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.
What Is an FM Translator or Booster?
FM Translator Stations
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 (FM and AM only)
Major Change Applications
No Multiple Ownership Limits
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)
Translator and Booster Rules in Part 74 (separate document)
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?
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 (for example, 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 at night.) 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).
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 listed in Part 74 of the FCC's rules (47 CFR Sections 74.1 through 74.34 and 47 CFR Sections 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
Contour protection. FM translator stations must meet the contour protection criteria specified in
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
Only one channel is authorized for each translator station to broadcast upon. The translator station can receive only one FM primary
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
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).
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's 60 dBu service contour is within the GREATER 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. See 47 CFR Section 74.1201(g). This limitation applies to all applications being filed by AM licensees for FM translator stations in 2016 and 2017 as part of the AM Revitalization effort.
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).
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)
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).
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
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)
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
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
Ownership. FM booster stations must be owned by the licensee of the primary FM station. See
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
Signal delivery to the booster station may be made by any means, such as terrestrial or satellite feed. See
Matters Common to FM Translator and FM Booster Stations
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
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
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
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
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.
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
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
Directional antennas. An applicant specifying use of a directional antenna must provide the
information specified in
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
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
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
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 854. See
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
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)
Washington, DC 20554 FAX: 202-418-1411
- ... 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
Grandfathered FM translators (authorized before June 1, 1991). FM translator stations that do not meet the requirements of
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.ecfr.gov/cgi-bin/text-idx? node=sp47.4.74.l