Translator to LPFM interference handling

How translators are supposed to protect LPFM stations

During the application preparation process (prior to filing)

Each FM translator has a primary service contour (60 dBu F[50, 50]) and interfering contours for co-channel (40 dBu F[50, 10]) and first-adjacent channel (54 dBu F[50, 10]). The basic rules on how an FM translator proposal is supposed to protect an LPFM station can be found in §74.1201(a) of the FCC Rules.  A proposed FM translator must be in a location, with a power and a directional antenna pattern where the translator's interfering contour does not overlap with the primary service contour (60 dBu F[50, 50]) of the existing LPFM station or construction permit.  In other words, the 40 dBu interfering contour of the proposed translator can not overlap the 60 dBu protected contour of an LPFM station on the same channel and the 54 dBu interfering contour of the proposed translator can not overlap the 60 dBu protected contour of an FM station on a first-adjacent channel (+/- 0.2 MHz).  FM translators are not required to protect LPFM stations on second or third adjacent channels.   An FM translator can propose a specific directional antenna pattern that can be used to "protect" the LPFM station and the translator can use different power levels if necessary.  The maximum size of an FM translator's 60 dBu service is contour is limited by specific parameters based on which type of service that it is rebroadcasting:

  • If the translator is rebroadcasting an AM station: The translator 60 dBu contour cannot exceed either 25 miles or the 2 millivolt per meter (mV/m) AM daytime contour, whichever is longer in the direction being examined but in no case shall the translator's ERP exceed 250 watts.
  • If the translator is rebroadcasting an FM station as a fill-in service (including the rebroadcast of HD Radio streams): The translator service contour must remain entirely within the service contour of the primary station but in no case shall the translator's ERP exceed 250 watts.
  • If the translator is rebroadcasting an FM station outside of its service contour (non-commercial stations, LPFM stations or translators owned by other entities such as municipal governments): The ERP is limited based on the maximum height above average terrain (HAAT) of the FM translator facility with a maximum equivalency of 250 watts at 32 meters HAAT in areas east of the Mississippi River as well as most of California, Puerto Rico and the Virgin Islands or the maximum equivalency of 250 watts at 107 meters HAAT in all other areas. In no case shall a translator be authorized more than 250 watts ERP.

As long as there is a lack of contour overlap between the FM translator's interfering contour and the LPFM station's (as well as other stations) protected service contour, then the application can possibly be granted. 

At the time of filing

Once an FM translator application is filed, the next step depends on the type of application that it is:

  • If the application is a short form filed during an initial window for new translator applications, then that application is merely a "concept" more than any thing.  A short form application can be identified through the fact that it is an application for a new permit (begins with BNPFT or in FCCdata with a "CP"or "CPA" indicator) and a lack of any information entered into the legal section of the application.  These short forms are used primarily to determine if the the application is proposing a facility that conflicts with another application to determine if the translator applicant will be going to auction.  Once the short form proposal is declared "singleton" (through either an original non-conflicting proposal, a proposal with conflicts that were resolved or as the winner of an auction), then the applicant will be given the opportunity to file a long form application during a designated restricted filing window. 
  • If the application is a long form filed during a designated restricted filing window for long form applications, this is a true application and it must protect all facilities using the contour method that was previously discussed.  These applications will be for new permits (begins with BNPFT or in FCCdata with a "CP"or "CPA" indicator) and will have the legal section filled out.  Once the FCC reviews the application, they will consider the application as "accepted for filing" which at that point, there will be a 15 day opportunity for those who wish to file a "petition to deny" can do so.  This process is used for all new broadcast stations (including LPFM) to give an opportunity for anyone with standing to discuss why this application should not be granted.  Informal objections can also be filed at any time up to the decision by any interested party.  If there are no objections or after all objections have been disposed of, then the application will be either dismissed (if there is an issue with the application) or will be granted.   Dismissed applicants will have 30 days to seek reconsideration of the dismissal.
  • If the application is a modification to an existing license or construction permit (as indicated by an application beginning with BPFT or BMPFT or in FCCdata with a "MOD" or "MODA" indicator), then there is no petition to deny process.  Modifications can be filed at any time (except during an announced application freeze). Once the application is "accepted for filing", then it could be granted or dismissed at any time.  In these cases, you may still be able to file an informal objection to make any claims about the modification proposal.

There were filing windows that involved the short form/long form process in 2017 and 2018.  While there may be some remnants of applicants filing long forms from those previous auction windows, expect a majority of applications in the translator service to be modifications.

For more information on this rule, see §74.1204(a).

What constitutes interference?

The FCC has two different rules related to FM translator interference.  §74.1204(f) relates to predicted interference prior to the grant of a construction permit where §74.1203(a)(3) relates to the actual interference that takes place after construction.  Complaints from listeners are limited to those who are within the 45 dBu F(50,50) service contour of the incumbent station. In both cases, the FCC demonstrates interference using this following guidelines:

  1. The required minimum number of listener complaints based on the population that the incumbent station has inside its protected service contour.
  2. A map plotting the specific locations of the alleged interference in relation to the complaining station's 45 dBu contour.
  3. A statement that the complaining station is operating within its licensed parameters.
  4. A statement that the complaining station licensee has used commercially reasonable efforts to inform the relevant translator licensee of the claimed interference and attempted private resolution.
  5. U/D Ratio data demonstrating that each listener location the undesired to desired signal strength exceeds -20 dB for co-channel situations, -6 dB for first-adjacent channel situations or 40 dB for second- or third-adjacent channel situations.

Tip: Use the Translator Interference functionality at myLPFM determine if a listener's address may be qualified to include in a package of complaints.

FAQ: What is a "U/D Ratio"?

What is a listener complaint?

§74.1201(k) defines it as a statement signed and dated by the listener and contains the following:

  1. The complainant's full name, address and phone number.
  2. A clear, concise and accurate description of the location where interference is alleged or predicted to occur.
  3. A statement that the complainant listens over-the-air to the desired station at least twice a month.
  4. A statement that the complainant has no legal, financial affiliation or relationship with the desired station.

Listeners should be advised that if they sign a complaint form, that their information will become public record and they could be contacted by the translator applicant who may try to compel them to participate in efforts to resolve the interference claim which may include gaining access to their property and purchasing them a new radio receiver.  Under the revised rules, listeners are not required to participate in the remediation efforts in order to maintain the validity of the listener complaint.

"Disinterested" listeners

On point #4, this is the "disinterested listener" rule.  The FCC has clarified that just because a listener likes or follows a station or personnel on social media does not constitute affiliation with the station, nor does membership in listener clubs, contests, events as well as individual contributions to the station. Entities that underwrite the station (as well as advertisers for commercial stations) are considered affiliated.  A disinterested listener can alos include a station volunteer as long as the volunteer does not hold a regular position at the station comprable to a station employee. 

How many listener complaints do I need?

The number of listener complaints required depends on the population of your station's coverage contour.  For LPFM stations, the coverage contour is 60 dBu (1 mV/m) in all cases.  

Population within the coverage contour Minimum number of disinterested listener complaints required
LPFM: 0~4,999 3
LPFM: 5,000~199,999 6
Non-LPFM: 1~199,999 6
200,000~299,999 7
300,000~399,999 8
400,000~499,999 9
500,000~999,999 10
1,000,000~1,499,999 15
1,500,000~1,999,999 20
2,000,000 or more 25

LPFM applicants making modifications

LPFM stations are required to protect FM translators based on a distance separation table as opposed to translators protecting LPFM stations using contours.  As long as the LPFM station meets the minimum distance separation to a translator (authorization or application) using the distance tables in §73.807, then there is no interference and any complaint is not actionable.  FM translators can file an interference complaint against an LPFM station if the LPFM station causes actual interference to the input channel of a translator (§73.827(b)).  

Listener complaint guidelines

First of all, we need to point out that in order for an LPFM to file a complaint against a translator, the LPFM must be up and running and fully licensed at the site experiencing interference prior to the translator applicant filing their application proposing their facilities (including the short form).  You cannot claim protection for a facility that is under a construction permit or awaiting a grant of a modification application.  

In order for a complaint to be valid, it must be from a disinterested listener.  The FCC defines disinterested as a person or entity without a legal stake in the outcome of the translator station licensing proceeding.  For the purposes of being over-cautious for an LPFM, that should include all board members, any paid staff at the station (engineers, managers, etc.), volunteers and underwriters.  

The complaint should be in a form that includes:

  • The listener's name.
  • Home address.
  • Locations where the FM translator interference occurs.  Please use actual street locations, not just city names.
  • A statement that the complainant is, in fact, a listener of the affected station. 

Filing pleadings with the FCC

For information on how to file an informal objection, petition to deny or petition for reconsideration, see our page on filing pleadings.

REC strongly recommends using an attorney.  For a list of attorneys, see our Recommendations page.