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John B. Johnston W3BE
When applying for an FCC amateur service license grant, you must use either FCC Form 605 or NCVEC Form 605. They both require signing, among other things, this certification:
I certify that I have read
and will comply with Section 97.13(c) of the Commission’s Rules regarding radiofrequency radiation safety and the amateur
service section of OST/OET Bulletin Number 65.
Here are the text and tables that you must certify that you have read, and for which
you must give your word to comply. You will need to understand the following terms in order to make these FCC documents meaningful.
amateur - A
duly authorized person interested in radio technique solely with a personal aim and without pecuniary interest who carries
out the purpose of self-training, intercommunication and technical investigations. Section 2.1.
station – a radio station operated by a duly authorized person interested in radio technique solely with a
personal aim and without pecuniary interest. Read SEC. 3. [47 USC 153](2) of the Communications Act. An amateur station consists of all of the transmitters, receivers and combinations thereof, and all accessory apparatus,
at any one location, necessary for carrying on radio-communications in any of our three amateur radio services. Read What
Is an Amateur Station? BE Informed No. 1.15.
– a metallic device for sending and/or receiving radiofrequency (RF) electromagnetic field waves.
band – a continuous radiofrequency
– centimeter (.01 meters).
dB – decibel (10 bels); named in honor of Alexander Graham Bell. The term bel is seldom
- ten times the logarithm to the base ten of the ratio of two power levels.
dipole - a radio antenna consisting of two metal conductors
of rod or wire, oriented parallel and in line with each other, with a small space between them.
EHF - extremely high frequency; range
30–300 GHz. Read Section 97.3(b)(1).
field – a physical combination of a magnetic field and an electric field. This phenomena is the basis of radio.
- effective radiated power (in a given direction). The product of the power supplied to the antenna and its gain relative
to a half-wave dipole in a given direction.
Exposure - Exposure occurs whenever and wherever a person is subjected to electric,
magnetic or electromagnetic fields other than those originating from physiological processes in the body and other natural
Frequency - The number of occurrences of a repeating event per unit time. An RF electromagnetic field wave is an
oscillation, and therefore it has a frequency.
Gain (of an antenna) - The ratio in decibels, of the power required at the input
of a loss-free reference antenna to the power supplied to the input of the given antenna to produce, in a given direction,
the same field strength or the same power density at the same distance. When not specified otherwise, the gain refers to the
direction of maximum radiation. Gain may be considered for a specified polarization. Gain may be referenced to an isotropic
antenna (dBi) or a half-wave dipole (dBd).
General population/uncontrolled exposure - For regulatory purposes, applies to human
exposure to RF electromagnetic fields when the general public is exposed or in which persons who are exposed as a consequence
of their employment may not be made fully aware of the potential for exposure or cannot exercise control over their exposure.
Therefore, members of the general public always fall under this category when exposure is not employment-related.
gigahertz; 1 billion Hertz.
Half-wave dipole antenna – one whose length in feet is approximately 468/frequency in MHz.
- high frequency; 3–30 MHz.
Hz - Hertz; the unit for expressing frequency. One Hertz equals one cycle per second.
kHz - kilohertz; 1000 Hz.
– uniform radiation in all orientations.
Joule - The energy expended in passing an electric current of one ampere through
a resistance of one ohm for one second.
M - Meter; a length of approximately 39.37 inches.
MF - medium frequency; 300–3000
kHz. Read Section 97.3(b)(5).
- megahertz – 1 million Hertz.
MPE - maximum permissible exposure. The rms and peak electric and magnetic field strength, their squares,
or the plane-wave equivalent power densities associated with these fields to which a person may be exposed without harmful
effect and with an acceptable safety factor.
Oscillation - The repetitive variation, typically in time, of some measure about a
central value or between two or more different states.
PEP – Peak envelope power; average power supplied to the antenna
transmission line by a transmitter during one RF cycle at the crest of the modulation envelope taken under normal operating
conditions. Read Section 97.3(b)(6).
- the transmission of signals through free space by modulation of oscillating electromagnetic field waves.
Repeater - An amateur
station that simultaneously retransmits the transmission of another amateur station on a different channel or channels. Read
rms - root-mean-square; the effective value, or the value associated with joule heating, of a periodic electromagnetic
wave. Obtained by taking the square root of the mean of the squared value of a function.
RF – Radiofrequency. A rate
of oscillation in the range of about 3 kHz to 300 GHz.
Super-high frequency (range 3–30 GHz).
Station - One or more transmitters
or receivers or a combination of transmitters and receivers, including the accessory equipment, necessary at one location
for carrying on a radio-communication service, or the radio astronomy service.
Transmitter - An electronic device that generates an
RF alternating current, which when applied to an antenna, propagates RF electromagnetic field waves.
UHF - ultra-high frequency (range
300–3000 MHz). Read Section 97.3(b)(9).
- very-high frequency (range 30–300 MHz). Read Section 97.3(b)(10).
– watt; one joule per second, a measure of the rate of energy conversion.
Watt – A unit of electrical power.
Wave - A disturbance
that transfers energy from point to point.
Wavelength – Distance from crest to crest in the line of advance of a wave.
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With regard to possible excessive RF exposure, Section 97.13(c) says: Before causing or allowing an amateur station to transmit from any place where the operation of the station could cause
human exposure to RF electromagnetic field levels in excess of those allowed under Section 1.1310 of this chapter, the licensee is required to take certain actions.
(1) The licensee must perform the routine RF environmental
evaluation prescribed by Section 1.1307(b) of this chapter, if the power of the licensee's station exceeds the limits given in the following table:
Evaluation required if
power1 (watts) exceeds
VHF (all bands)
SHF (all bands)
EHF (all bands)
Repeater stations (all bands)
non-building-mounted antennas: height above ground level to lowest point of antenna <10 m
and power >500 W ERP building-mounted antennas: power >500 W ERP
= PEP input to antenna except, for repeater stations only, power exclusion is based on ERP (effective radiated power).
(2) If the routine environmental evaluation indicates that the RF electromagnetic fields could exceed the limits contained
in Section 1.1310 of this chapter in accessible areas, the licensee must take action to prevent human exposure to such RF electromagnetic fields. Further information
on evaluating compliance with these limits can be found in the FCC's OET Bulletin Number 65, “Evaluating Compliance
with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields.”
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service section of OST/OET Bulletin Number 65 says:
Operations in the Amateur Radio Service
In the FCC's recent Report and Order, certain amateur
radio installations were made subject to routine evaluation for compliance with the FCC's RF exposure guidelines. Also, amateur
licensees will be expected to demonstrate their knowledge of the FCC guidelines through examinations. Applicants for new licenses
and renewals also will be required to demonstrate that they have read and that they understand the applicable rules regarding
RF exposure. Before causing or allowing an amateur station to transmit from any place where the operation of the station
could cause human exposure to RF radiation levels in excess of the FCC guidelines amateur licensees are now required to take
certain actions. A routine RF radiation evaluation is required if the transmitter power of the station exceeds the levels
shown in Table 1 and specified in 47 CFR Section 97.13(c)(1). Otherwise the operation is categorically excluded from routine RF radiation evaluation, except as a result of a specific
motion or petition as specified in Section 1.1307(c) and (d) of the FCC's Rules, (see earlier discussion in Section 1 of this bulletin).
The Commission's Report and
Order instituted a requirement that operator license examination question pools will include questions concerning RF safety
at amateur stations. An additional five questions on RF safety will be required within each of three written examination elements.
The Commission also adopted the proposal of the American Radio Relay League (ARRL) that amateur operators should be required
to certify, as part of their license application process, that they have read and understand our bulletins and the relevant
1. Power thresholds for routine evaluation of amateur radio stations.
Wavelength Band Transmitter Power (watts)
VHF (all bands)
SHF (all bands)
EHF (all bands)
When routine evaluation of an amateur station indicates that exposure to RF fields could be in excess of the exposure limits
specified by the FCC (see Appendix A), the licensee must take action to correct the problem and ensure compliance (see Section
4 of this bulletin on controlling exposure). Such actions could be in the form of modifying patterns of operation, relocating
antennas, revising a station's technical parameters such as frequency, power or emission type or combinations of these and
In complying with the Commission's Report and Order, amateur operators should follow a policy of systematic avoidance of excessive
RF exposure. The Commission has said that it will continue to rely upon amateur operators, in constructing and operating their
stations, to take steps to ensure that their stations comply with the MPE limits for both occupational/controlled and general
public/uncontrolled situations, as appropriate. In that regard, amateur radio operators and members of their immediate household
are considered to be in a "controlled environment" and are subject to the occupational/controlled MPE limits. Neighbors
who are not members of an amateur operator's household are considered to be members of the general public, since they cannot
reasonably be expected to exercise control over their exposure. In those cases general population/uncontrolled exposure MPE
limits will apply.
In order to qualify for use of the occupational/controlled exposure criteria, appropriate restrictions on access to high RF
field areas must be maintained and educational instruction in RF safety must be provided to individuals who are members of
the amateur operator's household. Persons who are not members of the amateur operator's household but who are present temporarily
on an amateur operator's property may also be considered to fall under the occupational/controlled designation provided that
appropriate information is provided them about RF exposure potential if transmitters are in operation and such persons are
exposed in excess of the general population/uncontrolled limits.
Amateur radio facilities represent a special case for determining exposure,
since there are many possible antenna types that could be designed and used for amateur stations. However, several relevant
points can be made with respect to analyzing amateur radio antennas for potential exposure that should be helpful to amateur
operators in performing evaluations.
First of all, the generic equations described in this bulletin
can be used for analyzing fields due to almost all antennas, although the resulting estimates for power density may be overly-conservative
in some cases. Nonetheless, for general radiators and for aperture antennas, if the user is knowledgeable about antenna gain,
frequency, power and other relevant factors, the equations in this section can be used to estimate field strength and power
density as described earlier. In addition, other resources are available to amateur radio operators for analyzing fields
near their antennas. The ARRL Radio Amateur Handbook contains an excellent section on analyzing amateur radio facilities for
compliance with RF guidelines (Reference ). Also, the FCC and the EPA conducted a study of several amateur radio stations
in 1990 that provides a great deal of measurement data for many types of antennas commonly used by amateur operators (Reference
Amateur radio organizations and licensees are encouraged to develop their own more detailed evaluation models and methods
for typical antenna configurations and power/frequency combinations. The FCC is working with the amateur radio community to
develop a supplement to this bulletin that will be designed specifically for evaluating amateur radio installations. For example,
the supplement will contain information on projected minimum exclusion distances from typical amateur antenna installations.
The supplement should be completed soon after release of this bulletin. Once the amateur radio supplement is released by the
FCC it will be made available for downloading at the FCC's World Wide Web Site for "RF safety." Amateur radio applicants
and licensees are encouraged to monitor the Web Site for release of the supplement. The address is: www.fcc.gov/oet/rfsafety. Information on availability of the supplement, as well as other RF-related questions, can be directed to the FCC's "RF
Safety Program" at: (202) 418-2464 or to: email@example.com.
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FCC Opens Docket: Our regulator calls for renewed discussion on both the currency
of its RF exposure limits and possible policy approaches regarding RF exposure.
The FCC is looking forward to developing a complete record to determine whether the current rules and policies
should remain unchanged, or should be relaxed or tightened. It says:
review of the government’s rules and regulations to ensure they have kept pace with current knowledge and changing needs
is an important characteristic of good government, and we here will advance the process of providing a comprehensive review
and modification, where appropriate, of this Commission’s various rules pertaining to the implementation of the National
Environmental Policy Act (NEPA) requirements for environmental reviews, specifically those reviews related to health and safety
of radiofrequency (RF) emissions from radio transmitters.
Our actions herein are intended to ensure that our measures are compliant
with our environmental responsibilities and requirements and that the public is appropriately protected from any potential
adverse effects from RF exposure as provided by our rules, while avoiding any unnecessary burden in complying with these rules.
This document is divided into three parts: a Report and Order (Order) and a Further Notice of Proposed Rulemaking (Further
Notice) in ET Docket No. 03-137, and a Notice of Inquiry (Inquiry) in a new docket, ET Docket 13-84.
In the Order we conclude several technical and semantic issues initiated in 2003 that revise and update our regulations implementing
NEPA; in the Further Notice we propose to further update and revise our procedures and treat all services equally; and in
the Inquiry we request comment to determine whether our RF exposure limits and policies need to be reassessed. The purpose
of the Order and Further Notice is to advance ET Docket 03-137 with respect to how to demonstrate compliance with NEPA and
our RF exposure limits, but that proceeding does not reach the issue of whether our exposure limits are appropriate.
Since consideration of the limits themselves is explicitly outside of the scope of ET Docket 03-137, we propose with the Inquiry
to open a new docket to consider those limits in light of more recent developments.
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In the Order in ET Docket No. 03-137, at para. 77, our regulator says: It should be helpful to licensees to codify our earlier adopted policy with regard the use of occupational/controlled limits
at amateur radio stations. This policy was established in the RF Report and Order of 1996, but was not incorporated in the
rules at that time. It allows amateur stations to be evaluated with respect to occupational/controlled exposure limits as
long as appropriate training and information has been provided to the amateur licensee and members of his or her immediate
household. We here codify this policy be adding a paragraph to new sub section 1.1310.
3. Section 1.1310 is amended to read as follows:
§ 1.1310 Radiofrequency radiation
(a) Specific absorption rate (SAR) shall be used to evaluate
the environmental impact of human exposure to radiofrequency (RF) radiation as specified in § 1.1307(b) within the frequency
range of 100 kHz to 6 GHz (inclusive).
(b) The SAR limits for occupational/controlled exposure are 0.4
W/kg, as averaged over the whole body, and a peak spatial-average SAR of 8 W/kg, averaged over any 1 gram of tissue (defined
as a tissue volume in the shape of a cube). Exceptions are the parts of the human body treated as extremities, such as hands,
wrists, feet, ankles, and pinnae, where the peak spatial-average SAR limit for occupational/controlled exposure is 20 W/kg,
averaged over any 10 grams of tissue (defined as a tissue volume in the shape of a cube). Exposure may be averaged over a
time period not to exceed 6 minutes to determine compliance with occupational/controlled SAR limits.
(c) The SAR limits for
general population/uncontrolled exposure are 0.08 W/kg, as averaged over the whole body, and a peak spatial-average SAR of
1.6 W/kg, averaged over any 1 gram of tissue (defined as a tissue volume in the shape of a cube). Exceptions are the
parts of the human body treated as extremities, such as hands, wrists, feet, ankles, and pinnae, where the peak spatial-average
SAR limit is 4 W/kg, averaged over any 10 grams of tissue (defined as a tissue volume in the shape of a cube). Exposure may
be averaged over a time period not to exceed 30 minutes to determine compliance with general population/uncontrolled SAR limits.
(d)(1) Evaluation with respect to the SAR limits in this section must demonstrate compliance with both the whole-body and
peak spatial-average limits using technically supported measurement or computational methods and exposure conditions in advance
of authorization (licensing or equipment certification) and in a manner that facilitates enforcement. Numerical computation
of SAR must be supported by adequate documentation showing that the numerical method as implemented in the computational software
has been fully validated; in addition, the equipment under test and exposure conditions must be modeled according to protocols
established by numerical computation standards or available FCC procedures for the specific computational method.
(2) For operation within the frequency range of 300 kHz and 6 GHz (inclusive), the limits for maximum permissible exposure
(MPE), derived from whole-body SAR limits and listed in Table 1 of paragraph (e) of this section, may be used instead of whole-body
SAR limits as set forth in paragraph (a) through (c) of this section to evaluate the environmental impact of human exposure
to RF radiation as specified in § 1.1307(b), except for portable devices as defined in § 2.1093 as these evaluations
shall be performed according to the SAR provisions in § 2.1093 of this chapter
(3) At operating
frequencies above 6 GHz, the MPE limits listed in Table 1 of paragraph (e) of this section shall be used in all cases to evaluate
the environmental impact of human exposure to RF radiation as specified in § 1.1307(b).
(4) Both the MPE
limits listed in Table 1 of paragraph (e) of this section and the SAR limits as set forth in paragraph (a) through (c) of
this section are for continuous exposure, that is, for indefinite time periods. Exposure levels higher than the limits
are permitted for shorter exposure times, as long as the average exposure over the specified averaging time in Table 1 is
less than the exposure limits. Detailed information on our policies regarding procedures for evaluating compliance with
all of these exposure limits can be found in the most current edition of FCC's OET Bulletin 65, “Evaluating Compliance
with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields,” and its supplements, all available
at the FCC’s Internet Web site: http://www.fcc.gov/oet/rfsafety.
Note to Paragraphs (a) through (d): SAR is a measure of the rate of energy absorption due to exposure to RF electromagnetic
energy. These SAR limits to be used for evaluation are based generally on criteria published by the American National
Standards Institute (ANSI) for localized SAR in Section 4.2 of “IEEE Standard for Safety Levels with Respect to Human
Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz,” ANSI/IEEE Std C95.1-1992, copyright 1992 by the
Institute of Electrical and Electronics Engineers, Inc., New York, New York 10017. These criteria for SAR evaluation
are similar to those recommended by the National Council on Radiation Protection and Measurements (NCRP) in “Biological
Effects and Exposure Criteria for Radiofrequency Electromagnetic Fields,” NCRP Report No. 86, Section 17.4.5, copyright
1986 by NCRP, Bethesda, Maryland 20814. Limits for whole body SAR and peak spatial-average SAR are based on recommendations
made in both of these documents. The MPE limits in Table 1 are based generally on criteria published by the NCRP in
“Biological Effects and Exposure Criteria for Radiofrequency Electromagnetic Fields,” NCRP Report No. 86, Sections
17.4.1, 18.104.22.168, 17.4.2 and 17.4.3, copyright 1986 by NCRP, Bethesda, Maryland 20814. In the frequency range from 100
MHz to 1500 MHz, these MPE exposure limits for field strength and power density are also generally based on criteria recommended
by the ANSI in Section 4.1 of “IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic
Fields, 3 kHz to 300 GHz,” ANSI/IEEE Std C95.1-1992, copyright 1992 by the Institute of Electrical and Electronics Engineers,
Inc., New York, New York 10017.
(e) Table 1 below sets forth limits for Maximum Permissible Exposure (MPE) to
radiofrequency electromagnetic fields.
Table 1—Limits for Maximum Permissible Exposure (MPE)
Electric field strength
Magnetic field strength
Limits for Occupational/Controlled Exposure
(B) Limits for General Population/Uncontrolled Exposure
f = frequency in
MHz * = Plane-wave equivalent power density
(1) Occupational/controlled exposure limits apply in situations in which persons are exposed as a consequence of their
employment provided those persons are fully aware of the potential for exposure and can exercise control over their exposure.
Limits for occupational/controlled exposure also apply in situations when a person is transient through a location where occupational/controlled
limits apply provided he or she is made aware of the potential for exposure. The phrase fully aware in the context of applying
these exposure limits means that an exposed person has received written and/or verbal information fully explaining the potential
for RF exposure resulting from his or her employment. With the exception of transient persons, this phrase also means that
an exposed person has received appropriate training regarding work practices relating to controlling or mitigating his or
her exposure. See § 1.1307(b)(2) of this chapter. The phrase exercise control means that an exposed person is allowed
and also knows how to reduce or avoid exposure by administrative or engineering work practices, such as use of personal protective
equipment or time averaging of exposure.
(2) General population/uncontrolled exposure limits apply in situations in which the general public may be exposed,
or in which persons who are exposed as a consequence of their employment may not be fully aware of the potential for exposure
or cannot exercise control over their exposure. For example, RF sources intended for consumer use shall be subject to
the limits for general population/uncontrolled exposure in this section.
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Proposed New Rule
In the Further Notice, Section 97.13 was proposed
to read as follows:
Restrictions on station location.
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(c) * * *
(1) The licensee shall ensure compliance with the Commission's
radio frequency exposure requirements in §§ 1.1307(b), 2.1091 and 2.1093 of this chapter, where applicable. In lieu
of evaluation with the general population/uncontrolled exposure limits, amateur licensees may evaluate their operation with
respect to members of his or her immediate household using the occupational/controlled exposure limits in § 1.1310, provided
appropriate training and information has been supplied to the amateur licensee and members of his/her household. Other nearby
persons who are not members of the amateur licensee’s household must be evaluated with respect to the general population/uncontrolled
exposure limits. Appropriate methodologies and guidance for evaluating amateur radio service operation is described
in the Office of Engineering and Technology (OET) Bulletin 65, Supplement B.
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Q. What was the power rule prior to the changeover to PEP output measurement?
A. Copies of the pre-changeover
rules show the power rule formerly specifying:
Each amateur transmitter may be operated with a power input not exceeding 1 kilowatt
to the plate circuit of the final amplifier stage of an amplifier-oscillator transmitter or to the plate circuit of an oscillator
transmitter. An amateur transmitter operating with a power exceeding 900 watts to the plate circuit shall provide means for
accurately measuring the plate power input to the vacuum tube or tubes supplying power to the antenna.
So, it was 900 watts DC into a transmitter
vacuum tube plate circuit unless the transmitter had on hand the means for accurately measuring 1,000 watts. That regulation
must have been sufficient for the straightforward low-power CW and AM amplifier and amplifier-oscillator vacuum tube, measurement-deprived,
ham-built transmitters back in the day.
Q. What was the basis for 1,000 watts?
A. Possibly it was to promote a more harmonious spectrum coexistence
with early commercial radio systems. Whatever it was, the 1 kW standard took on a life of its own and became our 1,000 watt
Q. For a CW emission,
1000 watts key-down makes sense. But for AM, an ammeter measures only the carrier power. Some hams seem to recall a 2,000
watt rule for SSB, although I think that was more a rule of thumb to comply with the average power rule rather than a codified
No, the rule expressly prohibited exceeding 1,000 watts, or 900 watts if the former value could not be measured accurately.
It wasn’t until the 1950s - when hams began showing interest in SSB and other emission modes - that the need for accurately
measuring a rapidly varying DC plate current became a necessity. The advent of solid-state technology concurrently rendered
obsolete the rule exclusively for vacuum tube transmitters.
The availability of transmitter peak-envelope-power output measuring means
made possible the changeover to the present regulation: Regardless of the emission mode, no station may transmit with a transmitter power exceeding 1.5 kW PEP. So, the
point of power measurement was relocated to the transmitter RF output, away from the often-dangerous DC high voltage final
vacuum tube input. Today’s 1.5 kW PEP output limit is, therefore, more or less an artifact carried over from our 1,000
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September 25, 2015
Supersedes all prior editions