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Notes Chapter 3
<br /> 'Static electricity is a collection of electrical charges that are nor in motion.Moving electrical charges
<br /> comprise electric current.
<br /> 2Typically,a diesel engine,or a steam,water,or wind turbine causes a magnet to rotate near a large coil of
<br /> wire.The rotating magnetic field induces an electric current to flow out from the coil and into the power
<br /> grid. Electric motors are essentially electric generators operating in reverse.They use attractive and repul-
<br /> sive magnetic forces generated by electromagnets to convert electricity into mechanical power.
<br /> 3Radio waves and other forms of electromagnetic radiation such as ultraviolet,X,and gamma rays had
<br /> nor yet been discovered.
<br /> That is how sunlight reaches the Earth.Sound,by contrast, is a pressure wave that can only propagate
<br /> through matter(air,water,or a solid).Sound cannot travel through empty space.
<br /> 5This means that some electrons are closer to the nucleus than others,and therefore feel a greater electrical
<br /> attractive force.Also,unlike the solar system,where each planet has a unique orbit,there can be more
<br /> than one electron at a given distance from the nucleus.
<br /> 6This is how microwave ovens operate.Microwaves are electromagnetic waves higher in frequency than
<br /> vhf television signals,but lower in frequency than infrared (heat)waves.
<br /> 7Another established thermal effect(again,one not tied to public exposures to fields from base stations)
<br /> is microwave hearing.An RF field,pulsed on and off at an AF rate,can stimulate physical vibrations in
<br /> the cochlea—the inner-ear organ that converts physical vibrations into nerve impulses.A person perceives
<br /> such vibrations as a physical sound,even though no one can"hear"RF fields in the normal sense of the
<br /> M word.Microwave hearing appears to be a mere scientific curiosity that sometimes occurs in the immediate
<br /> vicinity of a transmitting antenna.There are no documented claims that the phenomenon has permanently
<br /> effected anyone who has experienced it.
<br /> 8That is because we are warm-blooded.One participant at the Federal Focus Base Station Symposium
<br /> observed that the human body,acting as a`black body radiator,"typically emits microwave energy at levels
<br /> of 25 nanowatts per square centimeter(nW/cm2)or 0.025 microwatts per square centimeter(.iW/cm2).
<br /> One microwatt is one one-millionth of a watt,and one nanowatt is one one-trillionth of a watt.So,one
<br /> microwatt per square centimeter equals 1000 nanowatts per square centimeter.
<br /> 9The other standards discussed in the FCC's Notice of Proposed Rule Making are:the 1986 standard
<br /> promulgated by the National Council on Radiation Protection and Measurements(NCRP),a nonprofit
<br /> corporation chartered by Congress in 1964 to collect,analyze,develop,and disseminate information and
<br /> recommendations about radiation protection;and the 1988 standard published by the International
<br /> Radiation Protection Association(IR.PA).
<br /> 10 he Food and Drug Administration has an emission standard(as opposed to an exposure standard)
<br /> that defines acceptable levels of RE leakage from microwave ovens.In the last decade,the Environmental
<br /> Protection Agency(EPA)was developing federal guidelines for public exposure to RF power.However,
<br /> the EPA suspended that effort in the late 1980s.The EPA is now showing renewed interest in the issue,
<br /> and may release such guidelines later this year.
<br /> 11ANSI interest categories include producers,users,and general interests.One can break these categories
<br /> down further into consumers,directly affected members of the public,distributors and retailers,industrial/
<br /> commercial,insurance,labor,manufacturers,professional societies,regulatory agencies, test laboratories,
<br /> and trade associations.Dominance means a position or exercise of dominant authority,leadership,or
<br /> influence by reason of superior leverage,strength,or representation to the exclusion of fair and equitable
<br /> consideration of other viewpoints.To avoid dominance,no single interest category should comprise more
<br /> 4111 than one-third of a standards committee dealing with safety issues,or no single interest category should
<br /> constitute a majority of the membership of a committee dealing with product standards.
<br /> 12Substantial agreement means more than a simple majority,but it does not require unanimity.All views
<br /> and objections must have been considered,and an effort made toward their resolution.
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