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FM Translators and Boosters - General Information

General information about FM translator and FM booster stations is contained below.  You can click on any of the topic headings in the Table of Contents to jump directly to a particular section or scroll through the topics that start sequentially after the Table of Contents.

Contents

   What Is an FM Translator or Booster?
   FM Translator Stations
       Fill-In Translators
       Non-Fill-In Translators
   FM Booster Stations
   Matters Common to FM Translator & Booster Stations
       Fundraising by Translators
       Emergency Warnings Broadcast by Translators
       No Local Program Origination Authority
       Cross-Service Broadcasts Are Prohibited
       Major Change Applications
       No Multiple Ownership Limits
       Directional Antennas
       Interference Caused
       Noncommercial Educational Translators or Boosters on
       FM Channels 201 Through 220 Must Protect TV Channel 6

       Unattended Station Operation
       Discontinuance of Operation
       Identification of Translator & Booster Stations
       Grandfathered FM Translators (authorized before June 1, 1991)

   Translator and Booster Rules in Part 74 (separate document)
    Additional Information

Related information about applying for FM translator or FM booster stations is located at:
How To Apply For A Broadcast Radio Station

What Is an FM Translator or FM Booster Station?

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FM translators and FM boosters comprise a low power service on the FM broadcast band (88 to 108 MHz) that complements the primary FM service.  This service was first created in 1970 to allow FM stations to provide supplementary service to areas in which direct reception of radio service is unsatisfactory due to distance or intervening terrain barriers (e.g., a mountain).  Most translators or boosters may not originate programming, except for the limited fundraising efforts in the case of translators as explained below.  (Exception -- some FM translators relaying AM daytime-only stations may continue to transmit programming when the AM station is off the air.)  Translator stations rebroadcasting a commercial AM or FM station (the primary station) may be authorized on Channel 221 through 300 (92.1 MHz to 107.9 MHz), while a translator rebroadcasting a noncommercial educational station (the primary station) may be authorized on any FM channel (Channels 201 to 300, or 88.1 MHz to 107.9 MHz).  The maximum effective radiated power permitted for any translator station is 250 watts, while the maximum effective radiated power for a booster station is 20% of the main station's maximum class power.

Translator stations simultaneously rebroadcast the signal of a primary AM or FM station on a different frequency.  Those translator stations that provide service within the primary station's protected service area are classified as "fill-in" stations.  Fill-in translators can be owned by the main station or by an independent entity.  Commercial non-fill-in translators are generally owned by independent entities, with certain exceptions, while noncommercial educational non-fill-in translator stations are generally owned by the primary station being rebroadcast.

Booster stations are essentially "fill-in" translator stations on the same frequency as the main station.  Booster stations must be owned by the licensee of the primary FM station.  Booster stations are also restricted in that the service contour of the booster may not exceed the protected service contour of the primary station at any azimuth. 

FM translator call signs consist of W (if the transmitter location is east of the Mississippi River) or K (if the transmitter location is west of the Mississippi River), the FM channel number, and a two letter suffix (e.g., W285AD or K220AA). 

FM booster call signs incorporate the call sign of the main station with the suffix -FM (booster number) added (e.g., KBDR-FM1).  See 47 CFR Section 74.1283 A primary FM station may have more than one booster.

FCC Form 349 is used to file for a construction permit for an FM translator or booster station, and FCC Form 350 is used to license that translator facility once construction has been completed in accordance with the construction permit.  The rules governing FM translator and booster stations are covered in Part 74 of the FCC's rules (47 CFR Sections 74.1 through 74.34 and 74.1201 through 74.1290), with many references to the FM rules contained in Part 73.  More information about the application filing process is available at How To Apply For A Broadcast Radio Station.

All FM Translator Stations

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Contour protection.  FM translator stations must meet the contour protection criteria specified in 47 CFR Section 74.1204 with respect to all FM stations (including Class D noncommercial educational secondary stations) and all FM translator or booster stations.

Effective radiated power.  The maximum effective radiated power (ERP) for any translator station is 250 watts.  The maximum ERP permitted for a particular translator station is dependent on the antenna height above average terrain (HAAT) and the 12 radials (evenly spaced at 30° intervals) used to determine the antenna height above average terrain (HAAT), and whether the location of the translator station's transmitter site is east or west of the Mississippi River.  If the translator is a fill-in translator, the ERP may be further limited by the need to maintain the translator's service contour within the primary station's service contour.  See 47 CFR Section 74.1235.

Only one channel is authorized for each translator station to broadcast upon.  The translator station can receive only one FM primary station.  See 47 CFR Section 74.1232(c).

Changing the station rebroadcast by an FM translator station.  If the licensee of an FM translator station wants to change the primary station being rebroadcast, it may do so without prior authority from the Commission.  If the translator is owned by an entity other than the owner of the new primary FM station, the owner must secure the permission of the primary station to rebroadcast its programming before commencing operation.  This is a statutory requirement.  See 47 U.S.C. Section 325(a); see also Footnote 52 of the Report and Order in MM Docket 88-140, 5 FCC Rcd 7212, 7245 (1990).  The translator licensee must notify the Commission by letter of ANY change in the primary FM station rebroadcast, and the letter should be mailed to the following address:

   Federal Communications Commission
   Attn:  Audio Division
   445 12th Street SW
   Washington, DC 20554

This change will be examined to verify that the change in primary station complies with the Commission's translator rules, such as signal delivery requirements (see below).

Fill-In Translators

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Service contour requirements.  A fill-in translator is required to maintain its service contour within the service contour of the primary station.  For a Class A, C3, C2, C1, C0 (C-zero), C, or noncommercial educational Class B, B1, or D FM primary station, the fill-in translator station must maintain its 60 dBu (1 mV/m) F(50,50) service contour within the 60 dBu contour of the primary station.  The fill-in translator of a commercial Class B primary station must maintain its 54 dBu (0.5 mV/m) F(50,50) service contour within the 54 dBu F(50,50) contour of the primary station.  And the fill-in translator of a commercial Class B1 FM primary station must maintain its 57 dBu (0.7 mV/m) F(50,50) contour within the 57 dBu F(50,50) service contour of the primary station.  The distances to the primary station and translator station contours are to be predicted using the standard contour prediction method in 47 CFR Section 73.313, using as many radials as necessary to accurately locate the contours.

An FM translator may rebroadcast an AM station only if the translator is within the SMALLER of (1) a 25 mile (40 km) radius circle from the AM station's transmitter site AND (2) the AM station's 2.0 mV/m contour.

Ownership and financial support.  A fill-in translator station may be owned by the licensee of the FM primary station or by an independent entity.  If a fill-in translator is independently owned, the owner must secure the permission of the primary station to rebroadcast its programming before commencing operation.  This is a statutory requirement.  See 47 U.S.C. Section 325(a); see also Footnote 52 of the Report and Order in MM Docket 88-140, 5 FCC Rcd 7212, 7245 (1990).  The primary station may provide financial and technical support for an independently owned fill-in translator both before and after the translator commences operation.

Signal delivery to the translator.  Generally, a primary FM station's signal is simply received off the air at the fill-in translator's site, boosted in strength, and reradiated on the assigned translator channel and frequency.

A commercial fill-in translator may receive a primary station's signal via any terrestrial transmission method, including (but not limited to) microwave, phone, internet, and dedicated fiber optic cable.  Satellite delivery is prohibited.  These requirements also apply to noncommercial educational translators in the reserved band (88 to 92 MHz) that are not commonly owned with the primary station.

A noncommercial educational FM translator, that is commonly owned with the primary station, may deliver the signal to the translator by any means, including satellite delivery.

Aural intercity relay frequencies may also be used on a secondary basis (i.e., the use of the frequency would neither cause interference to or preclude use of the frequency by full service radio broadcast stations) after coordination with local frequency coordinating committees, or local broadcast users in the absence of a coordinating committee.  A relay through another translator station is only acceptable if the intermediate translator provides a signal to a populated area.  See 47 CFR Sections 74.1231(b) and (c)

Loss of primary station's signal.  The translator must be set up to go off the air if the main station's signal is lost.  See 47 CFR Sections 74.1234(a)(2) and 74.1263(b).

Non-Fill-In Translators

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The majority of FM translator stations fall into this category.

Service contour requirements.  The service contour for a non-fill-in translator station may extend outside the primary station's service contour or, in some cases, lie wholly outside it.

Ownership and financial support.  In general, commercial primary stations and anyone associated with a commercial primary station may neither own nor provide direct or indirect support to non-fill-in translator stations, both before and after the translator commences operation.  See 47 CFR Section 74.1232(d).  However, in order to facilitate service to white (or unserved) areas, the Commission is favorably disposed toward waiver of this rule to permit a commercial primary station to support its own translator, or an independently owned translator, which provides service to these unserved areas.  The primary commercial FM station may provide "technical support" to the independent translator station, which is defined as:

actual services provided by the primary station's technical staff or compensation for the time and services provided by independent engineering personnel.  Such support does not include the supply of equipment or direct funding for the translator's discretionary use.  We also reiterate that technical assistance by the primary station should occur after the issuance of the translator's construction permit or license in order to meet expenses incurred by installing, repairing, or making adjustments to equipment.  (Footnotes omitted)
Memorandum Opinion and Order in MM Docket 88-140 (PDF), 8 FCC Rcd 5093, 5096 at Paragraph 20.  See also 47 CFR Sections 74.1232(d) and (e).

For the purposes of translator station applications, "white area" is defined as any area outside the coverage area of any full service aural service (AM as well as FM). Paragraph 23, Report and Order in Docket 88-140, 5 FCC Rcd at 7216 (1990).  Where a translator provides both fill-in service and white area service, the procedures applicable to "white area" service should be followed.  A showing of the "white area" must be presented in the application with a request for waiver of the ownership requirement.  When locating the "white area" boundaries, the service contours for FM stations shall be predicted using the standard method in 47 CFR Section 73.313. 

If a non-fill-in translator is independently owned, the owner must secure the written permission of the primary station to rebroadcast its programming before commencing operation.  This is a statutory requirement.  See 47 CFR Section 74.1284(b); see also 47 U.S.C. Section 325(a) and Footnote 52 of the Report and Order in MM Docket 88-140, 5 FCC Rcd 7212, 7245 (1990).

Signal delivery.  Non-fill-in translators relaying commercial FM stations must receive the signal off the air, unless a waiver has been granted to feed a "white area" translator by other terrestrial means.  A showing of the "white area" must be presented in the application for construction permit, requesting waiver of the signal delivery requirement.

Noncommercial educational non-fill-in translators operating on Channels 201 through 220 that are owned by the licensee of the primary noncommercial educational FM translator station may use alternate means to receive the primary FM station's signal.  Non-fill-in noncommercial educational translators on Channels 221 through 300 are prohibited from any alternative methods of signal delivery, including programming feeds by satellite.  See 47 CFR Section 74.1231(b).

Loss of primary station's signal.  The translator must be set up to go off the air if the main station's signal is lost.  See 47 CFR Sections 74.1234(a)(2) and 74.1263(b).

Special note for commercial non-fill-in translator stations:  The Commission may terminate the operation of a non-fill-in translator station at any time if the circumstances in the community or area have changed such that its application would have been denied if those circumstances had existed at the time of its filing.  The notice of termination, when issued, will list a date at least 60 days from the notice date by which operations must be terminated.  However, notices of termination pursuant to 47 CFR Section 74.1232(h) are rare in practice.

FM Booster Stations

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Frequency.  An FM booster station may only operate on the same frequency or channel as the primary FM station.  See 47 CFR Section 74.1202(c).

Service contour requirements.  The service contour of an FM booster facility must remain within the predicted service contour of the main station.  For all booster stations relaying a noncommercial educational FM primary station, and for all boosters relaying a commercial FM primary station (except Class B and B1 commercial stations), the 60 dBu (1 mV/m) F(50,50) service contour of the booster facility must be wholly encompassed by the 60 dBu F(50,50) service contour of the primary station.  For booster stations relaying the programming of a Class B commercial FM station, the 54 dBu (0.5 mV/m) F(50,50) service contour of the booster station must be encompassed by the 54 dBu F(50,50) service contour of the primary station.  For booster stations relaying the programming of a Class B1 commercial FM station, the 57 dBu (0.7 mV/m) F(50,50) service contour of the booster station must be encompassed by the 57 dBu F(50,50) service contour of the primary station.  See CFR Section 74.1232(f) The distances to the primary station and booster station contours must be predicted using the standard method in 47 CFR Section 73.313.

Protection to first-adjacent channel and I.F. channel stations.  Booster stations must provide protection from interference to first-adjacent channel stations, and may be required to meet minimum separation requirements with respect to I.F. (intermediate frequency) channel stations (53 or 54 channels separated from the booster channel).  See 47 CFR Sections 74.1204(g) and (h).

Effective radiated power.  The maximum permitted effective radiated power (ERP) for an FM booster station is 20% of the primary station's maximum class effective radiated power. See 47 CFR Section 74.1235(c).

Ownership.  FM booster stations must be owned by the licensee of the primary FM station.  See 47 CFR Section 73.1232(f).

Interference to main station's signal.  Because booster stations operate on the same frequency as the primary station, operation of the booster may cause interference to reception of the main station's signal.  However, booster stations may not cause interference to reception of the primary station's signal within the community of license.  The main station's signal may also cause interference to reception of the booster station.  It is up to the licensee of the primary station to decide whether the gain realized by the booster offsets any potential interference.  See 47 CFR Section 74.1203(c).

Signal delivery to the booster station may be made by any means, such as terrestrial or satellite feed.  See 47 CFR Section 74.1231(i).

Loss of primary station's signal.  The booster station must be set up to go off the air if the main station's signal is lost.  See 47 CFR Sections 74.1234(a)(2) and 74.1263(b).

Matters Common to FM Translator and FM Booster Stations

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Fundraising by FM translators.  Translators may interrupt the rebroadcast programming for up to 30 seconds each hour to solicit and acknowledge funds used to maintain the translator station.  This interval may be broken up into smaller segments, e.g. two 15 second segments.  See 47 CFR Section 74.1231(g).

Emergency warnings broadcast by translators.  A translator station may interrupt the rebroadcast programming to broadcast an emergency warning of imminent danger.  Emergency transmissions shall be no longer nor more frequent than necessary to protect life and property.  See 47 CFR Section 74.1231(g).

No local program origination authority.  A translator station cannot originate local programming, except as covered in the Fundraising by FM Translators and Emergency Warnings Broadcast by Translators above.  See 47 CFR Section 74.1231(g) Exception -- An FM translator that is authorized to rebroadcast an AM daytime-only station may continue to transmit programming when the AM station is off the air for the night.

Technical need showing for service.  Applicants are generally not required to show that a technical need for the translator service exists before filing an application for construction permit for a translator station.  However, an applicant wanting to serve substantially the same area with a second translator must make an appropriate showing of technical need for the additional translator.  "Need" refers to the quality of the signal received and not to the programming content, format, or transmission needs of an area.  See 47 CFR Section 74.1232(b).

Cross-service broadcasts are generally prohibited.  An FM translator station may only rebroadcast the signal of an AM or FM station or another FM translator signal.  It may not rebroadcast the audio of a TV station, or any other service.  See 47 CFR Section 74.1284(b) Exception -- An FM translator that is authorized to rebroadcast an AM daytime-only station may continue to transmit programming even when the AM station is off the air for the night.

Major change applications.  In 1999, the Commission redefined what constitutes a major change for FM translator and booster stations.  See the First Report and Order in MM Docket 98-93, FCC 99-55, 14 FCC Rcd 5272 (1999).  Applications will be treated as major changes if:

  • the application proposes to change to a channel that is not an adjacent channel (an adjacent channel is one, two, or three channels above or below the authorized channel) or is not an I.F. channel (an intermediate frequency or I.F. channel is 53 or 54 channels above or below the authorized channel); or
  • the coverage is changed so that none of the originally served area within the 60 dBu (1 mV/m) contour will be served by the proposed facility's 60 dBu (1 mV/m) contour.

All other changes are considered minor.  Minor changes will be processed on a first come / first served basis.  See 47 CFR Section 74.1233(a)(1) All major and minor changes must be approved by the Commission prior to making any changes in the translator or booster operation, except for the limited changes specified in 47 CFR Section 74.1251.

No multiple ownership limits.  There are no multiple ownership limits on the number of translator and booster stations a single entity may own.  Nor are they counted as FM stations for the purposes of the primary station multiple ownership rule, 47 CFR Section 73.3555 See 47 CFR Sections 74.1232(b) and (g).

Directional antennas.   An applicant specifying use of a directional antenna must provide the information specified in 47 CFR Section 74.1235(g) through (i) with the Form 349 construction permit application.

Interference caused.  A translator or booster may not cause predicted or actual interference.  If any actual interference is created, the Commission requires the permittee or licensee to resolve all interference complaints by appropriate means.  If the interference cannot be resolved, the Commission will require the FM translator or booster station to discontinue operations.  See 47 CFR Section 74.1203 A translator construction permit application will not be granted if an objecting party provides convincing evidence that the proposed translator station would likely interfere with off the air reception of a full service FM station, even if there is no predicted prohibited contour overlap.

Noncommercial dducational translators or boosters on FM channels 201 to 220 must protect TV Channel 6.  A noncommercial educational FM translator or booster that operates on FM Channels 201 through 220 (88.1 to 91.9 MHz) must, in its construction permit application on FCC Form 349, demonstrate that it provides protection from interference to reception of TV Channel 6 as required by 47 CFR Section 74.1205 Alternatively, in lieu of demonstrating compliance with the rule, the applicant may submit a letter from an officer of the Channel 6 TV station stating that the TV station does not object to the FM translator or booster application.

Unattended station operation.  If the translator or booster station is intended to operate without a licensed radio operator in attendance, the construction permit application for the translator booster must so state and provide a showing demonstrating compliance with the provisions of 47 CFR Section 74.1234 If unattended operation is not specifically requested, the translator or booster station must have a licensed radio operator on duty whenever the station is in operation.  See also the Question and Answer Sheet on Unattended Operation.

Discontinuance of operation.  The licensee or permittee of a translator or booster station cannot discontinue service for 30 or more days without express Commission approval.

The licensee or permittee of a translator station that proposes to discontinue operation permanently must notify the Commission at the address indicated below of its intent to permanently discontinue operation at least two days before operation is discontinued.  Immediately after operation is permanently discontinued, the licensee shall forward the station license and other instruments of authorization (e.g., licenses, construction permits, unexpired Special Temporary Authority grants, etc.) to the indicated address for cancellation.  The station may not operate after this occurrence.  But if the tower on which the translator or booster antenna was required on the construction permit or license (or other authorization) to be painted and lighted for air safety reasons, and the translator or booster licensee or permittee is the owner of that tower, then the tower owner remains responsible for maintaining the obstruction painting and lighting until that tower is dismantled, and the Federal Aviation Administration (FAA) and FCC's Support Services Branch in Gettysburg, PA are notified of the dismantling via the filing of FCC Form 854See 47 CFR Section 17.57.

The licensee or permittee of a translator or booster station that temporarily discontinues operation and that plans to be off the air for more than 30 consecutive days must notify the Commission in writing within 10 days of the time that the translator station is first off the air.  The notice of temporary discontinuance of operation must be sent to the indicated address, with an explanation as to why the operation was discontinued and the date by when operations are expected to resume as authorized.  If the translator or booster station remains silent for a period of 30 days or longer, the permittee or licensee must also file a written request for Special Temporary Authority (STA) with the Audio Division for this period.  While no filing fee is required for an STA to remain silent, an anti-drug abuse certification statement is required.  See 47 CFR Section 1.2002(b); see also Anti-Drug Abuse Act of 1988, 6 FCC Rcd 7551, 57 Fed. Reg. 00186 (1991).  The permittee or licensee remains responsible for maintaining any required tower painting and lighting, to preserve air safety.

FM translator or booster stations that are silent for 30 or more consecutive days are considered to have permanently discontinued operations and the station's authorizations can be cancelled at the Commission's discretion.  However, this will not apply to those stations that have received prior approval from the FCC to remain off the air for 30 or more consecutive days.

The licenses of stations that remain silent for a year are automatically cancelled as a matter of law.  The Commission has limited authority to alter this result.

Notices of the temporary or permanent discontinuation of operations must be directed to:

   Federal Communications Commission
   Audio Division (1800B3), Room 2-B442
   Washington, DC 20554         FAX: 202-418-1411

Identification of translator and booster stations.  Translator stations must be identified by the licensee by the following means:

  • ... by arranging with the primary station whose signal is being rebroadcast to identify the translator by call sign and location.  The identification must occur 3 times daily:  once between 7 AM and 9 AM, once between 12:55 PM and 1:05 PM, and once between 4 PM and 6 PM.  Stations that do not begin operating before 9 AM must provide the identification at the beginning of the broadcast day.  The licensee of the translator station must arrange for the primary station to keep in the primary FM station's file (and to make available to FCC personnel), the call sign and location of the translator station.  This record must include the name, address, and telephone number of the translator licensee or his service representative to be contacted in the case of a malfunction of the translator.  See 47 CFR Section 74.1283(c)(1).
  • ... by transmitting the call sign in Morse Code at least once hour.  See 47 CFR Section 74.1283(c)(2) for additional requirements for transmission of the call sign in this manner.
Booster stations are identified by the primary station, by the broadcasting of the booster's call sign and location, in accordance with 47 CFR Section 73.1201.

Grandfathered FM translators (authorized before June 1, 1991).  FM translator stations that do not meet the requirements of 47 CFR Sections 74.1204, 74.1205, or 74.1235 as of June 1, 1991, and that were authorized prior to that date, are permitted to continue operations with the technical facilities authorized until a request for major modification of the facilities is made.  Effective June 1, 1994, all commercial translator stations were required to come into compliance with the revised fundraising and direct or indirect translator financial support rules.  See 47 CFR Sections 74.1204(j), 74.1205(d), and 74.1235(j).  At the time modification is requested, the applicant must demonstrate compliance with the provisions of 47 CFR Sections 74.1204, 74.1205, and 74.1235.

Additional Information

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Technical information for individual translator stations can be located using the FM Query.  Please note that the FCC does not collect information about what type of programming translators may be relaying.

FM translator and FM booster rules are listed at http://www.fcc.gov/mb/audio/bickel/part74rule.html

For more information about FM translators and FM boosters, please call the Audio Division at (202) 418-2700.

FCC > Media Bureau > Audio Division

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