NCE FM Reserved Band Translator Window Prequalification Tool

NOTE!!  READ THIS DOCUMENTATION FULLY BEFORE USING THIS TOOL! 

The Reserved Band Prequalification Tool is an REC system that can be used to eliminate reserved band (88.1~91.9 MHz) channels that can be considered for filing in the 2026 NCE FM Translator Filing Window.  

This tool is NOT a "channel search" in the way similar to previous channel search tools that are provided by REC.  A good result does NOT necessarily mean that a translator can be placed on that channel.  This is just a starting point to determine if there are potential channels that can be further researched and if a waiver for second and/or third adjacent channel overlap is needed (similar to how we do second-adjacent waivers in LPFM).

How translators protect other broadcast facilities

Unlike LPFM and full-service commercial (92.1~107.9) protections, FM translators use the prohibited contour overlap model.  Since translators are secondary, they can receive interference, but they cannot interfere with another facility, including previously authorized secondary facilities (including translators and LPFM stations).

Every broadcast station has a service contour.  This is also known as a "protected contour" or a "50,50 contour".  This is the service area of the existing station.  

Each station also has multiple interfering contours.  These are also known as "50,10 contours".  There is a different field strength value for the channel relationship between the proposed facility and the facility that needs to be protected.  This includes co-channel, first-adjacent, second-adjacent and third-adjacent.   The co-channel interfering contour is the largest where the second and third-adjacent channel interfering contours are the smallest.  

The contour protections to other facilities are as follows:

Using that chart above, the interfering contour of the proposed translator facility cannot overlap the service (protected) contour of the existing facility (including pending and granted construction permits). 

FM Translators are not required to protect vacant allotments (such as on 92.1) but be advised that if there is a vacant allotment on 92.1 in the area near the proposed translator, that channel could someday be activated for a full-service station and if that station is interfered with, it could result in displacement of the translator.  This search tool does not look for those vacant allotments.

Protecting facilities in Canada

Facilities in Canada are protected as allotments and will be protected to a specific radius based on station class, pursuant to the international agreement with Canada.  In these cases, the 34 dBu interfering contour of the proposed translator may not overlap into the specific radius inside of Canadian territory.  If there is overlap and the 34 dBu interfering contour of the translator remains entirely in the United States or crosses into Canada where it does not overlap the protected radius of the Canadian allotment, then operation may be possible. Second/third-adjacent waivers are not allowed towards foreign allotments.

Translator stations within 320 km of the Canadian border may not place a 34 dBu interfering contour that exceeds 60 km in any direction (including away from Canada).

Protecting facilities in Mexico

Facilities in Mexico are protected as allotments and will be protected to a specific radius based on station class, pursuant to the international agreement with Mexico.  In these cases, the 34 dBu interfering contour of the proposed translator may not overlap into the specific radius in either Mexican and/or in US territory.  Overlap is not allowed under any circumstances. Second/third-adjacent waivers are not allowed towards foreign allotments.

For proposed facilities that are within 125 km of the Mexican border, there is a limit of 50 watts ERP in all directions that are within 125 km of the Mexican border.  This can mean that a directional antenna can be used for power that exceeds 50 watts towards the north while power to the south must remain at 50 watts or less.  Also within 125 km of Mexico, there is a limit of the 60 dBu service contour (F50,50) of 8.7 km and a limit of the 34 dBu interfering contour (F50,10) of 32 km along the radials that are within 125 km of the Mexican border.  For stations more than 125 km away from the border, these distance measurements start once the radial reaches the point that is 125 km from the border.

Protecting Channel 6 TV facilities

FM translator proposals must demonstrate protection to all TV Channel 6 facilities.  This includes full-service TV stations, Class A TV stations, Low Power TV (LPTV) stations and TV translator stations.  TV Channel 6 facilities are protected out to their 47 dBu (F50,50) service contours.  The interfering contour will use will depend on the channel and can range from 54 dBu for Channel 201 (88.1) to 90 dBu for Channel 220 (91.9) (using the F50,10 table).  To protect the TV service, there cannot be any overlap of the TV station's 47 dBu service contour with the appropriate interfering contour of the translator proposal.  The Channel 6 protection requirement can be waived if the licensee of the affected TV Channel 6 facility/facilities provides a letter of consent concurring the operation of the translator.  REC advises against asking for the FCC to grant a waiver because of the fact that TV has converted to digital and this rule reflects analog TV.  Trust me, this has been tried and died.  For more information on Channel 6 protection requirements from reserved band translators, see §74.1205 of the FCC Rules.

Intermediate Frequency protection - reduced translator power

FM translator proposals with a peak effective radiated power of 100 watts or greater are also required to protect the intermediate frequency of domestic full-service FM facilities that are operating 53 or 54 channels (10.6 or 10.8 MHz) higher than the proposed translator channel.  The minimum distances will be based on the other full-service station's class.  LPFM and other translator stations do not need to be protected in this manner:

If there is an intermediate short-spacing, the translator can propose a peak ERP of 99 watts or less.  You cannot use a directional antenna to reduce the ERP to 99 watts or less in the direction of the IF short-spaced station in order to get 100 watts or greater in other directions.

Maximum Effective Radiated Power for FM translators

It is a huge myth that all translators, as long as they can protect other stations can operate up to 250 watts.  With the intermediate frequency example above, we showed one way that the myth is just that, a myth.  There are additional limitations based on the type of translator and the heights above average terrain.  Instead of reinventing the wheel in this long document, if you want to read more about those limitations, see this FAQ answer.

So what does the Translator Prequalification Tool do then?

To use the Translator Prequalification Tool, you will need to enter in the geographic coordinates (in degree, minute, second format) of the proposed translator transmitter site.  We call this the target location.

The tool will identify all active facilities that are within a certain radius of that site based on service type (full-service vs. translator vs. LPFM) and for each facility, it will determine the distance and bearing from the facility to the target location. Then, based on information from REC's eLMS service, we will also determine the distance from the facility to the service contour along that same bearing.  If the distance from the facility to the target location is shorter than the distance from the facility to the contour, then the target location is considered inside of the contour for that facility and will flag the co- and first-adjacent channels for exclusion and will flag second- and third-adjacent channels as possible with a waiver (though that availability may be excluded by another co- or first-adjacent channel facility).  If the target is near Canada and there is a Canadian allotment that puts a protected radius over the target, then a warning message will be shown.  If the target is near Mexico and there is a Mexican allotment, then the tool will exclude the co-, first-, second- and third-adjacent channels. 

This tool does not check the distance or power allowed towards any facilities that do not place a contour over the target location (in other words, how far an interfering contour can be extended).  Therefore, this tool is not the final decision on whether a translator can be placed on a certain channel, but instead is a starting point.  It can be used to determine:

• If there may be any channels that would be candidates where a second/third-adjacent channel is not required;
• Whether all potential channels at the target site will require a second/third-adjacent channel; or
• If there are no potential channels at all if all 20 channels are inside the service contours of existing facilities.

In other words, we are only looking at service contours of existing facilities.  We are not looking at the interfering contours of the proposed translator facility.

This tool will also check TV Channel 6 facilities and use a similar measuring method to determine the distance from the TV facility to the target and to the 47 dBu contour to warn that target location is inside the 47 dBu contour of one or more TV Channel 6 facilities.  Like with radio facilities, it does not check the interfering contour from the target so even though the target location is outside the Channel 6 contour, it may still not be available based on the size of the target's interfering contour to the TV Channel 6 facility.

FM translator applications are not easy like many LPFM applications are.  Special software and a skill set in how contours work and how stations are protected are needed to properly engineer and file an application for an NCE FM Translator in the reserved band during the filing window.

This tool is designed to work in the continental United States, Hawaii, Puerto Rico, US Virgin Islands and likely in Alaska.  It will not work for target locations in Guam, American Samoa or the Commonwealth of the Northern Mariana Islands.

If you fully understand the limitations of this tool, you may move forward and use the NCE FM Translator Prequalification Tool.  (You have been warned! - REC is not responsible for any damages related to the use of this tool.)

Click here to access the NCE FM Translator Prequalification Tool