Part 15 (FCC rules)
Encyclopedia
Code of Federal Regulations
, Title 47, Part 15 (47 CFR 15) is an oft-quoted part of Federal Communications Commission
(FCC) rule
s and regulation
s regarding unlicensed
transmissions. It is a part of Title 47 of the Code of Federal Regulations (CFR), and regulates everything from spurious emission
s to unlicensed low-power broadcasting
. Nearly every electronics device sold inside the United States
radiates unintentional emissions, and must be reviewed to comply with Part 15 before it can be advertised or sold in the US market.
states that any radiator (that which emits radio energy), whether or not intentional, must be licensed unless it meets 47 CFR 15 or is otherwise exempted by the FCC.
contains definitions.
contains a general provision that devices may not cause interference and must accept interference from other sources. It also prohibits the operation of devices once the operator is notified by the FCC that the device is causing interference. prohibits intentional damped wave
transmissions, which were common before the 1920s but cut across large sections of frequencies.
prohibits operating a device under Part 15 for the purpose of eavesdropping
, except when under lawful authority of law enforcement or when all parties in a conversation consent.
s — devices for which the purpose is not to produce radio waves, but which do anyway, such as computer
s. There are 16 sections between 15.101 and 15.123.
s. Specific to broadcasting
, 15.239 deals with the FM band, while 15.221 (and 15.219) deal with the AM band.
devices from 1910 to 1930MHz.
(U-NII) devices.
(UWB) devices, including ground-penetrating radar
.
- or low-voltage
lines.
These devices include personal computer
s and peripheral devices, and electrical ballast
s for fluorescent lights.
(88 to 108 MHz) are limited to a field strength
of 250 µV/m at a distance of 3 meters from the antenna
. This is equivalent to 0.01 microwatts. Emissions must be kept within the 88.0 to 108.0 MHz band under Part 15 rules.
The FM broadcast band is limited but not restricted to 87.9 MHz (but see note below on TV) to 107.9 MHz. There are two class D FM stations on 87.9 MHz. Any unlicensed 88 to 108 MHz broadcasting with a signal strength greater than 250 µV/m at a distance of 3 m from the antenna is punishable by law and confiscation of all broadcast equipment. Low power station licenses are available to noncommercial educational entities and public safety/travellers information entities, but not individuals or commercial operations. .
Unlicensed broadcasts on the TV broadcast bands are prohibited, except for certain medical telemetry
device
s, wireless microphone
s, and other 'low power auxilliary' stations with an output or 50 mW or less. 87.5 to 88.0 MHz is considered part of the VHF
TV low band
(channel 6 analog audio is on 87.75), though it shows up on most FM tuner
s. For TV, 15.241 and 15.242 deal with high VHF
(channels 7 to 13), 15.242 also deals with UHF (band IV
and band V
).
On the standard AM broadcast band, transmission power is limited by 100 milliwatts of DC input power to the final RF stage, (with restrictions on size, height and type of antenna) or, alternatively, under 15.221, if the AM transmission originates on the campus
of an educational institution, the transmission can theoretically be any power so long as it does not exceed the field strength limits stated in 15.209 at the perimeter of the campus, 24000/fkHz µV/m.
s to intentional transmitter
s can produce unwanted radio signals and are subject to FCC regulation. For digital devices including computers and peripherals, FCC Class B is the more stringent standard, applying to equipment marketed for use in the home, even if it could be used elsewhere. Home users are likely to be annoyed by interference
to TV and radio reception. Class A is a looser standard for equipment intended only for business
, industrial and commercial settings.
Transmitters also must adhere to a spectral mask
, to prevent adjacent-channel interference
, intermediate frequency
interference, and intermodulation
.
Code of Federal Regulations
The Code of Federal Regulations is the codification of the general and permanent rules and regulations published in the Federal Register by the executive departments and agencies of the Federal Government of the United States.The CFR is published by the Office of the Federal Register, an agency...
, Title 47, Part 15 (47 CFR 15) is an oft-quoted part of Federal Communications Commission
Federal Communications Commission
The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...
(FCC) rule
Rulemaking
In administrative law, rulemaking refers to the process that executive and independent agencies use to create, or promulgate, regulations. In general, legislatures first set broad policy mandates by passing statutes, then agencies create more detailed regulations through rulemaking.By bringing...
s and regulation
Regulation
Regulation is administrative legislation that constitutes or constrains rights and allocates responsibilities. It can be distinguished from primary legislation on the one hand and judge-made law on the other...
s regarding unlicensed
License
The verb license or grant licence means to give permission. The noun license or licence refers to that permission as well as to the document recording that permission.A license may be granted by a party to another party as an element of an agreement...
transmissions. It is a part of Title 47 of the Code of Federal Regulations (CFR), and regulates everything from spurious emission
Spurious emission
A spurious emission is any radio frequency not deliberately created or transmitted, especially in a device which normally does create other frequencies...
s to unlicensed low-power broadcasting
Low-power broadcasting
Low-power broadcasting is electronic broadcasting at very low power and low cost, to a small community area.The terms "low-power broadcasting" and "micropower broadcasting" should not be used interchangeably, because the markets are not the same...
. Nearly every electronics device sold inside the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
radiates unintentional emissions, and must be reviewed to comply with Part 15 before it can be advertised or sold in the US market.
A - General
Subpart A includes 21 sections from 15.1 to 15.38.states that any radiator (that which emits radio energy), whether or not intentional, must be licensed unless it meets 47 CFR 15 or is otherwise exempted by the FCC.
contains definitions.
contains a general provision that devices may not cause interference and must accept interference from other sources. It also prohibits the operation of devices once the operator is notified by the FCC that the device is causing interference. prohibits intentional damped wave
Damped wave
A damped wave is a wave whose amplitude of oscillation decreases with time, eventually going to zero. This term also refers to an early method of radio transmission produced by spark gap transmitters, which consisted of a series of damped electromagnetic waves...
transmissions, which were common before the 1920s but cut across large sections of frequencies.
prohibits operating a device under Part 15 for the purpose of eavesdropping
Eavesdropping
Eavesdropping is the act of secretly listening to the private conversation of others without their consent, as defined by Black's Law Dictionary...
, except when under lawful authority of law enforcement or when all parties in a conversation consent.
B - Unintentional radiators
Subpart B deals with unintentional radiatorUnintentional radiator
An unintentional radiator or Incidental radiator is any device which creates radio frequency energy within itself, which is then unintentionally radiated from the device...
s — devices for which the purpose is not to produce radio waves, but which do anyway, such as computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
s. There are 16 sections between 15.101 and 15.123.
C - Intentional radiators
Subpart C deals with devices that are specifically designed to produce coherent radio waves, such as small transmitterTransmitter
In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating...
s. Specific to broadcasting
Broadcasting
Broadcasting is the distribution of audio and video content to a dispersed audience via any audio visual medium. Receiving parties may include the general public or a relatively large subset of thereof...
, 15.239 deals with the FM band, while 15.221 (and 15.219) deal with the AM band.
D - Unlicensed PCS devices
Sections 15.301 to 15.323 deal with unlicensed PCSPersonal Communications Service
At the most basic level Personal Communications Service or PCS describes a set of wireless communications capabilities that allows some combination of terminal mobility, personal mobility, and service profile management...
devices from 1910 to 1930MHz.
E - Unlicensed NII devices
15.401 to 15.407 deal with unlicensed National Information InfrastructureNational Information Infrastructure
The National Information Infrastructure was the product of the High Performance Computing and Communication Act of 1991. It was a telecommunications policy buzzword, which was popularized during the Clinton Administration under the leadership of Vice-President Al Gore...
(U-NII) devices.
F - Ultra-wideband operation
15.501 to 15.525 deal with ultra-widebandUltra-wideband
Ultra-wideband is a radio technology that can be used at very low energy levels for short-range high-bandwidth communications by using a large portion of the radio spectrum. UWB has traditional applications in non-cooperative radar imaging...
(UWB) devices, including ground-penetrating radar
Ground-penetrating radar
Ground-penetrating radar is a geophysical method that uses radar pulses to image the subsurface. This nondestructive method uses electromagnetic radiation in the microwave band of the radio spectrum, and detects the reflected signals from subsurface structures...
.
G - Access Broadband over Power Line
15.601 to 15.615 deal with broadband over power lines (BPL) devices operating in the 1.705-80 MHz band over mediumLow voltage
Low voltage when used as an electrical engineering term concerning an electricity supply grid or industrial use, broadly identifies safety considerations of the system based on the voltage used. The meaning of the term "low voltage" is somewhat different when used with regard to a more typical end...
- or low-voltage
Voltage
Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
lines.
Unintentional radiators
Unintentional radiators are designated into two major classes:- Class A Intended for use in business/industrial/commercial environments
- Class B Intended for use in (or adjacent to) residential/small office environments
These devices include personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
s and peripheral devices, and electrical ballast
Electrical ballast
An electrical ballast is a device intended to limit the amount of current in an electric circuit. A familiar and widely used example is the inductive ballast used in fluorescent lamps, to limit the current through the tube, which would otherwise rise to destructive levels due to the tube's...
s for fluorescent lights.
Unlicensed broadcasting
Unlicensed broadcasts on the FM broadcast bandFM broadcast band
The FM broadcast band, used for FM broadcast radio by radio stations, differs between different parts of the world. In Europe and Africa , it spans from 87.5 to 108.0 megahertz , while in America it goes only from 88.0 to 108.0 MHz. The FM broadcast band in Japan uses 76.0 to 90 MHz...
(88 to 108 MHz) are limited to a field strength
Field strength
In physics, the field strength of a field is the magnitude of its vector value.In theoretical physics, field strength is another name for the curvature form...
of 250 µV/m at a distance of 3 meters from the antenna
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
. This is equivalent to 0.01 microwatts. Emissions must be kept within the 88.0 to 108.0 MHz band under Part 15 rules.
The FM broadcast band is limited but not restricted to 87.9 MHz (but see note below on TV) to 107.9 MHz. There are two class D FM stations on 87.9 MHz. Any unlicensed 88 to 108 MHz broadcasting with a signal strength greater than 250 µV/m at a distance of 3 m from the antenna is punishable by law and confiscation of all broadcast equipment. Low power station licenses are available to noncommercial educational entities and public safety/travellers information entities, but not individuals or commercial operations. .
Unlicensed broadcasts on the TV broadcast bands are prohibited, except for certain medical telemetry
Telemetry
Telemetry is a technology that allows measurements to be made at a distance, usually via radio wave transmission and reception of the information. The word is derived from Greek roots: tele = remote, and metron = measure...
device
Information appliance
In general terms, an information appliance or information device is any machine or device that is usable for the purposes of computing, telecommunicating, reproducing, and presenting encoded information in myriad forms and applications....
s, wireless microphone
Wireless microphone
A wireless microphone, as the name implies, is a microphone without a physical cable connecting it directly to the sound recording or amplifying equipment with which it is associated...
s, and other 'low power auxilliary' stations with an output or 50 mW or less. 87.5 to 88.0 MHz is considered part of the VHF
Very high frequency
Very high frequency is the radio frequency range from 30 MHz to 300 MHz. Frequencies immediately below VHF are denoted High frequency , and the next higher frequencies are known as Ultra high frequency...
TV low band
Band I
Band I is the name of a radio frequency range within the very high frequency part of the electromagnetic spectrum.Band I ranges from 47 to 88 MHz, and it is primarily used for radio and television broadcasting....
(channel 6 analog audio is on 87.75), though it shows up on most FM tuner
Tuner (radio)
A radio tuner is a subsystem that receives radio broadcasts and converts them into audio-frequency signals which can be fed into an amplifier driving a loudspeaker. FM tuner, AM tuner, Digital Audio Broadcasting DAB tuner, etc. are types of radio tuner dealing with transmissions using different...
s. For TV, 15.241 and 15.242 deal with high VHF
Band III
Band III is the name of a radio frequency range within the very high frequency part of the electromagnetic spectrum.Band III ranges from 174 to 230 MHz, and it is primarily used for radio and television broadcasting...
(channels 7 to 13), 15.242 also deals with UHF (band IV
Band IV
Band IV is the name of a radio frequency range within the ultra high frequency part of the electromagnetic spectrum.Sources differ on the exact frequency range of the band. For example, the Swiss Federal Office of Communications, the Broadcast engineer's reference book and Ericsson India Ltd all...
and band V
Band V
Band V is the name of a radio frequency range within the ultra high frequency part of the electromagnetic spectrum. It is not to be confused with the V band in the extremely high frequency part of the spectrum....
).
On the standard AM broadcast band, transmission power is limited by 100 milliwatts of DC input power to the final RF stage, (with restrictions on size, height and type of antenna) or, alternatively, under 15.221, if the AM transmission originates on the campus
Campus
A campus is traditionally the land on which a college or university and related institutional buildings are situated. Usually a campus includes libraries, lecture halls, residence halls and park-like settings...
of an educational institution, the transmission can theoretically be any power so long as it does not exceed the field strength limits stated in 15.209 at the perimeter of the campus, 24000/fkHz µV/m.
Common uses of Part 15 transmitters
Frequently encountered types of "Part 15" transmitters include:- 802.11x wireless LANWireless LANA wireless local area network links two or more devices using some wireless distribution method , and usually providing a connection through an access point to the wider internet. This gives users the mobility to move around within a local coverage area and still be connected to the network...
(e.g. WiFiWIFIWIFI is a radio station broadcasting a brokered format. Licensed to Florence, New Jersey, USA, the station is currently operated by Florence Broadcasting Partners, LLC.This station was previously owned by Real Life Broadcasting...
) 2.4 GHz, 5 GHz (U-NII)
- 802.15x PANs (e.g. BluetoothBluetoothBluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
, ZigBeeZigBeeZigBee is a specification for a suite of high level communication protocols using small, low-power digital radios based on an IEEE 802 standard for personal area networks. Applications include wireless light switches, electrical meters with in-home-displays, and other consumer and industrial...
) 2.4 GHz
- Cordless phones: 900 MHz, 1.9 (U-PCS), 2.4 GHz, 5 GHz (U-NII)
- Low-power broadcastingLow-power broadcastingLow-power broadcasting is electronic broadcasting at very low power and low cost, to a small community area.The terms "low-power broadcasting" and "micropower broadcasting" should not be used interchangeably, because the markets are not the same...
, often by hobbyists, or on college or high school campuses.
- Small FM radio transmittersFM transmitter (personal device)An FM transmitter is a portable device that plugs into the headphone jack or proprietary output port of a portable audio or video device, such as a portable media player, CD player, or satellite radio system. The sound is then broadcast through the transmitter, and plays through an FM broadcast...
designed to hook to the audio output of an iPodIPodiPod is a line of portable media players created and marketed by Apple Inc. The product line-up currently consists of the hard drive-based iPod Classic, the touchscreen iPod Touch, the compact iPod Nano, and the ultra-compact iPod Shuffle...
or other portable audio device and broadcast the audio so that it can be heard through a car audioCar audioCar audio/video , auto radio, mobile audio, 12-volt and other terms are used to describe the sound or video system fitted in an automobile. While 12-volt audio and video systems are also used, marketed, or manufactured for marine, aviation, and buses, this article focuses on cars as the most common...
system that is not equipped with an audio input.
- Very low power transmitters, often referred to as "talking roadsign", "talking houses" or "talking billboards", which will air a repeating loop of highway construction, traffic, promotional or advertising information. A sign placed near the transmitter is used to entice passersby (nearly always in automobiles) to tune in. The talking house gets its name from the fact that many such transmitters are installed at houses that are up for sale, thus enabling a passerby to find out details about the interior of the house without actually touring the building. Many talking houses have been noted by DXersDXingDXing is the hobby of tuning in and identifying distant radio or television signals, or making two way radio contact with distant stations in amateur radio, citizens' band radio or other two way radio communications. Many DXers also attempt to receive written verifications of reception from the...
apparently using unauthorized power levels and antenna systems, and thus audible far beyond the limitations authorized under Part 15. The FCC has also found some of these devices to exceed their limits.
- In the United States, state departments of transportation such as the Oregon Department of TransportationOregon Department of TransportationThe Oregon Department of Transportation is a department of the state government of the U.S. state of Oregon responsible for systems of transportation. It was first established in 1969. It had been preceded by the Oregon State Highway Department which, along with the Oregon State Highway...
and the Washington State Department of TransportationWashington State Department of TransportationThe Washington State Department of Transportation , was established in 1905. The agency, led by a Secretary and overseen by the Governor, is a Washington governmental agency that constructs, maintains, and regulates the use of the state's transportation infrastructure...
often set up temporary low power radio broadcasting system near road construction worksites to inform drivers of expected delays and detourDetourDetour may refer to:* Detour, a temporary routing to avoid an obstruction-Entertainment:Literature* Detour , a 1939 novel* Detour , an entertainment and fashion magazine published by the Detour Media GroupFilm and television...
s, duration, and history of the construction project drivers are passing. These systems are set up permanently to provide traffic information near airports and concert and sports arenas.
- Some wireless microphones and headsetsHeadset (telephone/computer)A headset is headphones combined with a microphone, or one headphone with a microphone. Headsets provide the equivalent functionality of a telephone handset with hands-free operation. Headsets typically have only one speaker like a telephone, but also come with speakers for both ears...
that broadcast to a receiver which amplifies the audio. Wireless microphones allow the user to move about freely, unlike a conventional microphone, and are thus popular with musicians. Some professional wireless microphones and 'low power auxilliary' stations(including those labeled as "UHF") must be licensed under Part 74, Subpart H of the FCC's rules. However, as of January 2010, many professional wireless microphones, and other Part 74 certified 'low power auxilliary' stations with a 50 mW output or less, can be operated in the "core TV band" (TV channels 2 through 51, except 37) frequencies without a license under a waiver of Part 15 rules. This waiver is expected to become permanent.Units using the high UHF channels (700Mhz band) revoked from the TV bandplanNorth American broadcast television frequenciesThe North American broadcast television frequencies are on designated television channels numbered 2 through 69, approximately between 54 and 806 MHz. Traditionally, the frequencies are divided into two sections, the very high frequency band and the ultra high frequency band. The VHF band is...
in June 2009 became illegal to operate in June 2010.
- Toys such as the popular late-1970s Mr. Microphone and its imitators, which would broadcast the user's voice to a nearby radio receiver. Variations on this type of transmitter were advertised for sale in radio magazineMagazineMagazines, periodicals, glossies or serials are publications, generally published on a regular schedule, containing a variety of articles. They are generally financed by advertising, by a purchase price, by pre-paid magazine subscriptions, or all three...
s as far back as the 1920s.
- Walkie talkies intended for children's use, baby monitors, and some older cordless phones all operate on frequencies in the 49 MHz band (or rarely at the upper end of the AM broadcast band) and have been known to interfere with one another.
- Remote Controls for various toys, garage door openers, etc.
Spurious emissions
Electronic equipment from computerComputer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
s to intentional transmitter
Transmitter
In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating...
s can produce unwanted radio signals and are subject to FCC regulation. For digital devices including computers and peripherals, FCC Class B is the more stringent standard, applying to equipment marketed for use in the home, even if it could be used elsewhere. Home users are likely to be annoyed by interference
Interference (communication)
In communications and electronics, especially in telecommunications, interference is anything which alters, modifies, or disrupts a signal as it travels along a channel between a source and a receiver. The term typically refers to the addition of unwanted signals to a useful signal...
to TV and radio reception. Class A is a looser standard for equipment intended only for business
Business
A business is an organization engaged in the trade of goods, services, or both to consumers. Businesses are predominant in capitalist economies, where most of them are privately owned and administered to earn profit to increase the wealth of their owners. Businesses may also be not-for-profit...
, industrial and commercial settings.
Transmitters also must adhere to a spectral mask
Spectral mask
In telecommunications, a spectral mask, also known as a channel mask or transmission mask, is a mathematically-defined set of lines applied to the levels of radio transmissions. The spectral mask is generally intended to reduce adjacent-channel interference by limiting excessive radiation at...
, to prevent adjacent-channel interference
Adjacent-channel interference
Adjacent-channel interference is interference caused by extraneous power from a signal in an adjacent channel. ACI may be caused by inadequate filtering , improper tuning or poor frequency control .ACI is distinguished from crosstalk.Broadcast...
, intermediate frequency
Intermediate frequency
In communications and electronic engineering, an intermediate frequency is a frequency to which a carrier frequency is shifted as an intermediate step in transmission or reception. The intermediate frequency is created by mixing the carrier signal with a local oscillator signal in a process called...
interference, and intermodulation
Intermodulation
Intermodulation or intermodulation distortion is the amplitude modulation of signals containing two or more different frequencies in a system with nonlinearities...
.
External links
- FCC OET rules
- FCC low power broadcast rules
- FCC Public Notice Dated July 24, 1991 Covers some basic questions about Part 15 and what is considered a compliant transmission distance.
- OET Bulletin 63 Dated October 1993 and Edited and Reprinted February 1996 Covers some popular FAQ's about low-power non-licensed transmitters.
- 2005 GPO index of 47 CFR §15
- HobbyBroadcaster.net – Online technical resource and reference for AM and FM broadcasting under Part 15 regulations
- Part15.us – a popular discussion board for Part 15 broadcasting hobbyists
- Part 15 AM Radio
- Part 15 Radio Stations of North America (from Archive.org April 2006)
- The Master List of Part 15 Radio Stations of North America (from tvWiki.tv)