Engineer's report on KOWS-FM antenna
Following is a detailed copy of an engineer's report done in 2006 when the Occidental Arts & Ecology Center (OAEC) spent $3000 to ascertain if the same antenna intended for their organic farm now intended for Pleasant Hill Rd. was harmless. The engineer concluded that it would be harmless. I welcome any qualified person to dispute this information. I await a study that the opponents might want to do on which to base their fears.
Please note the exhibit which compares it to cordless phones, TVs, and other common things which people have in their homes. Following is the conclusion, which indicates that your homes are more dangerous.
CONCLUSIONS
The proposed KOWS-LP facility will exhibit exposures that will be an extremely small fraction of the standards accepted by the Bioelectromagnetics Society, and adopted by Europe, Canada, and the United States. The primary contributors of RF exposure for most Occidental residents are likely in their homes.
The nearest home to the antenna will receive an exposure from KOWS-LP of 0.0016% of the standards, or a protection factor of 3.1 million.
"
RF EXPOSURE SUMMARY prepared for Occidental Arts and Ecology Center
KOWS-LP (CP), Occidental, CA
prepared by Michael D. Brown, Brown Broadcast Services, Inc., November 15,2006
BROWN BROAdcAST SERVicES INCORPORATED
Michael D. Brown , 3740 S.W. Comus St. , Portland, Oregon 97219-7418, 503-245-6065
mail:[email protected]
RF EXPOSURE SUMMARY
KOWS-LP, OCCIDENTAL, CA - CONSTRUCTION PERMIT
OVERVIEW
This summary examines and quantifies the RF Exposure that will result from the new KOWS-LP FM radio facility. KOWS-LP holds an FCC Construction Permit for a 3-watt facility near Coleman Valley Road, northwest of Occidental, California.
BACKGROUND
Radiofrequency energy produces non-ionizing radiation, which at excessively high levels, causes cellular heating. This is separate and distinct from ionizing radiation, which changes the molecular and chemical structure of tissue, leading to damage. Nuclear fission, X-Rays, and Gamma Rays are examples of ionizing radiation.
Thousands of studies on non-ionizing radiation have been conducted over the past 50+ years. In 1978, the Bioelectromagnetics Society (BEMS) was formed. With participation from 38 countries and hundreds of the best scientists and engineers in the field, hundreds of papers have been published. Among the results of this half-century of research have been exposure standards. While there are some differences with other frequency ranges in different countries, the standards for 30 to 300 megahertz (MHZ) - which includes the entire FM broadcast and VHF TV bands, are uniform throughout the United States (American National Standards InstituteANSI), Europe (International Council on Non-Ionizing Radiation Protection - ICNIRP), and Canada (Safety Code 6).
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STANDARDS
There are two tiers of maximum RF exposure standards, as defined by ANSI, ICNIRP, and Canada. The more conservative standard is for general public/uncontrolled areas, with a more permissive standard for controlled/occupational areas where the person would be aware of the presence ofRF energy. These standards are power densities of200µw/cm2 (microwatts-persquare-centimeter), and 1 OOOµ w/crrr', respectively 30 to 300rnhz. This range of frequencies includes all FM and VHF TV broadcast stations. Allowable exposures are based on the threshold of detectable cellular heating, with a safety factor of 10 for occupational exposure, and 50 for the general public. It is important to observe that there are no verified reports of adverse effects to human health, for persons who have been exposed to radiofrequency fields below these standards.
KOWS-LP SPECIFICS
KOWS-LP has approval from the Federal Communications Commission to move their station to a new location, operating with 3 watts Effective Radiated Power (ERP), at an antenna height of21 meters (69 feet) above the ground. As a part of the FCC approval process, KOWSLP made RF exposure computations, and certified under penalty of perjury that it would meet the pertinent FCC/ANSI standards. As with all FM stations, KOWS-LP proposes to employ an antenna that concentrates most of its energy at the horizon, and relatively little towards the ground nearby. With a "worst-case" of the commercially-available FM antennas, KOWS-LP would exhibit a maximum ofO.33µw/cm2 of power density at 5.2 meters (17 feet) from the tower base. This represents just 0.17% of the ANSVICNIRP standards for the general public, or 0.0034% of the threshold of detectable cellular heating. As shown by the chart in Exhibit 1, the exposure drops off sharply with greater distances.
The nearest private property boundary to the antenna is approximately 150 meters, and the nearest inhabited house not on OAEC property is approximate 250 meters. At 150 meters, the predicted exposure is 0.0086µw/cm2, or 0.004% of the standards. At 250 meters it is 0.0032µw/cm2, or 0.0016% of the standards. At 1000 meters from the tower, in central Occidental, the "safety factor" (below detectable cellular heating) would be over 50 million.
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COMPARATIVE STUDY - MAJOR LOCAL EMITTERS
Radio and TV broadcast stations are not the only major emitters ofRF energy, but are some of the easiest to model. The following chart lists the major FM and TV broadcast emitters I within approximately 92km (57 miles) of "downtown" Occidentaf . This includes stations as far away as San Francisco. Individual significant stations were listed out to 45km (28 miles). The Power Densities were computed using the methods contained in Bulletin 65 of the Office of Engineering and Technology (OET) at the FCC.3 Free-space "line of sight" attenuation, without additional adjustments for terrain, foliage, buildings, etc, was assumed. The final column is the % of the FCC/ANSI standards for exposure in uncontrolled areas."
EXIDBIT2
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MAJOR LOCAL FM & TV EMITTERS
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The bar-graph below charts the stations tabulated in Exhibit 2. As can be seen, the top contributors ofRF energy in downtown Occidental are distant UHF TV stations - most of which are over 40km (25 miles) away. Some of these TV stations broadcast with as much as 5 million watts Effective Radiated Power. Indeed, there are over a dozen TV and FM stations in San Francisco that contribute more RF exposure in Occidental, than will KOWS-LP. This, despite them being located more than 80km (50 miles) away.
EXHIBIT 3
MAJOR LOCAL FM & TV EMITTERS - BAR GRAPH - FOR RESIDENTS OF OCCIDENTAL
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The total from all FM & TV stations is 0.033% of the ANSI standards. Adding KOWSLP to this group increases the exposure relative to the ANSI standard by 0.0001 %. As a percentage of the actual exposure, KOWS-LP adds 0.3%.
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For many persons, the primary sources ofRF exposure are right in their own homes. For example, the base station of an inexpensive 49mhz cordless phone system typically operates at roughly 10mw (10 milliwatts, or 0.01 watts) of power. At 10 feet (3 meters) away, this represents .09% of the ANSI standards, which would utterly swamp all the radio and TV station emitters for a resident of Occidental, as shown below.
EXHIBIT 4
MAJOR LOCAL FM & TV EMITTERS WITH CORDLESS PHONE ADDED - FOR RESIDENTS OF OCCIDENTAL
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EXHIBIT 5
MAJOR LOCAL FM & TV EMITTERS WITH CORDLESS PHONE ADDED - FOR RESIDENTS OF OCCIDENTAL -
RELATIVE PORTIONS OF TOTAL EXISTING EXPOSURE
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CONCLUSIONS
The proposed KOWS-LP facility will exhibit exposures that will be an extremely small fraction of the standards accepted by the Bioelectromagnetics Society, and adopted by Europe, Canada, and the United States. The primary contributors ofRF exposure for most Occidental residents are likely in their homes.
The nearest home to the antenna will receive an exposure from KOWS-LP of 0.0016% of the standards, or a protection factor of 3.1 million.
Signed,
Michael D. Brown, President, Brown Broadcast Services, Inc.
Certified Senior Radio Broadcast Engineer by the Society of Broadcast Engineers FCC Licensed First Class / General Class Radio Engineer since 1974
Preparing exhibits and applications before the FCC since 1983.
32 Years continuous experience in Radio Engineering
