How To Decide If A Cell Phone Antennae Can Be Installed On A Condominium Roof

Transcription

1 A CONDO ODYSSEY Condominiums, PCS Base Station Antennae, Radiation and Health Issues By Rudy Fliegl, B.A.SC., P.ENG., M.ENG., C.I.H. One hundred years ago, the wireless revolution began with Guglielmo Marconi s transatlantic transmission of a wireless signal from Europe to Signal Hill, Nfld. Marconi felt his wireless system could reach places wired systems could not. While the start of the wireless revolution involved Marconi s telegraph, voice signals soon became commonplace, and the competition between wireless and wired, or cabled, systems has continued to this day. During the 1980s, Marconi s wireless and Alexander Graham Bell s wired telephone converged to produce what we know as the analogue cellular telephone, or cellphone. In the 1990s, the cellphone further evolved into a digital version called a personal communication service (PCS) that allows telephony as well as a host of other services and works perfectly at its level of signal detection, which analogue does not. The PCS revolution has led to the placement, or sitting, of digital base station antennae onto condominium roofs and, with that, PCS electromagnetic radiation (EMR) in the microwave (MW) bands and perceived health hazards. An exploration of these issues can help condominium board members better understand and deal with decisions regarding the placement of PCS antennae in their communities. Why are PCS Base Station Antennae Important? Whether they are analogue or digital, the basic theory of all wireless cellular telephone systems is that, as cellphone users roam through a licensee s service area, their transmissions are sent to a nearby base station that connects them directly to the wired public telephone network (PTN). (Base stations have electrically powered transmitting and receiving equipment, towers and antennae to link battery-powered wireless hand-held cellphones to the PTN.) When contact with one base station weakens, another one nearby becomes available to sustain communication, and then another, and then another. While the theory remained sound, exploding use of wireless analogue hand-held telephones resulted in complaints of dropped calls and a need for additional base stations to fill in the holes in this otherwise seamless cell network. In addition, more and more people were drawn to the wireless analogue cellphone and businesses provided personnel with cellphones, allowing anyone to talk to anyone else, almost anywhere, at any time. Most young people have come to regard the cellular telephone as their individual rite of passage. Consequently, the number of analogue cellphones rose steadily, placing increased demands on the limited analogue frequencies available and resulting in a need for more base stations. Something had to be done, so the Canadian government introduced a far superior PCS in about With PCS, either you have an excellent digital signal at its detection level or you have nothing. In comparison, analogue service had varying quality, from excellent to barely understandable. PCS uses higher frequencies requiring more base station power than analogue to transmit signals the same distance. But higher power was unacceptable to a public already concerned about analogue cellular base station emissions, so less power is now used for PCS and smaller corresponding cells are the consequence. PCS antennae need some minimum height above ground to produce reasonably good

2 transmission paths and higher placements yield more uniform coverage within a given cell. All the above factors have resulted in a continuing demand for PCS base station sites with both high- and lowrise buildings as likely candidates this includes buildings belonging to condominium corporations. The Condo Roof as a Source of Income Since the beginning of condominiums, developers and local telecommunications providers have coveted condo rooftops. Today, the sitting of PCS antennae within communities has become very complicated with health, aesthetic, public policy, property devaluation concerns and the NIMBY (not in my back yard) syndrome. To further complicate the PCS base station issue, the 1996 American Telecommunications Act allowed tower operators to locate their cellular antennae just about anywhere throughout the U.S., as a result of pre-emption clauses in the legislation. The clauses created frustration in communities because Americans were rendered powerless to object to tower placement. Such concerns have now spilled into Canadian neighbourhoods. However, the current annual revenue of $10,000 to $30,000 being offered by PCS licensees remains tempting for cash-strapped condo boards that have available roofs and are struggling with annual operating budget increases. What is the EMS and What is EMR? Any discussion about PCS installations on condominium roofs requires a brief understanding of the electromagnetic spectrum (EMS) believe it or not, you already know more about EMS than you realize. Scientists call the major energy source surrounding us the electromagnetic spectrum. Within the spectrum are groups of frequencies that behave similarly. The EMS originates with extremely low frequencies (ELFs) near a static field and extends to the high-frequency gamma ray region, with each region characterized by discrete frequencies and wavelengths. Extremely low frequencies have the longest possible wavelengths. A common ELF is the 60-hertz frequency, used to deliver current in electrical wiring in homes. ELFs have electrical and magnetic fields; however, there is no electromagnetic radiation (EMR) emitted at these frequencies. Beyond the ELFs, the frequencies progressively increase. Radio frequencies (RFs) begin where EMRs start to be emitted from microcurrent-carrying antennae. The RF spectrum includes the range of short-wave frequencies used by Marconi in 1901, those emitted by cellular PCS telephones, radio signals, television signals and microwave (MW) frequencies used by microwave ovens. Radiation begins at the beginning of the RF spectra of the EMS. Moving to an even higher frequency, we enter the very important infrared (IR) range that is essential for our existence. While IR frequencies can be artificially produced, it is the natural IR component from our sun s solar wind that permits life on Earth by interacting with our planet to help heat it and drive our weather patterns. Above the IR spectrum is the visible (VIS) portion of the EMS, the only part that we can see with the naked eye. When you turn on an electric light bulb, its VIS components radiate outward in every direction and the distance propagated depends on the intensity of the source. One of the features that flashlights and today s PCS base station antennae

3 share is the ability to concentrate their EMR in a single direction this directed focus of EMR is called gain. Beyond VIS, frequencies become very energetic. This region includes ultraviolet (UV), X-ray and gamma ray portions of the EMS. The EMR emitted here is very harmful to people. What are the Health Risks of EMR? Although ELFs have electrical and magnetic fields, they do not emit radiation (EMR) and cannot cause ionization damage to human tissue. In 1997, a U.S. National Research Council committee carried out an exhaustive study of the literature and concluded that no clear, convincing evidence exists to show that residential exposure to electric and magnetic fields (EMFs) are a threat to human health. However, the committee suggested further research of the EMS was appropriate. While RFs do radiate, they do not have sufficient energy to cause ionization and the currently acknowledged health effects are thermal only, meaning they cause a heating action. However, the receptor must be close enough to the emission s source to cause thermal effects to occur. The IR and VIS portions of the EMS also release EMR and their health effects are also acknowledged to be thermal. They do not cause ionization to occur. Every day, we hear UV levels predicted so that we can limit our exposure by shielding ourselves or avoiding this harmful radiation because it degrades our skin. By using chlorofluorocarbon (CFC) refrigerants, people have damaged the protective ozone layer in the upper atmosphere and allowed harmful UV to rain down on us. (Ozone present in the upper atmosphere acts as a UV shield.) [For more information, see Chillers and CFCs, by Rudy Fliegl, in CM Condominium Manager, Summer 1992, p. 33.] Beyond UV, the X-rays and gamma rays cause significant ionization of our tissues, this destroys human cells and exposure is to be avoided as much as possible. EMR can be seen as energy spreading out in all directions from a source while losing its power as the distance from the source increases. Note that both sound and electromagnetic energy radiate outward in all directions from their source. EMR can be compared to fire because both give us comfort but can also harm us if we do not take appropriate precautions. The traditional ways man learned to control fire separation from the source, shielding, limiting intensity at the source, limiting the duration of exposure or total avoidance have become part of our accumulated knowledge and apply equally to the control of EMR. Health Standards Throughout time, we have learned through experience and research. I do believe more research is needed about the health effects of the EMS. However, I fall back on the scientific knowledge I have today to avoid over-reacting to perceived hazards to populations far removed from rooftop PCS antennae emitting EMR. The health effects along the EMS vary with frequency. The higher the frequency, the greater the potential harm to people in the absence of appropriate controls. Today s exposure standard for PCS base station EMR is included in Health Canada s Safety Code #6, based on thermal effects. We fear what we do not know or understand. When information is presented in the media, we rarely question the sources and tend to accept it as fact. If you examine

4 literature related to cellphones, their antenna emissions or their likely health hazards, you will find endless references with scholarly research, some with not the best research, and still others with downright bad science, that remain in the references forever. To protect myself from misinformation, whenever I examine literature references, I look for verifiable and believable facts and seek answers to the following questions: Was the research published in a well-known, well-read and widely circulated peerreviewed publication? Was the published research reviewed, then successfully reproduced, and then repeated by the original researcher s peers? Was the peer-reviewed work of sufficient importance to be considered by the appropriate consensus standards-setting organizations that have been established to protect our health? In my opinion, unless these three minimum questions are answered, any research that you uncover has little value other than to inflame reactionary viewpoints. Some of the consensus standards-setting organizations you will encounter in the literature are: American National Standards Institute (ANSI), Canadian Standards Association (CSA), Institute of Electrical and Electronic Engineers (IEEE), National Council for Radiation Protection (NCRP), American Conference of Governmental Industrial Hygienists (ACGIH), Royal Society of Canada (RSC), Health Canada and the World Health Organization (WHO). While these bodies do not always agree on the same numerical exposure value, their resulting standards tend to be very similar. I should also point out that WHO has been engaged in a study to look into the health effects of the entire EMS and its report is expected by What Should a Condominium Board Do? Clearly, there is controversy about radiation at MW frequencies used by PCS cellular base stations. However, any condominium board considering installation of PCS base station towers and antennae should let their membership make that decision. Furthermore, if a condo s membership is to make an informed decision, the board must educate its owners about all the issues involved. If the decision to proceed with an installation is made, then appropriate legal and technical advice is needed so the provider s agreement has appropriate safeguards to protect the condo corporation. The following are some of these safeguards. Antennae. PCS employs high-gain, highly directive antenna equipment and the agreement should contain the number of antennae the provider wishes to install. In many rooftop installations, there are two PCS antennae for each of the four compass directions or eight in total and the service provider should be held to this number. The base station frequency used should also be mentioned and the provider should be held to this as well as to the maximum transmission power to be used. The height of the antennae on towers is also a consideration and should be high enough so that no significant spurious EMR will occur. Roofs. The roofs on most condominiums are high tech and care should be taken to ensure the licensee installing the antennae and towers does not harm them. Installation should include proper support bases, guy wires, adequate grounding and the like. It must be noted that condominium roofs are restricted-entry common elements and appropriate signage should be posted at roof entry doors as is presently done under Ontario s window cleaning regulations.

5 EMR Patterns. Most service operators have staff engineers capable of theoretically calculating radiation patterns of antennae ( modelling ) prior to installation. Both nearfield and far-field estimates should be included in the modelling and boards should insist these become part of any signed agreement. (The near field is that immediately in front and nearby an antenna s face while the far field is some distance outward, where the general public might be in the path of emissions.) Compliance with Standards. Any board signing an agreement with a service provider should insist it contain the standards for exposure for workers in the near field and for the public in far fields. Exposures should be measured on a regular basis and there should be compliance with all present and future standards, with this data kept in an on-site logbook. Changes. The condominium s board should be informed of, and approve, any changes or modifications to the original installation. This should trigger exposure re-measurement. In addition, whenever there is a complaint, the service operator must conduct exposure measurements. Other Concerns. How will the corporation s contractors be protected when working near the source of MW emissions? What if work needs to be done to the corporation s roof or swing stages are to be used? Are the antennae safe and appropriate distances from nearby buildings to protect their dwellers? Who will pay for the supply of electrical power? If damage to the condominium corporation occurs as a result of the installation, how is it to be handled by the service provider? Finally, the board should deal with one service provider only and not let the roof become an antenna farm for many providers because many sources cause multiple EMR effects. Rudy Fliegl, B.A.Sc., P.Eng., M.Eng., C.I.H., president of Fliegl Engineering, specializes in health and safety in the work environment and is also a certified industrial hygienist. He is a past-president of YCC #274 and since 1984, he has been chairperson of the Condominium Cable Communications (C-3) Committee.