996 American Radio Relay League, Inc. This material may be reproduced for noncommercial use, provided that credit is given.
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  RF Safety References

IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 KHz to 300 GHz, IEEE Standard C95.1-1991, Institute of Electrical and Electronics Engineers, New York, 1992.

For an unbiased assessment of ELF hazards, read the series in Science, Vol 249 beginning 9/7/90 (p 1096), continuing 9/21/90 (p 1378), and ending 10/5/90 (p 23). Also see Science, Vol 258, p 1724 (1992). You can find Science in any large library.

An excellent and timely document is available on the Internet by an anonymous FTP from:, /pub/usenet-by-group/news.answers/powerlines-cancer-faq/part1 and part2.

The Environmental Protection Agency publishes a free consumer-level booklet entitled, "EMF in Your Environment," document 402-R-92-008, dated December 1992. Look for the nearest office of the EPA in your phone book.

W. R. Adey, "Tissue Interactions with Nonionizing Electromagnetic Fields," Physiology Review, 1981; 61:435-514.

W. R. Adey, "Cell Membranes: The Electromagnetic Environment and Cancer Promotion," Neurochemical Research, 1988; 13:671-677.

W. R. Adey, "Electromagnetic Fields, Cell Membrane Amplification, and Cancer Promotion," in B. W. Wilson, R. G. Stevens, and L. E. Anderson, Extremely Low Frequency Electromagnetic Fields: The Question of Cancer (Columbus, OH: Batelle Press, 1989), pp 211-249.

W. R. Adey, "Electromagnetic Fields and the Essence of Living Systems," Plenary Lecture, 23rd General Assembly, International Union of Radio Sciences (URSI), Prague, 1990; in J. Bach Andersen, Ed., Modern Radio Science (Oxford: Oxford Univ Press), pp 1-36.

Q. Balzano, O. Garay and K. Siwiak, "The Near Field of Dipole Antennas, Part I: Theory," IEEE Transactions on Vehicular Technology (VT) 30, p 161, Nov 1981. Also "Part II; Experimental Results," same issue, p 175.

R. F. Cleveland and T. W. Athey, "Specific Absorption Rate (SAR) in Models of the Human Head Exposed to Hand-Held UHF Portable Radios," Bioelectromagnetics, 1989; 10:173-186.

R. F. Cleveland, E. D. Mantiply and T. L. West, "Measurements of Environmental Electromagnetic Fields Created by Amateur Radio Stations," presented at the 13th annual meeting of the Bioelectromagnetics Society, Salt Lake City, Utah, Jun 1991.

R. L. Davis and S. Milham, "Altered Immune Status in Aluminum Reduction Plant Workers," American J Industrial Medicine, 1990; 131:763-769.

F. C. Garland, et al, "Incidence of Leukemia in Occupations with Potential Electromagnetic Field Exposure in United States Navy Personnel," American J Epidemiology, 1990; 132:293-303.

A. W. Guy and C. K. Chou, "Thermograph Determination of SAR in Human Models Exposed to UHF Mobile Antenna Fields," Paper F-6, Third Annual Conference, Bioelectromagnetics Society, Washington, DC, Aug 9-12, 1981.

C. C. Johnson and M. R. Spitz, "Childhood Nervous System Tumours: An Assessment of Risk Associated with Paternal Occupations Involving Use, Repair or Manufacture of Electrical and Electronic Equipment," International J Epidemiology, 1989; 18:756-762.

D. L. Lambdin, "An Investigation of Energy Densities in the Vicinity of Vehicles with Mobile Communications Equipment and Near a Hand-Held Walkie Talkie," EPA Report ORP/EAD 79-2, Mar, 1979.

D. B. Lyle, P. Schechter, W. R. Adey and R. L. Lundak, "Suppression of T-Lymphocyte Cytotoxicity Following Exposure to Sinusoidally Amplitude Modulated Fields," Bioelectromagnetics, 1983; 4:281 -292.

G. M. Matanoski et al, "Cancer Incidence in New York Telephone Workers," Proc Annual Review, Research on Biological Effects of 50/60 Hz Fields, U.S. Dept of Energy, Office of Energy Storage and Distribution, Portland, OR, 1989.

D. I. McRee, A Technical Review of the Biological Effects of Non-lonizing Radiation, Office of Science and Technology Policy, Washington, DC, 1978.

G. E. Myers, "ELF Hazard Facts" Amateur Radio News Service Bulletin, Alliance, OH, Apr 1994.

S. Milham, "Mortality from Leukemia in Workers Exposed to Electromagnetic Fields," New England J Medicine, 1982; 307:249.

S. Milham, "Increased Mortality in Amateur Radio Operators due to Lymphatic and Hematopoietic Malignancies," American J Epidemiology, 1988; 127:50-54.

W. W. Mumford, "Heat Stress Due to RF Radiation," Proc IEEE, 57, 1969, pp 171-178.

W. Overbeck, "Electromagnetic Fields and Your Health," QST, Apr 1994, pp 56-59.

S. Preston-Martin et al, "Risk Factors for Gliomas and Meningiomas in Males in Los Angeles County," Cancer Research, 1989; 49:6137-6143.

D. A. Savitz et al, "Case-Control Study of Childhood Cancer and Exposure to 60-Hz Magnetic Fields," American J Epidemiology, 1988; 128:21-38.

D. A. Savitz et al, "Magnetic Field Exposure from Electric Appliances and Childhood Cancer," American J Epidemiology, 1990; 131:763-773.

I. Shulman, "Is Amateur Radio Hazardous to Our Health?" QST, Oct 1989, pp 31-34.

R. J. Spiegel, "The Thermal Response of a Human in the Near-Zone of a Resonant Thin-Wire Antenna," IEEE Transactions on Microwave Theory and Technology (MTT) 30(2), pp 177-185, Feb 1982.

B. Springfield and R. Ely, "The Tower Shield," QST, Sep 1976, p 26.

T. L. Thomas et al, "Brain Tumor Mortality Risk among Men with Electrical and Electronic Jobs: A Case-Controlled Study," J National Cancer Inst, 1987; 79:223-237.

N. Wertheimer and E. Leeper, "Electrical Wiring Configurations and Childhood Cancer," American J Epidemiology, 1979; 109:273-284.

N. Wertheimer and E. Leeper, "Adult Cancer Related to Electrical Wires Near the Home," Internat'l J Epidemiology, 1982; 11:345-355.

"Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields (300 kHz to 100 Ghz)," ANSI C95.1-1991 (New York: IEEE-American National Standards Institute).

"Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic fields," NCRP Report No. 86 (Bethesda, MD: National Council on Radiation Protection and Measurements, 1986).

US Congress, Office of Technology Assessment, "Biological Effects of Power Frequency Electric and Magnetic Fields-Background Paper," OTA-BP-E53 (Washington, DC: US Government Printing Office), 1989.

  Table 9.1--Typical 60-Hz Magnetic Fields Near Amateur Radio Equipment & AC-Powered Appliances

Values are in milligauss.
Item                Field     Distance       

Electric blanket    30-90     Surface        

Microwave oven      10-100    Surface        

                    1-10      12"            

IBM personal        5-10      Atop monitor   

                    0-1       15" from       

Electric drill      500-2000  At handle      

Hair dryer          200-2000  At handle      

HF transceiver      10-100    Atop cabinet   

                    1-5       15" from       

1-kW RF amplifier   80-1000   Atop cabinet   

                    1-25      15" from       

(Source: measurements made by members of the ARRL RF Safety Committee)

  Table 9.2--Typical RF Field Strengths Near Amateur Radio Antennas

A sampling of values as measured by the Federal Communications Commission and Environmental Protection Agency, 1990
Antenna Type        Freq    Power   E       Location         

                    (MHz)   (W)     (V/m)                    

Dipole in attic     14.15   100     7-100   In home
Discone in attic    146.5   250     10-27   In home          

Half sloper         21.5    1000    50      1 m from base    

Dipole at 7-13 ft   7.14    120     8-150   1-2 m from       

Vertical            3.8     800     180     0.5 m from base  

5-element Yagi at   21.2    1000    10-20   In shack         
   60 ft                                                        
                                    14      12 m from base   

3-element Yagi at   28.5    425     8-12    12 m from base   
   25 ft                                                        

Inverted V at       7.23    1400    5-27    Below antenna    
   22-46 ft                                                     

Vertical on roof    14.11   140     6-9     In house         

                                    35-100  At antenna       

Whip on auto roof   146.5   100     22-75   2 m from         

                                    15-30   In vehicle       

                                    90      Rear seat        

5-element Yagi at   50.1    500     37-50   10 m from        
   20 ft                                    antenna

  Table 9.3--RF Awareness Guidelines

These guidelines were developed by the ARRL RF Safety Committee, based on the FCC/EPA measurements of Table 9.2 and other data.
  • Although antennas on towers (well away from people) pose no exposure problem, make certain that the RF radiation is confined to the antennas' radiating elements themselves. Provide a single, good station ground (earth), and eliminate radiation from transmission lines. Use good coaxial cable, not open-wire lines or end-fed antennas that come directly into the transmitter area.

  • No person should ever be near any transmitting antenna while it is in use. This is especially true for mobile or ground-mounted vertical antennas. Avoid transmitting with more than 25 W in a VHF mobile installation unless it is possible to first measure the RF fields inside the vehicle. At the 1-kW level, both HF and VHF directional antennas should be at least 35 ft above inhabited areas. Avoid using indoor and attic-mounted antennas if at all possible.

  • Don't operate high-power amplifiers with the covers removed, especially at VHF/UHF.

  • In the UHF/SHF region, never look into the open end of an activated length of waveguide or point it toward anyone. Never point a high-gain, narrow-bandwidth antenna (a paraboloid, for instance) toward people. Use caution in aiming an EME (moonbounce) array toward the horizon; EME arrays may deliver an effective radiated power of 250,000 W or more.

  • With hand-held transceivers, keep the antenna away from your head and use the lowest power possible to maintain communications. Use a separate microphone and hold the rig as far away from you as possible.

  • Don't work on antennas that have RF power applied.

  • Don't stand or sit close to a power supply or linear amplifier when the ac power is turned on. Stay at least 24 inches away from power transformers, electrical fans and other sources of high-level 60-Hz magnetic fields.

Thanks: American Radio Relay League, Inc.

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  RF Safety Reference Books

Click on a Title Below for a Direct Link to Purchase

Buy this book
RF/Microwave Interaction with Biological Tissues (Wiley Series in Microwave and Optical Engineering), by Andr@#eacute; Vander Vorst, Arye Rosen, Youji Kotsuka. Hardcover, 344 pages, 1st edition (January 30, 2006).

Focusing on frequency ranges from 100 kHz to 10 GHz, RF/Microwave Interaction with Biological Tissues is aimed at medical applications. However, several of the chapters address fundamentals in Electromagnetics, the penetration of RF/microwaves into biological tissues; the near field of an antenna; and microwave measurements.
Buy this book
Rf and Microwave Radiation Safety Handbook, by Ronald Kitchen. Hardcover, 448 pages, 2nd edition (October 24, 2001).

This is a good practical book for anyone involved in RF safety work. There are many useful references and illustrations. Topics include an introduction to RF and microwave radiation, sources and effects of RF radiation, the development of safety standards, calculation of RF field quantities, and more.
Buy this book
Radio-Frequency and ELF Electromagnetic Energies: A Handbook for Health Professionals, by R. Timothy Hitchcock and Robert M. Patterson. Hardcover, 522 pages (February 22, 1995).

Tailored especially for the working health professional, this book is a practical guide to understanding, evaluating, and controlling the human health effects of radio-frequency (RF) and extremely low frequency (ELF) electromagnetic fields. Providing a perfect blend of applied information and theory, you'll find all you need to know about radiation safety, from the basic physics to how to set up a safety program.

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