Low-power broadcasting
Low-power broadcasting is electronic 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...

 at very low power and low cost, to a small community area.

The terms "low-power
In electronics, the term low-power may mean:* Low-power broadcasting, that the power of the broadcast is less, i.e. the radio waves are not intended to travel as far as from typical transmitters....

 broadcasting" and "micropower broadcasting" (more commonly "microbroadcasting
Microbroadcasting is the process of broadcasting a message to a relatively small audience. This is not to be confused with low-power broadcasting....

") should not be used interchangeably, because the markets are not the same. The former term is more often used to describe stations who have applied for and received official licenses. The relationship between broadcasting power and signal range is a function of many things, such as the frequency
Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...

 band it uses e.g., Medium Wave shortwave
Shortwave radio refers to the upper MF and all of the HF portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are shorter than 200 m which marked the original upper limit of the medium frequency band first used...

 or FM
Frequency modulation
In telecommunications and signal processing, frequency modulation conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant...

, the topography
Topography is the study of Earth's surface shape and features or those ofplanets, moons, and asteroids...

 of the geographical area in which it operates (mountainous or flat), atmospheric conditions, and finally the amount of radio frequency
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...

 energy it transmits. As a general rule, the more energy a station transmits, the further its signal goes.

LPFM, LPAM, and LPTV are in various levels of use across the world, varying widely based on the law
Law is a system of rules and guidelines which are enforced through social institutions to govern behavior, wherever possible. It shapes politics, economics and society in numerous ways and serves as a social mediator of relations between people. Contract law regulates everything from buying a bus...

s and their enforcement.

FM radio

Low Power FM, or LPFM is a form of FM Broadcasting
FM broadcasting
FM broadcasting is a broadcasting technology pioneered by Edwin Howard Armstrong which uses frequency modulation to provide high-fidelity sound over broadcast radio. The term "FM band" describes the "frequency band in which FM is used for broadcasting"...

 that uses a low amount of energy to broadcast a signal that does not travel very far. FM, or frequency modulation
Frequency modulation
In telecommunications and signal processing, frequency modulation conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant...

 radio is often transmitted on a higher frequency than AM radio. Because of the low power usage and short range, LPFM is often seen as a niche radio station that plays things that relate more to the small surrounding community.

In the U.S., the 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) partially re-legalized LPFM licenses, after the National Association of Broadcasters
National Association of Broadcasters
The National Association of Broadcasters is a trade association, workers union, and lobby group representing the interests of for-profit, over-the-air radio and television broadcasters in the United States...

 (NAB), Corporation for Public Broadcasting
Corporation for Public Broadcasting
The Corporation for Public Broadcasting is a non-profit corporation created by an act of the United States Congress, funded by the United States’ federal government to promote public broadcasting...

 (CPB), and National Public Radio (NPR) convinced them to stop issuing the FM class D license in 1978.

The new LPFM licenses in the United States may only be issued to nonprofit educational organizations and state and local governments. (47 CFR 73.853) Also, the one and so far only "window" for applications closed in 2003, and at present, the FCC is not entertaining any new broadcast license
Broadcast license
A broadcast license or broadcast license is a specific type of spectrum license that grants the licensee the privilege to use a portion of the radio frequency spectrum in a given geographical area for broadcasting purposes. The licenses are generally straddled with additional restrictions that...

 applications, instead conducting auctions of frequencies for full-power uses only.

LPFM classes

  • Class L1 (LP100) is to 100 watt
    The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...

    s effective radiated power
    Effective radiated power
    In radio telecommunications, effective radiated power or equivalent radiated power is a standardized theoretical measurement of radio frequency energy using the SI unit watts, and is determined by subtracting system losses and adding system gains...

     (ERP). 47 CFR 73.811
  • Class L2 (L10) is at least 1 and up to 10 watts ERP. 47 CFR 73.811
  • Class D is 10 watts Transmitter power output
    Transmitter power output
    In radio transmission, transmitter power output is the actual amount of power of radio frequency energy that a transmitter produces at its output....

     (TPO) or less, regardless of ERP, and are no longer issued for LPFM services (since 1978).

Officially, class D is still assigned to broadcast translators, though the rules are actually much looser (up to 250 watts ERP) than for true LPFM stations, though they may not broadcast their own programming. This is due to the influence of NPR and religious broadcasting
Religious broadcasting
Religious broadcasting refers to broadcasting by religious organizations, usually with a religious message. Many religious organizations have long recorded content such as sermons and lectures, and have moved into distributing content on their Internet websites.While this article emphasises...

 companies, which often rely on translators. Since true class D stations can bump translators, they therefore have less competition in getting or keeping their own translators on the air with new class D stations kept off the air.

New classes L1 and L2 are still considered amateur class D for international purposes, but are considered to be equal in status to translators, and subordinate to full-class D stations still operating.

Broadcast Auxiliary-Low Power stations are authorized in the frequency band 76–88 MHz; however, such stations must remain 129 kilometres (80.2 mi) or more distant from any other Part 73 Broadcast Station or LPTV/TV Translator station on Channel 6 if using the 87.8 to 88.0 MHz segment of the band. [] Therefore, these particular stations authorize the use of FM Channel 200 (87.9 MHz). Such stations permit transmissions of live broadcast events. [] To qualify, you must own another broadcast station, or produce TV/motion picture programming (which, with the proliferation of online TV Webcasting, is not difficult). [] Power is limited to 50 milliwatts (1/20th of 1 watt). [] These stations are licensed through the FCC's Wireless Telecommunications Bureau online by accessing ULS. There are equipment requirements in the FCC's rules, but none are too daunting for the typical citizen with an average level of income and savings. Unusual antennas are not allowed; however, gain antennas (up to about 6 db/D gain) are permitted under the rules. The license fee is currently $135 for a 4–8 year term license. Such stations are NOT restricted to filing windows, so a qualified applicant could be licensed at any time. As of January 22, 2010 Low Power Broadcast Auxilliary Stations using the 'Core TV Bands' (Ch.2-51) are permitted to be operated without a license under a waiver of Part 15 rules, although they are required to follow certain technical rules that are proposed to become permanent. These stations are not protected from interference by other broadcast entities under Parts 73 or 74 of the FCC's rules, and are not protected from interference by the Part 15 transmitters described below.

Part 15 rules are quite strict for FM, making it nearly impossible to operate a legally-unlicensed station that can be heard more than a few yards away. One manufacturer's online guidelines show that an average FM receiver can receive a legal Part 15 FM stereo transmitter over 1000 feet away, barring interference from walls, geography, etc. The rule is a signal strength
Signal strength
In telecommunications, particularly in radio, signal strength refers to the magnitude of the electric field at a reference point that is a significant distance from the transmitting antenna. It may also be referred to as received signal level or field strength. Typically, it is expressed in...

 of 250 µV/m at 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...

 within the band 88 to 108 MHz, set forth in . Radiating cable antenna systems do allow for longer, if still narrow, radiated fields and are commonly used for building broadcast systems (stadiums, dormitories, apartments, etc...) with high success. Such systems are also used for specialized audiences for hearing assistance and language translation at events. Some communities have attempted to have multiple Part 15 stations align to form a sort of neighborhood "syndication" and legally increase the outreach, but it becomes impractical in light of the new technologies that allow for information to reach a wider audience more efficiently.
Radio Act of 1912

The Radio Act of 1912
Radio Act of 1912
The Radio Act of 1912 is a United States federal law that mandated that all radio stations in the US be licensed by the federal government, as well as mandating that seagoing vessels continuously monitor distress frequencies....

 required all amateur radio operators to be licensed and outlawed their ability to transmit over main commercial and military wavelengths. It also required all seafaring vessels to maintain 24 hour radio watch and maintain contact with ships and coastal radio stations in the area. This act set a model for international and federal legislation of wireless communications. This act also required all nonprofessional radio operators to obtain a license and forbid them from transmitting over the main commercial and military wavelengths.
The Radio Act of 1912 also prevented the Marconi Company
Marconi Company
The Marconi Company Ltd. was founded by Guglielmo Marconi in 1897 as The Wireless Telegraph & Signal Company...

 from dominating and dictating the activities of the people who used its equipment (this company had been forcing operators to refuse to communicate with those who had purchased and were using other companies' equipment).
The Radio Act of 1927

The Radio Act of 1927 placed most of the responsibility for radio to a newly developed Federal Radio Commission. The Federal Radio Commission
Federal Radio Commission
The Federal Radio Commission was a government body that regulated radio use in the United States from its creation in 1926 until its replacement by the Federal Communications Commission in 1934...

 now had the most control over regulating radio broadcasting. This act showed Congress's acknowledgment of broadcasters' right to "free speech", allowing stations to be free of government censorship and/or government programming. In addition, the broadcaster gained responsibility for their own operation and the government could not legally interfere unless the operator had been failing to meet the standard of public interest. All in all, the Radio Act of 1927 set up licensing and frequency allotment networks for commercial radio stations.
Communications Act of 1934

The Communications Act of 1934
Communications Act of 1934
The Communications Act of 1934 is a United States federal law, enacted as Public Law Number 416, Act of June 19, 1934, ch. 652, 48 Stat. 1064, by the 73rd Congress, signed by President Franklin D. Roosevelt, codified as Chapter 5 of Title 47 of the United States Code, et seq. The Act replaced the...

 established the 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). The Federal Communications Commission now oversees the licensing of all Low Power Broadcasting Stations.

Public Broadcasting Act of 1967

The Public Broadcasting Act of 1967
Public Broadcasting Act of 1967
The Public Broadcasting Act of 1967 set up public broadcasting in the United States, establishing the Corporation for Public Broadcasting, and eventually the Public Broadcasting Service and National Public Radio .When Lyndon B...

 was established by President Lyndon B. Johnson on November 7, 1967 to create the Corporation for Public Broadcasting
Corporation for Public Broadcasting
The Corporation for Public Broadcasting is a non-profit corporation created by an act of the United States Congress, funded by the United States’ federal government to promote public broadcasting...

, the Public Broadcasting Service
Public Broadcasting Service
The Public Broadcasting Service is an American non-profit public broadcasting television network with 354 member TV stations in the United States which hold collective ownership. Its headquarters is in Arlington, Virginia....

 (PBS) and National Public Radio (NPR). Congress declared the Act to be in the "public interest to encourage the growth and development of public radio and television broadcasting. In the 1950s and 1960s, arts and education were often ignored by commercial radio and television producers. Independent, non-profit radio and television stations worked to provide arts education and education broadcasts but they often didn't have the funding. In 1965 the Carnegie Corporation, Ford Foundation and locally owned broadcasting stations lobbied congress to provide the funding for public broadcasting. The goal of the Public Broadcasting Act is to address the entertainment need of audiences like children and minorities and to nationally distribute high quality radio and television programs that provide education and arts education. Because the Corporation for Public Broadcasting is federally funded,the Corporation is not permitted to schedule, produce or dessiminate programs. This prevents federal agencies from interfeering with the Corporation or the programming. The Corporation for Public Broadcasting must conform to the annual federal budgeting and appropriation process, making adequate funding an issue for the Corporation. This act has been amended several times since 1967.
Telecommunications Act of 1996

The Telecommunications Act of 1996
Telecommunications Act of 1996
The Telecommunications Act of 1996 was the first major overhaul of United States telecommunications law in nearly 62 years, amending the Communications Act of 1934. This Act, signed by President Bill Clinton, was a major stepping stone towards the future of telecommunications, since this was the...

 was implemented in order to foster competition between the firms in the Telecommunications Sector including those stations of LPFM. Reed Hundt, the FCC chair at the time, said that the FCC imposed the act to encourage “diversity in programming and diversity in the viewpoints expressed on this powerful medium that so shapes our culture.” The act “mandates interconnection of telecommunications networks, unbundling, non-discrimination, and cost-based pricing of leased parts of the network.” However the act relies upon the behaviors of companies to do what is in their best interest and does not enforce punishment towards firms that do not abide by the act. Furthermore research suggests that the Act has led to “less competition, fewer viewpoints, and less diversity in programming.”
Foundation of LPFM
  • Jan. 2000: FCC established new class of stations called Low Power FM (LPFM) Stations. These stations were allowed to operate at 1–10 or 50–100 watts of power (compared to the minimum requirement for commercial stations at 100 watts. 47 CFR 73.211)
  • Originally it was supported by activists, music artists (such as Bonnie Raitt
    Bonnie Raitt
    Bonnie Lynn Raitt is an American blues singer-songwriter and a renowned slide guitar player. During the 1970s, Raitt released a series of acclaimed roots-influenced albums which incorporated elements of blues, rock, folk and country, but she is perhaps best known for her more commercially...

    ), church leaders, and educators (for example, American Library Association
    American Library Association
    The American Library Association is a non-profit organization based in the United States that promotes libraries and library education internationally. It is the oldest and largest library association in the world, with more than 62,000 members....

    , Communication Workers of American labor union, National League of Cities
    National League of Cities
    The National League of Cities is an American advocacy organization representing 19,000 cities, towns, and villages, and encompassing 49 state municipal leagues....

    , United Church of Christ
    United Church of Christ
    The United Church of Christ is a mainline Protestant Christian denomination primarily in the Reformed tradition but also historically influenced by Lutheranism. The Evangelical and Reformed Church and the Congregational Christian Churches united in 1957 to form the UCC...

  • Original purpose of LPFM, as described in J&MC Quarterly Journal, as "... Necessary to offset the growing consolidation of station ownership in the wake of the Telecommunications Act of 1996, which removed caps on radio ownership, as well as the decline of locally produced radio programming." (Stavisky, Alan G., Robert K. Avery, and Helena Vanhala. "From Class D to LPFM: The High-Powered Politics of Low-Power Radio." Journalism & Mass Communication Quarterly 78 (2001): 340–54.)
  • Main opposition came from National Association of Broadcasters
    National Association of Broadcasters
    The National Association of Broadcasters is a trade association, workers union, and lobby group representing the interests of for-profit, over-the-air radio and television broadcasters in the United States...

     (NAB). The reason behind their opposition to the act was to "maintain spectrum integrity" for commercial broadcasting, according to NAB President Edward O. Fritts (Stavisky, Alan G., Robert K. Avery, and Helena Vanhala. "From Class D to LPFM: The High-Powered Politics of Low-Power Radio." Journalism & Mass Communication Quarterly 78 (2001): 340–54.).

Radio Broadcasting Preservation Act of 2000
  • Pressure from National Association of Broadcasters urged Congress to slip the Radio Broadcasting Preservation Act of 2000 into a general spending bill that circulated through Congress. In December 2000, President Clinton signed the bill, albeit reluctantly.
  • Here is a copy of the actual bill that went through Congress.
  • This act was meant to tighten standards for LPFM stations, in an effort to make it harder for stations to be approved in order to protect full-power FM stations.

  1. The FCC has the ability and jurisdiction to license LPFM stations.
  2. Third adjacent channel interference protections require LPFM stations to be separated by at least 0.6 MHz from all other stations with the intent of preventing signal interference.
  3. Applicants who have engaged in the unlicensed operation of any station cannot receive LPFM licenses.
  4. The FCC agreed to commission studies on the interference effects and economic impact of LPFM on full-power stations. (The findings, later published in the MITRE Corporation Report, suggest that third adjacent channel interference protections may not be necessary.)

  • Basically, this act shifts policy making from the FCC to Congress, which was considered an insult against the FCC. (Stavisky, Alan G., Robert K. Avery, and Helena Vanhala. "From Class D to LPFM: The High-Powered Politics of Low-Power Radio." Journalism & Mass Communication Quarterly 78 (2001): 340–54.)

Local Community Radio Act of 2005
  • Introduced by U.S. Senators John McCain
    John McCain
    John Sidney McCain III is the senior United States Senator from Arizona. He was the Republican nominee for president in the 2008 United States election....

    , Maria Cantwell, Patrick Leahy
  • After the FCC complied with the provisions of the Radio Broadcasting Act of 2000 by commissioning the MITRE Report to test if there was significant interference from LPFM stations on the full-power stations, the study showed that the interference of LPFM is minimal and won't have a significant effect on other stations.
  • According to Sen. Leahy, "This bill will open up the airwaves to truly local broadcasting while protecting full-power broadcasters from unreasonable interference and preserving important services such as reading services for the blind."

Local Community Radio Act of 2007

Sponsored in the U.S. House of Representatives by Congressmen Mike Doyle and Lee Terry
Lee Terry
Lee Raymond Terry is the U.S. Representative for , serving since 1999. He is a member of the Republican Party.A lifelong Nebraskan, Congressman Lee Terry has worked continually to empower the people of the Second District. Terry has been a leader for Nebraska, advocating American energy...

 and in the U.S. Senate by Senators Maria Cantwell
Maria Cantwell
Maria E. Cantwell is the junior United States Senator from the state of Washington and a member of the Democratic Party....

 and John McCain
John McCain
John Sidney McCain III is the senior United States Senator from Arizona. He was the Republican nominee for president in the 2008 United States election....

 the Local Community Radio Act of 2007 failed to be voted on. The House bill, H.R. 2802, was referred to the Subcommittee on Telecommunications and the Internet on June 21, 2007. Since the bill was not passed in FY 2007, the bill was removed from the docket as Never Passed.
Local Community Radio Act of 2009

This bill is an update of the Local Community Radio Act of 2007. It will require FCC to alter current rules in order to get rid of the minimum distance separation between low-power FM stations and third-adjacent channel stations. Previously, there had been a minimum distance requirement, however the FCC found that LPFM stations did not cause any interference on third-adjacent channel stations, thus eliminating the need for such a requirement.

The Local Community Radio Act of 2009 also requires that the FCC keep the rules that offer interference protection to third-adjacent channels that offer a radio reading service
Radio reading service
A radio reading service or reading service for the blind is a service of many universities, community groups and public radio stations, where a narrator reads books, newspapers and magazines aloud for the benefit of the blind and vision-impaired. It is most often carried on a subcarrier, with...

 (the reading of newspapers, books or magazines for those who are blind or hearing impaired.) This protection will ensure that such channels are not subject to possible interference by LPFM stations.

The final part of the bill requires that when giving out licenses to FM stations, the FCC must make sure that these licenses are also available to LPFM stations and that licensing decisions are made with regard to local community needs.

The bill had unanimous bipartisan support from FCC leadership. It was passed by the House and referred to the Senate.
Local Community Radio Act of 2010

The Local Community Radio Act of 2010 (based upon legislation originally introduced in 2005) was signed into law by President Obama on January 4, 2011 as , after passage in the House on December 17, 2010, and the U.S. Senate on December 18, 2010. In a statement after the bill became law, Federal Communications Commission Chair Julius Genachowski said, "Low power FM stations are small, but they make a giant contribution to local community programming. This important law eliminates the unnecessary restrictions that kept these local stations off the air in cities and towns across the country." The Act states the following: The Federal Communications Commission, when licensing new FM translator stations, FM booster stations, and low-power FM stations, shall ensure that--
(1) licenses are available to FM translator stations, FM booster stations, and low-power FM stations;
(2) such decisions are made based on the needs of the local community; and
(3) FM translator stations, FM booster stations, and low-power FM stations remain equal in status and secondary to existing and modified full-service FM stations.
In General- The Federal Communications Commission shall modify its rules to eliminate third-adjacent minimum distance separation requirements between--
(1) low-power FM stations; and
(2) full-service FM stations, FM translator stations, and FM booster stations.

Arguments for LPFM

  • Freepress.net is a "national, nonpartisan organization working to reform the media. Through education, organizing and advocacy, we promote diverse and independent media ownership, strong public media, and universal access to communications." Freepress.net supports LPFM for a variety of reasons:
    • It strengthens community identity.
    • It creates an outlet for amateur musicians to get their music heard.
    • It creates diversity on the air because women and racial minorities are represented.
    • It creates an opportunity for young people, especially college students, who are interested in radio to learn about the business.
    • It provides farmers with up to date agricultural information.

  • Prometheus Radio Project is a non-profit organization that "builds, supports, and advocates for community radio stations which empower participatory community voices and movements for social change."
    • The media should not limit democratic participation but should provide a way for communities and movements to express themselves
    • Public airwaves shouldn't be concentrated in private/corporate hands
    • Low Power FM gives a voice to communities
    • Low Power FM needs to be protected from big broadcasters

  • A NY Times article focusing on a LPFM station called KOCZ highlights a number of key arguments for LPFM:
    • "In Louisiana, a large African-American community appreciate how LPFM plays a genre of music called zydeco, a potent blend of Cajun, rhythm and blues and, among a younger generation, hip-hop, often features accordion and washboard.“
    • LPFM influences commercial radio to offer listeners a wider range of music. “Commercial stations had started playing more zydeco since KOCZ started broadcasting in 2002. 'They know that we make them better,' an advocate said.”
    • Because LPFM is non-commercial, schools and organizations are able to promote many community service-related projects that help better the local neighborhood. "KOCZ is licensed to the Southern Development Foundation, a civil rights group that grants scholarships and runs a business incubator but has fallen on hard times. The foundation treats the station as a 24-hour form of community outreach. "
    • LPFM promotes a very close community. "A woman walked into the station ... asked for an announcement to be broadcast about her lost dog... 'She was able to get her dog back the next day’”
    • LPFM is crucial for small communities in times of emergencies. “A low power FM radio station can stay on the air even if the power goes out. Low power FM saved lives during Katrina.”

  • President Bill Clinton is a known advocate of LPFM saying it is "giving voice to the voiceless" including schools, community groups, churches, and ethnic groups.

  • Brown Paper Tickets CEO Steve Butcher supports LPFM, stating in a letter to the FCC, "We hear from event producers frequently who can't afford radio ad buys on commercial stations. These local entrepreneurs can afford underwriting on smaller stations that can help build awareness about their events."

  • An average FM station can cost a million dollars and only businesses and very wealthy people can afford it. LPFM stations are affordable. An antenna and transmitter can cost $2000–$5000.

Arguments against LPFM

  • Signal Interference on FM Station: High-power FM stations express concern that LPFM stations may cause interference with their signals if third adjacent channel interference protections are not observed. While the Mitre Report suggests that the likelihood for interference is not as threatening as previously thought, high-power FM stations question the methodology, scope and validity of the study and its results.

  • FM translators: These devices allow a radio station to rebroadcast its signal to reach a greater area. FM translators could benefit religious broadcasters wishing to reach a larger audience, as well as many AM radio stations who, due to ionospheric refraction
    Ionospheric reflection
    Ionospheric reflection is a bending, through a complex process involving reflection and refraction, of electromagnetic waves propagating in the ionosphere back toward the Earth....

    , are required to emit weaker signals during the night. FM translators are low-power, so compete with LPFM for limited space on the airwaves.

  • In some states, the local Department of Transportation
    Department of Transportation
    The Department of Transportation is the most common name for a government agency in North America devoted to transportation. The largest is the United States Department of Transportation, which oversees interstate travel. All U.S. states, Canadian provinces, and many local agencies also have...

     operates large networks of LPFM stations that act as highway advisory radio
    Highway advisory radio
    Travelers Information Radio Stations , are sometimes also called Highway Advisory Radio Stations by Departments of Transportation in the United States. These radio stations are licensed low-power AM radio stations set up by local transport departments to provide bulletins to motorists and other...

     stations—a service traditionally operated at the fringes of the AM
    Amplitude modulation
    Amplitude modulation is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent...

     band—restricting the number of available channels. (These systems can be licensed to the entire AM band, but the LPFM service provides considerably greater coverage at 100w than the 10w limit on AM—hence the considerable appeal for government agencies).

  • Some investors in radio believe LPFM services prevent the development of digital radio
    Digital radio
    Digital radio has several meanings:1. Today the most common meaning is digital radio broadcasting technologies, such as the digital audio broadcasting system, also known as Eureka 147. In these systems, the analog audio signal is digitized into zeros and ones, compressed using formats such as...


  • NPR is one opponent to low power FM.. Their stance is that allowing more flexible rules for LPFM would burden other stations by forcing them to deal with interference problems and because of the fact that full-power broadcasters reach a broader audience and provide a greater service, they should be favored regarding spectrum availability.

  • NAB is the other major source of opposition. Their stance is that full-power FM broadcasters “enhance localism” by providing community responsive information such as emergency information. Allowing low power FM stations to have equal spectrum rights could be detrimental to these necessary programs.

LPFM vs. broadcast translators

Unlike the former FM class D license, an LPFM station has no priority over broadcast translators in the allocation of available spectrum. This is problematic insofar as a loophole in the regulations for broadcast translators exempts non-commercial stations from the requirement that translators be within the coverage area of the original station that they rebroadcast.

An FCC licensing window for new translator applications in 2003 resulted in over 13,000 applications being filed, most of them coming from a few religious broadcasters. Although many believe that these broadcasters were exploiting a loophole allowing non-commercial stations to feed distant translators from satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....

-delivered programming hundreds or even thousands of miles outside the parent station's coverage area, this is incorrect. Except for local fill-in translators and those located on channels 201–220, all translators on commercial frequencies must be fed by a direct, over-the-air source, regardless of who owns the translator per FCC rule 74.1231(b). One station cannot apply for hundreds or thousands of translators nationwide, using automated means to generate license applications for all available channels, unless all of their applications are exclusively on the non-commercial part of the broadcast band (88–91.9 MHz). (47 CFR 74.1231(b)) As with any new service that shares the FM spectrum, when translators are added to an area, they can reduce or eliminate the availability of channels both for new LPFM applicants and for relocation of any existing LPFM stations displaced by full-service broadcasters.

Unlike an LPFM station, a translator is not required to (and legally not authorized to) originate any local content except as permitted by 47 CFR 74.1231(g).

AM radio

LPAM is generally not licensed in the U.S.. There are several manufacturers of "Part 15" AM transmitters with a power of about 0.1 watt. Higher output powers are allowed within the campus of any school, so long as the normal Part 15 rules are adhered to when measured at the edge of the campus. Many currently licensed college radio
Campus radio
Campus radio is a type of radio station that is run by the students of a college, university or other educational institution. Programming may be exclusively by students, or may include programmers from the wider community in which the radio station is based...

 stations started out this way. Stations may have freestanding radio antennas, or may use carrier current
Carrier current
Carrier current is a method of low power AM radio transmission that uses the AC electrical system of a building to propagate a medium frequency, AM signal to a relatively small area, such as a building or a group of buildings...

 methods to ride on power line
Electric power transmission
Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...

s. These signals cannot pass through transformer
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field...

s, however, and are prone to the electromagnetic interference
Electromagnetic interference
Electromagnetic interference is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source. The disturbance may interrupt, obstruct, or otherwise degrade or limit the effective performance of the circuit...

 of the alternating current
Alternating current
In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....

. Stations may also use 'leaky' or radiating cable transmission systems. Tens of thousands of these stations have been in operation around the country since the 1940s, and many continue to thrive where conventional licensing is unavailable and the operators still desire to conform to Federal laws.

The exception is Travelers' Information Stations (TIS), sometimes also called highway advisory radio
Highway advisory radio
Travelers Information Radio Stations , are sometimes also called Highway Advisory Radio Stations by Departments of Transportation in the United States. These radio stations are licensed low-power AM radio stations set up by local transport departments to provide bulletins to motorists and other...

 (HAR). These are licensed LPAM stations set up by local transport departments to provide bulletins to motorists and other travelers regarding traffic and other delays. These are often near highways and airports, and occasionally other tourism attractions such as national park
National park
A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or...

s. Only governments may have licenses for TIS/HAR stations, and music is disallowed. These operate under FCC Part 90.242 and may be licensed by quasi-governmental agencies as well (many are used by chemical and nuclear facilities for emergency evacuation information systems) as well as by public safety entities for mobile operations.


There are more than 2,450 licensed LPTV stations in the U.S. and they are in markets of all sizes, from New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...

 (5 stations) down to Junction City, Kansas
Junction City, Kansas
Junction City is a city in and the county seat of Geary County, Kansas, United States. As of the 2010 census, the city population was 23,353. Fort Riley, a major U.S. Army post, is nearby...

 (2 stations).

LPTV (-LP) is common in the U.S., Canada and most of the Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...

 where most stations originate their own programming. Stations that do not originate their own programming are designated as translators (-TX). The Community Broadcasters act of 1998 directed the FCC to create classification of LPTV licenses called Class A
Class A television service
The class A television service is a system for regulating some low-power television stations in the United States. Class A stations are denoted by the broadcast callsign suffix "-CA" or "-CD" , although very many analog -CA stations have a digital companion channel that was assigned the -LD...

 (-CA). Digital low power and Class-A television stations have an ERP limit of 3000(3KW) watts for VHF, and 15 kilowatts for UHF.

The LPTV service is considered a secondary service by the FCC, which means the licensee is not guaranteed protection from interference or displacement. An LPTV station must accept harmful interference from full-service television stations and may not cause harmful interference to any full-service television station. (The FCC defines what interference levels are deemed to be "harmful".) The problem with potential displacement was made evident during the transition of broadcasting in the United States from analog to digital. All television stations operating on channels 52 and above were required to move to channel 51 or below. Full-service stations were guaranteed a place to land in the new compressed band while LPTV stations operating on channels 52 and above were forced to find their own channel to move to. If a station was not able to find a displacement channel it runs the risk of losing its license.

Class A LPTV stations

The FCC provided for a one-time filing opportunity for existing LPTV stations to become Class A stations. The designation was available only to those LPTV stations that were producing two hours per week of local programming. Class A status provides for protected channel status and Class A stations are required to produce two hours per week of local programming, maintain a production studio within their Grade B contour, and comply with many of the requirements placed on full-service television stations.


One of the key distinctions between full-service television stations and low-power stations is cable TV and Direct Broadcast Satellite
Direct broadcast satellite
Direct broadcast satellite is a term used to refer to satellite television broadcasts intended for home reception.A designation broader than DBS would be direct-to-home signals, or DTH. This has initially distinguished the transmissions directly intended for home viewers from cable television...

 (DBS) carriage. Full-service stations are guaranteed carriage in their local DMA through "must-carry
In cable television, governments apply a must-carry regulation stating that locally-licensed television stations must be carried on a cable provider's system.- Canada :...

" and LPTV stations are not. In 2008 there was an effort put forward by FCC Chairman Kevin Martin to grant must-carry rights to Class A LPTV stations. The effort failed due to a lack of support from the other FCC Commissioners.

Network affiliates

Though many low-power TV stations are either unaffiliated, or broadcast programming from small networks meant for their use, some LPTV stations are affiliated with major broadcast networks like Fox
Fox Broadcasting Company
Fox Broadcasting Company, commonly referred to as Fox Network or simply Fox , is an American commercial broadcasting television network owned by Fox Entertainment Group, part of Rupert Murdoch's News Corporation. Launched on October 9, 1986, Fox was the highest-rated broadcast network in the...

, The CW
The CW Television Network
The CW Television Network is a television network in the United States launched at the beginning of the 2006–2007 television season. It is a joint venture between CBS Corporation, the former owners of United Paramount Network , and Time Warner's Warner Bros., former majority owner of The WB...

 or My Network TV. Examples include in Youngstown, Ohio
Youngstown, Ohio
Youngstown is a city in the U.S. state of Ohio and the county seat of Mahoning County; it also extends into Trumbull County. The municipality is situated on the Mahoning River, approximately southeast of Cleveland and northwest of Pittsburgh, Pennsylvania...

, where a pair of LPTV stations based at WYFX
WYFX-LD is the Fox-affiliated television station for the Mahoning Valley of Northeastern Ohio, licensed to Youngstown. It broadcasts a low-powered digital signal UHF channel 19 from a transmitter on Sunset Boulevard in Boardman Township. Owned by New Vision Television, the station is sister to CBS...

 broadcast Fox programming, along with the digital subchannel
Digital subchannel
In broadcasting, digital subchannels are a means to transmit more than one independent program at the same time from the same digital radio or digital television station on the same radio frequency channel. This is done by using data compression techniques to reduce the size of each individual...

 of the co-owned CBS
CBS Broadcasting Inc. is a major US commercial broadcasting television network, which started as a radio network. The name is derived from the initials of the network's former name, Columbia Broadcasting System. The network is sometimes referred to as the "Eye Network" in reference to the shape of...

 affiliate, WKBN-TV
WKBN-TV is the CBS-affiliated television station for Youngstown, Ohio. It broadcasts a high definition digital signal on UHF channel 41 from a transmitter at WKBN's studios on Sunset Boulevard in Boardman Township. Owned by New Vision Television, WKBN is sister to and shares studios with low-power...

, or in the Lima, Ohio
Lima, Ohio
Lima is a city in and the county seat of Allen County, Ohio, United States. The municipality is located in northwestern Ohio along Interstate 75 approximately north of Dayton and south-southwest of Toledo....

 area, whose low-power stations are affiliates of major networks, such as NBC
The National Broadcasting Company is an American commercial broadcasting television network and former radio network headquartered in the GE Building in New York City's Rockefeller Center with additional major offices near Los Angeles and in Chicago...

 and ABC
American Broadcasting Company
The American Broadcasting Company is an American commercial broadcasting television network. Created in 1943 from the former NBC Blue radio network, ABC is owned by The Walt Disney Company and is part of Disney-ABC Television Group. Its first broadcast on television was in 1948...


Digital transition

The FCC has not set a date (as of November 2008) whereby LPTV stations are required to convert to digital broadcasting. Therefore LPTV stations are exempt from the June 12, 2009 deadline to cease analog transmissions. The FCC did open a filing window for existing LPTV stations to file for a secondary digital channel to operate in parallel of its analog channel.

Unlike FM and AM, unlicensed use of TV bands is prohibited for broadcasting. The amateur television
Amateur television
Amateur television is the transmission of Broadcast quality video and audio over the wide range of frequencies of allocated for Radio amateur use. ATV is used for non-commercial experimentation, pleasure and public service events...

 channels do allow for some very limited non-entertainment transmissions however, with some repeater
A repeater is an electronic device that receives asignal and retransmits it at a higher level and/or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances.-Description:...

s airing NASA TV
NASA TV is the television service of the United States government agency NASA. NASA TV is broadcast by satellite with a simulcast over the Internet. Local cable television systems across the U.S. and amateur television repeaters may carry NASA TV at their discretion, as NASA-created content is...

 during Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...

Space exploration
Space exploration is the use of space technology to explore outer space. Physical exploration of space is conducted both by human spaceflights and by robotic spacecraft....

s when they are not in local use.

The Low Power Television industry was represented by the Community Broadcasters Association (CBA), which held its annual convention each year in October and an annual meeting each year in April at the National Association of Broadcasters Convention in Las Vegas. The meeting was always held on Monday night of the NAB convention in Ballroom B of the Las Vegas Hilton and was open to anyone interested in the Low Power Television industry. On August 13, 2009, the CBA announced in a statement that it would shut down after 20 years of representing LPTV stations. One reason given was the "restrictive regulations that kept the Class A and LPTV industry from realizing its potential". Another was the inability to reach most viewers, partly due to Multichannel Video Programming Distributor
Multichannel Video Programming Distributor
A multichannel video programming distributor is a service provider delivering video programming services, usually for a subscription fee...

s refusing to carry these channels. Also, Amy Brown, former CBA executive director, said, "some 40% of Class A and LPTV station operators believe they will have to shut down in the next year if they are not helped through the digital transition."


In February 2006, the FCC released its Notices of Proposed Rules for Digital Radio. The Commission reaffirms its commitment to provide broadcasters with the opportunity to take advantage of digital audio broadcasting
Digital audio broadcasting
Digital Audio Broadcasting is a digital radio technology for broadcasting radio stations, used in several countries, particularly in Europe. As of 2006, approximately 1,000 stations worldwide broadcast in the DAB format....

 (DAB) technology, proposed criteria for evaluating models and systems, such as the In Band On Channel (IBOC) system, and inquired on the needs for a mandatory DAB transmission standard.

In section 39 of the Notice, the FCC inquires as how to balance incentives for broadcasters to switch to digital systems with incumbents of new entrance opportunities, stating that they “seek analyses of the minimum power levels that would preserve service within protected service areas in an all-digital environment, and alternatively, the levels that would not result in significant disruptions to current listening patterns.”

The DAB system that has been identified as the best fit for LPFM is IBOC system. This is a hybrid system that uses existing frequencies and can operate carrying digital information along with analog broadcast signal on the sidebands. However, the digital carriers require the bandwidth to be widened, which would cause interference to stations on the first adjacent channel. If LPFM adopts IBOC, then LPFM would also need to accept a second adjacent channel restriction between two LPFM stations, as there is a potential that the sidebands of two LPFM stations would overlap causing interference. Currently, imposing a second adjacent channel restriction would impact less than 10 LPFM stations.


Radio communications in Canada are regulated by a branch of Industry Canada
Industry Canada
Industry Canada is the department of the Government of Canada with responsibility for regional economic development, investment, and innovation/research and development. The department employs 6104 FTEs across Canada....

 called Radio Communications and Broadcasting Regulatory Branch together with Canadian Radio-television and Telecommunications Commission (CRTC). This means, interested parties must apply for both a certificate from Industry Canada and a license from CRTC in order to operate a radio station. Industry Canada manages the technicalities of spectrum space and technological requirements whereas content regulation is conducted more so by CRTC.

LPFM is broken up into two classes in Canada, Low (50w) and Very Low (10w). The transmitters therefore range from 1-50 watts, as opposed to 1-100 watts in the U.S. As of 2000, 500 licenses (very low and low power FM) have been issued. These transmitters are generally only allowed in remote areas.

The regulation of spectrum space is strict in Canada, as well having restrictions on 2nd and 3rd adjacent channels along with other protections for AM and FM commercial radio. In addition, because there have been a few cases that found that FM frequencies have caused interference to the aeronautical navigation and communications (NAV/COM) spectrum, (though evidence is not very concrete presently) pirate radio regulation has remained very strict as well. However, the two regulating bodies do have certain exemptions. For example, low power announcement transmitters that meet the requirement of Broadcasting Equipment Technical Standards 1, Limited Duration Special Events Distribution Undertakings, Temporary Resource Development Distribution Undertakings, and Public Emergency Radio Undertakings are a few instances, which according to certain criteria, may be exempt from certificate/license requirements.

United Kingdom

Temporary low-power stations are allowed at times via a Restricted Service Licence
Restricted Service Licence
A UK Restricted Service Licence , is typically granted to radio stations and television stations broadcasting within the UK to serve a local community or a special event...


Since 2001 longterm LPFM licences have been available in remote areas of the country. These are currently used for many establishments including military base
Military base
A military base is a facility directly owned and operated by or for the military or one of its branches that shelters military equipment and personnel, and facilitates training and operations. In general, a military base provides accommodations for one or more units, but it may also be used as a...

s, universities and hospitals with fixed boundaries.

New Zealand

In New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

 residents are allowed to broadcast licence free at a maximum of 1 watt EIRP in the FM guardbands from 87.6 to 88.3 and from 106.7 to 107.7 MHz under a General User Radio License (GURL) issued by Radio Spectrum Management
Spectrum management
Spectrum management is the process of regulating the use of radio frequencies to promote efficient use and gain a net social benefit.The term radio spectrum typically refers to the full frequency range from 3 kHz to 300 GHz that may be used for wireless communication...

. Prior to June 2010, the lower band was located between 88.1 and 88.8 and a maximum of 500mW EIRP allowed. Broadcasters on these frequencies are required to cease operations if they interfere with other, licensed broadcasters and have no protection from interference from other licensed or unlicensed broadcasters, contacts details must also be broadcast every hour.
There exists a 25 km rule: You may operate two transmitters anywhere (close together), but a third transmitter must be at least 25 km away from at least one of the first two transmitters.

There are efforts on self-regulation of the broadcasters themselves.

Smart radio

J. H. Snider and Lawrence Lessig say that low power "smart" radio is inherently superior to standard broadcast radio.

"Technologists are increasingly discussing a related kind of gain called 'cooperation gain.' ... think about a party. If I need to tell you that it's time to leave, I could choose to shout that message across the room. Shouting, however, is rude. So instead, imagine I choose to whisper my message to the person standing next to me, and he whispered it to the next person, and she to the next person, and so on. This series of whispers could get my message across the room without forcing me to shout." — "Wireless Spectrum: Defining the 'Commons'" by Lawrence Lessig
Lawrence Lessig
Lawrence "Larry" Lessig is an American academic and political activist. He is best known as a proponent of reduced legal restrictions on copyright, trademark, and radio frequency spectrum, particularly in technology applications, and he has called for state-based activism to promote substantive...

 2003 (mirror)

"if nodes repeat each other's traffic. If I want to talk to someone across the room, I don't have to shout. I can just whisper it to someone near me, who can pass it on, and so on. ... as we add more transmitters, the total capacity goes up slightly, but we still have to face the fact that each transmitter's capacity goes down (just slower). Even better, we all end up using less energy (since we don't have to transmit as far), saving battery life." — Open Spectrum: A Global Pervasive Network by Aaron Swartz
Aaron Swartz
Aaron Swartz is an American programmer, writer, political organizer and Internet activist. He is best known in programming circles for co-authoring the RSS 1.0 specification...

"Every time a broadcaster receives a license, the amount of available spectrum goes down. ... New technology, however, increases bandwidth with the number of users." — "Why Open Spectrum Matters: The End of the Broadcast Nation" by David Weinberger
David Weinberger
David Weinberger is an American technologist, professional speaker, and commentator, probably best known as co-author of the Cluetrain Manifesto David Weinberger (born 1950 in New York) is an American technologist, professional speaker, and commentator, probably best known as co-author of the...

"If we lose ... open spectrum, we're also going to lose the open Internet" — "The war against open spectrum" by Dana Blankenhorn 2007

See also

  • List of broadcast station classes — Explanation on broadcasting classes
  • North American call sign
    North American call sign
    Call signs in North America are frequently still used by North American broadcast stations in addition to amateur radio and other international radio stations that continue to identify by call signs around the world...

     — How call sign
    Call sign
    In broadcasting and radio communications, a call sign is a unique designation for a transmitting station. In North America they are used as names for broadcasting stations...

    s and classes are used in North America
  • ITU prefix
    ITU prefix
    The International Telecommunication Union allocates call sign prefixes for radio and television stations of all types. They also form the basis for, but do not exactly match, aircraft registration identifiers. These prefixes are agreed upon internationally, and are a form of country code...

     — How callsigns and classes are used worldwide
  • List of LPFM stations in New Zealand

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.