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By Greg Lapin, N9GL
Chairman, ARRL RF Safety Committee
August 7, 2000
My "July" column is tardy because I've been overseas. During my travels, I discovered that other countries do not face the same kinds of RF exposure rules that we have here in the US. So, where does that leave a US ham operating in another country?
I just returned from a trip to France. Thanks to the agreement between the US and the European CEPT, I was able to operate a ham radio during my travels. These arrangements allow a ham from the US to operate in a CEPT-participating country with privileges based on a combination of license class and the corresponding rules of the member country. There are some frequency allocations that you have to get familiar with when visiting a country. In France, for instance, SSB privileges from 7.040 to 7.100 MHz, but in all of Europe, the 40 meter band ends at 7.100 MHz. It is also legal in France to operate SSB from 14.100 to 14.150 MHz and from 21.150 to 21.200 MHz.
As long as I was checking out the Amateur Radio regulations in France (Réglementation radioamateur), I thought I'd look to see what their RF safety regulations were, and how they differed from ours. After brushing up on my rusty French, I was a little surprised at what I found. The French RF safety regulations are very different from those in the US--they do not exist! Likewise, the CEPT recommendation (T/R 61-01) that codifies general Amateur Radio regulations common to all its member countries does not mention RF safety.
In the United Kingdom, the rules governing Amateur Radio operation (BR68) contain a table ("schedule") of frequency allocations and power limitations. The only mention of RF safety follows that table. It does not contain much detail, but rather is a general caution:
Notes to the Schedule
(a) Maximum Power refers to the rf power supplied to the antenna. Maximum power levels will be specified by the peak envelope power (pep).
(b) In all frequency bands, high intensities of RF radiation may be harmful and safety precautions should be taken, particularly in locations to which people have access. Advice concerning safe levels of exposure to RF radiation is provided by the National Radiological Protection Board.
Does the absence of specific RF safety regulations in the French and CEPT Amateur Radio regulations mean that while I was operating in France I was not obligated to make sure that my transmissions were safe to my family, others and myself? I suppose the legal answer is "yes." Of course, there may be some general civil law in France that would cover this situation, but it is not well defined with regard to radio waves. Just as I could transmit SSB on frequencies that can only be used for CW in the US, I could legally overexpose people to my transmissions while in France. But, why would I want to?
In my travels, I was limited to stringing a dipole antenna across my hotel room. With my family of five present during the best hours for DX propagation, the potential for dangerous operation existed. Even if the Réglementation radioamateur did not specifically require it, I preferred to operate a station that was RF-safe. In addition to endangering my family, I would have looked pretty silly--or at least hypocritical--if I didn't make sure that the exposures from my transmissions were below the accepted Maximum Permissible Exposure (MPE) limits.
Since I was unable to move my antenna farther away from people, I made sure that they kept their distance from the wire and that I operated with as little power as necessary. The transceiver that I was using, the SGC SG-2020, had a maximum output power of 20 W and I made many of my QSOs with the transmitter set between 5 and 10 W. I also tended to use lower frequencies (most of my contacts were on the 30 and 20-meter bands), since the MPE limits increase as frequency decreases in the HF bands. I listened a lot and only transmitted when necessary, keeping transmissions short. These simple precautions helped to insure that the MPE limits for my family, and any people in the rooms next to and above mine, would not be exceeded.
Why Regulate?
A common libertarian view favors a decrease (or absence) of government regulation. I met many people in France who hold that view, leading me to believe that this might be a general trait of the French people. This is in keeping with the absence in France of regulations that I have become used to in the US. In particular, I found that there are no enforced electrical codes for private homes in Nice, but that is a whole other story. Certainly, Réglementation radioamateur, T/R 61-01, and BR68 are far smaller than Part 97.
I have heard many comments about the FCC RF safety regulations. Some people find them to be cumbersome and consider them to be bureaucratic nonsense. They don't think that such rules are necessary and do not believe that they need to be told how to be RF-safe.
I disagree with this attitude. When the FCC RF safety regulations were written, and then later applied to hams, I welcomed them. RF safety is less tangible than many other safety issues. If you have exposed electrical wires in your home, it is pretty obvious that they are dangerous. No one should need to tell you that a dead tree should be removed before it falls on someone. If, however, your station exposes people to unsafe levels of RF, it is not immediately obvious. You often cannot sense that your body is absorbing too much RF energy, and it requires sophisticated measuring devices or complicated modeling estimates to tell that a dangerous situation is occurring.
The FCC RF safety regulations for hams are very wisely written. They not only require certain standards of operation but also provide for training of all newly licensed hams to familiarize them with the subject. Thus, the FCC regulations intend that hams be trained to understand RF safety. With this kind of understanding, hams can apply RF safety principles wherever they operate, whether legally required to or not. As a US-licensed ham operating in France, that part of the FCC regulations followed me no matter where I transmitted.
By providing a set of guidelines that we are required to follow with regard to human exposure to our transmissions, the FCC has given us a tool that we can use to help insure safety. The FCC RF safety regulations provide us with a legitimacy to help us assure the public that we are not causing them any harm. The regulations are based on conclusions arrived at by the scientific community after reviewing over a thousand research studies on the topic. The person at the FCC who is responsible for RF safety is a scientist who is involved in the process of standardization and is intimately aware of the issues that have been considered in deriving the MPE limits.
Think of the advantages of having the FCC regulate RF safety. Anti-RF hype is in the news often, usually dealing with cellular telephones. If your neighbor is frightened by this and makes the connection that hams are transmitting the same stuff as cellular telephones, will they believe us when we say that our radios are safe? After all, we are transmitting far more power than cell phones. Having FCC regulations that specify what levels are safe goes a long way toward convincing people that we are aware of the problem and have determined that there is no danger.
The FCC has made it much easier for us to verify that we are in compliance with the regulations, providing us with worksheets and tables of numbers that describe the fields around the most common antennas. If your neighbors are still not convinced, they can contact the FCC and an engineer will review your calculations. It would cost you thousands of dollars to hire a consultant to verify that your exposure evaluation was done correctly. Because there are FCC RF safety regulations, the FCC is obligated to deal with public concerns, which usually means that they make a determination that your station is in compliance and don't charge you anything. The FCC is interested in keeping you on the air as long as you follow the regulations.
What is Safe?
As I've been stressing from month to month in my column, the science of RF safety is extremely complicated, with a large amount of conflicting information to consider. The FCC is not a health and safety organization, but a regulatory one. They have chosen to subscribe to a combination of standards that have already been published and accepted by the scientific community. The standards are developed by hundreds of volunteer experts in the field of RF effects over many years. They take into account all related research that has been performed over the past 30 years, which numbers over 1000 studies.
The National Council on Radiation Protection and Measurements, NCRP, (not to be confused with the National Radiological Protection Board, NRPB, in Great Britain) is chartered by the US Congress to develop information and recommendations concerning radiation protection. Their latest publication to standardize safe levels of RF exposure is entitled Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Fields, NCRP Report No. 86, Bethesda, Maryland, 1986.
The Institute of Electrical and Electronic Engineers--IEEE--RF safety standard is updated every decade or so to take into account new information. It is then reviewed by the American National Standards Institute--ANSI--and usually accepted verbatim. The latest published version of the standard is ANSI/IEEE C95.1-1992. A new revision is currently in the works and is scheduled to be completed in 2001.
The FCC has taken the best information and interpretation about RF safety that is available and generated a set of rules that we all must follow. If future revisions of the standards identify different exposure levels that are considered to be safe the FCC would most likely adopt the new levels. It is encouraging to note that there is very little difference between the NCRP and ANSI/IEEE standards, and the successive revisions of the IEEE standard have not had any major changes in RF exposure levels that are considered to be safe. This implies that we should not expect any drastic changes in the future. After 30 years of research it is unlikely that a new danger will suddenly be discovered.
If you plan to operate in another country, make sure you follow that nation's regulations regarding Amateur Radio, but don't forget about the ones that we have at home, particularly when it comes to RF safety.
Editor's note: Greg Lapin, N9GL, started working in the RF safety world after spending many years first studying cardiac function imaging and then brain tumor kinetics. He serves as chairman of the ARRL RF safety Committee and as a member of the IEEE Committee on Man and Radiation. A former professor of Biomedical Engineering and Neurology at Northwestern University, Lapin now works as a consulting professional engineer in the electronics industry. He was first licensed while a teenager in 1969 and continues to be fascinated by virtually all aspects of Amateur Radio. One of his many interests is electronic design, and he is the author of Chapter 8, "Analog Signal Theory and Components" in The ARRL Handbook for Radio Amateurs. His non-ham interests include making things grow in his garden and serving as commissioner of the local children's softball league. At other times--when he is not working or helping his kids with their homework--you might find him with the local emergency services agency, climbing his tower, building a new QRP rig, playing with his APRS setup, responding to QSL cards, going off on a DXpedition, or trying to get that "new one." You can reach him by email at g.lapin@ieee.org.
