13 Planning Commission Calendar 1997
January —._ April July October
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11th -Annual Meeting 5th -9th APA Nation Conference 14th -Workshop
14th -Workshop 8th -Workshop 8th -Workshop
21st- Thompson-City Council 21st-Sullivan-City Council 21st-Kuester-City Council 20th Cote-City Council
p y 22nd-PlanningCommission 28th - Planning Commission
28th-Planning Commission 22nd-Planning Commission
February May August ' November
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11th -Workshop 13th -Workshop 12th -Workshop 11th -Workshop
18th -Anderson-City Council 19th -Minton-City Council 18th - Thompson-City Council 17th- Sullivan-City Council
24th -Joint Mtg.w/City Council 27th-Planning Commission 26th -Planning Commission 25th -Planning Commission
&Plan. Dept.Annual Report
25th -Planning Commission
March June September December
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11th -Workshop 10th-Workshop 9th Workshop
17th- Cote-City Council 16th -Mesich-City Council 15th -Anderson-City Council 9th Workshop
25th P ing Commission 24th Planning Commission 23rd-Planning Commission 15th -Minton-City Council
Oh -26th State Planning Conf. 23rd-Planning Commissi.
tofMEMORANDUM
y
lk •
River TO: Planning Commission
FROM: Scott Harlicker, Planning Assistant 's
DATE: January 3, 1997
SUBJECT: Information on Cellular Towers
Attached is some supplemental information on the cellular communication
industry. The document titled " Federal Focus National Symposium on
Wireless Transmission Base Station Facilities" was put out by the wireless
industry and represents an industry slant. However, there is some good
background information on the industry an their base station siting
procedures. Also included is some background information on the
Telecommunications Act of 1996. The City of Ramsey is considering adopting
an ordinance regulating towers and antennas; a copy of their proposed
ordinance is included in the packet. The proposed ordinance is on their
• January 7th Planning Commission meeting.
1111
13065 Orono Parkway • P.O. Box 490 • Elk River, MN 55330 • (612) 441-7420 • Fax: (612) 441-7425
•
Federal Focus
National Symposium
on Wireless
Transmission Base
Station Facilities:
A Tutorial
Funded by
•
Wireless Technology Research, LL.C.
:r.
✓Yid
� a
�Y¢
_Yp
Federal Focus, Inc.
11 Dupont Circle, NW
Washington, DC 20036
Telephone: (202) 797-6368
4111 Telecopier: (202) 939-6969
Agenda
4110
Federal Focus National Symposium on
Wireless Transmission Base Station Facilities
Sponsored by:
Scientific Advisory Group on Cellular Telephone Research
University of Pennsylvania
Faculty Club
36th&Walnut Streets
Philadelphia, Pennsylvania
October 28, 1994
8:00-9:00 AM Registration&Brealdast
9:00-9:15 AM Opening Remarks
Introductory Statement
Discussions on Wireless Transmission Base Station Fndliips
9:15- 10:45 AM Session 1
BACKGROUND:DESCRIPTION OF CURRENT AND PLANNED
TECHNOLOGIES
10:45- 11:00 AM Break
11:00- 12:45 PM Session 2
41110
TYPICAL EXPOSURES TO BASE STATION RF AND EXPOSURE
STANDARDS
What are Typical Exposures to Base Station RF?
What Do Field Measurements of Base Station Emissions Indicate?
12:45- 1:45 PM Lunch
1:45-2:45 PM Session 3
BASE STATION FACILITIES AND FT FCI ROMAGNETIC
INTERFERENCE(EMI)OR COMPATIBILITY(EMC)
EMI:Non-Medical Issues
2:45-3:00 PM Break
3:00-430 Session 4
LAND USE ISSUES
How Should Base Station Siting Projects be Managed?
Can Base Station Facilities be Successfully Sited on Public School Property?
430-4:45 PM Break
4:45-5:45 PM Session 5
GENERAL AL DISCUSSION,FLOOR STATEMENTS,AND CONCLUSIONS
5:45-6:00 PM Summation and Closing •
41
•
Power Flux Density-The degree of con- Association for the Advancemeru of Medical
centration of radio signal power(such as one Instrumentation.
rrucroa.art) in a given unit of area(such as Spectrum-The full range of frequencies
one square centimeter).
occupied by radio waves,infrared waves,
Preamplifier-An electronic component visible light, ultraviolet,X,and gamma rays.
which boosts the strength of low-level input
signals. In audio systems,a preamplifier TDMA-A means of transmitting more
strengthens the weak output signal from a than one signal over a givencommunications
magnetic phonograph cartridge to a level circuit by breaking up ecirhinal into a
usable by a power amplifier. series of sequential samples,assigning a
particular"window"in pine to each signal,
Preclusion-Prevention; in radio contexts, and then sequentially transmitting the
the prevention of the use of a given frequency samples of different signalsin.their assigned
or frequencies in a given area due to the use time windows; also called time division
of the same or adjacent frequencies by others. multiplexing(TDM). Short far Tune
Division Multiple Access.
Range-The geographic area within which a
radio system provides effective coverage. Telephone Switching Equipment-
Radio Fre quer y-A well above Electromechanical or electronic equipment
"� for the routing of telephone calls.
the range of human hearing.Abbreviated as
RF. Thermal Exposure-Exposure to radio-
eceiver-An electronic device which fray potver at levels which cause
measurable warming of biological tissue.
converts radio-frequency currents into audio
or video programming or electronic data. Time Division Multiple Access-See
TDMA.
Resonance-A condition in which an elec-
tronic circuit responds strongly to a particular Transmitter-An electronic device which
frequency. converts power frvrvt a battery or the electric
Resonant-A circuitdisplayi utility into radio-frequency current for the
ng ' purpose of serving information via radio
tone of resonance,or the frequency at which
waves.
a circuit displays such symptoms.
UHF-Ultra High Frequency; the part of
RF-See Radio Frequency. the radio spectrum in which UHF television
Selectivity-The ability of a receiver to stations operate. The FCC has converted
ignore signals on frequencies above and scrne UHF TV channels mea frequency
below the channel to which the receiver is bands for cellular telephone systems. Ultra
tuned. high frequencies lie above very high frequen-
cies(VHF),and are deemed part of the
Shielding-The use of a particular material microwave region of the spec rum.
to shield an electronic component or circuit
from the effects of external electric or VHF-Very High Frequency; the par t of the
magnetic fields. radio spectrum in which VHF television
stations operate. Very high frequencies lie
Signal Strength-The amount of power above very ultra frequencies(UHF).
ipiontained in an intercepted radio wave.
Vot-The fundamental unit of electrical
..xoctety of Biomedical Equipment pressure or electromotive force.
Technicians -A professional association of
the operators of biomedical electronic equip- Watt'The fiordantental Unit of electrical
40 mom'and an ancillary group of the power,equal to one volt times one ampere.
•
ELF- Extremely Low Frequency electric protection societies in the world. IRPA Microwaves -The portion of the electro-
and magnetic fields, such as those which recommendations form part of the World magnetic spec nan abae very high frequencies
emanate from a high-tension power line. Health Organization's Environmental (VHF)and below infrared(heat)rays.
Health Criteria Programme,which the
Federal Communications Commission Milliwatt-One ane thousandth of a watt.
(FCC) -The independent federal regulatory United Nathan Environment Programme
Funds. The International Labour Office and NCRP-The National Council on
Agency charged with administering the radio doe Commission of the European Communities
spectrum for civilian aalso support IRPAs cold state governmental Radiation Protection and Measurements,a
activities. nonprofit corporation chartered by Congress
uses.
Kilohertz(kHz) -One thousand hertz; in 1964 to collect,analyze,develop.and
Feedback-The rerouting of a portion of an formerly one kilocycle per second. disseminate information and recornmenda-
amplifier's output signal brick to the input, tions about radiation protection.
primarily for the purpose of reducing any Lines of Force-The components of an Nonionizing Emissions-Radio waves,
distortion introduced by the amplifier or elecric or magnetic field.
sustaining oscillation. infrared rays and visible light rays, none of
Magnetic Field-A way to describe the which can affect an atom's electrical balance.
Field-A way to describe the spatial distrib- spatial distribution of a magnetic force.The
ution of a contactless physical force such as field can arise from a permanent magnet,an NEPA The National Environmental
gravity, magnetism, or electric force. electromagnet, or a flow of charged electric Policy Act of 1969.An Act of Congress
particles.Measured in amperes per meter,
iieres per meter,ar iperes per which requires Federal Agencies to take into
Filtering-The use of an electronic circuit to consideration the potential environmental
mllampmcroam
pass a signal with a desired frequency or to meter. effects of a particular proposal such as
suppress a signal with an undesired frequency. construction of a radio station.
Magnetic Force-A force which attracts
•
FM Broadcast-The radio broadcast service Nondirectional Antenna-An antenna
which or steel, which attracts or repels a per-
which provides high-fidelity stereo music and manenrane or which that transmits and receives equally well in all
bendsthepath
other forms of entertainment programming in s 1. , de t electromagnet, direction, usually in one plane;also called
the frequency band from 88 to 108 MHz. of moving, decrial/charges.
Whether the force is repulsive or attractive an omnidirectional antenna.
Frequency-The number of times an electric depends of the Polarities of the underlying Nonthermal Exposure-See Athermal
or magnetic field changes polarity in one magnetic field and the pommy of the affect Exposure.
second. magnet. Whether(and if so,how) the force
affects moving electric panicles depends on Ohm-The fundamental unit of electrical
Full Duplex-A method of two-way radio the geometry between the magnetic field and resistance.
or telephone communications in which both the panicles path.
parties to a conversation may transmit Omnidirectional Antenna-See Nandir-
(speak) at the same time. Megahertz (MHz)-One million hertz; ectiorwi Antenna.
formerly one megacycle per second. Oscillator-An electronic circuit which
Hertz(Hz)-One hertz is the frequency of
an electric or magnetic field which changes Microcell-A cellular base station with very generates an audio-frequency or radio-
polarity once each second;formerly one cycle low otapta power designed to cover a very frequency signal without requiring an input
per second. limited area,such as a shopping center or sib.
Interference -Full or partial disruption of sports stadium. Picard'-A cellular base station with
the reception of a desired signal or of the Microwatt-One one-millionth of a watt. rely low outPut power designed to
operation of electronic product. cover an extremely small area,such as one
Microwave Hearing-A perceived soundfloor of an office
Ionizing Emissions-Ultraviolet rays,X in the presence of certain pulsed electromag-
rays, and gamma rays,all of which can neat fields,due to physical vibranons set up Power Amplifier-An electronic device
affect an atom's electrical balance. in the inner ear by those fields. There is no which generates a substantial amours of out- 0
actual external sound,and the experience in pro Power when driven by an input signal of
IRPA-The International Radiation and of itself has no permanent consequences sufficient strength.
Protection Association,a nongovernmental on a person's hearing.
international organization whose membership
includes most of the national radiation- 39
Glossary of Technical Terms
•
AC-Current which periodically reverses Audio Frequency-See AF. Current-The
flow of electric charges.
direction at a certain frequency; also called
Alternating Current. Audio Rectification Interference- dB-A logarithmic method of expressing the
Interference to stereo equipment, telephones, ratio of one signal power level to another.
AF-A frequency that corresponds to the and similar devices which occurs when an Short for decibel.
range of human hearing. Short for Audio electronic component in the device converts a
DC Frequency. radio-frequency current induced by a passing Current which flows in one direction
radio weave into an audio-frequen y signal, only;also called Direct Current.
Alternating Current-See AC. which is then amplified along wiz the desired
Decibel-See dB.
Ampere-The fundamental unit of electrical program material.
Detection-The process of extracting the
Base Station-A radio transmission facility intelligence embedded in or impressed upon a
._ Amplification-The process of increasing in a fixed location designed to communicate radio signal. Sometimes, electronic compo-
the strength(amplitude) of an input signal, with mobile and portable armmunications nents like transistors in stereo amplifiers can
• ideally without altering the signals frequency devices. inadvertently perform detection,resulting in
or other characteristics. BlanketingOverloadinterferenceaudio rectification interference.
- to a
Amplifier-An electronic circuit chat per- radio or television receiver civisFa by a strong Detector-The portion of a radio receiver or
farms the function of amplification. signal. The FCC has rules and policies an component that performs the function of
requiring licensees to remedy the effects of detection.
Analog-An electrical signal whose strength blanketing in certain situations.
or frequency can vary continuously over a Digital-An electrical signal whose strength
defined range; or a circuit which generarPs or Calcium Efflux-The migration of calcium or frequency can vary in discrete steps;or a
4111rocesses analog signals. ions from the brain in the presence of certain circuit which generarPs or processes digital
RF fields. No one has tied any demonstrable sigma
ANSI-The American National Standards medical health consequences to this effect.
Institute, the nation's preeminent private Direct Current-See DC.
standard-coordinating body.ANSI is a non- CDMA-A means of digitally transmitting
profit, privately funded membership organi- more than one signal in a given frequency Directional Antenna-An antenna which
zation that coordinates the development of 1'Y breaking up each signal into a series transmits or receives more effectively in
U.S. voluntary national standards and is the of sequential samples,assigning each signal a certain directions than others.
U.S.representative to nontreaty international Particular" '"which sprains the original Electric Field-A way to describe the
standards-setting entities including the frequencies over a much greater frequency source of an electric force.The field arises
International Organization for Standardization band,and then simultaneously transmitting
the diand can affect charged electric particles.
(ISO) and the Internationalerent signals Electrotechnical different within the one large Measured in volts per meter,millivolts per
Commission. frequency band;a form of Spread Spectrum or microvolts per meter.
Transmission. Short for Code Division
Antenna-A device which converts radio- Multiple Ie Access. Electric Force-A force which can attract
frequency currents from a transmitter into or repel charged electric particles,depending
radio waves which then travel through space, Cell,dnr Base Station-A base station in on the polarityof the electric field from which
or one which converts part of a passing radio the cellular telephone radio service. the farce arises and the polarity of the electri-
wave into a radio-frequency current for
Channel-A bond of radio frequencies used tally charged panicles affected.
further processing by a receiver. to transmit certain information.
Electromagnet-A coil of wire which gen-
Apnea Monitor-A biomedical electronic
Code Di" `midtipie Access'See CDMA. atones a magnetic field when electric Current which generates a warning signal upon
Current
flows through it.
sensing irregularities in the breathing of the Crosstalk-The leakage of one or both sides
person being monitored(typically an infant). of a telephone conversation into another Electromagnetic Fields-The electric and
likExposure-Exposure to radio- conversation,caused,for example,by the magnetic fields that underlie a radio wave.
frequency power at levels below those which errnal
lack of synchronization of Trine Division The fields are at right angles to each other
Multiple Access equipment or inadequate and to the direction of travel of the radio
rrucse measurable warming of biological tissue• shielding between two sets of wireswave.
rnr
(Alternatively,Nontheal Exposure.) carrying
the two different conversations.
•
a piece of affected equipment Ls still in warranty, ■ There is no conclusive evidence that cellular
the manufacturer will sometimes provide a base stations significantly impact property
remedial filter. values.There are studies which have shown
■ Electromagnetic interference can affect medical no negative property value impact from base
electronics.There have been a number of stations.Broad anecdotal evidence from real
reported incidents of interference in susceptible estate specialists and municipal tax assessors
also indicate no evidence of a decline in prop-
electronic patient monitors involving the nearby
use of security guards'walkie-talkies or visitors' erry values due to the presence of base stations.
There
portable cellular telephones.However,there is also positive evidence that the presence
apparently have not been incidents involving . of even extensive and visually obvious antenna
sites does not effect the desirability of the
cellular base stations,because of the low power immediate area for residential use.This includes
levels they typically employ.One reported inti- the development of land at the base of an
dent involved a 150-watt paging transmitter existing 400 foot television transmission tower,
mounted on the roof of a hospital.Activation of which served as a platform for cellular trans-
the transmitter caused a slight fluctuation in the
reading of a patient's blood pressure.The use of mission and other special purpose antennas,for
inexpensive filtering and shielding components
new houses with prices starting at$700,000.
can often readily resolve such interference,as is ■ State and local zoning codes govern base station
the case for interference CO stereo equipment. construction.Zoning codes usually govern both
■ The food and drug administration has an the permitted type of construction (residential,
electromagnetic interference immunity guide- commercial etc.)in each regulated zone as well
line for medical equipment.The FDA requires as the maximum permissible height of structure
that medical electronic devices be able to within the zone.Because cellular base station
o rate unim towers often are higher than otherwise permis-
pe peded in a strong ambient radio sible and may not be aspecificallypermitted
frequency field of 3 volts per meter.Powered •
wheelchairs must be able to operate without land use,they usually require a zoning variance
interference in an even stronger, 20 volt-per- or waiver from the local zoning authority
meter field.Fields generated by cellular base ■ Base stations are"inherently beneficial."
stations in areas frequented by the public are Public utilities and other necessary infrastruc-
usually much,much weaker than values of ture are often granted more lenient treatment
concern CO the FDA. under state and local regulations for obtaining
variances.The legal term for this type of socially
D. Lessons Learned Cellular Base important infiasm,cture is"inherently beneficial"
Stations and Land-Use Issues The Appellate Division of New Jersey Superior
Court,as well as other courts,ruled that cellular
■ There is no known case of a cellular base station base stations are inherently beneficiaL
tower falling.Base stations facilities are required,
by ANSI standards,to be built to with-stand a
S0-year storm event and are typically over built
by 50%.Cellular towers have even been known
to survive unscathed extreme storms that
destroyed structures on surrounding properties.
■ Base stations are usually no more and often
less visually intrusive than other commonly
accepted infrastructure.Base stations,particu-
larly in suburban and rural areas,are distinctly
visible. When possible,cellular base stations
often attempt to use existing structure such as
water towers and office buildings.When a new
structure must be erected,care should be taken
minimize the visual impact CO the extent prac-
ticable.Careful site selection—consistent with
network needs—visual impact studies and
4111
remediation of appearance through camouflage
can be used to render the facility as unobtru-
sive as possible.
Chapter 6: Lessons Learned
A summary of the lessons learned from the Federal IN To protect public health, standards-setting
Focus Wireless Transmission Base Station Symposium organizations have established limits for expo-
follows. The lessons learned reflect Ferleral Focus' sures to radio-frequency fields. There is cur-
understanding of and conclusions drawn from the rently no single national exposure standard
recognized by all Federal agencies and State
Symposium's presentations and discussions.
Governments although several Federally and
A. Lessons Learned About How Base internationally recognized standards-setting
Stations Operate
organizations as well as several States have set
detailed exposure limits.In the absence of a
■ Base stations are essential for cellular tele- single Federal standard,the Federal Commun-
phones.Without a network of cellular tele- ications Commission (FCC) in 1985 adopted a
phone base stations,cellular telephone corn- 1982 standard promulgated by the American
munications would not be possible. National Standards Institute (ANSI), the
preeminent private-sector standards-setting
■ Base stations are low-power radio relay sta- )may.The FCC is in clic process of updating its
tions.Cellular telephone base stations are own standard and has proposed to use the
radio relay stations which operate in the UHF revised (1992)ANSI standard.
portion of the radio spectrum near TV Channel
69. Base stations operate at a small fraction of ■ RF exposure from base stations are vastly
the power of most commercial radio and tele- below all exposure standards.Measurements
vision stations. at numerous cellular base stations conclusively
■ An increasing number of cellular base demonstrate that the ground-level exposures
from such facilities are extremely low,hundreds
stations areneeded to increase system capaci- or thousands of times below the levels permitted
rY and minimize transmission power.Building by the various standards the FCC is currently
additional base stations in an area already coy- considering.One participant who has performed
• erect,a technique known as"cell splittif,"per- such measurements called the matter of RF
mits the same channels to be reused in an area exposure from cellular base stations as"almost
relatively close to the base station.This not only a non-issue in terms of actual exposure levels."
increases the network's capacity,it also mini-
mizes transmission power and antenna height. ■ R.F.exposure from cellular base stations is
■ Cellular networks are �'different from to electromagnetic
beginning to deploy fields from power lines.Power line fields are
advanced digital technologies to further much lower in frequency(by a factor of 14
increase system capacity.Digital technologies, million),and interact with the human body by
such as Time Division Multiple Access vastly different physical mechanisms of interac-
(TDMA)and Code Division Multiple Access tion than do the RF fields from a cellular base
(CDMA),permit cellular networks to handle station.
greater traffic levels in the same amount of
radio spectrum than traditional analog tech- C. Lessons Learned About Base Stations
nology allows. and Interference
B. Lessons Learned About Base Stations ■ Cel a lar base stations rarely cause electro-
and Public Health magnetic interference.The radio waves emitted
• Cellular base stations emit radio waves..Each by cellular base stations can theoretically interact
with electronic equipment,and theoretically
radio wave comprises electric and magnetic
cause the affected equipment to exhibit symptoms
fields.Those fields can affect the atoms,ions,
and molecules that make up living cells.The of interference.However,it usually takes a very
most common effect of strong fields is a warm- strong radio signal for such interference to
manifestung of tissue.Intense fields can produce enough and interference to electronic
equipment rarely involves base stations.
heating to cause many significant biological
effects.Weaker fields can produce subtle chemi- ■ There are no governmental electromagnetic
cal changes with no known adverse health interference standards for consumer electronics.
effects. Some manufacturers build certain amounts
• shielding and filtering into their equipment
based on assumed ambient levels of RF energy;
others employ little or no shielding.Inadequate
immunity can be remedied after the fact,and if
36
•
•
ofPo tential controversies. Other places,the requires.Otherwise,cellular licensees risk the
panelist noted,are attempting to simply outlaw FCC denying their license renewal applications
towers.This may result in federal-state tensions, for failing to improve their systems to meet the
however,as the next section will discuss. public's increased demand for service.
3. FCC Requirements of Cellular Licensees If the FCC denies an incumbent's renewal appli-
Under the Communications Act,the FCC can cation on this basis,the newcomer will face the
only license radio transmission facilities for a same burden of installing additional base stations
during its first license term.The newcomer's failure
specific period of years.This is true of cellular
telephone networks and all broadcast radio and to do so will imperil its own chances for a license
renewal.The FCC's rules and regulations,there
television stations.As Symposium participants
observed,during the term of its license,any fore,codify a strong Federal interest in the
licensee must operate its licensed facilities in the construction of new base stations to meet the
public interest as the trustee of a public trust. public'sis
demand for service.Moreover,a petition
Incumbent licensees may seek renewal of their Pending before the FCC for a ruling preempting
local
licenses as their current terms expire,but their officials from adopting unnecr-cvary burdens
on the placement of new base station facilities.
renewal applications may draw challenges by
overfilers. FCC practice is to give worthy incum- 4. Distinguishing RF from ELF
bent licensees a renewal expectancy.A renewal
One participant,although noting the very different
expectancy is the most important factor the FCC
considers in determining whether to grant the technologies involved in cellular transmissions
incumbent licensee's renewal application,or to and power lines,asked two questions.One,to
instead grant a new license to the overfiler.The what extent will the type of litigation on ELF and
assertions of reduced property values come the RF
Commission's conferral of a renewal expectancy
depends on the licensee's stewardship of its portion field?Second,to what extent do health effects
of the radio spectrum during the most recent issues raised with respect to ELF translate into the
RF arena?
license term.
Section 22.941 of the FCC's Rules and Regulations One panelist immediately noted the vast differ-
sets explicit standards for determining whether ences between the two contexts and the impor-
any cellular licensee is entitled to a renewal tante of maintaining the clear distinctions
between the two.The participant who posed the
expectancy. Under that rule,the incumbent must question noted significant litigation in the ELF
demonstrate,among other things,that it:
arena and questioned to what extent one could
1. has substantially used its spectrum for its distinguish RF from ELF in discussions of health
intended purpose;and effects and property values.
2. has substantially complied with applicable
Commission rules,policies,and the Participants and panelists had a variety of opinions.
Communications Act. One participant noted that electric utilities would
do well to reduce exposures to the very low levels
As part of its showing,the licensee must submit: of RF from base stations.Another,responding to
a. a description of its current service area in the statements made on RF and ELF,made three
terms of geographic coverage and population points.First,most residents'key objection to base
served,as well as the system's ability to accom- stations was simply nor wanting to see a tower.
modate the needs of roamers(transient cellular Second,people are concerned about potential or
users in the system's service area who are actually feared risks,not just demonstrable risks.The par-
subscribers in distant cellular networks);and ticipant's final point was that her company(a
b. an explanation of its record of expansion, cellular carrier)had hired real estate appraisers at
including a timetable of the construction of various locations to discern any effects by base
new cell sites(base stations)to meet changes stations on housing prices.The studies had found
in demand for cellular radio service. that,in every case,housing prices near the towers
had at least kept pace with the real estate market4111/
Clearly,the FCC intends cellular networks to for the general area.
construct new base stations as the growth in traffic
110
Will theQ proposed facility on the photograph.Then one Beyond its primary broadcasting duties, the tower
construction of a can see the surrounding area and evaluate whom serves as a platform for an extensive array of
base station reduce the facility might affect.Experience has shown antennas, including dish antennas and the whip
nearby property values? these exhibits to be helpful because they illustrate antennas often used by cellular base stations.
everything in relationship to the proposed site. On adjoining g parcels,construction of custom
A frequent result of visual impact studies is that houses ranging in price from$700,000 to over
No conclusive realize that the base station facility does
evidence has
people $1,000,01 was underway.The presence of a large
not appear obtrusive,as they may have feared. antenna rower did not prevent high-value develop-
been presented to date Often,people who are unfamiliar with cellular ment of immediately adjacent land. In summary,
demonstrating that base stations do not know that they regularly see there is currently no credible evidence that wire-
base stations signifi- such facilities without even really noticing them. less transmission base stations affect the value of
cantly affect property A good visual impact study may show that a facility, nearby properties.
values. while visible, is comparable to a telephone pole,a
water tower,a large flag pole, lighting poles at a E. STATEMENTS OF PARTICIPANTS
high-school playing field,or other common stnrc-
1. Prior Experience with Siting Base Stations
cures on the contemporary landscape.
on Public School Property
D. BASE STATIONS AND PROPERTY One Symposium participant noted his involve-
VALUES ment in a Sacramento case where a cellular system
For some neighbors of a proposed transmission sought to place a base station on elementary school
site,the primary concern is the possibility that the grounds.One person voiced mild opposition on
potential bioeffects grounds,but the proposal was
facility will reduce property values.
far less controversial than a simultaneous contro-
4110 1. No Evidence of Property Devaluation from versy over location of a bus stop.Applause followed
Base Stations the school board's unanimous approval of the base
To date,no conclusive evidence demonstrates that station.The school was financially strapped and
was very glad to receive rent from the carrier.The
cellular base stations depress property values.In
fact,there are studies that have shown no negative following night,the participant also attended a
property value impact from base stations.Broader meeting about placing a base station on a fire
anecdotal evidence from real estate specialists also station tower Local residents strongly opposed the
suggests no evidence of a decline in property values proposal.City commissioners approved the base
• station.There is also station largely,in the participant's view,because
due to the presence of a base
positive evidence that the presence of even the they worked in was dangerous at night.
substantial,visually obvious antenna towers does Half the commissioners were women who appre-
QShould a base not affect the desirability of the immediate area for crated having reliable cellular phone service.
station be located residential use. 2. Zoning Regulations and Base Stations
near a school or other
A zoning specialist participating in the Federal Oneg
potentially sensitive
Focus Symposiumparticipant asked if zoning boards were trying
area? noted that he had discussed the to establish more restrictive provisions for cellular
question of base stations and property values with base stations.A panelist voiced awareness of such
municipal tax assessors.Those assessors responded attempts,citing Cherry Hill,New Jersey as an
that they had never lowered the tax assessment on example.Cherry Hill used to have many zones in
AThere is no reason to a Proper due to a nearby base station.The zoning which one could site a tower.When a carrier cried
exclude schools and specialist also said that,in his extensive experience, to locate a base station where city officials
he had never heard a credible real estate witness thought was inappropriate,they changed the
similar areas as poten-
testify that a base station had depressed property zoning
al base station sites. ordinance to mandate athree-w-one fall
ti
Base stations have values. zone,requiring the distance to any boundary line
been successfully 2. Expensive Homes Near Transmission Towers Co be three times the tower's full height.
rated on school In one affluent New Jersey area that a Symposium The panelist also stated an awareness that some
roperties with the participant had studied,a 400-foot New Jerseymunicipalities have enacted ordinances creating
support of the school
Public Broadcasting Network tower stands_ specific areas where towers were appropriate.
and the community. Apparently,the towns hope to manage the scope
34
1110
4. The New Jersey Radiation Protection Act The shed can be visually shielded and is physically Q Can a base
The issue of potential effects of a base secured to prevent unauthorized entry.The shed station fall over
station's radiofrequency health effects
received does not require any water or sewage hookup,and or be blown away in a
does not emit noise,except if it is equipped with a storm.
extensive treatment in Chapter Three.However,
New Jersey, used as a case study at the Federal modest air condidaner.Depending on a base station's
Focus Symposium, has its own RF exposure scan- height and proximity to airports,the Federal
dard to which transmission facilities must adhere. Aviation Administration may require that a There is no
The New Jersey exposure standard is 2700 monopole may have a light at the top to warn air- A record of this
microwatts
rare centimeter,about that per- craft of its presence.The light may be a flashing ever happening, even
mitred by the 1982 ANSI standard.Typical expo per
red lamp or white light. during extreme storms.
sure six feet off the ground near a base station is 1. Limiting a Base Station's Visual Impact
about 1.4 microwatrs per square centimeter—less A number of base stations will be visible,although
than one thousandth of the state limit.So RF not nearly as much as television and radio anten-
exposure from a base station is not a zoning issue. na towers.Two key techniques ameliorate the
B. BASE STATION PHYSICAL INTEGRITY visual impact of base stations:
■ camouflage;and
Neighbors of a proposed base station might wonder I appropriate site selection.
whether the antenna tower will withstand adverse
weather conditions.ANSI standards require Camouflage entails diverse techniques such as
construction of base station towers to withstand painting the pole blue to blend in with the sky or
50-year storm events.Moreover,relative to that using a tower designed to look like a pine tree can
standard,carriers usually overbuild base station disguise the antenna structure.Depending on the
towers by 50%.Cellular carriers could have to facility's location and the nature of the surrounding
compensate for damages if the physical facility were area,there may be a limit to how well this tech-
to fail and damage persons or property.As far as nique will work.
•
we can determine,no cellular transmission tower Careful site selection is probably the most impor-
has ever blown over.Indeed,there are documented tart way to reduce visual impact.Appropriate site
cases in which an extreme weather event such as a selection would suggest,to the extent possible,
tornado has left a base station tower the only that a base station:
undamaged structure in the storm's path—even
when trees,buildings,and utility poles have suffered ■ be in a commercial,industrial,or other area
damage or total destruction.In California,base where it is most likely to blend in with the
station towers must also meet earthquake safety immediate surroundings;
codes.Towers have also withstood major forest fires. ■ u5e an existing cower or other appropriate
structure;or
C. BASE STATION PHYSICAL ■ be in a sparsely populated area. Q How does a base -
APPEARANCE station's visual
Reducing the structure's visibility is desirable,but appearance fit into a
Often,the first question asked regarding a proposed each base station must fit into the overall tiansinis-
base station is what will it look like.Base stationcommunity?
Sion network..Sake base stations are low power facili-
appearance varies widely.Many are inconspicuous ties,they must be near service subscribers,which
or not readily visible.Some base stations facilities, often means their construction in residential areas. AAlthough base
particularly those with their own towers in suburban
and rural areas,are distinctly visible.However, 2. The Benefrt of Visual Impact Studies stations are
amelioration of appearance and careful site selectionoften visible, they
1?P One effective way to evaluate a site's appropriate usually blend into the
can render the facility as unobtrusive as possible. ness is to prepare a visual impact study.Such a landscape with other
As we have discussed earlier,most base stations study simulates—through models,computer- municipal infrastruc-
have two key structures: anted graphics,or similar techniques—what tore. Careful site
the facility will look like from different vantage selection and tower
■ a one-story equipment shed approximately 12 points.Aerial photographs of the proposed site, •
design may also
feet wide x 28 feet deep; and available from government and private sources, reduce any visual
• antennas on top of a monopole. are often useful.One draws or outlines the impact.
Chapter 5: Base Stations and Land Use Issues
•
How do localQ As base Stations become more common in urban and cellular transmission tower may require a zoning
zoning codes suburban landscapes, local residents may want to variance,especially n a residential neighborhood.
treat base stations? know what local zoning rules guide base station place- In New Jersey,a state used as an example during
merit. They may also wart to know if the facii<y makes the symposium,the municipal land use law allows
a good neighbor,or if it could affect their property values for two kinds of variances. Planning boards process
ABase stations are or otherwise affect their lives other than by providing requests for"C"variances,also lmown as bulk vari-
usuaIiy treated reliable wireless communications services. ances.Zoning boards administer"D"variances.
as any other public In this chapter,we will answer the following questions Grant of a"C"variance requires a majority vote
utility infrastructure. of the quorum of a planning board present at each
about base stations and local land use issues:
Courts have recognized meeting.Grant of a"D"variance requires five out
that base station facil- ■ How do local zoning codes treat base stations? of seven votes on the zoning board.Thus, if only
ities are "inherently ■ Could a base station tower fall over in a storm? five members attend a given meeting of a zoning
beneficial"uses of ■ How will the base station's appearance fit into the board,grant of a"D"variance requires a unani-
land. community? mous vote.Therefore,carriers prefer to apply for
■ Will a base station affect nearby property cetlues? "C"variances whenever possible.
A. BASE STATIONS AND ZONING CODES Each type of variance has a different burden of
proof.That for a"D"variance is more stringent.
State laws and municipal zoning and building The preamble of the municipal land-use law sets
codes govern the placement and building of wire- forth the special circumstances required for grant of
less transmission base stations.These codes guide a"D"variance.A"D"variance is appropriate for
virtually every step of the siting and construction uses deemed to promote the general safety,health,
process.They specify acceptable potential locations and welfare of the citizens,and deemed to provide
and height limitations.Sometimes, they even pre- for the efficient and best use of space from various
• scribe required notice to and consultations with perspectives.Obtaining a"D"variance in New
neighboring residents.Court decisions interpreting Jersey also requires the carrier to satisfy the law's
zoning codes also shape which construction activi- "not substantially impair"clause.That is,that the
ties are permissible in a given area. facility must not substantially impair the intent and
1. Base Stations as Public Utilities purpose of the zoning plan or ordinance.Despite
the tougher standards for obtaining a"D"variance, _.
Zoning laws usually specify what"uses"are appro- cellular carriers can usually satisfy those standards.
priate for each parcel.In terms of use,zoning codes 3. Zoning Variances and Inherently Beneficial Use
classify wireless base stations either as a commercial
use or as a public utility.Cellular carriers strive for The criteria for a"D"variance(or its counterpart
public utility status because that usually provides in other jurisdictions)have lead to debate and liti-
more flexibility under the zoning code. Public gation over what forms an"inherently beneficial
utility status means that a cellular carrier can build use."Cellular carriers assert that their facilities are
a base station in almost any area,as a"permitted an inherently beneficial use because they create
use,"or as a"conditional use."(A conditional use wireless communications networks. Base stations,
requires the grant of a special permit or variance.) therefore,not only improve the area's communi-
Tower and antenna height then remain as the pri- cations infrastructure,but also enhance the public
mary criteria of the legality of the proposed facility good,including public health and safety, in ways
in a given location.However,in states such as New that otherwise would not be possible.The ability
Jersey,the municipal land-use law does not define of motorists to report accidents,resulting in speedier
a"public utility."This has lead a few municipalities emergency response,is but one example.
in that state to challenge the idea that cell-1112r A base station that is inherently beneficial would
carriers are public utilities.However,zoning auth- satisfy the municipal land use law's"special reasons"
orities usually accept base stations as public utility
infrastructure. criteria.The carrier would then only have to satisfy
the"not substanrially impair"criterion.The Appellate
410 - 2. Zoning Variances Cour of New Jersey,in an important decision known
Most municipalities as the"Hazlet"case,ruled that a cellular base station
ipal' ' regulate the permissible heights is an inherently beneficial use of land.
of structures in most zoned areas.A structure like a
I
Notes Chapter 4
1A digital radio's tuning system employs a frequency synthesizer. At its heart is an oscillator that
generates a very precise reference frequency from which the synthesizer derives all possible output
frequencies.
2Unintended acoustic feedback causes squeals or howls in public address systems. Too much sound
from the loudspeakers reaches the microphone and creates a self-sustaining oscillation.
3Often, a preamplifier, tuner, and power amplifier are packaged as a receiver.A.combination pre-
amplifier and power amplifier is an integrated amplifier. Multichannel"home theater"systems
include special signal processors,additional speakers, and amplifiers.
4Audio rectification generally does not cause stereo-system interference which arises only when
the FM tuner is selected. Such interference is due to RF signal overload,also called blanketing. We
will cover blanketing later.
5Almost 20 years ago, Congress authorized the FCC to set RF immunity standards for consumer
electronic devices, but the Commission has never exercised that power.
6Cellular networks employ frequencies that used to be high-numbered UHF TV channels.
•
•
•
QCan the radio ment,but RF interference is sometimes a problem. When interference does occur,such as might
waves from a Audio rectification is the typical cause of interfer- occur when a passing police car activates its
base station affect ence,with signals picked up by the wires that run onboard radio transmitter,the interference results
medical equipment or throughout the vehicle.Additional shielding of from audio rectification.Wires between the body-
monitors? the affected module,and filtering of the wires run- worn transducers and the monitoring electronics,
ping to it,are the cures.As is the case with audio or between the wheelchair's control joystick and
rectification interference in home-stereo systems, control electronics,pick up the RF signal.A
AIt takes a strong the field strengths at ground level from base stations component in the control electronics then rectifies
radio wave for are so weak that interference to onboard systems the RF,and the detected signal interferes with
interference to occur is extremely unlikely. normal functioning.
to medical equipment. I. MEDICAL ELECTRONICS Once detected,the interference can be dealt with
The radio waves from by adding shielding or filtering or both,using
a base station are Today,electronics commonly monitor a patient's techniques common to resolving home-stereo
usually much too weak heartbeat,breathing,brain waves,temperature, interference.One participant described curing
Pan
by the time they reach
blood pressure,etc.Body-worn sensors(transducers) interference in a susceptible apnea monitor by
anybody's residence or convert the vital signs into electrical signals,which installing a very simple, inexpensive electronic
a medical facility to are then processed by electronic circuits.When a component which acts as a filter.
affect biomedical critical variable falls outside acceptable limits,an
equipment. alarm sounds.Often,body-worn sensors connect to To prevent such interference from arising in the
the monitoring electronics via leads several feet long. first place,the Food and Drug Administration has
issued guidelines and testing protocols for biomed
Ambulatory patients sometimes wear"wireless"
monitors that transmit signals about their vital signs ical equipment.Standards-setting organizations
without tying the patients to the end of an electronic have also issued standards for such equipment.
• cable.And such medical electronics are not just found The International Electrotechnical Commission's
in the hospital.Apnea monitors,for example,which Standard No.601-1-3 (1992)requires medical
monitor breathing irregularities,are used in the home. devices to be immune from interference when
subjected to fields of 3 volts/meter over a frequency
Sometimes,RF fields can affect such devices.The range of 26 to 1000 MI-h.That frequency span
primary effect is audio rectification that can includes the band in which base stations operate.
prompt false alarms,which are certainly a nuisance,
or a device's failure to sound an alarm when it The question of biomedical interference involving
should—which can be life-threatening.One base stations is expected to arise,if at all,only
Symposium participant described a paper which when a base station is mounted on the hospital
reported 100 such incidents, including the lock-up roof.A participant described a case in which a
of a ventilator(which assists breathing)when a 150-watt paging transmitter mounted on a hospital
security guard keyed his walkie-talkie or a visitor roof caused a blood-pressure monitor's reading to
began using a portable cellular telephone. jump 10 mm of mercury—a"minor but not
Portable cellular telephones have also reportedly insignificant failure."The same participant related
interfered with infant incubators and drug-infusion that the Society of Biomedical Equipment
pumps.Because of the potential for such incidents, T (SBET),which is an ancillary group
many hospitals have policies restricting the use of of the Association for the Advancement of
portable radios and cellular phones near intensive- Medical Instrumentation,has issued a recommen-
care facilities.However,cellular base stations have dation that hospitals ban the use of portable cellular
not been implicated in any of these incidents. telephones in hospitals.The recommendation
does not prohibit the installation or operation of
Powered wheelchairs depend on electric motors cellular base stations.The SBET has also designed
and electronic control systems. Interference to the a warning sticker for placement on equipment
control systems can occur in the presence of proven to be susceptible to the nearby use of a
strong RF fields,causing unintended chair move- security guard's walkie-talkie,but again,base
ment.As is the case with interference to home stations do not appear to cause any such problems.
• audio systems and telephones,base stations do not
appear to pose any significant problems to powered
wheel chairs or electronic medical devices.
30
I
local telephone companies will install RF filters for G. REMEDIES FOR RADIO AND TV Can radio waves
a fee.) If the device is still under warranty, the RECEIVERS from a base
manufacturer might provide an interference filter, station affect my radio
or the dealer might take the unit back in In the case of TV or radio interference,the ambient or television set?
exchange for another model with better RF immu- strength of an interfering signal is again usually
niry.The FCC's Last Licensee On policy does not beyond the control of the person experiencing
apply to telephones or answering machines. interference.So the two primary ways to suppress AA strong radio
interference are,again,shielding and filtering. wave can cause
F. RADIO AND TV RECEIVERS using grounded metal baffles and enclosures to interference to a radio
Radio and television receivers respond to RF sig- keep interfering RF fields from reaching the sensi- or television receiver if
nals,and interference can result if a receiver tive electronic components inside the tuner or it is strong enough to
receiver,and using circuits to block out-of-band overload the receiver
responds to an undesired radio signal.No rectifica
cion is needed,as is the case with interference to frequencies,or to shunt them to ground without or to overcome the
stereo amplifiers and telephones.However,signals weakening the desired signals. receiver's inherent
from cellular base stations are rarely involved in There are no government regulations specifying ability to distinguish
radio or TV interference. Interference which minimal acceptable levels of shielding or filtering between signals of
occurs through overloading of the receiver's RF for radio and TV receivers and FM stereo tuners. different frequencies.
circuits is called blanketing. It can occur near an Some radios,FM receivers and tuners,and televi- However, radio waves
AM or FM radio or television transmitter. sion sets include no or minimal shielding or filtering; fro„►abase station are
Blanketing becomes more likely as the Effective others employ enough to have good RF immunity usually much too weak
Radiated Power increases.When blanketing As is the case with audio components,radio and by the time they reach
occurs, the audio output from an FM tuner or TV manufacturers assume a certain ambient RF anybody's residence to
receiver can be heavilydistorted or sound like field strengthaffect a radio or televi-
and design their products to func-
gibberish.Sometimes,there is no audio output at tion under those conditions.However,if the Sion receiver.
all.A television subject to blanketing can display ambient field exceeds the mar. facturer's assump0
-
a faint to moderate herringbone pattern on top of tions,built-in shielding and filtering may be inad-
the desired image,alternating black-and-white equate,and more must be added to eliminate the
horizontal bars,or,in severe cases,a totally dark interference.The FCC's Last Licensee On policy
screen. Blanketing can also affect the television makes a newcomer licensee,for a limited period of ^Can the radio
program's audio. time,resolve reasonable complaints of new inter- ( J waves from a
Each receiver has a certain selectivity which helps ference to radio and television receivers.However, base station affect my
the Last Licensee On policy does not require car's electronic systems?
it ignore off channel signals.The better the
licensee
receiver's design and construction,the greater the s to cure interference to radio or television
selectivity,and the greater the receiver's immunity receivers connected to special deep-fringe,high-
gain antennas or signal boosters. AS radio waves
to out-of-band signals.And the greater the
1g
frequency difference between the interfering and H. AUTOMOBILE SYSTEMS can cause inter-
desired signals,the better a receiver can tolerate ference to a car's
strong interfering signals without succumbing to Today's cars include many electronic devices and onboard electronics in
overload. systems.Transducers convert such mechanical much the same way as
quantities as coolant temperature,oil pressure, strong signals can
FM broadcast tuners and receivers have enough wheel speeds,engine revolutions,throttle opening, affect stereos and tele-
selectivity,and cellular operating frequencies are fuel flow,and exhaust emissions into electrical phones. However,
far enough removed from the FM broadcast band, signals for processing by electronic brains.The radio waves from a
that blanketing interference from cellular base stations signal processors generate control signals in base station are much
to FM broadcast reception is very rare.Even response to these variables and thereby control too weak at ground
though UHF television receivers are theoretically such items as spark timing,the richness of the level to affect onboard
more susceptible (because they are broadband air/fuel ratio,brake-fluid pressure,and cooling fans. automotive systems.
devices,and because UHF TV channels are much Also, most car manu-
closer to cellular operating frequencies than FM The automotive environment is a very demanding facturers build in a
broadcast channels are6),the FCC has no reported one,with great temperature extremes and large good measure of inter-
•
complaints of interference to TV reception from amounts of mechanical vibration.Automotive Terence immunity.
base stations. engineers have made great progress in adapting
electronics to the rigors of this hostile environ-
29
•
Can radio waves effect on operations,because other than FMtuners, Some consumer electronic devices include little
from a base stereo components are designed to respond only or no shielding or filtering.Others employ mean-
station affect my tele- to AF signals,not RF signals. However,active ingful amounts.No government regulations specify
phone or answering components can inadvertently act as detectors minimal acceptable levels of shielding or filtering
machine? that convert RF signals into AF signals.Once for stereo components.5 Manufacturers usually
detection happens, the system can no longer assume a certain average ambient RF field
distinguish between the desired audio program strength,and design their products to function
AA strong radio material and the undesired signal extracted from under those conditions.However, if the ambient
wave can cause the intercepted radio wave (such as your CB field exceeds the assumed value,any built-in
interference to a regular neighbor's voice). shielding and filtering may be inadequate.
telephone e or ng Interference in a stereo system typically arises when Additional after-market measures must be taken
system if an electronic the wires runningto the to eliminate interference.The FCC has a"Last
component in the speakers pick up radio
p Licensee On"policy which makes a newcomer
device converts the
signals.Speaker cables can be 10 or more feet long, who has set up a radio transmitter responsible for
radio wave into an and can inadvertently act as fairly efficient receiving resolving reasonable complaints of newly arising
audio-frequency sr antennas.Recovered RF current can pass back
g7tQl through the amplifier's speaker-output terminals interference to radio and television receivers—
However, as is the case and through the feedback loops to the amplifier's for a limited period of time.However,the policy
with potential interfer- weak-signal(input)section. If the ambient RF does not require licensees to cure interference to
ence to stereo systems, field and recovered RF current are strong enough, audio equipment(other than FM tuners as dis-
the radio waves from a a transistor in the amplifier's input section can cussed below). -
base station are much detect or rectify the RF current and extract any E. TELEPHONES
too weak by the time
audio-frequency information
they reach ,, ybody's Y riding on the carrier.
The detected audio passes back out through the Modern telephones and telephone answering
+tesidence to zffect various amplifier stages,getting stronger along the machines contain electronic circuits,but many
elephone equipment. way,until heard through the have little or no shielding.Verylongwires con-
g loudspeakers.This is
audio rectification interference. nect such devices to the public telephone net- - ..- -
work,and such wires can act as efficient anten-
It usually takes an RF field of several volts pernas for RF energy.Also,the wires in a cord sev- = L.-
meter for such interference to arise.Fields as strong eral feet long that might run between the hand- - --
as that exist only very close to a transmitting piece and the phone body can also act as anten-
antenna.A stereo system is hardly ever that close nas.Not surprisingly,telephones and answering
to a cellular base station antenna,so audio rectifi- machines can be vulnerable to audio rectifica-
cation interference involving signals from base tion interference.One Symposium participant
stations is very rare.4 with extensive field experience in the deploy-
D. REMEDIES FOR AUDIO SYSTEMS ment of base stations remarked that interference
to consumer-grade telep ones was the most fre-
Usually,in home settings,the strength of an inter- quent interference problem he had encountered,
fering signal is beyond the control of the person although interference involving base stations
whose equipment is experiencing interference.So does not appear to be widespread.
the two primary ways to suppress audio-rectification Just as in home stereo interference, it usually
interference are shielding and filtering.
takes a strong RF field for such interferen:e to
Shielding sensitive electronics with grounded arise.So those problems which do arise generally
metal baffles and enclosures prevents interfering occur if telephone wires nm close to a transmit-
RF fields from reaching susceptible components. ting antenna.The remedies are shielding and fil-
Electric fields cannot pass through such metal tering,just as with home stereo system compo-
shields,and that blocking action prevents RF nents. If someone has purchased a telephone
currents from arising that could otherwise disrupt subject to interference,the responsibility for
circuit operations.Filtering employs circuits to solving the problem lies with the purchaser,not
40 pass desired frequencies and block undesired ones, the local telephone company. (However,many
or to short out undesired frequencies without
weakening desired ones.
28
I
1-3The 1992 ANSI Standard also has limits for Specific Absorption Rate (SAR),which expresses how
much power a given amount of body tissue absorbs from ambient RF fields.There are different permissible
SARs for different parts of the body,and a maximum whole-body average SAR.SAR limits are expressed
in watts of power per gram(or kilogram)of body tissue.For the general public,the SAR limits are 0.08
watt/kg,as averaged over the entire body,and 1.6 watts/kg,as averaged over any one gram of tissue (other
than the hands,wrists,feet,and ankles,where higher limits apply).
14The five-fold increase in the safety margin for the general public sterns from the fact that worst-case
continuous exposures of members of the public are about five times longer than occupational exposures—
168 hours per week vs.35 hours per week,respectively.
15-Monitors can be worn on the body or installed around the perimeter of a base station.The monitors
generate alarm signals if exposures exceed ANSI-permissible levels.
160f course,as Symposium participants observed,any RF source adds to the overall ambient RF level—
even if only infinitesimally.
1 7The base station in question had three sectors,and in each sector, 16 channels and 80 watts per channel
of ERR.No specific attempt was made to measure exposures with all channels activated,but another
participant observed that,from his experience,each channel contributed about 20 nanowatts(0.02
microwatts)per square centimeter to the overall exposure level.
180f course,visible light is much higher in frequency than signals from a base station,and the mechanisms
by wh;ch visible-light power interacts with cells differ from those by which microwave-frequency power
interacts.In general,at higher frequencies,power deposits much more superficially(closer to the surface).
But the power flux densities would be comparable.
19"!he FDA was referring to the phones available for about$50 to$150,which people install for cord-
•
free conversations in their homes.
20Base stations operate at higher frequencies(about 850 MHz) than 49 MHz cordless phones,but the
frequencies base stations employ do not inherently pose any greater risk-
•
Notes Chapter 3
'Static electricity is a collection of electrical charges that are nor in motion.Moving electrical charges
comprise electric current.
2Typically,a diesel engine,or a steam,water,or wind turbine causes a magnet to rotate near a large coil of
wire.The rotating magnetic field induces an electric current to flow out from the coil and into the power
grid. Electric motors are essentially electric generators operating in reverse.They use attractive and repul-
sive magnetic forces generated by electromagnets to convert electricity into mechanical power.
3Radio waves and other forms of electromagnetic radiation such as ultraviolet,X,and gamma rays had
nor yet been discovered.
That is how sunlight reaches the Earth.Sound,by contrast, is a pressure wave that can only propagate
through matter(air,water,or a solid).Sound cannot travel through empty space.
5This means that some electrons are closer to the nucleus than others,and therefore feel a greater electrical
attractive force.Also,unlike the solar system,where each planet has a unique orbit,there can be more
than one electron at a given distance from the nucleus.
6This is how microwave ovens operate.Microwaves are electromagnetic waves higher in frequency than
vhf television signals,but lower in frequency than infrared (heat)waves.
7Another established thermal effect(again,one not tied to public exposures to fields from base stations)
is microwave hearing.An RF field,pulsed on and off at an AF rate,can stimulate physical vibrations in
the cochlea—the inner-ear organ that converts physical vibrations into nerve impulses.A person perceives
such vibrations as a physical sound,even though no one can"hear"RF fields in the normal sense of the
M word.Microwave hearing appears to be a mere scientific curiosity that sometimes occurs in the immediate
vicinity of a transmitting antenna.There are no documented claims that the phenomenon has permanently
effected anyone who has experienced it.
8That is because we are warm-blooded.One participant at the Federal Focus Base Station Symposium
observed that the human body,acting as a`black body radiator,"typically emits microwave energy at levels
of 25 nanowatts per square centimeter(nW/cm2)or 0.025 microwatts per square centimeter(.iW/cm2).
One microwatt is one one-millionth of a watt,and one nanowatt is one one-trillionth of a watt.So,one
microwatt per square centimeter equals 1000 nanowatts per square centimeter.
9The other standards discussed in the FCC's Notice of Proposed Rule Making are:the 1986 standard
promulgated by the National Council on Radiation Protection and Measurements(NCRP),a nonprofit
corporation chartered by Congress in 1964 to collect,analyze,develop,and disseminate information and
recommendations about radiation protection;and the 1988 standard published by the International
Radiation Protection Association(IR.PA).
10 he Food and Drug Administration has an emission standard(as opposed to an exposure standard)
that defines acceptable levels of RE leakage from microwave ovens.In the last decade,the Environmental
Protection Agency(EPA)was developing federal guidelines for public exposure to RF power.However,
the EPA suspended that effort in the late 1980s.The EPA is now showing renewed interest in the issue,
and may release such guidelines later this year.
11ANSI interest categories include producers,users,and general interests.One can break these categories
down further into consumers,directly affected members of the public,distributors and retailers,industrial/
commercial,insurance,labor,manufacturers,professional societies,regulatory agencies, test laboratories,
and trade associations.Dominance means a position or exercise of dominant authority,leadership,or
influence by reason of superior leverage,strength,or representation to the exclusion of fair and equitable
consideration of other viewpoints.To avoid dominance,no single interest category should comprise more
4111 than one-third of a standards committee dealing with safety issues,or no single interest category should
constitute a majority of the membership of a committee dealing with product standards.
12Substantial agreement means more than a simple majority,but it does not require unanimity.All views
and objections must have been considered,and an effort made toward their resolution.
24
•
BASE STATION EXPOSURES AT CELLULAR FREQUENCIES
Standard General-Public Occupational Typical Typical Typical expo-
Limit(averaged Limit(averaged ambient ground-level sure 30 inches
over 30 minutes) over six minutes) level maximum from antenna
exposure proper
1982 ANSI 2900 pW/cm2 Same 0.0005% 0.034% 103%
1992 ANSI 580 pW/cm2 2900 pW/cm2 0.0025% GP 1.7% GP 517% GP
0.0005% 0 0.034% 0 103% 0
1986 NCRP 580 pW/cm2 2900 pW/cm2 0.0025% GP 1.7% GP 517% GP
0.0005% 0 0.035% 0 103% 0
1986 NCRP with 580 pW/cm2 580 pW/cm2 0.0025% 1.7% 517%
modulation
derating
1987 IRPA 435 pW/cm2 2175 pW/cm2 0.0034% GP 0.2% GP 690% GP
0.0007% 0 0.046% 0 138% 0
DISTANCES TO ACCEPTABLE EXPOSURES FROM BASE STATION ANTENNAS
The following table shows distances,as a function of ERP,to the power flux densities permitted by stan-
dards discussed at the Federal Focus Symposium. The underlying calculations assume no reflection or
absorption, 15 active channels,and omnidirectional antennas.Actual base stations tend to emit less signal
power downward than outward,so the table probably overstates real exposures at the base of a tower.
Because most base-station antennas are 150 feet or so in the air,minimum distances to both the general-
public and occupational limits are more than satisfied.Fewer channels(less exposure)or more channels
(more exposure)may be active at a given base station than the 15 channels assumed.
•
Standard General-Public Distance to Occupational Distance to
Limit General-Public Limit Occupational
Limit Limit
1982 ANSI 2900 pW/cm2 15.01t(500 W) Same As General Same As General
10.5 ft.(250 W)
6.7 ft(100W)
4.7 ft(50 W)
3.0 ft (20 W)
1992 ANSI 580 pW/cm2 33.0 ft(500 W) 2900 pW/cm2 15.0 ft(500 W)
23.5 ft.(250 W) 10.5 ft(Z50 W)
14.9 ft(100W) 6.7 ft.(100W)
10.5 ft(50 W) 4.7 ft(50 W)
6.7 ft(20W) 3.0 ft (20W)
1986 NCRP 580 pW/cm2 33.0 ft(500 W) 2900 pW/cm2 15.0 ft.(500 W)
23.5 ft(250 W) 10.5 ft(250 W)
14.9 ft(100W) 6.7 ft(100W)
10.5 ft(50 W) 4.7 ft(50 W)
6.7 ft(20 W) 3.0 ft.(20 W)
1986 NCRP with N/A N/A 580 pW/cm2 33.0 ft.(500 WI
Modulation 23.5 ft(250 W)
Derating 14.9 ft(100W)
10.5 ft(50 W)
6.7 ft(20 W)
1987 IRPA 435 pW/cm2 38.4 ft(500 W) 2175 pW/cm2 17.2 ft.(500 W)
27.2 ft.(250 W) 12.2 ft(250 WI
17.2 ft.(100W) 7.7 ft(100W)
12.2 ft(50 W) 5.4 ft(50 W)
7.7 ft.(20 W) 3.4 ft(20 140
•
The consensus among Symposium participants in the limits of frequency and SAR specified by
was that public exposures from base stations are previous ANSI standards,including ANSI 095.1-
extremely low—hundreds or thousands of times 1982.In the promulgation of revised guidelines,
below the more conservative,uncontrolled ANSI the responsibility of the current Subcommittee IV
limit.Does this mean that base stations are safe? is adherence to the scientific base of data in the
One Symposium participant expressed concern determination of exposure levels that will be safe
about a lack of data on long-term(chronic) not only for personnel in the working environ-
exposures.However,another pointed out that 11 of ment,but also to the public at large.
the 121 studies that the IEEE standards-setting One participant described the FCC's position as
committee reviewed involved long-term exposures. that the ANSI standard sets the threshold of safety,
The 1992 ANSI standard,which stems from the and that normally base stations are not an envi-
IEEE work,answers the safety question this way:
ronmental problem.
The members of Subcommittee IV[one of the The FDA has also spoken on low-level RF expo-
IEEE's standards-setting subcommittees]believe sures. Specifically in connection with cordless
that the recommended exposure levels should be telephones,19 which create RF fields comparable
safe for all,and submit as support for this conclu- in strength CO those from base stations, the FDA
sion the observation that no reliable scientific data observed,in its'Talk Paper T93-7" (February 4,
exist indicating that: 1993),that
(1)Certain subgroups of the population are more
at risk than others; The safety of so-called"cordless phones,"
(2)Exposure duration at ANSI C95.1-1982 levels which have a base unit connected to the
is a significant risk; telephone wiring in a house and which
(3)Damage from exposure to electromagnetic operate at far lower power levels and ire-
fields is cumulative;or quencies[than mobile or portable cellular
phones]has not been questioned.[20]
(4)Nonthermal[athermal] (other than shock)or
modulation-specific sequelae[aftereffects]of In sum,for public exposu--es,base stations have a
exposure may be meaningfully related to safety margin in the range of hundreds or thousands
human health. of times,relative to standard limits.
No verified reports of injury to human beings or of
adverse effects on the health of human beings who
have been exposed to electromagnetic fields with-
HOW MUCH IS ONE MICROWAIT/CMZ?
Participants at the Federal Focus National
Symposium on Wireless Transmission Base MODULATION ISSUES
Station Facilities agreed that typical public
exposures from base stations is one micro watt
or less per square centimeter.How much is that? Report No.86 by the NCRP suggests that low-
This may provide some idea.A typical night light frequency modulated RF carriers may call for
consumes four watts of power,of which 5% greater protection in occupational settings.
(200,000 microwatts)emanates as visible light Accordingly,the NCRP Standard calls for use of
Assume the light spreads evenly in all directions, general population exposure limits for workers if
its power flux density decreasing with the square carrier strength varies 50%or more at frequencies
of distance from the bulb.At just over four feet; between 3 and l09 Hz Certain digital transmission
one micro watt of light power falls on one square formats such as TDMA may call for such addi-
centimeter—about the area in a middle-aged tional precautions for mobile or portable digital
• adult's wide-open pupil.So,neglecting reflec- This is not an issue for base stations,
tions,a power flux density of one microwatt per however—digital or analog.
square centimeter of visible light enters a viewer's
eye at just over four feet from a night lighti8
•
For example,one Symposium participant observed ground noise levels(about 5 to 15 microwatts,or
that, for tower-mounted omnidirectional base 1 to 3%of the 1992 ANSI uncontrolled standard),
station antennas,measured exposures near ground "bur far,far below any standards that are used to
level are less than one microwatt per square protect health."
centimeter—less than 0.2%of the 1992 ANSI Another participant shared measurement data
standard.The participant also observed that direc- taken in the vicinity of several different base
tional antennas result in very low ground-level stations.At a distance of about 100 feet from a
exposures.Based on the participant's measure- tower supporting several directional antennas,in a
ments of exposures from base stations mounted on
shopping-centerlot,typical midday cellular
office-building roofs,the only time exposures even PPS parking
approach 1992 ANSI limits is when one gets with- power densities were"2 to 15 nanowarts per square
in a yard or so of an actual transmitting antennas centimeter...extremely low..."16 That is less than
themselves—as opposed to an inert metal pole 0.002%of the 1992 ANSI uncontrolled limit.17
At another directional base station,with roof-
which supports such an antenna up in the air
mounted antennas about 16 feet up in the air,
Other Symposium participants provided similar exposure levels at three to six feet above the roof
observations, based on their own measurements. line were 5 to 15 microwatts per square centime-
You may recall from Chapter 2 that as cellular ter.This is about 0.9% to 2.6%of the 1992 ANSI
traffic increases,base-station antenna heights and uncontrolled exposure limit, but the roof was
ERPs decrease.Because exposure levels rise closer inaccessible to the general public.Measured power
to an antenna but decrease as ERP falls,the two flux densities were about 0.2%to 0.6%of the 1992
factors tend to cancel each other out.One partici- ANSI controlled limit.
pant described surveying the interior of a hospital Because actual measurements require sophisticated
adjacent to a building with a roof-mounted base
station.The base station's signal levels were at equipment and can be time consuming and costly,
4110
background noise levels in the hospital kitchen, engineers have developed various techniques for
and from 1 to 3 microwarts per square centimeter predicting exposure levels.One participant
on a terrace and in other parts of the 27th floor— described a sophisticated method of computer
very low levels.In another setting,one floor below analysis that takes into account a base station's
a roof-mounted base station(a vertical distance of antenna types,antenna heights,transmitter powers,
about 10 to 15 feet),exposure levels were 10 number of active channels,and the effects of any
microwatts per square centimeter—less than 2% intervening construction materials.This method
of the 1992 ANSI limit for uncontrolled settings. allows estimates of exposures to people within,say,
an office building that has a base station mounted
A Symposium participant also described measure- on its roof.The participant described a good corre-
merits at a base station with wall-mounted direc- lation between the predicted exposures and those
tional antennas designed to serve the inside of an actually measured.
office building.Measured signal levels were within The participant described how he had used this
1992 ANSI limits except in the immediate vicinity method to analyze a proposed base station at a fire
and in the main beam of the antenna.The signals station.The proposal had engendered some
measured in the equipment room,behind the controversy among area residents.For many years,
antenna's reflector and therefore outside the main the fire department had used the tower for its own
beam, were extremely weak,essentially at back- antennas.The highest predicted signal levels from
ground-noise levels.
the base station would be about 3.5 microwatts
One participant reported that the EPA had per square centimeter,less than 0.7%of the 1992
surveyed typical background noise levels from all ANSI uncontrolled exposure limit.In fact,the par-
sources(including TV and FM broadcast stations) ticipant observed,exposure from the fire depart-
in a variety of settings,and had arrived at an average merit transmitter was probably much higher than
level of 0.005 microwatts (five nanowarts)per any from the base station.
square centimeter.That is less than 0.00190 of the Several participants observed that exposures
1992 ANSI limit for uncontrolled exposures.The •
from cellular towers are usually less than those
participant observed that,close to a base station,
exposures usually are considerably above back- from UHF TV stations,police and fire radio
transmitters, and FM broadcast stations.
III
How do exposures by 14 different biological-validation workingQ
D. DO BASE STATIONS COMPLY WITH
to radio waves groups,each made up of experts in a specific field THE 1992 ANSI AND OTHER SAFETY
from base stations of biology.The groups looked for study results that STANDARDS?
compare to those indicated a measurable effect,regardless of whether
permitted by applicable the power flux density required for that effect In short,yes.Gauging actual exposures from
safety standards? caused measurable tissue warming(the so-called cellular base stations requires specialized equipment
thermal effect).The most sensitive indicator and measurement techniques.'5 Measure-ments
turned out to be behavioral.Laboratory animals can be time-consuming,but the techniques are
ABase stations would modify their performance of trained tasks now well established.Participants at the Federal
result in public when the absorbed dose of power was about four Focus Symposium shared their experiences measur-
exposures well below warts per kilogram of body mass.A safety factor of ing actual signals in the vicinity of base stations.
the limits permitted 10 for occupational exposures was then imposed. The consensus of the participants was that expo-
not only by the 1992 The committee increased the safety margin sure levels from cellular base stations do not even
ANSI standard, but another five-fold to arrive at the stricter limit for begin to approach ANSI limits except in the
also by all other stan- uncontrolled exposures.14 immediate vicinity of energized transmitting
dards under considera- antennas.
tion by the FCC. As
one government official
stated at the Federal
Focus National --
Symposium on Wireless FCC STATEMENTS ABOUT RF EXPOSURE FROM "worst-case"ground-level exposures near the-:
Transmission Base BASE STATIONS typical cellular tower are on the order of 1 pW/cm1
Station Facilities the or less. Calculations corresponding
estion of adverse The FCC's December 1994 "Information On Human to a "worst
Exposure to Radiofrequency Fields From Cellular case"situation(all transmitters operating simu/ta
alth effects fromRadio Transmitters"states the following about neously and continuously at the maximum licensed
base stations is "almost base stations: power)show that in order to be exposed to levels
a nonissue in terms of near the 1982 ANSI limits for cellular frequencies;
actual exposure levels." The signal from a cellular base station antenna is an individual would essentially have to be in.the-
essential/y directed toward the horizon in a tela- main transmitting beam(at the height of the tively narrow beam in the vertical plane.For exam antenna)and within a few feet of the antenna. This
p/e,the radiation pattern for an omnidirectional makes it extremely unlikely that a member of the
antenna might be compared to a thin doughnut or
general public could be exposed to RF levels in.-:
pancake centered around the antenna,while the excess of those guidelines.
pattern for a sector[directional]antenna is fan-
shaped,like a wedge cut from a pie.As with all Potential exposure can also be compared to the
forms of electromagnetic energy,the power density more restrictive limits recommended by the
from a cellular transmitter decreases rapidly National Council on Radiation Protection and
(according to an inverse square law)as one moves Measurements(NCRP),the International Radiation
away from the antenna. Consequently,normal Protection Association(IRPA),or the Institute of
ground-level exposure is much less than exposure Electrical and Electronics Engineers(IEEE). The
very close to the actual antenna.Measurements IEEE guidelines(IEEE/ANSI C95.1-1992)have been
made near typical cellular towers have shown that recently adopted by ANSI to replace the 1982
ground-level power densities are well below limits guidelines mentioned above. The NCRP and ANSI/
recommended by RF/microwave safety experts. IEEE guidelines recommend a limit for exposure of
At a frequency of 869 MHz(the lowest base station the general public(or exposure in "uncontrolled"
frequency used),the RF protection guidelines of environments)of about 580 pW/cm2 at 869 MHz
the American National Standards Institute(ANSI The corresponding IRPA recommendation is about
C95.1-1982), which is used by the FCC and others, 435 pW/cm2 The exposure levels measured at
recommend that human exposure should be limited ground level around typical cellular towers are
to a power density of about 2900 micro watts per hundreds or thousands of times lower than the
square centimeter(pW/cm2),as averaged over any above limits. The FCC has recently proposed
• six-minute period. This limit is many times greater
than RF levels found near the base of a typical adopting the new IEEE/ANSI guidelines for thepurposes of evaluating environmental RF fields
cellular towers.Measurement data obtained from from transmitters such a cellular radio antennas.
various sources have consistently indicated that
20
4110
calls these controlled and uncontrolled environ- same as the 1962 ANSI limit,which did not dis-
ments. A controlled exposure occurs when a per- tinguish between controlled and uncontrolled
son is aware of and can control the exposure.A exposures for all settings.At cellular frequencies,
worker climbing a base station to install a new in terms of power flux density,the limit for con-
antenna is in the controlled environment.An trolled exposures is about 2.9 milliwatts(2900
uncontrolled exposure is one where the person has microwatts)per square centimeter,averaged over
no lmowledge or control over their exposure.Some- six minutes. For uncontrolled exposures,the limit
one living near a base station experiences an is 0.58 milliwatts(or 580 microwatts)per square
uncontrolled exposure.They may be aware there centimeter,averaged over 30 minutes.13
is a base station nearby,but they have no idea How did the standard-setting committee arrive at
whether the base station is active at any given time. these values?To establish the limit for controlled
The 1992 ANSI standard's limits for controlled exposures, the committee undertook an extensive
exposures at cellular frequencies are essentially the critical review of the pertinent scientific literature
APOUT ANSI ■Rigorous ANSi standards for due process have
The American National Standards institute is the been met;and
nation's preeminent private standard-coordinating •A consensus for approval exists among those
body.ANSI is a nonprofit;privately funded member- directly and materially affected(persons represent-
ship organization that coordinates the development ing organizations, companies,government agencies,
of U.S. voluntary national standards and is the U.S. and individuals)who chose to participate in the
representative to nontreaty international standards- approval process.
setting entities including the International ANSI defines due process as follows:
•
Organization for Standardization(ISO)and the
International Electrotechnical Commission.ANSi's Due process means that any person(organization,
membership roster includes approximately 1300 company,government agency,individual,etc.)
companies,250 professional,technical,trade, with a direct and material interest has a right to
labor,and consumer organizations,and about 30 participate by (a)expressing a position and its
government agencies.ANSI's key functions are: basis;(b)having that position considered;and(c)
appealing if adversely affected.Due process allows
■To coordinate the self-regulating,due-process,con- for equity and fair play.
sensus-based U.S. voluntary standards system;
•To administer the development of standards and to To satisfy due process,standards-setting activities
approve them as American National Standards; must be open and balanced. Open Hess means all
persons directly and materially affected can par-
•To provide the means for the U.S.to influence the ticipate without having to overcome undue finan-
development of international and regional standards; tial or technical-qualification barriers,and without
■To disseminate information about national,regional, having to join any particular organization. There
and international standards activities to U.S.indus- must be timely,clear notice to all known directly
try;and and materially affected interests concerning any
■To promote awareness of the importance of proposed creation,revision,reaffirmation,or with-
standards technology and its relationship to U.S drawal of a standard.Balance requires that varied
global competitiveness. interests should participate in standards-setting,
ANSI itself does not develop standards.Rather, with no single interest category dominating the
Process.ii Before taking any action,a standards-
ANSI accredits standards-developing bodies
which include technical and professional societies, setting committee must find that consensus has
and industry associations. Those bodies submit been achieved,meaning that substantial agreement
candidate standards to ANSI for approval by has been reached.12 Any party disappointed with a
standards committees. Volunteer experts from result may file an appeal to ANSI's Appeals Board.
industry, nonprofit organizations,and government Every five years,each standard-setting committee
agencies make up ANSi committees.ANSI com must review the ANSI standards within its jurisdic-
mittees consider comments from all who make tion. The committee can recertify the standard,
submissions,keep records of their proceedings, adopt an entirely new one,or make such changes
and adopt standards if they find that as are appropriate.
19
QAre there safety lic is exposed from base stations—can damage tis- Environmental Policy Act of 1969 (NEPA)
standards for sue if the body cannot dissipate the resulting heat charges the FCC(among other federal agencies)
exposure to the radio quickly enough.External body tissues,especially with evaluating the extent to which Commission-
waves from base sta- corneas and testes,are most vulnerable because authorized facilities may have a significant impact
tions? they lack enough blood circulation to quickly on the quality of the human environment.In
carry away large amounts of heat. Intense thermal 1985,to perform its duty under NEPA, the FCC
exposures can thus cause cataracts or temporary adopted a 1982 exposure standard (C95.1-1982)
AYes. The Federal male sterility.7 Modest exposures to nonionizing promulgated by ANSI,the American National
Communications fields,however,appear to be benign.Indeed,we " Standards Institute,the preeminent private scan-
Commission, the federal ourselves generate low levels of microwave power.8 dard-coordinating body. Based on an extremely
agency that licenses low risk of exposures in excess of the 1982 ANSI
base stations, has At cellular frequencies,it takes power flux densi- standard,the FCC
ties in the range of at least tens of milliwatts per categoricallyexcluded applica-
adopted exposure limits square centimeter to cause measurable tissue dons for new or modified cellular base stations,
for the RF fields from police and fire transmitters,etc. from having to
base stations. Some
warming.As we will see in greater detail below, demonstrate compliance with the standard.
state and local govern- such power flux densities generally occur only
ments and industry within feet or yards of a transmitting antenna.At In 1992,ANSI supplanted its 1982 standard with
ground level,exposures from cellular base stations a 1991 RF-exposure standard drawn up by the
standard-setting bodies
are extremely low,one-thousandth or less of those Institute of Electrical and Electronic Engineers
have also adopted
exposure limits or that cause any measurable tissue warming. (IEEE),a prestigious professional society. In
response,the FCC started an update of its envi-
guidelines. There is some debate whether atherrnal exposures ronmental rules.The FCC proposes to adopt the
—especially those involving nonionizing power 1992 ANSI standard as the most recent and com-
flux densities significantly higher than those in prehensive of all the standards published since
the public areas around base stations,but still too 1985,when the agency adopted the 1982 ANSI
weak to cause tissue warming—can nonetheless standard.9 The FCC is also rethinking its categori-
have any effects on tissue,such as the enhanced cal exclusion of various base-station and mobile-
migration of calcium ions (calcium efflux).A radio facilities from scrutiny for compliance with
minority of scientists believe so.Other scientists RF exposure limits.The FCC received many com-
have been unable to reproduce claimed results in menta in the rule-making proceeding in the first
their own laboratory experiments.Most of these four months of 1994.The great majority of the
studies have nothing to do with health effects, comments favor replacing the 1982 ANSI stan-
and the exposure levels are significantly above dard with the 1992 ANSI standard.'°
those to the public from base stations.
Note that this monograph discusses only exposures All of the standards under consideration by the
to RF fields.The issue of exposure to electric and FCC share common elements.Each sets time-
magnetic fields from high-tension lines is a separate averaged exposure limits,and all permissible expo-
sures
question altogether.Fields emanating from base are much less than those which cause the
stations have frequencies of about 850 MHz, 14 slightest measurable thermal effects.The averag-
ing times differ,but each standard allows continu-
million times higher in frequency than those from
power lines,which are at 60 Hz.Base-station fields, ous exposures that do not exceed a certain value.
except when very close to the transmitting antennas, Also,permissible exposure levels vary with fre-
are weak;at comparable distances,the fields from quency.The strictest limits occur in the frequency
power lines are much,much stronger.So different range where the physical dimensions of human
are the respective frequencies and field intensities bodies correspond to those of resonant antennas.
that one simply cannot make any meaningful At these frequencies(roughly 30 to 300 MHz),
the body can most efficiently absorb RF power
comparisons. from ambient fields.Thermissible
pe exposures at
C. RF EXPOSURE LIMITS FOR BASE cellular frequencies under the various standards
• STATIONS are comparable.
The FCC,which licenses base stations and other The newer standards also have in common differ-
civilian radio transmitters,has been active in con- ant tiers of exposure limits for occupational and
general-public settings.The 1992 ANSI Standard
trolling RF exposure.The National
18
•
thereby display a net negative charge. Such elec- As mentioned above,ionization of atoms in DNA
rrically unbalanced atoms are called ions.They molecules can have profound consequences.That
usually try to return to an electrically neutral state, is why ultraviolet rays,X-rays,and gamma rays
if possible.This makes them highly reactive chem- can be so dangerous.
ically,and ions can behave in ways that 4. Absorption and Reflection
neutral atoms do not.
Often,two or more atoms enter into electron- When a radio wave strikes a material,how the
wave interacts with that material depends on the
sharing arrangements for mutual benefit.This
material's electromagnetic characteristics.For
binds the atoms into a molecule.Two hydrogen
acorns and one oxygen atom sharing electrons form example, if the material is not a good conductor
of electricity,the material will be essentially trans
-
a water molecule.More complicated organic
parent to the radio wave.The wave will pass
molecules,comprising atoms of carbon,hydrogen, through it largely unimpeded,and will not affect
and certain other elements,are the stuff of life. the material.If the material is a very good
2. Cells conductor of electricity,the material will reflect
the radio wave with little loss of signal power.If
Each human being is a collection of millions of
living cells,many of which group together as an the material is somewhat conductive,some signal
organ to perform an essential function.Each living power will be reflected,some will be absorbed by
cell, in turn, is a large collection of organic mole- the material,and the rest will pass through the
cules.A cell membrane or cell wall forms the materia(.
boundary between a cell and its surroundings.. 5. Thermal and Athermal Nonionizing Exposures
Inside the cell wall is a viscous material called Nonionizing photons (radio,infrared,and visible
cytoplasm.Unlike nonliving collections of mole- light waves)cannot upset the electrical balance of
cules, a living cell can reproduce itself. It does so atoms,but they can affect atoms,hence molecules, •
through a splitting process called fission.A cell and hence living tissue in some ways.We learned
reproducing itself uses a blueprint stored in genetic
material in the cell's nucleus.The genetic material above that electric fields can attract or repel elec-
material
encoded as a very long sequence of a handful of trically charged particles,and that magnetic fields
can deflect them.We also learned that electrically
different organic molecules that bind togetherelectrically
DNA.So long as the encoded cell plans are not charged electrons orbit the nucleus at varying
corrupted, the daughter cell will be identical to the distances.
parent. However,if one or more constituent atoms A radio wave's electric and magnetic fields,which
in an organic molecule becomes ionized,it can alter switch polarity at the radio wave's frequency,can
that molecule's behavior. Ionization of atoms in cyclically affect electrons in orbit about the nucleus.
DNA molecules can cause profound consequences. The fields can pull the electrons first one way and
The structure of the DNA can change,and when then the other,but not strongly enough to liberate
the cell tries to reproduce,a mutation occurs. them from their orbits around the nucleus.
Through such effects on electrons,as the fields
3. Nonionizing and Ionizing Energy
cycle through their polarity reversals,those fields
Electromagnetic energy behaves in some ways like can alternately twist and untwist a molecule's
waves,and in others like particles.As a group of shape,or cause molecules to line up first one way,
particles,electromagnetic energy travels in units and then another.
called photons.The amount of energy packed in a Strong nonionizing fields(that is,those from high
photon depends on the wave's frequency.The radio-wave power flux densities,much higher
higher the frequency,the greater the energy.A than those to which the public is exposed from
nonionizing photon is not energetic enough to cellular base stations)can cause water molecules
knock electrons away from parent atoms.Radio
in
waves, infrared,and visible-light waves are non- a measuring cup(or in living cells) CO gyrate
ionizing.An ionizing photon(an ultraviolet,X,or vigorously and rub against each other Such fields
gamma ray),which has a much higher frequency can also cause ions to move.The result is a ther410
-
than a nonionizing photon,contains enough energymal effect,a warming of the water in the cup or of
the cells in living tissue.6 Intense nonionizing
to strip one or more electrons away from the atom. fields—far stronger than those to which the pub-
m
i
Can radio waves We have just seen that magnetism and electricity AC)stops.Conversely,when an alternating
from base are intimately associated with fields.The more magnetic field cuts across a coil of wire, it induces
stations harm me or intense the field,the more lines of force per cen- AC to flow in the wire.That is how an electric
my family? timeter(or inch),and the stronger the force on generator works.=The generator stops producing
external objects.Also,magnetism and electricity current if the magnetic field collapses.
are themselves closely interrelated. A magnetic
AThe radio waves or electric force weakens dramatically as the dis- When RF current flows in an antenna,electric
from base stations tante from the source of the field increases.A and magnetic fields arise and emanate out into
are "nonionizing" and magnet has two poles,North and South.A battery space.The result is a radio wave.Each of the two
very weak in areas has two terminals,one positive and one negative. fields has a certain strength or amplitude which
frequented by the So does an electric generator. In operation,a DC depends on the power contained in the radio wave.
public. At such low One measures strong electrnc field in 1.olts per
generator's positive terminal always remains poli- meter (V/m);weaker ones in millivolts per meter
levels, there is no tive,and the negative terminal remains negative. (mV/m);and very weak ones in microvolts per
evidence that they can This is also true of a battery. But an AC generator's meter (pV/m).One measures strong magnetic
cause genetic damage two terminals flip polarity at the ACs frequency. fields in amperes per meter (A/m);weaker ones
or any other harm to Electrically charged bodies (such as the hard rub-
inmilliamperes per meter(mA/m);and very
living tissue. ber comb)can be of one polarity only(positive or weak ones in microamperes
negative),but a magnet always has two poles. per meter µA/m).
Two magnets will attract each other if their nearest B. ELECTROMAGNETIC FIELDS AND
poles are opposite;if alike,they will repel.Two LIVING CELLS
electrically charged bodies, if of opposite polarity, The Nineteenth Century physicist James Clerk
will attract each other;if alike,they will repel.An Maxwell correctly theorized that light waves and
electric field of one polarity will pull an oppositely• heat rays are two forms of electromagnetic radiation
electrically charged particle toward the field's that share basic characteristics.3 Each comprises a
source;the field will repel a charge of like polarity. pair of time-varyingelecaic and
Magnetic fields can exert forces on moving electric magnetic fields at
charges and bend the particles'paths —unless the right angles to each other.The pair of fields(and
charges are moving parallel to the lines of magnetic the wave they comprise)race outward from their
force. source at the speed of light and can travel through
empty space.4 The basic difference between radio
A coil of wire wrapped around an iron or steel bar waves,visible light,and other forms of electro-
will act as an electromagnet if electric current flows magnetic waves is the rate at which their fields
in the coil.The resulting electromagnetic field reverse polarity(their frequencies). Infrared(heat)
strength depends on the amount of current,the rays have higher frequencies than radio waves,and
number of turns in the coil,and the bar's magnetic visible light higher frequencies than infrared rays.
characteristics.If direct current flows in the coil, The other main difference is how the various
the polarity of the magnetic field is fixed,like that forms of electromagnetic waves affect matter.
of a horseshoe magnet or a bar magnet.If AC 1. Atoms,Ions,and Molecules
flows in the coil,the magnetic field's polarity
switches back and forth in step with the AC itself. Matter consists of atoms.Atoms comprise:electrons,
The magnetic field collapses if the current(DC or with a negative electric charge;protons,which
carry a positive electric charge;and neutrons,
WHAT/S RADIATION? which carry a neutral(that is,no)electric charge.
Protons and neutrons make up an atom's nucleus.
To most people,radiation is a frightening word. Electrons orbit the nucleus,much as planets orbit
However,radiation is simply power emitted from the suns A typical atom has equal numbers of
a source in waves or particles.It is not the same
as radioactivity.Manyprotons and electrons.The positive balance
types of radiation have
nothing to do with nuclear physics.Some are the negative ones,and the atom is electrically
1111 not even electromagnetic.Sound is one form of neutral.However, if an electron acquires enough
radiation;ripples on a pond are another.Radio energy,it can fly off into space.The atom
waves,sunligh4 and the wa,urth emitted by a becomes electrically imbalanced,and displays a
fireplace or a radiator are all forms of electro- net positive charge.On the other hand,an atom
magnetic radiation. can pick up one or more vagabond electrons and
16
Chapter 3: Base Stations and the Public Health
4111
As cellular networks need to deploy more base stations A. RECAP OF ELECTROMAGNETIC
to keep up with the public's demand for service, base FIELDS
stations are closer to each other and to where people
live and work. This naturally causes people to ask the In the last chapter,we learned that cellular base
following questions: stations transmit radio waves at frequencies around
II Can radio waves from base stations harm me or 850 MHz. Each radio wave comprises two fields—
my family? one electric,the other magnetic.The fields are at
■ Are there safety standards for exposure to the radio right angles to each other and to the wave's direc-
waves from base stations? tion of travel. But just what are fields? Fields are
■ How do exposures to radio waves from base sta- the way scientists explain certain natural forces.
dons compare to those permitted by applicable safe- Until recently,people could only understand forces
ty standards? produced by direct physical contact.A spoon on
the ground would only move if someone picked it
In this chapter, we will answer those questions,in light
of the larPtt reported scientific rlarn. up,kicked it,or pulled on a string that was tied to
it. If the spoon moved without any direct physical
The topic of base stations and the public health contact,magic or a spirit was to blame.
was a major area of discussion at the Federal Focus People also had no idea why a spoon knocked off
National Symposium on Wireless Transmission a table would always fall down to the ground,never
Base Station Facilities.Experts from both the up into the sky.Today,of course,we know that
public and the private sectors who participated in the force of the earth's gravity pulls the spoon to
the Symposium agreed that the radio signals from the ground.Gravity is one of the natural forces
base stations pose no threat to public health. that requires no physical contact between two
First,we will see that the magnetic and electric physical objects(the earth and the spoon).Physicists
fields that make up radio waves can interact with use the concept of a gravitational field to explain
•
the atoms and molecules that comprise matter, how the force of gravity arises.Any massive object
including living cells.When the fields are weak, such as the earth sets up a gravitational field
the interactions are very subtle.Most scientists around it.When another object with mass enters
who have investigated those interactions hold that that gravitational field,a gravitational force arises
the interactions pose no health risks at the very which tends to pull the two objects together.The
low exposure levels associated with cellular base intensity of the force depends on the masses of the
stations.While a few scientists have claimed two objects and their proximity to each other.
biological effects from fields at frequencies other Today,we also know we can move a stainless steel
than those used by cellular base stations,others spoon without directly touching it by bringing a
have not been able to reproduce the claimed strong magnet near it.A magnetic force attracts
results in laboratory experiments,or the effects the spoon to the magnet.That force arises without
have no obvious significance.Stronger fields can any physical contact between the magnet and the
produce measurable warming of living tissue.Very spoon.Rather,it arises from the spoon's immersion
intense fields can cause significant thermal effects in the magnetic field emanating from the magnet.
such as cataracts and temporary sterility in males,
but the fields from cellular base stations are far,far There is also an electric force that arises without
below the levels required to produce these effects physical contact.You can prove this for yourself
in members of the public. by running a hard rubber comb briskly through
To protect the general public and workers,various your hair,and then bringing the comb near small
pieces of tissue paper on a countertop.Some of the
government and private bodies have adopted Stan- bits of paper will fly toward the comb because an
dards establishing permissible exposure levels.The electric force causes them to move.As with the
public's exposure from base stations is extremely magnet and the spoon,the force arises without
low,usually less than one percent of the levels direct physical contact between the comb and the
permitted by the standards.And workers who come paper.The force arises from the paper's immersion
close to antennas during maintenance activities in an electric field. The electric field results from .
can take simple precautions to keep their exposures a static electric charge set up in the comb by the
within the limits of the standards. brisk rubbing.t
i
9Among the uses of the spectrum are: radio and television broadcasting; police, fire, ambulance,
and other public-safety communications; taxicab and truck dispatching; aircraft communications;
satellite links; radar; CB and ham radio communications; industrial,scientific, and medical applica-
tions; and mobile and portable telecommunications.
10There are 1000 milliwatts, or 1,000,000 microwatts, in a watt.
11ERP referenced to a half-wave dipole is the cellular industry's standard way of expressing the
signal power emitted from a base-station antenna. In other contexts, communications engineers
sometimes speak of Effective Isotropic Radiated Power or EIRP. EIRP is the radio signal power that
would escape into space from an isotropic antenna—a theoretical antenna that would radiate
equally well in all directions. EIRP is not the same as ERP referenced to a half-wave dipole. A
dipole is somewhat directional and, in the dipole's most favored direction, exhibits 2.1 decibels
(dB) of gain (a power multiple of 1.62 times) relative to an isotropic antenna.
12The large bulb does not generate 100 watts of light. Rather, it draws 100 watts from the power
source. Most of those 100 watts is wasted as heat. (A great portion of the heat radiates as invisible,
infrared radiation.) Only five watts might actually radiate as visible light.
13A ten-fold power increase corresponds to a +10-dB gain, a hundred-fold increase to +20 dB, and
a thousand-fold increase to +30 dB. A doubling of power is a +3-dB increase, and a quadrupling +6
dB. A two-fold drop in power is a -3-dB loss;a four-fold decrease -6 dB. A ten-fold drop in power is
a -10-dB loss, and so on.
14Signal power in watts equals signal voltage in volts times signal current in amps. A 100-watt
• cellular transmitter generates the same amount of power that a 100-watt bulb draws from a wall
socket. In very rural areas where traffic is light and base stations few and far between, ERP can be
as high as 500 watts per channel.
15Why not just increase the number of channels?Because the FCC assigns a limited amount of
spectrum to each cellular carrier,and using more channels at a given base station entails more
channel preclusion in adjacent service areas or"cells."Cutting ERP and antenna height while
increasing the number of channels helps the network handle the localized demand without pre-
venting other base stations from using the added channels.
16A Symposium participant who is a cellular communications engineer also described picocells,
which have even smaller coverage areas, that cellular networks can deploy to cope with the highest-
demand situations.
17Those are two major reasons why FM broadcast radio stations sound so much better than AM
radio stations.
18This analog FM cellular telephone signal format is also called Advanced Mobile Phone Service
or AMPS.
4110
i
Notes Chapter 2
lAn older term for hertz is cycles per second. Frequencies are also expressed in kilohertz (kHz,
formerly kilocycles per second or kc/s) or megahertz (MHz, formerly megacycles per second or
Mc/s). One kilohertz is one thousand hertz. One megahertz is one million hertz or one thousand
kilohertz.
2Radio signals have frequencies, like sounds have pitch. Flutes are higher in pitch than trombones,
and cellular base stations have higher operating frequencies than FM broadcast stations. FM broad-
cast frequencies are from 88 to 108 megahertz (MHz). Base stations transmit and receive in a band
of frequencies roughly nine times higher (about 850 MHz), near TV channel 69.
3Of course, the other parry might also be using a cellular phone, in which case his or her half of
the conversation might pass back out over the airwaves via a base station.
4The technical term for this is full duplex operation.
5This is why, except in very unusual circumstances,we cannot—by direct reception—pick up UHF
television stations from more than 60 miles away. Rural homes often have television receiving
antennas on very tall masts co increase the reception range.
6The smaller the frequency difference between the desired and the interfering signals, and the
stronger the interfering signal, the harder it is to decode the desired signal. Special signal-process-
ing techniques can suppress interference, but there are limits to their effectiveness.
7One measures electric field strength in volts per meter, millivolts per meter,or microvolts per
meter. One thousand millivolts per meter is the same as one volt per meter,or one million micro-
volts per meter. Depending on the effective length of a particular antenna, and depending on the •
strength of the electric field impinging on that antenna, an RF signal will appear at the antenna's
output terminals. One measures that output signal in volts, millivolts,or microvolts (as opposed to
volts per meter, millivolts per meter, or microvolts per meter, the units of electric field strength).
There are one thousand millivolts (or one million microvolts) in one volt, the standard unit of
electrical pressure or"potential difference."
The voltage and the resistance in an electrical circuit determine the current flowing in that circuit.
Current is measured in amperes or amps; electrical pressure,as noted above, in volts;and resistance
in ohms. A fresh"AA"penlight battery generates 1.5 volts.A charged car battery generates 12
volts. Utility power is usually at 115 to 120 volts, but high-current circuits (e.g., those for electric
stoves and furnaces) often are at 230 volts.
Electrical pressure is like water pressure. Open a faucet a bit, and a certain amount of water will
flow out each second. The water pressure overcomes the resistance put up by the walls of the pipe
and the partially open valve.The flow increases if the pressure increases or the resistance decreases,
that is, the faucet opens further. Similarly, more current flows in a circuit if the voltage increases or
the resistance decreases.
Receiving antennas usually generate output signals as strong as one volt only when they are close
to the transmitting antenna,where fields are one volt per meter or more.
8The 32-dBµV/m contour is where FCC propagation curves predict a base station's signal will
have a field strength of 39.8 microvolts per meter. Because the prediction curves include a statisti-
cal factor, not every point within the contour will enjoy the predicted signal strength. At some
points, the signal will be weaker due to local terrain effects (e.g., loss of line of sight); at others, the
signal will be stronger.
i
m
•
TDIVLq thus triples a base station's traffic capacity and three or more times more calls than TDMA
without any change in ERE antennas,or the systems. However,CDMA requires specialized
number of active channels.This means that one equipment at both the base station and subscriber
fully digital base station(or one N-AMPS base ends,and is currently undergoing field trials.
station)can carry the same number of calls as
three conventional analog(AMPS) base stations.
Another digital format cellular systems are intro-
ducing is Code Division Multiple Access or
CDMA.CDMA differs greatly from TDMA.Each
signal is uniquely coded with a key that spreads
the signal over a very wide bandwidth,much
wider than the 30-kHz TDMA standard.A CDMA
receiver responds only to the desired transmitter's
key and can pick out("decode") and demodulate
the associated signal.CDMA is also called spread
spectrum transmission.CDMA systems can
ignore narrow-band undesired signals as well as
CDMA signals occupying similar bandwidths but
coded with different keys.Some engineers estimate
that CDMA networks can handle 10 or more
times more traffic than analog cellular systems,
•
WHAT ISA CHANNEL? number of channels that can occupy a given
In radio communications,a channel is a band of segment of the radio spectrum.
frequencies used to convey information. The span The signal from an N-AMPS narrowband analog
of frequencies in a channel is its bandwidth in FM cellular telephone occupies 10 kHz of spectrum,
hertz kilohertz,or megahertz.Depending on various while that from an AMPS conventional analog FM
factors including the signal format, the transmitted cellular phone occupies 30 kHz.An AM broadcast
signal may not occupy every frequency in a channel station occupies a channel about 10 kHz wide,
at any one time—or ever. Often,a channel includes while an FM broadcast station transmitting high-
guardband frequencies at the channel's lower and fidelity,full-range orchestral music in stereo occu-
upper edges. The guardbands do not contain pies 200 kHz of bandwidth.Sending images and an
appreciable signal power,but rather serve as associated stereo soundtrack entails the transmis-
protective buffers to suppress interference to and sion of much more information each second than
from other channels'signals. sending just sound alone.A conventional television
A basic tenet of communications theory states that broadcast station occupies 6 MHz of spectrum—as
a channel's bandwidth determines the amount of much as the aggregate bandwidth of 30 stereo FM
information it can convey in a set period of time. broadcast signals,or that of the signals from 300
The bandwidth of the baseband modulating signal AMPS cellular phones.
(the information to be communicated,such as in North American TDMA digital cellular systems,
speech,music,images,or a stream of digital data the channel bandwidth is 30 kHz(the same as for
words)also plays a key role in determining the AMPS),but time-slicing techniques permit the
minimum bandwidth a channel must have.A simultaneous transmission of three separate
channel that carries telephone-grade voice conversations in the same amount of spectrum.
communications usually needs three or more kHz And in a COMA digital cellular transmission format
of bandwidth.In FM transmission formats,the undergoing field tests,the signal occupies 1.23
channel bandwidth affects the useful effective MHz. With guardbands,the CDMA channel is 1.8
S communications range,so FM communications MHz wide. That channel,however,by virtue of
systems often employ greater channel bandwidth spread-spectrum technology,simultaneously
than that of the baseband signal. The trade-off,of handles the signals associated with many different
course,is that greater bandwidth limits the total conversations.
•
In Digital Frequency Modulation or Digital Even though there is only one telephone wire
Phase Modulation, the carrier frequency does between the two cities,each couple gets to speak
not sweep smoothly in step with the information for a total of 20 minutes each hour. But after one
signal. Rather, the c-trier frequency or phase minute of conversation,each couple must wait
(almost the same thing) jumps in fixed incre- another two minutes for their next time slot.All
ments based on the instantaneous sample of six callers must wear synchronized watches,and
the input signal. TDMA is a particular digital plugging and unplugging the telephones is tedious.
signal format that some cellular networks have To avoid such problems,TDM systems automate
begun to use. TDMA takes advantage of a and speed up the process.Switching occurs hun-
technique called Time Division Multiplexing dreds or thousands of times per second,so fast that
(TDM) which breaks up each conversation two people cannot tell that they are sharing one
into samples, and then interleaves samples of telephone line with many others.
the different conversations into one signal
"pipeline" in a particular sequence,using specific Cellular networks combine TDM and digital
modulation in the format called TDMA. A
time slots for each sample.
TDMA cellular phone continuously samples its
Using wired telephones, let us explore the core user's voice and converts those samples into
concept of TDM.Suppose geography separates strings of digital words.The phone then transmits
three couples who want CO speak to each other. the digital words via FM or PM in a specific time
There are three telephones in each city,but only slot assigned by the base station handling the call.
one wire spans the distance between the two The TDMA format used in North America allows
cities involved.The members of Couple A plug three phone conversations to share one 30-kHz
their telephones into the long-distance circuit and channel and the same base-station equipment
speak for the first minute of each hour.They then without confusion by sampling each conversation
unplug their phones,and the members of Couple twice during one basic TDMA time frame.The •
B plug theirs in.Then they speak for the next sequence of samples is A1/B1/C1/A2/B2/C2(sam-
minute and disconnect.The members of Couple ple 1 of conversation A,followed by sample 1 of
C plug in and speak until three past the hour.The conversation B, then sample 1 of conversation C,
entire process then repeats. followed by sample 2 of conversation A,etc.)
ANALOG vs.DIGITAL user's voice into an analog AC electrical current
Electronic circuits fall into two categories:analog An electronic circuit continuously samples the
and digital.,Analog signal levels vary over a con- microphone's output signal and converts it into a
tinuous range.A phonograph is analog.Its mag- sequence of digital words,made up of binary
netic cartridge generates a smoothly varying signal numbers,that describe the voice's instantaneous
as the stylus moves up and down and side to side volume and pitch,just as each movie frame
in the record groove.But the simplest digital circuit captures the actors'instantaneous positions and
has only two output levels(1 and 0),generated by expressions. The more bits in each word,and the
turning on or turning off an electronic switch.By more digital words per second,the greater the
sequentially keying the switch on and off like a system's ability to distinguish among subtle differ-
telegraph,one can construct strings of digital bits ences in signal values.
and digital words(bytes). The digital telephone then transmits the sequence
Both analog and digital circuits can be used for of digital words encoded in radio form. The base
communications. Traditional home telephones,as station receives the radio signal,extracts the digital
well as AM/FM broadcast and television receivers, words, converts them back into analog form,and
are analog.Certain state-of-the-art office telephones; introduces the regenerated analog signal into the
cordless telephones,and satellite transmitters are telephone network.It all happens so quickly that a
digital. listener is unaware the speaker's voice travelled
Digital telephone systems(both wired and wireless) as a series of discrete samples. This is like an
audience remaining unaware(so long as the
are actually part digital and part analog.Human projector works properly)that a movie is really a
voices vary continuously over a range of volumes sequence of still images.
and frequencies in analog fashion.So the micro-
phone in the telephone handset converts the
El
•
9aWhar is the differ- I. SPECIALIZED SIGNAL FORMATS receivers reconstruct the music or speech by
ence between converting the acellular system's traffic-handlingfrequency swings(frequency
g and digital cello- To increase )of the received signal into AF current.
capacity,the licensee must use the limited amount
lar communications? Analog FM has good fidelity and immunity to static,
of radio spectrum available to it more efficiently. such as that from car ignition systems,fluorescent
There are two basic ways to accomplish this.The lights,and electrical appliances.17 However,analog
first is to increase channel reuse by suppressing
A conventional FM channels take up a good bit of radio spectrum.
cellular phone preclusion.This alternative,however,requires Conventional analog FM celh,lar phones use 30-kHz-
smaller base station service areas,and more base
employs an analog wide channels.18 An FM broadcast station occupies
transmission format. stations to serve a given region.And even using a channel about seven times wider.
The transmitted radio microcells or picocells, the demand for vacant
signal's instantaneous channels can eventually outstrip the supply.The Participants at the Base Station Symposium
frequency varies cortin- other course of action,as Symposium participants described various ways cellular systems can use the
uously within certain explained,is to change the signal format from analog radio spectrum more efficiently than the conven-
limits in step with the to digital.The use of digital signal formats can tio:.al AMPS transmission format does.For example,
user's voice. This is mean that a cellular system needs fewer base stations a narrowband version of AMPS called N-AMPS
called analog frequency to meet the public's demand for service.In areas of (Narrowband-AMPS)employs channels that are
modulation. More extremely high demand for cellular communications, only 10 kHz wide,as opposed to an AMPS chan-
for the ultimate in spectral efficiency,a system can nel's 30-kHz bandwidth.N-AMPS permits a
advanced systems employ
digital trans-mission employ both options simultaneously(use many, threefold increase in traffic density,but at some
formats, in which users' closely spaced base stations with very small service sacrifice in coverage and recovered audio at the
voices are repeatedly areas,and use a digital signal format). receiver end.
sampled and converted Analog Frequency Modulation (FM) is the trans- Also,for greater spectral efficiency than AMPS,
filznumerical values• mission format used by FM broadcast stations and cellular networks can also employ digital signal
numerical values conventional cellular phones. During moments of formats.Digital Frequency Modulation or its
are then transmitted silence,the transmitted signal (the carrier,because cousin Digital Phase Modulation(PM),Time
using digital modulation it carries information) is at full power,but the Division Multiple Access (TDMA),and Spread
techniques, recovered at carrier rests at the transmission channel's center Spectrum Transmission are the major digital
the receiver, and used frequency.As speech or music begins,the carrier technologies currently deployed by cellular systems.
to reconstruct the starts swinging up and down within the channel,
speaker's voice. The in step with the modulating signal's strength.FM
process is similar to the
digital techniques corn- BASE STATION PARAMETERS
pact discs and CD The table below summarizes the antenna heights,signal powers,number of channels,and distances
players use to record between base stations that cellular networks employ. We classify the base stations by phase.Phase is not
and play back music. a standard industry usage,just our attempt to convey the changes in base station operating parameters as
a cellular network evolves and traffic grows.
Cellular systems using
digital technology can
serve more subscnaers Type of base Antenna height Antenna type ERP per Number Distance
than analog cellular station channel of between base
systems, all other things channels stations
being equal. Rural 250 feet Omnidirectional 500 watts 10 to 15 20 miles or more
Phase I 250 feet Omnidirectional 100 watts 10 to 15 10 to 15 miles
Phase ll 100 to 150 feet 120'Directional 20 to 50 watts 30 to 45 7 to 10 miles
Phase III 100 to 150 feet 120'Directional 10 watts 30 to 57 4 to 5 miles
Phase IV 100 feet or less 60'Directional 2 to 5 watts 30 to 90 2 miles or less
• Microcell 100 feet or less 60'Directional Less than 1 watt 30 to 90 Less than 1 mile
Picocell 100 feet or less 60'Directional 0.2 watt or less 30 to 90 Less than 1 mile
10
411
As system traffic increases,the preclusive effect of In areas of very high cellular traffic density,such
what we will call a Phase I base station becomes as major highway interchanges and downtown
too great. Several changes must occur as the base areas,even Phase III base stations cannot cope
station evolves into a higher capacity Phase II with the demand. Special techniques become
facility to cope with growing demand without also necessary if the network is to provide enough
precluding channel reuse nearby.First,antenna channels for the extremely high local demand for
heights must drop to 100 to 150 feet.Second,ERP service. In a Phase IV base station,antennas
must decrease to about 20 to 50 watts per channel. become even more directional,and ERP can
Nondirectional antennas give way to directional decrease to only a few watts.The base station's
antennas aimed to serve just a slice of the overall service radius shrinks to a mile or less.Sometimes,
coverage area(a swath 60°to 120°wide).The even these dramatic changes are inadequate.
number of active channels within the entire service Special microcell base stations will serve the
area increases,to perhaps 30 to 45,but the number inside of an airport terminal,or a particular inter-
in any one sector lessens. In some cases,what we section.Highly directional antennas, 100 feet or
will call a Phase III base station will have an ERP less above ground,will focus on narrow swaths of
below 10 watts per channel,and as many as 57 area,and ERP will be well under one watt per
channels.'5 Phase II base stations must be substan- channel.16
tially closer together,within four or five miles.
ANTENNAS AND ANTENNA GAIN directions,the antenna emits little or no power.
Any transmitting antenna,when driven by a trans- The more directional the antenna,the narrower its
mitter, emits a portion of the power applied to it as main beam,and the higher its gain in that direction. •
a radio wave.All practical antennas emit more if you disassemble a flashlight and loosely inter-
signal power in some directions than others. The connect the bulb and batteries with wire on your
amount of signal power that escapes in a given tabletop,the bulb's filament glows,but not blindingly
direction depends on the exact performance char- Let us suppose the filament radiates 50 milliwatts
acteristics of the antenna.A simple half-wave of visible light perpendicular to itself,and little off
dipole,mounted vertically,is omnidirectional in its ends(like a half-wave dipole).if you pass a light
the horizontal plane.At a fixed distance out from meter over the bulb,tracing out a circle at a right
the antenna(except in the so-called near field,in angles to the filament;you get a constant reading.
the immediate vicinity of the antenna),the radiated The reading decreases if you move the meter to
signal toward the horizon is the same at all points measure the light output off the filament's ends.
on the compass.By contrast;the vertical dipole is Now reassemble the flashlight The reflector
directional in the vertical plane. The antenna emits focuses the bulb's total light output into a tight
little power off its ends(straight up and down), beam. The intense,narrow beam might illuminate
intermediate power levels at angles in between a spot as well as the 5 watts of light from a 100-
straight up or down and out toward the horizon, watt light bulb without a reflector.12 The reflector
and maximum signal straight out toward the horizon. provides an optical gain of 100 times,also
For some antennas,in a favored direction,the expressed in decibels as 20 dB.13 In the flashlight's
radiated signal power can appear to exceed the small cone of light;the light meter's reading is
RF power into the antenna,at least relative to the very high.But in most directions,the needle will
signal power that a reference antenna(such as a not even budge. The tiny bulb's peak ERP is five
half-wave dipole)would radiate when driven by watts, 100 times its total light-power output;but it
the same transmitter.How can that be? After all, is nil outside the cone of light formed by the
no device can generate more power than the total reflector. The flashlight's peak ERP matches the
power applied to it five watts of visible light from the much larger,
The answer lies in antenna gain.A directional unfocussed bulb,but only in the flashlight's narrow
antenna redirects power that would otherwise beam. The diffuse light from the larger bulb illumi-
radiate on certain bearings and concentrates it in nates a much larger area. •
others. This redirection of power intensifies the
signal level in the favored direction.But in other
9
•
QWhy do cellular cities and their suburbs,and even along heavily systems,which use different radio channels like
usystems have so travelled country highways. maps use different colors.To prevent interference,
many base stations? a cellular network breaks a region down into sub-
Cellular base stations exist to circumvent the natural
cap on radio channels.As the public demands units,and builds one base station with a specific
more mobile telecommunications service,more set or block of frequencies (channels)for each.
A
A cellular system Immediately adjacent base stations use ocher
and more base stations are needed.In contrast to
employs many the traditional handful of wide-coverage base stations, blocks of channels,and ocher base stations a bit
base stations with further away can reuse the original block of radio
deliberately limited cellular base stations have modest signal powers,
range to allow reuse of
channels employed at the first base station.
antenna heights,and service areas.The primary
goals are to suppress preclusion and permit Because base stations have limited range,
the strictly limited mobile
number of radio than- frequency reuse in nearby areas.Of necessity, this users often reach the edge of a base station's service
eels available for requires more base stations-to cover the same area area before the phone call ends.A key aspect of
mobile telecommunica- as a first-generation radiotelephone system with cellular technolo'v is that,when a base station
tions. The more base just one or two base stations. senses the mobile signal weakening, it"hands off"
stations a system uses, In other words,cellular systems invest in items responsibility for servicing that call to the next
the more subscribers available in quantity(towers and the other items base station down the line.The transition is
the system can handle that comprise base stations) to stretch out a strict- designed to happen so quickly that there is no
at any one time. ly limited resource—the radio channels available break in the conversation,and the conversation
for mobile telecommunications.Constructing smoothly continues on a different radio channel.
This
more,but smaller base stations allows a cellularfrees up the first base station to serve another
network to serve many more people at the same mobile unit on the original channel.
time.Subscribers within the.same general area can H. TYPICAL BASE STATIONS
• use and reuse the allotted radio channels,without
mutual interference. At the Federal Focus National Symposium on
Wireless Transmission Base Station Facilities,
A good analogy to spectrum reuse through the cellular engineers explained that a base station's
construction of more,lower-power base stations is ERP,antenna height,and complement of channels
the map-coloring problem studied in some math depend on the traffic load.At the onset of cellu-
courses.Suppose you have a black-and-white lar network operations,when phone traffic is the
county map of a state and some colored pencils. lightest,a typical base station might have a 250-
You must shade the counties such that no two foot tower, 10 to 15 active channels,and about
adjacent ones are the same color.If you have just a 100 watts per channel of ERP.14 Antennas are
few colors,you run into problems.The solution is omnidirectional;the service radius of each base
to break counties down into smaller units,and to station is about five to eight miles.The base
reuse your pencils such that adjacent sub-d stric stations are about 10 to 15 miles apart.
do not have the same color.So it is with cellular
SIGNAL POWER watts of RF output The missing power becomes
Two frequently used,closely related terms are 40 watts of waste heat and the transmitter .
energy and power.Energy is the ability to do work; becomes warm to the touch.Of the 100 watts of
transmitter RF output power,some will be lost as
power is performance of a certain amount of work
in a fixed time. heat in the antenna feedline and in the transmit-
tingThe physical concepts of energy and power also antenna itself.Let us suppose that loss is
apply to radio.A transmitter-generated RF signal 10%.Ninety watts of signal power remain.If the
has power.A radio wave leaving a transmitting transmitting antenna is a half-wave dipole(one
antenna also has power.It can stimulate an RF whose electrical length is half of the radio signal's
current in a receiving antenna. The power is wavelength,or half the distance the radio wave
measured in watts,or,if it is weak,in milllwatts or travels during one cycle),the 90 watts escape out
microwatts.to into space as a radio wave. The dipole emits the
• most signal at right angles to itself,and relatively
No radio component is 100%efficient;some power little off its ends,in a doughnut-shaped pattern.
is always lost as heat.A transmitter draw The Effective Radiated Power or ERP is 90
140 watts from the power grid to produce just 100 watts."At any point a given distance from the
El
•
2. Line Of Sight.We cannot see past the horizon E. BASE STATION INTERFERENCE AREAS Q Why do cellular
due to the earth's curvature.So unless we are on base stations have
top of a mountain,our view of short,ground- Undesired signals can be substantially weaker than limited range?
based objects extends only about four miles.Even desired ones and still cause interference,especially
then,line of sight rarely exceeds 60 miles.This is if the signals are on the same frequency(are
because light waves travel in straight lines.Beyond co-channel).So,a base station's cochannel inter AA cellular base
the horizon,objects are below the line of sight and Terence area always exceeds its service area. station can only
are not visible.At UHF television and cellular
frequencies,radio waves also travel in straight lines. F. PRECLUSION AND THE SCARCITY OF cover a limited geo-
They too have an horizon.When radio wavesgraphic area because
strike the earth,the earth absorbs at least some of SPECTRUM radio waves weaken
the power that the radio waves contain.This also A major consequence of interference is preclusion. with distance and
limits a radio system's range.The horizon for That is,use of a frequency prevents similar uses of because the earth is
antennas on mountaintops is further.out than for the same and adjacent frequencies in the same and curved and cellular
antennas that are not as high.5 surrounding areas.There are many keys on a piano, radio waves travel in
Sometimes,even two close antennas will not share a but never more than 88.Two people can play on straight lines. Rough
line of sight.Just as we cannot see more than a block the same piano simultaneously, if one uses lower or hilly terrain, limited
if a skyscraper is in the way,buildings,hills,or dense octaves and the other the upper registers. Both, transmitter power,
foliage can obstruct a cellular radio signal's path. however,cannot use the same keys at the same limited receiver sensi-
Depending on how severe the obstruction is,the instant without disrupting each other's melodies. tivity, and the effects of
obstruction's effect can range from slightly weakening For similar reasons,two transmitters in the same interference also con-
the radio signal to totally blocking it(a drop out). area cannot use the same channel simultaneously. strict a base station's
Thisrise to a scarcityof spectrum,because service area. However,
gives
3. Interference.A clear line of sight between as we will see later,
transm ittin and receivingantennas helpsproduce the number of channels which make up the radio
g 1p cellular systems turn •
high-quality communications,but it does not spectrum is finite.Moreover,the radio spectrum the limited range of a
guarantee them.Just as one can have problems lends itself to many different applications.9 cellular base station
trying to understand someone speaking nearby in Because of the finite number of radio channels into an advantage.
available,the FCC allots only certain channels for
a crowded,noisy room,so,too,a transmitter and
receiver only a few miles apart and with perfect each use,based on international treaty,relative
line of sight may not communicate because of demand,and social importance.And in any area,
strong interference from undesired radio energy. the demand for radio channels outstrips the supply.
For cellular communications,the FCC has allotted
There are many different sources of interference, a total of 50 MHz of spectrum,split between two
and the interfering radio wave can be on the same licensees in each part of the country,the local
or a nearby frequency.6 A radio transmitter is telephone company(the wireline carrier),and
often the culprit,but interference can come from another service provider(the nonwireline carrier).
such generators of radio noise as computers,elec-
tric motors,car ignition systems,thunderstorms, G. GETTING AROUND THE SCARCITY
or fluorescent lights. PROBLEM
D. BASE STATION SERVICE AREAS The first generation of radiotelephone systems
Modern radio receivers are very sensitive. If inter- (some of which are still in use)employ high trans-
ference levels are low,a receiver can produce a lis- muter powers and transmitting antennas,because
tenable output from a very weak signal—one with their primary goal was reliable,wide-area service.
a field strength measured in microvolts per But even though first-generation systems offer
meter. The Federal Communications wide-area,drop-out-free coverage, they have a
Commission(FCC),which licenses base stations, major disadvantage:their preclusion areas are
deems the 32-dB1V/m contour the outer edge of even larger.Such systems inherently prevent reuse
a base station's service area.8 The extent of that of their own and adjacent channels over large
service area depends mainly on the base station's distances.And as more and more people need to •
antenna height,signal power,and the nature of use mobile telecommunications,the limit on the
the surrounding terrain.Higher antennas and pow- number of radio channels available for that purpose
ers,and flatter terrain,yield larger service areas. becomes a major problem—especially in major
•
What is a remains negative. But an AC generator's two ter- manned,except during regular maintenance visits.
cellular base mink flip polarity at the AC's frequency. Network engineers monitor system performance
station? A air of AC electric and from a mobile telephone switching office which
P magnetic fields forming communicates with base stations via radio or tele-
a right angle make up a radio wave.Each field is
also at right angles to the wave's direction of travel. phone links.
AA cellular base The fields change polarity ac the frequency of the As mentioned earlier,base stations serve as bridges
station is the link
between the wired radio wave. to the wired telephone network for portable or
telephone network and B. CELLULAR BASE STATION mobile cellular phones,which are specialized
a portable or mobile radio sets.A phone's receiver section lets the sub-
cellular phone, or FUNDAMENTALS scriber hear the conversation's other half trans-
between one portable Whenever anyone uses a cellular telephone,a base miffed by radio from the nearest base station.
or mobile phone and station acts as the gateway to the wired telephone When the subscriber talks his portable or mobile
another. It is a combi- network or to another cellular phone.A base sta-
unit transmits his voice,encoded in a radio wave.
nation radio relay tion plays this key role by acting as a radio relay sta- The nearest base station receives that signal,
station and telephone non and telephone switching center.Base stations extracts the subscriber's voice,and sends it through
switching center. have lower transmission powers than many FM the wired telephone network to the other party.3
broadcast stations(those between 88 and 108 on To make natural conversation possible,the two
the dial),and have higher operating frequencies.2 radio links(those to and from the base station)
remain active simultaneously4
Base stations vary widely in appearance,but every -
base station has a set of transmitting and receiv- C. COMMUNICATIONS RANGE
ing antennas which often look like vertical whips Any radio system has a certain limited range
• or panels.The antennas are usually 50 to 250 feet within which reliable communications is possible.
above the ground.A receiving antenna handles Range limitations are caused by distance, terrain
the half of the conversation originating from a obstructions,and interference.
subscriber's cellular telephone,while a correspond-
ing transmitting antenna relays the other half of 1. Signal Strength vs.Distance.Radio waves
the telephone conversation to that cellular phone. weaken over distance.This aspect of their behav-
One pair of receiving and transmitting antennas for is much like that of light from a candle;or...�
can handle the signals associated with a number heat from a fire.Close up,the light or heat from_.
of different telephone conversations.The precise even a modest source can be intense.Five hundred
number of antennas and the type of antennas used feet away,however,the same light source is a feeble
at a particular base station will depend on the glow, the fire's warmth is imperceptible even
amount of radiotelephone traffic handled by that though the total radiant power remains the same.
facility and by neighboring base stations. Why is this?What we perceive as brightness or
warmth is actually the degree of concentration of
To keep their base station antennas up in the air,
light or heat.Very close to the source,even mod-
cellular systems use various structures.Depending est amounts of power are densely packed. But
on the circumstances,the support structure might moving away from the source,the total power
be a pole or tower built especially for that purpose, spreads out over an ever-larger surface area.The
a preexisting radio or television tower,a short pole power concentrated in a given area—(say,one
on the roof of a building,or a short pole or tower
square centimeter)—the power flux density
installed on a municipal water tower.
drops off sharply.Likewise,radio signals near a
An equipment shed at the tower's base or an transmitting antenna are also strong,but weaken
equipment cabinet in the office budding houses dramatically as they travel outward.This weakening
the radio receivers,transmitters,and computerized restricts communications range.Within practical
telephone switching gear that make up the rest of limits,one can counter it by increasing:
the base station's equipment.Sometimes,an • transmitter output power,
• emergency generator or an array of batteries permits ■ transmitting antenna efficiency;
a base station to provide uninterrupted service ■ receiving antenna efficiency;
during power blackouts. • receiver sensitivity to weak signals;or
Base stations operate automatically.They are not is two or more of the above.
6
Chapter 2:A Base Station Primer
•
In the early 1980s,an entirely new form of mobile A. ELECTROMAGNETIC FIELDS AND n What is a radio
telecommunications became available to the American RADIO WAVES u wave?
people—cellular telephony. This advanced form of
telecommunications combines modem radio, telephone, Any electric charge sets up an electric field around
and computer technologies. Cellular telecommunica- it. If another electrical charge enters that field,an radio wave is a
cons employs fixed relay facilities (base stations)and attractive or repulsive force arises.The force will AA pair of electric
mobile and portable phones. Cellular systems are attract the charges to each other if the charges are and magnetic fields
designed to provide mobile telephone service to many of the opposite polarity.The force will repel the that can travel through
people in a given area even though there is only a limited charges if the charges are of the same polarity.The space at the speed of
amount of radio spectrum available for such use. This force's strength depends on the size of the charges light and can convey
Chapter provides the basics of cellular technology,and and the distance between them.A moving elec- information. It has a
describes trends in cellular system development. tic charge (an electric current) is direct current certain frequency, the
Of course, like any new technology, cellular telecom- (DC) if the motion is in one direction only.An way visible light has a
electric charge that moves back and forth corn- certain color and con-
munirntvns poses a number of questions.Among the prises alternatingcurrent(AC).An electric cur
questions about cellular telecommunications that we tains a power. A radio awave
ount
rent sets up a magnetic field.A magnetic field can, of A wave
will answer are: in some cases,bend the path of a moving electric emanates from a trans-
"' What is a radio wave? charge.A magnetic field can also exert a physical mining antenna and
■ What is a base station? force on magnetic material such as iron or steel. can be picked up by a
■ Why do base stations have limited communications An electrical charge will be of one polarity only receiving antenna. A
range? (positive or negative),but a magnet or magnetic radio receiver of the
■ Why do cellular systems need so many base stations? field always has two poles,North and South. proper design can
■ What is the difference between analog and digital A batteryhas two terminals,onepositive and one extract the information
cellular communications? impressedradio
So does an electric generator.In opera- mp upon a •negative.
tion,a battery or a DC generator's positive terminal wave.
always remains positive,and the negative terminal
BASIC RADIO CONCEPTS AND RADIO-SYSTEM Transmitters are to some extent like stereo ampli-
COMPONENTS fiers, which change 60-Hz AC into AF currents
corresponding to music or speech that can drive a
■Flowing electrical charges constitute electricity loudspeaker.
or current.Stationary charges constitute static
electricity.One can liken charge to water standing III
A transmitting antenna converts RF current
in a bucket,and current to the water flowing out from the transmitter into radio waves,similar to a
of the bucket when the bucket is tipped toward loudspeaker that transforms AF current from a
the ground. Current can flow in one direction only, stereo amplifier into sound waves. The radio
or it can regularly reverse direction—like the waves travel outward from the antenna like sound
tides,or ocean waves,that crash on a beach and waves from the loudspeakers,or ripples from a
then retreat back out to sea. Current flowing in disturbance on a pond.
one direction only is direct current or DC. Current ■A receiving antenna extracts some of the signal
that regularly reverses direction is alternating power from a passing radio wave and converts it
current or AC.Power used by batteries is DC;power into an RF current One can liken a receiving
used by utilities is AC. The number of times in one antenna to a microphone placed in front of a loud-
second that AC reverses direction is its frequency speaker, which captures part of the sound wave
in hertz(Hz).n AC with a frequency comparable to and changes it back into AF current
a pitch within the range of human hearing(up to ■A radio receiver extracts information encoded
20 kHz)can be called audio-frequency(AF) in an RF current and presents it to the user.A tele-
current Higher-frequency AC is radio-frequency vision set;for example,is a specialized radio
(RF)current.Radio frequencies range from tens of receiver.it reproduces the images and sounds •
kilohertz to thousands of megahertz encoded into the radio wave captured by the
■A radio transmitter converts electricity from a receiving antenna.
battery or the power grid into RF current
Chapter 1: Introduction
I
On October 28, 1994, Federal Focus,Inc.,a tax-exempt,nonprofit educational organiation,held a
Symposium on Wireless Transmission Base Station Facilities.The setting for the Symposium was the
campus of the University of Pennsylvania in Philadelphia.To satisfy the public's increasing demand for
reliable mobile and portable wireless communications,cellular telephone system operators must erect more
and more base stations around the country.However,some recent base station construction proposals
have triggered opposition from residents of surrounding areas. Issues that opponents have raised include:
■ feared health hazards from base stations'radio transmissions;
• potential interference to radio and television reception and to other nearby electronic devices;and
• possible negative effects on the resale values of homes due to aesthetic and other concerns.
The Federal Focus Symposium explored these and other issues that arise when a cellular telephone system
operator seeks to construct a new base station facility.Among the Symposium participants were government
officials and private-sector professionals,including communications engineers,experts on radio energy's
effects on living tissue,experts on radio signals'effects on medical and consumer electronics,and profes-
sionals in the field of land-use regulation.The participants shared their past experiences dealing with these
issues and discussed likely future trends in the public-policy discourse,given the public's growing demand
for wireless telecommunications services and cellular systems'concomitant need for more base stations.
Some of the issues that arise in this context are very complex.Nonetheless,this monograph will strive to
explore those issues in plain language,providing the scientific,public-policy,and legal information necessary
to make informed decisions about proposed base stations.We will also attempt to clarify those issues which
are not relevant in the base station context,such as feared adverse health effects of so-called ELF(Extremely
Low Frequency)radiation,the electromagnetic fields that emanate from high tension power lines.
•
•
s
•
III
base station,cannot cause such effects. stations,indicates that base stations expose As mentioned previously,a typical base
The most common effect of fields from the public to levels of RF energy many station consists of a small shed or enclosure
base stations is a slight warming of tissue hundreds or thousands of times less than for radio equipment and a set of antennas
near an energized transmitting antenna. the modem limits set by standards-setting mounted 100 or more feet above ground.
This is called the thermal effect.Some organizations, including ANSI,ANSI/ In many cases,base stations can be
people have wondered whether athermal IEEE,the National Council on Radiation designed to be unobtrusive. If there is
effects from weak radio fields pose any Protection (NCRP),and International already an antenna tower,water tower,or
health consequences.Most scientists say Radiation Protection Agency(IRPA). office building in the area where a system
no,and claims to the contrary have not One expert at the Symposium described licensee needs to install a new base station,
been reproduced in laboratory experiments. exposures from base stations as almost a the licensee can use that existing structure
"nonissue"in terms of applicable safety and avoid putting up its own antenna
Various srandartis-setting bodies have adopted
standards. tower.Where new tower cons
limits or guidelines for the exposure of people
construction is
necessary camouflage can, in some cases,
to radio frequency(RF)energy. In 1985,
IV. There Is No Evidence Base mitigate the visual impact of the structure.
the FCC adopted the"C95.1-1982"expo Stations Pose Interference
sure standard issued by the American Symposium participants presented
National Standards Institute.(ANSI is the Problems anecdotal evidence and summaries of
ration's preeminent private standard- Radio signals—if they are strong enough studies to the effect that base stations do
coordinating body.)That standard set a —can sometimes interfere with electronic not appear to depress the values of
single exposure limit for both works and devices such as radio and television surrounding parcels and homes.Participants
the general public.Permissible exposure receivers,stereo systems,medical monitors, also described the public-interest benefits
under the 1982 ANSI standard from a cel- and automotive systems in unintended of locating base stations on public property.
lular base station is about 2700 micro- ways.Consumer electronic devices vary There appear to be no benefits to iebuicting
warts per square centi-meter,averaged in their ability to coexist with radio signals. base stations from areas with potentially
,er
six minutes. (One microwatt is one Some manufacturers build high levels of sensitive populations such as school children.
e-millionth of a wu„and one square immunity to interference into their prod- Finally,Symposium participants and pan-
centimeter is an area about the size of an uccs.Other manufacturers include none, elists described the strong federal interest
adult's pupil in dim light.) or virtually none.The signals from base
in a well-developed telecommunications
Based on an extremely low risk of exposure stations diminish rapidly with distance.As infrastructure.The FCC requires a cellular
in excess of the 1982 ANSI standard,the a result,in areas where people live and system operator to detail,when filing for
FCC excused cellular base stations from work,the signals are too weak to upset renewal of its system license,how it has
having to demonstrate compliance with electronic devices.There is no evidence expanded system capacity to meet the
the standard.In 1992,ANSI supplanted that the placement of a base station in or public's demand for service.If an operator
its 1982 standard with a 1991 exposure near a community has resulted in elec- fails to install new base stations to satisfy
standard drawn up by the Institute of tronic interference to consumer electronics. that demand,the operator may not gamer
Electrical and Electronic Engineers(11-_r1-), There have been reports of interference a"renewal expectancy,"and may not
a prestigious professional society.For to medical devices from the radio waves obtain a renewal of its license.The strong
occupational exposures from cellular base emitted by portable cellular phone or federal policy preference for system
stations, the 1992 limit is the same as the security guards'walkie-talkies;there have expansion can conflict with local govern-
1982 limit,and the six-minute averagingnot been any reports of such interference
ment efforts to restrict new base stations.
period remains the same.In areas frequented from cellular base stations. This conflict could be a source of signifi-
by the general public,the 1992 standard's IV. Base Stations and Land Use cant federal-local tension in the future.
limit is five times lower than the 1982
standard,although the averaging time Issues
increased CO 30 minutes. The construction of a base station usually
The FCC is updating its exposure limits. requires one or more municipal permits.
The FCC has proposed to adopt the 1992 Depending on state and local zoning laws,
ANSI standard as the most recent and corn- the required permit ranges from a simple
Oensive of all the published standards. building permit issued upon application to
FCC is also reevaluating its exclusion a special exception or zoning variance
of base stations from having to demonstrate requiring a public hearing.Where the law
compliance with RF exposure limits, considers a base station to be part of the
public utility infrastructure,obtaining the
A large body of data,based on actual necessary authorization to build such a
3 measurements of exposures from base facility is usually not complicated.
Executive Summary
•
I. The Purpose of this Publication then routes that half of the phone conversa- TDMA(Time Division Multiple Access)
tion into the wired telephone network,or and CDMA(Code Division Multiple
According to recent news reports, retransmits it by radio to a second subscriber's Access)manipulate digital words associated
Americans are signing up for mobile tele-
mobile or portable unit_The second half with a number of conversations so that
phone service at the rate of about 28,000 of the conversation reaches the base one radio channel can handle more than
per day.For reasons described below,as station by wire or radio link.Then the one call at a time.
the ranks of subscribers grow,so must the base station transmits it by radio to the
number of the fixed facilities known as TDMA is already in use.As implemented
first subscriber unit.To make natural
"base stations"that relay such phone calls. in North America,TDMA interleaves
conversation possible,subscriber units and sequential samples of a few conversations
A typical base station employs a small base stations both transmit and receivein one relatively narrow radio channel.A
shed for electronic equipment and a set of radio signals simultaneously.
TDMA system employs many such narrow-
antennas on a support structure.More Each radiotelephone cull entails use of a band channels.CDMA,now undergoing
base stations means that more people end portion of the radio spectrum dedicated to field tests,employs a much wider radio
up living or working near them.Some the service.Using one particular frequency channel that carries many uniquely coded
have voiced concerns about base stations or span of frequencies (channel)generally signals simultaneously.
on the grounds of aesthetics,fear of precludes use of the same and nearby
adverse health effects,depression of prop- frequencies or channels by others in the More and more conventional ("analog")
ern;values,or interference to electronic cellular systems will likely convert to a
devices and systems.To examine these same area.Otherwise, interference will digital format as demand for service
result.The spectrum available for radio-
issues,the Scientific Advisory Group on continues to increase and the neer-scary
telephone communications is limited. digital equipment drops in price through
Cellular Telephone Research(SAG), Without the use of special communications
predecessor to Wireless Technology technologies,demand quickly outstrips supply. mass production.
Research,L.L.C. (WTR),commissioned
Federal Focus,Inc.,a nonprofit educa- Cellular radio technology is the key to III. There Is No Scientific •
tional organization,to convene a National meeting the public's growing demand for Evidence that Base Stations
Symposium on Wireless Transmission mobile telecommunications service.This Pose Public Health Risks
Base Station Facilities.Experts in a number technology compensates for the limited
of fields from the public and private sectors amount of spectrum available by using Modern radiotelephone systems,like other
participated.This publication,Federal base stations with modest service areas. forms of radio communications, employ
Focus National Symposium on Wireless This allows the reuse of radio frequencies the transmission and reception of radio
Transmission Base Station Facilities:A in nearby areas without interference.The signals.Each radio signal consists of electric
Tutorial,funded by WTR,provides a reuse of spectrum, in turn, increases the and magnetic fields whose strengths vary at
recap of the experts'presentations at the radiotelephone network's call-handling a certain frequency.The same is true of
Symposium and examines the issues asso- capacity.As demand for radiotelephone infrared (heat)rays,visible light,and
ciated with construction of base stations service grows,the service areas of base other forms of electromagnetic energy.
to meet public demand for mobile stations must shrink through reductions Electric and magnetic fields can interact
communications. in transmitter power,antenna height,orwi
i living and nonliving matter in various
both.This technique,called cell splitting, ways,depending mainly on the fields'
II. Base Stations Are a requires construction of more base stations strengths and frequencies.Radio signals
Technological Response to the near the people they serve. are called nonionizing electromagnetic
Scars' of Radio Spectrum any because they do not upset the elec-
p Cell splitting has practical limits.To keep trical balance of positive and negative
Mobile and portable telephones are acnially up with the demand for service,a radio- charges within each atom (ionize the
specialized radio transceivers(transmitter/ telephone network approaching those atom).Higher-frequency forms of electro-
receivers) that employ frequency bands limits can bring additional technologies magnetic energy,such as ultraviolet rays,
set aside by the Federal Communications to bear.One is the use of special direr- can upset an atom's electrical balance.
Commission (FCC)for that purpose.A tional antennas that cover narrow swaths Individual atoms group together to fuuu
subscriber's unit impresses the user's voice of area.Digital signal foiwats are a principal
onto a radio signal byvaryingsome basic means of using available radio frequencies molecules,and each living cell is a collec-
tion of many molecules.A cell reproduces
property of that signal in steptepwith the even more effectively.Digital formats
•
speech.An antenna affixed to the unit or entail the conversion of sequential samples using a blueprint stored chemically in the
to the subscriber's vehicle launches the of each half of a radiotelephone conversa- cell's nucleus.Ionizing electromagnetic
radio signal into space.A nearby base tion into digital words,strings of ones and energy is dangerous because it can alter
station intercepts the signal and extracts zeroes that describe the samples in mathe- the chemical blueprint and cause the cell
the embedded speech.The base station matical terms.Digital formats such as to mutate.Weak nonionizing energy,such
as the radio waves at ground level from a lill
Synopsis
FEDERAL FOCUS NATIONAL SYMPOSIUM ON WIRELESS
TRANSMISSION BASE STATION FACILITIES:
A TUTORIAL
Executive Summary Page 1
Chapter One: Introduction Page 3
Chapter Two: A Base Station Primer Page 5
Chapter Three: Base Stations and the Public Health Page 15
Chapter Four Base Stations and Electromagnetic Compatability Page 26
•
Chapter Five: Base Stations and Land Use Issues Page 32
Chapter Six: Lessons Learned Page 36
Glossary of Technical Terms Page 38
Agenda of the Federal Focus National Symposium Page 41
on Wireless Transmission Base Station Facilities
•
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S.652
Telecommunications Act of 1996(Enrolled Bill (Sent to President))
SEC. 704. FACILITIES SITING; RADIO FREQUENCY EMISSION
STANDARDS.
(a) NATIONAL WIRELESS TELECOMMUNICATIONS SITING POLICY- Section 332(c) (47
U.S.C. 332(c)) is amended by adding at the end the following new paragraph:
'(7) PRESERVATION OF LOCAL ZONING AUTHORITY-
'(A) GENERAL AUTHORITY-Except as provided in this paragraph, nothing in this Act
shall limit or affect the authority of a State or local government or instrumentality thereof
over decisions regarding the placement, construction, and modification of personal wireless
• service facilities.
'(B) LIMITATIONS-
'(i) The regulation of the placement, construction, and modification of personal wireless
service facilities by any State or local government or instrumentality thereof--
'(I) shall not unreasonably discriminate among providers of functionally equivalent
services; and
'(II) shall not prohibit or have the effect of prohibiting the provision of personal
wireless services.
'(ii) A State or local government or instrumentality thereof shall act on any request for
authorization to place, construct, or modify personal wireless service facilities within a
reasonable period of time after the request is duly filed with such government or
instrumentality, taking into account the nature and scope of such request.
'(iii) Any decision by a State or local government or instrumentality thereof to deny a
• request to place, construct, or modify personal wireless service facilities shall be in
writing and supported by substantial evidence contained in a written record.
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'(iv) No State or local government or instrumentality thereof may regulate the
• placement, construction, and modification of personal wireless service facilities on the
basis of the environmental effects of radio frequency emissions to the extent that such
facilities comply with the Commission's regulations concerning such emissions.
'(v) Any person adversely affected by any final action or failure to act by a State or local
government or any instrumentality thereof that is inconsistent with this subparagraph
may, within 30 days after such action or failure to act, commence an action in any court
of competent jurisdiction. The court shall hear and decide such action on an expedited
basis. Any person adversely affected by an act or failure to act by a State or local
government or any instrumentality thereof that is inconsistent with clause (iv) may
petition the Commission for relief.
'(C) DEFINITIONS- For purposes of this paragraph--
'(i) the term 'personal wireless services' means commercial mobile services, unlicensed
wireless services, and common carrier wireless exchange access services;
'(ii) the term 'personal wireless service facilities' means facilities for the provision of
personal wireless services; and
• '(iii) the term 'unlicensed wireless service' means the offering of telecommunications
services using duly authorized devices which do not require individual licenses, but does
not mean the provision of direct-to-home satellite services (as defined in section
303(v)).'.
(b) RADIO FREQUENCY EMISSIONS-Within 180 days after the enactment of this Act, the
Commission shall complete action in ET Docket 93-62 to prescribe and make effective rules
regarding the environmental effects of radio frequency emissions.
(c) AVAILABILITY OF PROPERTY- Within 180 days of the enactment of this Act, the
President or his designee shall prescribe procedures by which Federal departments and agencies
may make available on a fair, reasonable, and nondiscriminatory basis, property, rights-of-way,
and easements under their control for the placement of new telecommunications services that are
dependent, in whole or in part, upon the utilization of Federal spectrum rights for the transmission
or reception of such services.
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Bill Summary & Status for the 104th Congress
• PREVIOUS BILL I NEXT BILL
PREVIOUS BILL:DIGEST I NEXT BILL:DIGEST
NEW SEARCH I HOME I HELP I ABOUT DIGESTS
S.652
PUBLIC LAW: 104-104, (became law 02/08/96)
SPONSOR: Sen Pressler, (introduced 03/30/95)
MAJOR LEGISLATION
DIGEST:
(REVISED AS OF 01/31/96 -- Conference report filed in House)
TABLE OF CONTENTS:
• Title I: Telecommunication Services
• Subtitle A: Telecommunications Services
• • Subtitle B: Special Provisions Concerning Bell Operating Companies
• Title II: Broadcast Services
• Title III: Cable Services
• Title IV: Regulatory Reform
• Title V: Obscenity and Violence
• Subtitle A: Obscene, Harassing, and Wrongful Utilization of Telecommunications Facilities
• Subtitle B: Violence
• Subtitle C: Judicial Review
• Title VI: Effect on Other Laws
• Title VII: Miscellaneous Provisions
Telecommunications Act of 1996 - Title I: Telecommunication Services - Subtitle A:
Telecommunications Services -Amends the Communications Act of 1934 (the Act) to
establish a general duty of telecommunications carriers (carriers): (1) to interconnect directly or
indirectly with the facilities and equipment of other carriers; and (2) not to install network
features, functions, or capabilities that do not comply with specified guidelines and standards.
Sets forth the obligations of local exchange carriers (LECs), including the duty: (1) not to
prohibit resale of their services; (2) to provide number portability; (3) to provide dialing parity;
(4) to afford access to poles, ducts, conduits, and rights-of-way consistent with pole
attachment provisions of the Act; and (5) to reestablish reciprocal compensation arrangements
for the transport and termination of telecommunications.
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Imposes additional obligations on incumbent LECs (incumbent LEC requirements), including
• the duty to: (1) negotiate in good faith the terms and conditions of agreements; (2) provide
interconnection at any technically feasible point of the same quality they provide to themselves,
on just, reasonable, and nondiscriminatory terms and conditions; (3) provide access to network
elements on an unbundled basis; (4) offer resale of their telecommunications services at
wholesale rates; (5) provide reasonable public notice of changes to their networks; and (6)
provide physical collocation, or virtual collocation if physical collocation is impractical.
Directs the Federal Communications Commission (FCC) to complete, within six months, all
actions necessary to establish regulations to implement such requirements. States that nothing
precludes the enforcement of State regulations that are consistent with those requirements.
Requires the FCC to create or designate one or more impartial entities to administer
telecommunications numbering and to make such numbers available on an equitable basis.
Directs that the cost of numbering administration and number portability be borne by all
carriers on a competitively neutral basis.
Exempts a rural telephone company from incumbent LEC requirements until such company has
received a bona fide request from interconnection, services, or network elements and the State
commission determines that such request is not unduly economically burdensjme, is technically
feasible, and is consistent with universal service provisions, except the public interest
determination. Sets forth provisions regarding: (1) State termination of the exemption and the
establishment of an implementation schedule; and (2) limits on the exemption.
IDAuthorizes an LEC with fewer than two percent of the subscriber lines installed in the
aggregate nationwide to petition for a suspension or modification of specified requirements for
the telephone exchange service facilities specified in the petition. Directs the State commission
to grant such petition to the extent that it is necessary to avoid significant adverse economic
impacts on users of telecommunications services or to avoid imposing an undue economic
burden or a technically infeasible requirement, where such suspension or modification is in the
public interest.
Provides for the continued enforcement of exchange access and interconnection requirements.
Authorizes an incumbent LEC to voluntarily negotiate and enter into a binding agreement with
a requesting carrier without meeting incumbent LEC requirements. Directs that such
agreement: (1) include a detailed schedule of itemized charges for interconnection and each
service or network element included in the agreement; and (2) be submitted to the State
commission. Permits any party negotiating such an agreement to ask a State commission to
participate in the negotiation and to mediate any differences arising in the course of the
negotiation.
Authorizes the carrier or any other party to the negotiation, from the 135th through the 160th
day after the date on which an incumbent LEC receives a request for negotiation, to petition a
State commission to arbitrate any open issues. Sets forth provisions regarding the duty of the
petitioner, opportunity to respond, action by the State commission, refusal to negotiate,
• standards for arbitration, and pricing standards. Requires any interconnection agreement
adopted by negotiation or arbitration to be submitted for approval to the State commission.
Sets forth provisions regarding grounds for rejection, preservation of authority by the State
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commission, the schedule for decision, failure of the State commission to act, and review of
State commission actions.
• Authorizes a Bell operating company (BOC) to prepare and file with a State commission a
statement of the terms and conditions that such company generally offers within that State to
comply with incumbent LEC requirements and applicable regulations and standards. Sets forth
provisions regarding State commission review, the schedule for review, and authority to
continue review. Specifies that submission or approval of the statement shall not relieve a BOC
of its duty to negotiate the terms and conditions of an agreement regarding interconnection.
Sets forth provisions regarding: (1) consolidation of State proceedings; (2) a required filing by
the State commission; and (3) availability of any interconnection, service, or network element
provided under an approved agreement to which the LEC is a party to any other requesting
carrier on the same terms and conditions as those provided in the agreement.
Preempts any State and local statutes, regulations, or requirements that prohibit or have the
effect of prohibiting any entity from providing interstate or intrastate telecommunications
services. Preserves a State's authority to impose, on a competitively neutral basis and consistent
with universal service provisions, requirements necessary to preserve and advance universal
service, protect the public safety and welfare, ensure the continued quality of
telecommunications services, and safeguard the rights of consumers.
Authorizes a State, without violating the prohibition on barriers to entry, to require a
competitor seeking to provide service in a rural market to meet the requirements for
• designation as an eligible carrier. Makes this provision inapplicable to: (1) a service area served
by a rural telephone company that has obtained an exemption, suspension, or modification that
effectively prevents a competitor from meeting such requirements; and (2) a provider of
commerc'al mobile services.
Requires: (1) the FCC to institute and refer to a Federal-State Joint Board a proceeding to
recommend changes to any of its regulations to implement specified requirements, including the
definition of the services that are supported by Federal universal service support mechanisms
and a specific timetable for completion of such recommendations; (2) one member of the Board
to be a State- appointed utility consumer advocate nominated by a national organization of
State utility consumer advocates; and (3) the Board, after notice and opportunity for public
comment, to make its recommendations to the FCC within nine months.
Directs the Board and the FCC to base policies for the preservation and advancement of
universal service on: (1) availability of quality services at just, reasonable, and affordable rates;
(2) access to advanced telecommunications and information services to all regions of the
nation; (3) access and costs in rural and high cost areas that are reasonably comparable to that
provided in urban areas; (4) equitable and nondiscriminatory contribution by all
telecommunications services providers; (5) specific and predictable support mechanisms; (6)
access to advanced telecommunications services for schools, health care, and libraries; and (7)
such other principles as the Board and the FCC determine are in the public interest.
Defines "universal service" as an evolving level of telecommunications services that the FCC
• shall establish periodically, taking into account advances in telecommunications and
information technologies and services.
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Requires all carriers providing interstate telecommunications services to contribute to the
preservation and advancement of universal service. Authorizes the FCC to exempt a carrier or
1111 class of carriers if their contribution would be "de minimis."
Provides that only designated eligible carriers shall be eligible to receive specific Federal
universal service support.
Grants States authority to adopt regulations not inconsistent with the FCC's rules. Requires all
providers of intrastate telecommunications to contribute to universal service within a State in
an equitable and nondiscriminatory manner, as determined by the State. Permits a State to
adopt additional requirements with respect to universal service in that State as long as such
requirements do not rely upon or burden Federal universal service support mechanisms.
Directs: (1) the FCC, within six months, to adopt rules to require that the rates charged by
providers of interexchange telecommunications services to subscribers in rural and high cost
areas shall be no higher than those charged by each such provider to its subscribers in urban
areas; and (2) such rules to require that a provider of interstate interexchange
telecommunications services provide such services to its subscribers in each State at rates no
higher than those charged to its subscribers in any other State.
Requires a carrier, upon receiving a bona fide request, to provide telecommunications services:
(1) which are necessary for the provision of health care services in a State, including instruction
relating to such services, to any public or nonprofit health care provider that serves persons
who reside in rural areas in that State at rates that are reasonably comparable to those charged
• for similar services in urban areas in that State; and (2) for educational purposes included in the
definition of universal service for elementary and secondary schools and libraries at rates that
are less than the amounts charged for similar services to other parties, as necessary to ensure
affordable access to and use of such services. Permits a carrier providing such service to have
an amount equal to the amount of the discount treated as an offset to its obligation to
contribute to the mechanisms, or receive reimbursement utilizing the support mechanisms, to
preserve and advance universal service.
Directs the FCC to establish competitively neutral rules to: (1) enhance access to advanced
telecommunications and information services for all public and nonprofit elementary and
secondary school classrooms, health care providers, and libraries; and (2) define the
circumstances under which a carrier may be required to connect its network to such public
institutional telecommunications users.
Specifies that: (1) telecommunications services and network capacity provided to health care
providers, schools, and libraries may not be resold or transferred for monetary gain; and (2)
for-profit businesses, elementary and secondary schools with endowments of more than $50
million, and libraries that are not eligible to participate in State-based plans for funds under the
Library Services and Construction Act are ineligible to receive discounted rates.
Requires the FCC and the States to ensure that universal service is available at rates that are
just, reasonable, and affordable.
• Prohibits a carrier from using services that are not competitive to subsidize those that are
subject to competition. Requires the FCC, with respect to interstate services, and the States,
for intrastate services, to establish any necessary cost allocation rules, accounting safeguards,
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and guidelines to ensure that services included in the definition of universal service bear no
more than a reasonable share of the joint and common costs of facilities used to provide those
• services.
Requires that: (1) if readily achievable, manufacturers of telecommunications and customer
premises equipment ensure that equipment is designed, developed, and fabricated to be, and
providers of telecommunications services ensure that service is, accessible and usable by
individuals with disabilities; and (2) whenever such requirements are not readily achievable,
such a manufacturer o:provider shall ensure that the equipment or service is compatible with
existing peripheral devices or specialized customer premises equipment commonly used by
such individuals to achieve access, if readily achievable.
Directs the Architectural and Transportation Barriers Compliance Board to develop guidelines
for accessibility of telecommunications and customer premises equipment in conjunction with
the FCC and to review and update the guidelines periodically.
Requires the FCC to establish procedures for its oversight of coordinated network planning by
carriers and other providers of telecommunications service for the effective and efficient
interconnection of public telecommunications networks used to provide such service.
Authorizes the FCC to participate in the development by industry standards-setting
organizations of public telecommunications network interconnectivity standards that promote
access to public telecommunications networks used to provide service, network capabilities
and services by individuals with disabilities, and information services by subscribers of rural
telephone companies.
• Directs the FCC to: (1) complete a proceeding for the purpose of identifying and eliminating
market entry barriers for entrepreneurs and other small businesses in the provision and
ownership of telecommunications and information services, or in the provision of parts or
services to providers of such services; (2) seek to promote the policies and purposes of the Act
favoring diversity of media voices, vigorous economic competition, technological
advancement, and promotion of the public interest; and (3) periodically review and report to
the Congress on any regulations prescribed to eliminate such barriers and the statutory barriers
that it recommends be eliminated, consistent with the public interest.
Prohibits a carrier from submitting or executing a change in a subscriber's selection of a
provider of telephone exchange service or telephone toll service except in accordance with
such verification procedures as the FCC shall prescribe. Makes any carrier that violates such
procedures and collects charges for such a service from a subscriber liable to the carrier
previously selected by the subscriber in an amount equal to all charges paid by such subscriber
after such violation.
Directs the FCC to prescribe regulations that require incumbent LECs to share network
facilities, technology, and information with qualifying carriers where the qualifying carrier
requests such sharing for the purpose of providing telecommunications services or access to
information services in areas where the carrier is designated as an essential carrier. Establishes
the terms and conditions of such regulations. Requires LECs sharing infrastructure to provide
• information to sharing parties about deployment of services and equipment, including software.
Prohibits any LEC subject to interconnection requirements under this Act from: (1) subsidizing
its telemessaging service directly or indirectly from its telephone exchange service or its
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exchange access; and (2) preferring or discriminating in favor of its telemessaging service
operations in its provision of telecommunications services. Directs the FCC to establish
110 procedures or regulations thereunder for the expedited receipt and review of complaints
alleging violations that result in material financial harm to providers of telemessaging services.
(Sec. 102) Specifies that a common carrier designated as an "eligible telecommunications
carrier" shall: (1) be eligible to receive universal service support; and (2) throughout the service
area for which the designation is received, offer the services that are supported by Federal
universal service support mechanisms either using its own facilities or a combination of its own
facilities and resale of another carrier's services, and advertise the availability of such services
and the charges therefor using media of general distribution.
Requires a State commission to designate such a carrier for the service area. Authorizes (in the
case of an area served by a rural telephone company) or requires (in the case of all other areas)
the State commission to designate more than one common carrier as an eligible carrier for a
service area designated by the State commission, as long as each additional requesting carrier
meets the requirements of this section and such designation is in the public interest.
Sets forth provisions regarding: (1) designation of eligible carriers for unserved areas; and (2)
relinquishment of universal service (in areas served by more than one eligible carrier).
(Sec. 103) Amends the Public Utility Holding Company Act of 1935 (PUHCA) to allow
registered holding companies to diversify into telecommunications, information, and related
services and products where the Securities and Exchange Commission (SEC) determines that a
• registered holding company is providing telecommunications, information, and other related
services through a single purpose subsidiary, designated an "exempt telecommunications
company" (ETC). Requires prior State approval before any utility that is associated with a
registered holding company may sell to an ETC any asset in the retail rates of that utility as of
December 19, 1995.
Specifies that the ownership of ETCs by registered holding companies shall not be subject to
prior approval or other restriction by the SEC, but the relationship between an ETC and a
registered holding company shall remain subject to SEC jurisdiction, with exceptions.
Requires any registered holding company or subsidiary thereof that acquires or holds the
securities, or an interest in the business, of an ETC to file with the SEC such information as the
SEC may prescribe concerning: (1) investments and activities by the registered holding
company, or any subsidiary thereof, with respect to ETCs; and (2) any activities of an ETC
within the holding company system that are reasonably likely to have a material impact on the
financial or operational condition of the holding company system.
Prohibits public utility companies from assuming the liabilities of an ETC and from pledging or
mortgaging the assets of a utility for the benefit of an ETC.
Sets forth provisions regarding: (1) protection against abusive affiliate transactions; and (2)
non-preemption of rate authority.
Prohibits reciprocal arrangements to avoid the provisions of this section among companies that
are not affiliates or associate companies of each other.
Authorizes State commissions to: (1) examine the books and records of the ETC and any
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public utility company, associate company, or affiliate in the registered holding company
• system as they relate to the activities of the ETC; and (2) order an audit of a public utility
company that is an associate of an ETC.
(Sec. 104) Amends the Act to specify that a purpose of the Act is to make available service to
all the people of the United States without discrimination on the basis of race, color, religion,
national origin, or sex.
Subtitle B: Special Provisions Concerning Bell Operating Companies - Requires a BOC to
obtain FCC authorization prior to offering "interLATA" (i.e., long-distance; "LATA" means
"local access and transport area") service within its region unless those services are previously
authorized or incidental to the provision of another service, in which case interLATA service
may be offered after the date of this Act's enactment. Permits a BOC to offer out-of-region
services immediately after such date.
Sets forth requirements for a BOC's provision of interLATA services originating in an in-region
State, including: (1) the presence of a facilities-based competitor or competitors (but the
presence of a competitor offering exchange access, telephone exchange service offered
exclusively through the resale of the BOC's telephone exchange service, and cellular service
does not meet such requirement); or (2) the failure of a facilities-based competitor to request
access or interconnection.
Establishes specific interconnection requirements, including a competitive checklist that a BOC
must satisfy as part of its entry test (e.g., interconnection in accordance with specified
• requirements, nondiscriminatory access to 911 services, and reciprocal compensation
arrangements).
Sets forth administrative provisions regarding applications for BOC entry. Authorizes the
Attorney General to provide to the FCC an evaluation of an application using any standard the
Attorney General deems appropriate. Sets forth provisions regarding FCC determinations,
limits on FCC actions, publication of determinations, and enforcement of conditions required
for approval. Directs the FCC to establish procedures for the review of complaints concerning
failures by BOCs to meet such conditions.
Prohibits joint marketing of local services obtained from the BOC and long distance service
within a State by carriers with more than five percent of the nation's presubscribed access line
for three years after the date of enactment, or until a BOC is authorized to offer interLATA
services within that State, whichever is earlier.
Requires any BOC authorized to offer interLATA services to provide intraLATA toll dialing
parity coincident with its exercise of that interLATA authority. Bars States from ordering a
BOC to implement toll dialing parity prior to its entry into interLATA service. Provides that
any single-LATA State or any State that has issued an order by December 19, 1995, requiring
a BOC to implement intraLATA toll dialing parity is grandfathered under this Act, with the
prohibition against "non-grandfathered" States expiring three years after this Act's enactment
date.
• Sets forth "incidental" interLATA activities that the BOCs are permitted to provide upon the
date of enactment.
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Prohibits a BOC (including any affiliate) which is an LEC from providing specified services
• (including manufacturing activities, origination of interLATA telecommunications services
other than incidental interLATA services, out-of-region services, or previously authorized
activities and interLATA information services other than electronic publishing and alarm
monitoring services) unless it does so through an entity that is separate from any entities that
provide telephone exchange service.
Delineates structural and transactional requirements that apply to the separate subsidiary,
including operating independently from the BOC, maintaining separate books and records,
having separate officers, not obtaining credit under any arrangement that would permit a
creditor upon default to have recourse to the BOC's assets, and conducting transactions with
the BOC on an arm's length basis.
Sets forth provisions regarding: (1) non-discrimination safeguards; (2) biennial audit
requirements; (3) sunset of provisions of this section; and (4)joint marketing.
Permits a BOC to: (1) engage in manufacturing after the FCC authorizes the company to
provide interLATA services in any in-region State; (2) collaborate with a manufacturer of
customer premises or telecommunications equipment during the design and development of
hardware or software; and (3) engage in research activities relating to manufacturing and enter
into royalty agreements with manufacturers of telecommunications equipment.
Requires each BOC to maintain and file with the FCC information on protocols and technical
requirements for connection with and use of its telephone exchange service facilities.
Sets forth provisions regarding: (1) manufacturing limitations for standard-setting
organizations; (2) alternate dispute resolution; (3) BOC equipment procurement and sales; and
(4) FCC enforcement authority.
Prohibits a BOC or any affiliate from engaging in the provision of electronic publishing that is
disseminated by means of such BOC's or any of its affiliates' basic telephone service, but allows
a separated affiliate or electronic publishing joint venture (EPN) operated in accordance with
this section to engage in electronic publishing.
Requires a separated affiliate or EPJV to be operated independently from the BOC and to
maintain separate books and records. Prohibits the affiliate from incurring debt in a manner that
would permit a creditor upon default to have recourse to the BOC's assets. Sets forth
provisions governing the manner in which transactions by the affiliate must be carried out (to
ensure that they are fully auditable) and governing the valuation of assets transferred to the
affiliate (to prevent cross subsidies). Prohibits the affiliate and the BOC from having corporate
officers or property in common.
Prohibits the separate affiliate or EPJV from marketing the name, trademarks, or service marks
of an existing BOC except for those that are owned by the entity that owns or controls the
BOC.
Prohibits a BOC from engaging in joint marketing of any promotion, marketing, sales, or
Sadvertising with its affiliate, except that a BOC may: (1) provide inbound telemarketing or
referral services related to the provision of electronic publishing if the BOC provides the same
service on the same terms, conditions, and prices to non-affiliates as to its affiliates; (2) engage
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in non-discriminatory teaming or business arrangements; and (3) participate in EPJVs, provided
that the BOC or affiliate has not more than a 50 percent (or, for small publishers, 80 percent)
• direct or indirect equity interest in the publishing joint venture.
Requires a BOC that enters the electronic publishing business through a separated affiliate or
EPJV to provide network access and interconnection to electronic publishers at just and
reasonable rates that are not higher on a per-unit basis than those charged to any other
electronic publisher or any separated affiliate engaged in electronic publishing.
Entitles a person claiming a violation of this section to file a complaint with the FCC or to
bring suit as provided in the Act.
Prohibits a BOC or affiliate thereof from engaging in the provision of alarm monitoring
services before five years after the date of this Act's enactment, except for such services by a
BOC that was engaged in providing such services as of November 30, 1995, directly or
through an affiliate (but such BOC may not acquire an equity interest in or obtain financial
control of any unaffiliated alarm monitoring services entities from November 30, 1995, until
five years after the enactment date).
Provides that an incumbent LEC engaged in the provision of alarm monitoring services shall:
(1) provide nonaffiliated entities, upon reasonable request, with the network services it
provides to its own alarm monitoring operations on non-discriminatory terms and conditions;
and (2) not subsidize its alarm monitoring services directly or indirectly from telephone
exchange service operations. Requires the FCC to establish procedures for the receipt and
• review of complaints concerning violations of such provision or the regulations thereunder that
result in material financial harm to a provider of alarm monitoring service. Bars an LEC from
recording or using in any fashion the occurrence or contents of calls received by providers of
alarm monitoring services for purposes of marketing such services on behalf of such LEC or
any other entity.
Directs the FCC to adopt rules that eliminate discrimination between BOC and independent
payphones and subsidies or cost recovery for BOC payphones from regulated interstate or
intrastate exchange or exchange access revenue. Authorizes the FCC, if it determines that it is
in the public interest, to allow the BOC's to have the same rights as independent payphone
providers in negotiating with the interLATA carriers for their payphones. Grants the location
provider the ultimate decision-making authority in determining interLATA services in
connection with the choice of payphone providers.
Title II: Broadcast Services - Requires the FCC, if it determines that it will issue additional
licenses for advanced TV services, to: (1) limit the initial eligibility for such licenses to persons
who are licensed to operate a TV broadcast station, who hold a permit to construct such a
station, or both; and (2) adopt regulations that allow such licensees or permittees to offer such
ancillary or supplementary services on designated frequencies as may be consistent with the
public interest, convenience, and necessity. Provides for the: (1) recovery for FCC reallocation
or reassignment of the original or additional license of a person licensed to operate a TV
broadcast station; and (2) charging and collection of fees from licensees by the FCC for the
40 authorized use of designated frequencies. Requires a report from the FCC to the Congress on
the implementation of this provision. Requires the FCC, within ten years after the first issuance
of additional licenses, to conduct an evaluation of the advanced TV services program.
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(Sec. 202) Directs the FCC to modify its multiple ownership rules to eliminate its limitation on
the number of radio stations which may be owned or controlled nationally. Limits the number
•
of radio stations an entity may own, operate, or control in a local market, with an exception
when the FCC determines that such ownership, operation, or control will increase the number
of radio broadcast stations in operation. Directs the FCC to: (1) eliminate its limitation on the
number of TV stations which may be owned or controlled nationally; (2) increase to 35 percent
the national audience reach limitations for TV stations; and (3) conduct a rulemaking
proceeding to determine whether its rules restricting ownership of more than one TV station in
a local market should be retained, modified, or eliminated.
Directs the FCC to extend its waiver policy with respect to its one-to-a-market ownership rules
to any of the top 50 markets. Directs the FCC to permit a TV station to affiliate with an entity
that maintains two or more networks unless such networks are composed of: (1) two or more
of the four existing networks (ABC, CBS, NBC, FOX); or (2) any of the four existing
networks and one of the two emerging networks (WBTN, UPN). Directs the FCC to: (1)
permit an entity to own or control a network of broadcast stations and a cable system; and (2)
revise ownership regulations if necessary to ensure carriage, channel positioning, and
nondiscriminatory treatment of nonaffiliated broadcast stations by a cable system. Requires the
FCC to revise all such rules biennially. Repeals current restrictions on broadcast- cable
crossownership under the Communications Act.
(Sec. 203) Provides an eight-year license term for both TV and radio broadcast licenses.
(Sec. 204) Revises provisions regarding renewal procedures for the operation of TV broadcast
• stations. Includes standards for both renewal and denial of an application. Requires each
renewal applicant to attach to such application a summary of comments and suggestions from
the public regarding violent programming. Makes such amendment effective with respect to
applications filed after May 1, 1995.
(Sec. 205) Extends to direct broadcast services current protections against signal piracy.
Empowers the FCC with exclusive jurisdiction to regulate direct-to-home satellite services.
(Sec. 206) Provides that any ship documented under U.S. laws operating under the Global
Maritime Distress and Safety System provisions of the Safety of Life at Sea Convention shall
not be required to be equipped with a radio telegraphy station operated by one or more radio
officers or operators.
(Sec. 207) Directs the FCC to promulgate regulations to prohibit restrictions that impair a
viewer's ability to receive video programming services through devices designed for
over-the-air reception of TV broadcast signals, multichannel multipoint distribution service, or
direct broadcast satellite services.
Title III: Cable Services - Revises the definitions of"cable service" and "cable system" for
purposes of the Act. Directs the FCC to: (1) review any complaint submitted by a franchising
authority after the date of enactment of this Act concerning an increase in rates for cable
programming services; and (2) issue a final order within 90 days, unless the parties agree to
extend the review period. Terminates such review authority for cable programming services
provided after March 31, 1999. Makes such provision inapplicable with respect to: (1)
operators providing video programming services in areas subject to effective competition (as
defined); or (2) any video programming offered on a per channel or per program basis.
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Exempts from certain cable rate regulation provisions small cable operators (serving fewer than
one percent of all cable subscribers in the United States, serving no more than 50,000
•
subscribers, and not affiliated with any entity whose gross annual revenues exceed $250
million). Revises provisions with respect to cable TV market determinations, requiring an
expedited decisionmaking process. Prohibits any State or franchising authority from restricting
in any way a cable system's use of any type of subscriber equipment or transmission
technology. Sets forth provisions with respect to: (1) cable equipment compatibility; and (2)
subscriber notice (allowing any reasonable means at the cable operator's discretion). Repeals
anti-trafficking restriction provisions of the Act. Directs the FCC to allow cable operators to
aggregate equipment costs into broad categories, regardless of the function levels of such
equipment within such categories. Provides for the treatment of prior-year losses of a cable
system.
(Sec. 302) Subjects common carriers providing video programming to subscribers using radio
communications to the requirements of title III and to the ownership and joint venture
restrictions set forth in the following paragraph, but not to other requirements of title VI of the
Act. States that such carriers providing such programming on a common carrier basis shall be
subject to such requirements and restrictions, but not to other requirements of title VI. Allows
such carrier to elect to provide such programming by means of an open video system, stating
that such a provider need not make capacity available on a nondiscriminatory basis to any other
person for the provision of cable service directly to subscribers.
Prohibits any LEC or affiliate from purchasing or otherwise acquiring more than a ten percent
• financial interest, or any management interest, in any LEC providing telephone exchange
service within such cable operator's franchise area. Prohibits an LEC and a local cable operator
from entering into a joint venture to provide video programming directly to subscribers or to
provide telecommunications services within such market. Provides exceptions, including
exceptions for joint ventures in rural areas,joint use of transmission facilities in limited
circumstances, acquisitions made in competitive markets, exempt cable systems (cable systems
serving less than 17,000 subscribers, with other restrictions), and small cable systems located in
nonurban areas. Authorizes the FCC to waive such financial interest or joint venture
restrictions in cases of undue economic distress, economic viability, anticompetitive effects of
such restrictions, or when the local franchising authority approves such waiver.
Authorizes an LEC to provide cable service to its subscribers through an open video system
that complies with this section. Outlines, with respect to the provision of such service through
such system, provisions concerning: (1) certificates of compliance; (2) dispute resolution; (3)
FCC regulations; (4) consumer access; (5) reduced regulatory burdens for such systems; and
(6) FCC implementation of appropriate rules and regulations within six months after the
enactment of this Act. States that an operator of an open video system may be subject to the
payment of fees based on gross revenues in lieu of cable TV franchising fees.
(Sec. 303) Sets forth provisions regarding preemption of franchising authority regulation of
telecommunications services. Prohibits a franchising authority from ordering a cable operator
to discontinue the provision of a telecommunications service or a cable system to the extent it
is used to provide a telecommunications service by reason of the failure of the cable operator to
1110 obtain a franchise or franchise renewal for the provision of such service. Prohibits a franchising
authority from requiring a cable operator to provide any telecommunications service or
facilities, other than institutional networks, as a condition of the initial grant of a franchise,
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franchise renewal or franchise transfer.
• (Sec. 304) Directs the FCC to adopt regulations to ensure the commercial availability of
convertor boxes, interactive equipment, and related equipment used to access multichannel
video programming (MVP) from manufacturers, retailers, or other vendors not affiliated with
any MVP distributor. Ensures the continued system security of MVP services. Provides FCC
waiver authority with respect to provisions adopted under this section.
(Sec. 305) Directs the FCC, within 180 days after the enactment of this Act, to complete an
inquiry to ascertain the level at which video programming is closed captioned. Provides closed
captioning accountability criteria and requires a schedule of deadlines for the provision of such
service. Provides exemptions from such requirements in cases of economic burden,
inconsistency with current contracts, or undue burden of a significant difficulty or expense
(with specified factors). Directs the FCC to: (1) commence an inquiry to examine the use of
video descriptions on video programming in order to ensure the accessibility of such
programming to persons with visual impairments; and (2) report to the Congress on its
findings.
Title IV: Regulatory Reform - Directs the FCC to forbear from applying any regulation or
provision of the Act to a telecommunications carrier or service if it determines that: (1)
enforcement is not necessary to ensure that charges, practices, and classifications are just and
reasonable and not discriminatory; (2) enforcement is not necessary for the protection of
consumers; and (3) forbearance is consistent with the public interest. Directs the FCC to
consider whether such forbearance will promote competitive market conditions. Allows any
• carrier to petition for such forbearance, requiring an FCC ruling within one year of such
petition. Prohibits State enforcement of a regulation or provision after FCC-granted
forbearance.
(Sec. 402) Directs the FCC, in every even-numbered year beginning with 1998, to: (1) review
all regulations issued under the Act that apply to the operations or activities of a provider of
telecommunications services; and (2) determine whether such regulation is no longer necessary
in the public interest. Requires the FCC to repeal or modify any regulation so determined.
Provides procedures for streamlining such repeals or modifications.
(Sec. 403) Eliminates or reduces specified FCC regulations, functions, and authority with
respect to: (1) amateur radio examination procedures; (2) the designation of inspection entities;
(3) instructional TV fixed service processing; (4) the setting of depreciation rates; (5) the use
of independent auditors; (6) the delegation to private laboratories of equipment testing and
certification; (7) the uniformity of license modifications; (8)jurisdiction over
Government-owned ship radio stations; (9) the operation of domestic ship and aircraft radios
without licenses; (10) fixed microwave service licensing; (11) foreign directors; (12) limitations
on silent station authorizations; (13) construction permit requirements; (14) inspections of
broadcast station equipment and apparatus; and (15) inspections by entities other than the
FCC.
Title V: Obscenity and Violence - Subtitle A: Obscene, Harassing, and Wrongful
• Utilization of Telecommunication Facilities - Communications Decency Act of 1996 -
Revises provisions of the Communications Act prohibiting obscene or harassing telephone calls
and conversation to apply to obscene or harassing use of a telecommunications facility and
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communication. Increases the penalties for violations. Prohibits using a telecommunications
device to: (1) make or initiate any communication which is obscene, lewd, lascivious, filthy, or
•
indecent with intent to annoy, abuse, threaten, or harass another person; (2) make or make
available obscene communication; (3) make or make available an indecent communication to
minors.
Provides that no person shall be held to have violated such prohibition solely for providing
access or connection to a telecommunications facility, system, or network not under such
person's control. Provides employers with a defense for actions by employees unless the
employee's conduct is within the scope of employment and is known, authorized, or ratified by
the employer. Establishes as a defense to prohibited communications that a person has taken, in
good faith, reasonable, effective, and appropriate actions to prevent access by minors or has
restricted access by requiring use of a verified credit card, debit account, or adult access code
or personal identification number.
(Sec. 504) Requires cable operators, upon request, to fully scramble or block programming to
which the subscriber does not subscribe.
(Sec. 505) Requires a multichannel videoprogramming distributor: (1) to fully scramble or
block sexually explicit adult programming so that nonsubscribers do not receive it; and (2) until
it complies with such requirement, to not provide such programming during the hours of the
day when a significant number of children are likely to view it.
(Sec. 506) Allows cable operators to refuse to transmit any public access or leased access
program which contains obscenity, indecency, or nudity.
(Sec. 507) Amends the Federal criminal code to specify that current obscenity statutes prohibit
using a computer to import or transport in interstate or foreign commerce, for sale or
distribution, obscene material, including material designed, adapted, or intended for producing
abortion or for any indecent or immoral use.
(Sec. 508) Prohibits using any facility or means of interstate or foreign commerce to persuade,
induce, entice, or coerce a minor to engage in prostitution or any sexual act for which any
person may be criminally prosecuted.
(Sec. 509) Provides that no provider or user of an interactive computer service shall be held
liable for any voluntary action taken to restrict access to, or to enable information content
providers to restrict access to, material that the user or provider considers to be objectionable,
whether or not such material is constitutionally protected.
Subtitle B: Violence - Directs the FCC, if it determines that video programming distributors
have not, within one year, voluntarily established rules for rating programming that contains
sexual, violent, or other indecent material about which parents should be informed before it is
displayed to children and voluntarily agreed to broadcast signals that contain such ratings, to:
(1) establish an advisory committee to recommend guidelines and procedures for rating such
programming; (2) prescribe such guidelines and procedures; and (3) prescribe rules requiring
programming distributors to transmit such rating to permit parents to block inappropriate
• programming. Directs the FCC, not less than two years after enactment of this Act, to require
apparatus designed to receive TV signals that are shipped in interstate commerce or
manufactured in the United States and that have a picture screen of 13 inches or greater
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(measured diagonally) to be equipped with a feature designed to enable viewers to block
• display of all programs with a common rating. Authorizes the FCC to allow apparatus
manufacturers to comply with such requirement using alternative technology that meets certain
standards of cost, effectiveness, and ease of use.
(Sec. 552) Encourages broadcast television, cable, satellite, syndication, and other video
programming distributors to establish a technology fund to encourage electronics equipment
manufacturers to facilitate the development of technology which would empower parents to
block programming deemed inappropriate for children and to encourage availability of such
technology to low income parents.
Subtitle C: Judicial Review - Provides for the expedited review of any civil action
challenging the constitutionality of this title by a district court of three judges and by direct
appeal to the Supreme Court.
Title VI: Effect on Other Laws - Provides that any conduct or activity that was, before the
enactment of this Act, subject to any restriction or obligation imposed by the AT&T Consent
Decree, the GTE Consent Decree, or the McCaw Consent Decree shall, after enactment of this
Act, be subject to the restrictions and obligations imposed by the Communications Act as
amended by this Act.
Provides that nothing in this Act shall be construed to modify, impair, or supersede: (1) the
applicability of the antitrust laws; or(2) any State or local law pertaining to taxation, except
with respect to fees for open video systems. Repeals a provision of the Communications Act
. permitting the FCC to render a proposed merger of competing local telephone companies
exempt from any Act of Congress making the transaction unlawful.
(Sec. 602) Exempts any provider of direct-to-home satellite service from the collection or
remittance of any local tax or fee on such service.
Title VII: Miscellaneous Provisions -Prohibits a party calling a toll-free telephone number
from being assessed a charge by virtue of being asked to connect or otherwise transfer to a
pay-per-call service. Prohibits the calling party from being charged for information conveyed
during a call to a toll-free (800) number unless the calling party: (1) has a written agreement
specifying the material terms and conditions under which the information is offered and which
includes the rate at which charges are assessed and certain identifying information; or (2) is
charged for the information only after the information provider includes an introductory
disclosure message regarding the charge, rate, and means of billing for the call and the calling
party is charged by means of a credit, prepaid, debit, charge, or calling card. Outlines
provisions concerning: (1) billing arrangements; (2) required use of a personal identification
number by the subscriber to obtain access to the information provided; (3) exceptions to the
written agreement requirement; and (4) termination of service if a telecommunications carrier
reasonably determines that a complaint against an information provider is valid.
Amends the Telephone Disclosure and Dispute Resolution Act to authorize the FCC to extend
the definition of"pay-per-call services" under such Act to other services that the FCC
determines are susceptible to the unfair and deceptive billing practices addressed by such Act.
•
(Sec. 702) Makes it the duty of every telecommunications carrier to protect the confidentiality
of proprietary information of other carriers, equipment manufacturers, and customers. Permits
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a carrier that receives proprietary information from another carrier or a customer for purposes
• of providing any telecommunications service to use such information only for such purpose.
Directs a carrier to disclose customer proprietary network information upon the customer's
request. Permits a carrier to use, disclose, or permit access to aggregate customer information
for other purposes. Requires a carrier that provides telephone exchange service to provide
subscriber list information to any person upon request for the purpose of publishing directories
in any format.
(Sec. 703) Directs the FCC to prescribe regulations to: (1) govern the charges for pole
attachments used by telecommunications carriers to provide telecommunications services,
when the parties fail to resolve a dispute over such charges; and (2) ensure that utilities charge
just, reasonable, and nondiscriminatory rates for the pole attachments. Requires a utility to
apportion the cost of providing space on a pole based on the number of attaching entities.
Requires any increase in the rates for pole attachments to be phased in over a five-year period.
Requires a utility to provide a cable television system or any telecommunications carrier with
nondiscriminatory access to any pole or right-of-way owned by it. Allows a utility company
providing electric service to deny a cable television system or telecommunications carrier
access to such poles when there is insufficient capacity and for reasons of safety, reliability, and
generally applicable engineering purposes. Requires utilities that engage in the provision of
telecommunications services or cable services to impute to its costs of providing such service
an equal amount to the pole attachment rate for which such company would be liable. Requires
utilities to provide written notification to attaching entities of any plans to modify or alter its
poles or other rights-of-way. Requires any attaching entity that modifies its own attachments to
• bear a proportionate share of the costs of such modifications. Prevents a utility from imposing
the cost of rearrangements to other attaching entities if done solely for the benefit of the utility.
(Sec. 704) Preserves State or local authority over decisions regarding the placement,
construction, and modification of personal wireless service facilities, but prohibits State or local
regulation thereof from: (1) unreasonably discriminating among providers of functionally
equivalent services; or (2) prohibiting the provision of personal wireless services. Requires
State or local action on requests regarding such facilities to occur within a reasonable time,
with denials of requests to be in writing and supported by substantial evidence in a written
record. Prohibits State or local regulation of such facilities on the basis of environmental effects
of radio frequency emissions to the extent such facilities comply with FCC regulations.
Provides for expedited judicial review and petitions of the FCC for relief from adverse State or
local actions.
Directs the President to prescribe procedures by which Federal agencies may make available
property and rights-of-way for the placement of new telecommunications services that are
dependent upon the utilization of Federal spectrum rights.
(Sec. 705) Prohibits a commercial mobile services provider from being required to provide
equal access to common carriers for the provision of telephone toll services. Directs the FCC,
if it determines that subscribers to such services are denied access to the provider of telephone
toll services of the subscribers' choice, contrary to the public interest, to prescribe regulations
4111 to afford subscribers unblocked access to the provider of telephone toll services of the
subscribers' choice through the use of a carrier identification code assigned to such provider or
other mechanism. Provides that such regulations shall not apply to mobile satellite services
unless the FCC finds it to be in the public interest.
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(Sec. 706) Requires the FCC and each State telecommunications commission to encourage the
• deployment of advanced telecommunications capability to all Americans by utilizing price cap
regulation, regulatory forbearance, measures that promote competition, or other regulating
methods that remove barriers to infrastructure investment. Requires the FCC to regularly
initiate a notice of inquiry concerning such availability and, if it determines it to be necessary, to
take action to accelerate deployment of such capability by removing barriers to infrastructure
investment and by promoting competition in the telecommunications market.
(Sec. 707) Establishes the Telecommunications Development Fund as a corporate body in the
District of Columbia to promote access to capital for small businesses in order to enhance
competition in the telecommunications industry, to stimulate new technology development, to
promote employment and training, and to support universal service. Directs the Fund to: (1)
make loans, investments, or other extensions of credit and provide financial advice to eligible
small businesses; and (2) prepare research, studies, or financial analyses.
(Sec. 708) Recognizes the National Education Technology Funding Corporation as a nonprofit
corporation independent of the Federal Government and operating under the laws of the
District of Columbia. Authorizes the Corporation to receive discretionary grants, contracts,
gifts, contributions, or technical assistance from any Federal department or agency.
Requires audits of the Corporation by independent certified public accountants. Provides
reporting and recordkeeping requirements. Requires the accessibility of Corporation books for
audit and examination. Directs the Corporation to report annually to the President and the
Congress on operations and activities of the previous fiscal year. Requires Corporation
• members to be available to testify before the Congress concerning such operations and
activities.
(Sec. 709) Directs the Assistant Secretary of Commerce for Communications and Information
to report annually to specified congressional committees concerning the activities of the Joint
Working Group on Telemedicine, together with any findings in the studies and demonstrations
on telemedicine funded by the Public Health Service or other Federal agencies. Specifies that
such reports shall examine questions related to patient safety, the efficacy and quality of the
services provided, and other legal, medical, and economic issues related to the utilization of
advanced telecommunications services for medical purposes.
(Sec. 710) Authorizes appropriations.
s
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CASE #
• REVIEW PROPOSED ORDINANCE TO ESTABLISH
REGULATIONS FOR TOWERS AND ANTENNAS
By: Planning Intern Kirk Skoog
Background:
On November 12, 1996, the Ramsey City Council approved a 180 day moratorium that prohibits
construction,erection, placement, reconstruction, enlargement, or expansion of towers within the
City and on the development and use of property for such purposes. This moratorium took effect
on January 6, 1997. The moratorium was established in order to allow Staff the necessary time to
research the development of Personal Communication Services (PCS)and the need for towers and
antennas to facilitate the provision of these services.
Observations:
Staff has researched the technological changes that have resulted in the development of PCS and
the need for towers and antennas to accommodate the demand for these services. Based on this
research, Staff has prepared a proposed ordinance to amend Chapter 9 of the City Code which will
establish regulatory controls on the siting of antennas and towers. Also, the City currently has no
regulations pertaining to amateur radio, satellite dishes, TV antennas, etc. Therefore, a section is
included in the proposed ordinance that addresses these issues.
Recommendation:
City Staff recommends that an ordinance be adopted to amend Chapter 9 of the City Code that will
• establish regulatory controls on the siting of antennas and towers. A proposed ordinance is
attached for your consideration.
Commission Action:
Motion to Recommend that the City Council adopt the proposed ordinance to amend Chapter 9 of
the City Code which will establish regulatory controls on the siting of antennas and towers.
Review Checklist:
Zoning Administrator
• PC: 1/7/97
JAN-02-1997 11 47 CITY OF RAMSEY 612 427 5543 P.03/11
PROPOSED ORDINANCE #9b-
CITY OF RAMSEY
• ANOKA COUNTY
STATE OF MINNESOTA
AN AMENDMENT TO CHAPTER 9 WHICH IS KNOWN AS THE
"ZONING AND SUBDIVISION OF LAND" CHAPTER OF THE CITY
CODE OF RAMSEY, MINNESOTA.
AN ORDINANCE ADDING SECTION 9.15 "TOWERS", OF CHAPTER 9
OF THE CITY CODE OF RAMSEY, MINNESOTA.
The City of Ramsey ordains:
9.15.01 DEFINITIONS
The following words and terms when used in this Chapter shall have the following
meanings unless the context clearly states otherwise:
Antenna • Any structure or device used for the purpose of collecting or
transmitting electromagnetic waves, including but not limited to directional antennas, such
as panels, microwave dishes, and satellite dishes, and omni-directional antennas, such as
whip antennas.
Commercial Wireless Telecommunication Services - Licensed commercial
• wireless telecommunication services including cellular, personal communication services
(PCS), specialized mobilized radio (SMR), enhanced specialized mobilized radio (ESMR),
paging, and similar services that are marketed to the general public.
Tower • Any ground or roof mounted pole, spire, structure, or combination
thereof, including supporting lines, cables, wires, braces, and masts, intended primarily
for the purpose of mounting an antenna, meteorological device, or similar apparatus above
grade.
Communication Tower, Guyed - A tower that is supported, in whole or in
part by wires and ground anchors.
Communication Tower, Monopole - A tower consisting of a single pole,
constructed without guyed wires and anchors.
Communication Tower, Lattice or Self-Support - A tower that has three
or four sides of open-framed steel supports.
Height of a Communication Antenna or Tower - The height of a
freestanding communication antenna or tower is determined as the distance from ground
level to the highest point on the tower, including the antenna.
Height of a Roof or Wall Mounted Antenna or Tower - The height of a
communication antenna that is mounted on a roof or wall shall be measured from the point
where the base of the antenna and its supporting structure appends to the roof or wall to the
• highest point of the supporting structure, including the antenna.
JAN-02-199? 11:49 CITY OF RAMSEY 612 427 5543 P.04/11
9.15.02 ?URPQ,SE
• In order to accommodate the communication needs of residents and business while
protecting the public health, safety, and general welfare of the community, the Council
finds that these regulations are necessary in order to:
(a) facilitate the provision of wireless telecommunication services to the
residents and businesses of the City;
(b) minimize adverse visual effects of towers through careful design and siting
standards;
(c) avoid potential damage to adjacent properties from tower failure through
structural standards and setback requirements; and,
(d) maximize the use of existing and approved towers and buildings to
accommodate new wireless telecommunication antennas in order to reduce the number of
towers needed to serve the community.
9.15.03 TOWERS IN RESIDENTIAL ZONING DISTRICTS
Towers shall be allowed only in the following residentially zoned areas:
(a) Towers supporting commercial antennas and conforming to all applicable
provisions of this Code shall be allowed only in the rear yard of residentially zoned parcels.
(b) Towers supporting commercial antennas and conforming to all applicable
provisions of this Code shall be allowed only in the following residentially zoned locations:
• (1,) Church sites, when camouflaged as steeples or bell towers;
(2) Park sites, when compatible with the nature of the park; and,
(3) Government, school, utility, and institutional sites.
9.15.04 USE OF CITY OWNED LAND FOR WIRELESS
TELECOMMUNICATION ANTENNAS AND TOWERS
(a) Priority of Users
(1) City of Ramsey;
(2) Public safety agencies, including law enforcement, fire, and
ambulance services, which are not part of the City of Ramsey and private entities with a
public safety agreement with the City of Ramsey;
(3) Other governmental agencies, for uses which are not related to
public safety; and,
(4) Entities providing licensed commercial wireless telecommunication
services including cellular, personal communication services (PCS), specialized mobilized
radio (SMR), enhanced specialized mobilized radio (ESMR), paging, and similar services
that are marketed to the general public.
(b) Minimum Requirements
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The placement of wireless telecommunication antennas or towers on City
owned property must comply with the following requirements_
• (1) The antennas or tower will not interfere with the purpose for which
the City owned property is intended;
(2) The antennas or tower will have no adverse impact on surrounding
private property;
(3) The applicant is willing to obtain adequate liability insurance and
commit to a lease agreement which includes equitable compensation for the use of public
land and other necessary provisions and safeguards. The fees shall be established by the
City Council after considering comparable rates in other cities, potential expenses, risks to
the City, and other appropriate factors;
(4) The applicant will submit a letter of credit, performance bond, or
other security acceptable to the City to cover the costs of the antenna or tower's removal;
(5) The antennas or tower will not interfere with other users who have a
higher priority as discussed in Section (a);
(6) Upon reasonable notice, the antennas or tower may be required to be
removed at the user's expense.
(7) The applicant must reimburse the City for any costs which it incurs
because of the presence of the applicant's antennas or towers and,
• (8) The user must obtain all necessary land use approvals, including a
conditional use permit from the City.
(c) Special Requirements
The use of certain City owned property, such as water tower sites
and parks, for wireless telecommunication antennas or towers brings with it special
concerns due to the unique nature of these sites. The placement of wireless
telecommunication antennas or towers on these special City owned sites will be allowed
only when the following additional requirements are met.
(1) Water Tower Sites
The City's water tower represents a large public investment
in water pressure stabilization and peak capacity reserves. Protection of the quality of the
City's water supply is of prime importance to the City. As access to the City's water
storage system increases, so too increases the potential for contamination of the public
water supply. For these reasons, the placement of wireless telecommunication antennas or
towers on existing or future water tower sites will be allowed only when the City is fully
satisfied that the following requirements are met.
(i) The applicant's access to the facility will not increase the
risks of contamination to the City's water supply;
(ii) There is sufficient room on the structure and/or on the
grounds to accommodate the applicant's facility;
(iii) The presence of the facility will not increase the water tower
maintenance costs to the City; and,
JAN-02-1997 11:48 CITY OF RAMSEY 612 427 5543 P.06/11
• (iv) The presence of the facility will not be harmful to the health
of workers maintaining the water tower.
(2) Parks
The presence of certain wireless telecommunication antennas
or towers represents a potential conflict with the purpose of some City owned parks.
Wireless telecommunication antennas or towers will be considered only in the following
parks after the recommendation of the Park and Recreation Commission and approval of
the City Council.
(i) Public parks of a sufficient scale and character that are
adjacent to an existing commercial or industrial use; and,
(ii) Park maintenance facilities
(d) Application Process
All applicants who wish to locate a wireless telecommunication antenna or
tower on City owned property must submit to the City Administrator, or his/her designee, a
completed application and detailed plan that complies with the submittal requirements of the
Zoning Ordinance along with other pertinent information requested by the City.
(e) Termination
The City Council may terminate any lease if it determines that any one of the
• following conditions exist:
(1) A potential user with a higher priority cannot find another adequate
location and the potential use would be incompatible with the existing use;
(2) A user's frequency broadcast unreasonably interferes with other
users of a higher priority, regardless of whether or not this interference was adequately
predicted in the technical analysis; or,
(3) A user violates any of the standards in this policy or the conditions
attached to the City's permission.
Before taking action, the City will provide 30 days notice to the user of the
intended termination and the reasons for it, and provide an opportunity for the user to
address the City Council regarding the proposed action. This procedure need not be
followed in emergency situations.
(f) Reservation of Right
Notwithstanding the above, the City Council reserves the right to deny, for
any reason, the use of any or all City owned property by any one or all applicants.
(g) Use of Revenue
All revenue generated through the lease of city owned property for wireless
telecommunication towers and antennas shall be made payable to the City of Ramsey and
• transmitted to the City's Department of Finance.
Revenue shall be credited as follows:
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(i) To the specific operating activity using the land upon which
• the wireless telecommunication towers and antennas are located(for example, Water Utility
Fund when located on water utility property);
(ii) To the Park Improvement Fund if located on park or open
space land;
(iii) Any revenues not meeting the above criteria shall be applied
as general revenues of the General Fund.
9.15.05 CO-LOCATION REOUIREMENTS
All commercial wireless telecommunication towers erected, constructed, or located
within the City shall comply with the following requirements:
(a) A proposal for a new commercial wireless telecommunication service tower
shall not be approved unless the City Council finds that the telecommunications equipment
planned for the proposed tower cannot be accommodated on an existing or approved tower
or building within a one mile search radius of the proposed tower due to one or more of the
following reasons:
(1) The planned equipment would exceed the structural capacity of the
existing or approved tower or building, as documented by a qualified and licensed
professional engineer, and the existing or approved tower cannot be reinforced, modified,
or replaced to accommodate planned or equivalent equipment at a reasonable cost.
(2) The planned equipment would cause interference materially
• impacting the usability of other existing or planned equipment at the tower or building as
documented by a qualified and licensed professional engineer and the interference cannot be
prevented at a reasonable cost.
(3) Existing or approved towers and buildings within the search radius
cannot accommodate the planned equipment at a height necessary to function reasonably as
documented by a qualified and licensed professional engineer.
(4) Other unforeseen reasons that make it infeasible to locate the planned
telecommunications equipment upon an existing or approved tower or building.
(b) Shared use of existing communication towers shall be preferred to the
construction of a new tower. Any proposed commercial wireless telecommunication
service tower shall be designed, structurally, electrically, and in all respects, to
accommodate both the applicant's antennas and comparable antennas for at least two
additional users if the tower is one hundred(100) feet or more in height or for at least one
additional user if the tower is more than sixty(60) feet but less than one hundred (100) feet
in height.
9.15.06 TOWER CONSTRUCTION REQUIREMENTS
All towers erected,constructed,or located within the City, and all wiring therefor,
shall comply with the requirements set forth of Chapter 8 of this code.
9.15.07 TOWER AND ANTENNA DESIGN REOUIREMENTS
• Proposed or modified towers and antennas shall meet the following design
requirements.
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(a) Towers and antennas shall be designed to blend into the surrounding
• environment through the use of color and camouflaging architectural treatment, except in
instances where the color is dictated by federal or state authorities such as the Federal
Aviation Administration.
(b) Commercial wireless telecommunication service towers shall be of a
monopole design unless the City Council determines that an alternative design is preferred
in cases where structural, radio frequency (RF), design considerations, neighborhood
compatibility, locational availability, or the number, of co-locators warrants this
consideration.
(c) All towers must be designed so that the tower site and setbacks will contain
guyed wires, debris, and the tower in the event of a collapse.
9.15.08 TOWER SETBACKS
Towers shall conform with each of the following requirements.
(a) No part of any communication antenna or tower, equipment, guyed wires,
or braces shall at any time extend across or over any part of the public right-of-way, public
street, highway, sidewalk, or recreation trail.
(b) Towers shall meet the setbacks of the underlying zoning district with the
exception of industrial zoning districts, where towers may encroach into the rear setback
area, provided that the rear property line abuts another industrially zoned property and the
tower does not encroach upon any easements.
• (c) Towers shall not be located between a principal structure and a public street,
with the following exceptions:
(1) In industrial zoning districts, towers may be placed within a side
yard abutting an internal industrial street.
(2) On sites adjacent to public streets on all sides, towers may be placed
within a side yard abutting a local street.
(d) A tower's setback may be reduced or its location in relation to a public street
varied, at the sole discretion of the City Council, to allow the integration of a tower into an
existing or proposed structure such as a church steeple, light standard, power line support
device, or similar structure.
9.15.09 TOWER HEIGHT
(a) In residential and commercial districts, the height of a communication tower
shall not exceed seventy-five (75) feet. The City Council may increase the height of a
tower if the applicant is able to demonstrate to the satisfaction of the City Council that:
(1) The additional increase in height is needed to accommodate a second
u ser.
(2) The surrounding topography, structures, vegetation, and other
factors make a seventy-five (75) foot tall tower impractical.
• (b) In industrial districts, the height of a communication tower shall not exceed
one hundred seventy-five (175)feet. The City Council may increase the height of a tower
if the applicant is able to demonstrate to the satisfaction of the City Council that:
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(1) The additional increase in height is needed to accommodate a second
user.
• (2) The surrounding topography, structures, vegetation, and other
factors make a one hundred seventy-five (175)foot tower impractical.
9.15.10 TOWER LIGHTING
Towers shall not be illuminated by artificial means and shall not display strobe
lights unless such lighting is specifically required by the Federal Aviation Administration or
other federal or state authority for a particular tower. When incorporated into the approved
design of the tower, light fixtures used to illuminate ball fields, parking lots, or similar
areas may be attached to the tower.
9.15.11 SIGNS AND ADVERTISING
The use of any portion of a tower for signs other than warning or equipment
information signs is prohibited.
9.15.1.2 ACCESSORY UTILITY BUILDINGS
All utility buildings and structures accessory to a tower shall be architecturally
designed to blend in with the surrounding environment and shall meet the minimum setback
requirements of the underlying zoning district. Ground mounted equipment shall be
screened from view by suitable vegetation, except where a design of non-vegetative
screening better reflects and complements the architectural character of the surrounding
neighborhood, as determined by the City Council.
9.15.13 ABANDONED OR UNUSED TOWERS OR PORTIONS
410
OF TOWERS
Abandoned or unused towers or portions of towers shall be removed as follows:
(a) All abandoned or unused towers and associated facilities shall be removed
within 12 months of the cessation of operations at the site unless a time extension is
approved by the City Council. A copy of the relevant portions of a signed lease which
requires the applicant to remove the tower and associated facilities upon cessation of
operations at the site shall be submitted at the time of application.
(b) Unused portions of towers above a manufactured connection shall be
removed within six months of the time of antenna relocation. The replacement of portions
of a tower previously removed requires the issuance of a new conditional use permit.
9.15.14 ANTENNAS MOUNTED ON ROOFS. WALLS. AND
EXISTING TOWERS
The placement of wireless telecommunication antennas on roofs, walls, and
existing towers may be approved by the City Council, provided the antennas meet the
requirements of this Code, after submittal of 1) a final site and building plan as specified by
Chapter 8 of this Code, and 2) a report prepared by a qualified and licensed professional
engineer indicating the existing structure or tower's suitability to accept the antenna, and the
proposed method of affixing the antenna to the structure. Complete details of all fixtures
and couplings, and the precise point of attachment shall be indicated.
• 9.15.15 INTERFERENCE WITH PUBLIC SAFETY
TELECOMMUNICATIONS
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No new or existing telecommunications service shall interfere with public safety
telecommunications. All applications for new service shall be accompanied by an
intermodulation study which provides a technical evaluation of existing and proposed
transmissions and indicates all potential interference problems. Before the introduction of
new service or changes in existing service, telecommunication providers shall notify the
City at least ten calendar days in advance of such changes and allow the City to monitor
interference levels during the testing process.
9.15.16 ADDITIONAL. SUBMITTAL. REQUIREMENTS
In addition to the information required elsewhere in this Code, development
applications for towers shall include the following supplemental information:
(a) A report from a qualified and licensed professional engineer which
(1) describes the tower height and design including a cross section and
elevation,
(2) documents the height above grade for all potential mounting
positions for co-located antennas and the minimum separation distances between antennas,
(3) describes the tower's capacity, including the number and type of
antennas that it can accommodate,
(4) documents what steps the applicant will take to avoid interference
with established public safety telecommunications,
• (5) includes an engineer's stamp and registration number, and,
(6) includes other information necessary to evaluate the request.
(b) For all commercial wireless telecommunication service towers, a letter of
intent committing the tower owner and his or her successors to allow the shared use of the
tower if an additional user agrees in writing to meet reasonable terms and conditions for
shared use.
(c) Before the issuance of a building permit, the following supplemental
information shall be submitted:
(1) Proof that the proposed tower complies with regulations
administered by the Federal Aviation Administration, and,
(2) a report from a qualified and licensed professional engineer which
demonstrates the tower's compliance with the aforementioned structural and electrical
standards.
9.15.17 ANTENNAS DESIGNED FOR PRIVATE RECEPTION OF
TELEVISION AND RADIO SIGNALS
Antennas designed for private reception of television and radio signals, including
antennas (less than fifty (50) feet in height if free-standing and fifteen (15) feet in height if
roof mounted) used for amateur or recreational purposes,provided they are not located in a
front yard and do not infringe upon requirements of the Federal Aviation Administration,
• shall be exempt from the provisions of Chapter 9.15. Antennas that are intended to be fifty
(50) feet or more in height if free-standing and fifteen (15) feet or more in height if roof-
mounted shall require a conditional use permit from the City.
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9.15.18 VIOLATIONS
41) Any person who shall violate any of the provisions of this Section shall be guilty of
a misdemeanor.
SUMMARY
The following official summary of Ordinance #96-_ has been approved by the City
Council of the City of Ramsey as clearly informing the public of the intent and effect of the
Ordinance.
In order to accommodate the communication needs of residents and business while
protecting the public health, safety, and general welfare of the community, the Council
finds that these regulations are necessary in order to:
(a) facilitate the provision of wireless telecommunication services to the
residents andbusinesses of the City;
(b) minimize adverse visual effects of towers through careful design and siting
standards;
(c) avoid potential damage to adjacent properties from tower failure through
structural standards and setback requirements; and,
• (d) maximize the use of existing and approved towers and buildings to
accommodate new wireless telecommunication antennas in order to reduce the number of
towers needed to serve the community.
EFFECTIVE DATE
The effective date of this Ordinance is thirty (30) days after its passage and publication,
subject to City Charter Section 5.07.
Adopted by the Ramsey City Council the day of , 1996.
Mayor
ATTEST:
City Administrator
Introduction Date:
Posting Dates
Adoption Date:
Publication Date:
Effective Date:
p
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