FM Translator & Booster Stations


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

Table of Contents


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What Is An FM Translator or FM Booster Station?

FM Translators and Boosters comprise a low power service on the FM broadcast band (88 to 108 MHz) which 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). Translators or boosters may not originate programming, except for the limited fundraising efforts in the case of translators as explained below. Translator stations rebroadcasting commercial FM stations may be authorized on Channel 221 through 300 (92 MHz to 108 MHz), while translators rebroadcasting a noncommercial educational FM station may be authorized on any FM channel (201 to 300). 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 power.

Translator stations simultaneously rebroadcast the signal of a primary FM station on a different frequency. Those translator stations which provide service within the primary station's protected service area are classified as "fill-in" stations. Fill-in translators may be owned by the main station, or they may be owned 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 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 or service contour of the primary station at any azimuth.

FM Translator Call Signs consist of W (east of the Mississippi River) or K (west of the Mississippi River), the 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.

In the following sections, we provide basic information pertaining first to translator stations, and then to booster stations, and lastly a summary of the policies and rules applicable to both types of stations. 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 74.30 and 74.1201 through 74.1284), with many references to the FM rules contained in Part 73.

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Translator FM Stations

All FM Translator Stations

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 HAAT, and whether the location of the translator station is east or west of the Mississippi River. See 47 47 CFR Section 74.1235 for further information.

Only one channel is authorized for each translator station broadcast upon. The translator station may 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 desires 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 (scanned document), 5 FCC Rcd 7212, 7245. 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
Audio Division (2-A223)
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).

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Fill-In Translators

Service Contour Requirements. A fill-in translator is required to maintain its service contour within the service contour of the primary station. Thus, 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) 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) contour within the 54 dBu F(50,50) contour of the primary station. Similarly, 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) 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.

Ownership & Financial Support. A fill-in translator station may be owned by the licensee of the FM primary station, or it may be owned 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 (scanned document), 5 FCC Rcd 7212, 7245. 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 at the fill-in translator's site, boosted in strength, and reradiated on the assigned translator frequency. However, a fill-in translator may also receive a primary station's signal via any terrestrial transmission facility, including (but not limited to) microwave, phone company circuits, and dedicated fiber optic cable. 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).

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Non-Fill-In Translators

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 & 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 areas", the Commission will be 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 (scanned document), 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. 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 requesting 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 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.

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 requesting waiver of the signal delivery requirement.

Noncommercial educational non-fill-in translators operating on Channels 201 through 220 which 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 so as to have prohibited grant of the application if those circumstances had existed then. 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.

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FM Booster Stations

Frequency. An FM Booster station may only operate on the same frequency 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) contour of the booster facility must be wholly encompassed by the 60 dBu F(50,50) 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) contour of the booster station must be encompassed by the 54 dBu F(50,50) 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) contour of the booster station must be encompassed by the 57 dBu F(50,50) 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 IF 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 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(h).

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).

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Matters Common to FM Translator and FM Booster Stations

Fundraising by FM Translators

Translators may interrupt the rebroadcasted 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).

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Emergency Warnings Broadcast by Translators

A translator station may interrupt the rebroadcasted 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).

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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).

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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).

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Cross-Service Broadcasts are Prohibited

An FM translator station may only rebroadcast the signal of an FM station or another FM translator signal. It may not rebroadcast an AM station, the audio of a TV station, or any other service. See .

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Major Change Applications

Effective May 21, 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, 64 FR 19498PDF ]. Applications will be treated as major changes if

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.

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Conflicting Applications

Where two or more translator or booster applications conflict, they are considered to be "mutually exclusive", since both applications cannot be granted without causing interference to one another. Competing applicants are encouraged to resolve their conflicts without Commission intervention. Where this is not possible, mutually exclusive conflicts will be resolved by the Commission as follows: