Attachment B
LPFM Preclusion Showings for Certain FM Translator Applications:
The Grid Test and the Top-50 Transmitter Site Test
Each tech box proposal identified in Attachment A specifies a transmitter site location that is 
inside a Spectrum Limited market and/or within 39 km
1
of one or more Spectrum Limited Market Grids.  
Every identified application must be amended to include a Preclusion Showing, consisting of a “Grid 
Test” and/or a “Top-50 Transmitter Site Test.”  These tests are described below.
The Bureau recently released an updated version of the LPFM grid tool.
2
  The files provided in 
that tool can be used in conjunction with the Grid Test to identify the appropriate coordinates to center 
each Market Grid.  The LPFM grid tool can be used to identify the protected LPFM channel/point 
combinations within each Market Grid.
NOTE:  With the exception of Example C., below, the following examples discuss both tech box 
“amendments” consisting of only Preclusion Showings and amendments which include both Preclusion 
Showings and Technical Amendments e.g., changes in site, power, height, antenna pattern and/or channel.
A. Grid Test Statement for Technical Amendments and Preclusion Showings with proposed 
transmitter site locations 39 km or greater from all Spectrum Limited and Spectrum Available 
Market Grids.    
An applicant filing a Technical Amendment or Preclusion Showing proposing a transmitter site 
that is at least 39 km from all Market Grids is required to file a tech box amendment.  The following 
statement is sufficient:  “The proposed transmitter site is at least 39 km from all Market Grids, and 
therefore cannot preclude any LPFM licensing opportunities in any grid.”  
B.  Grid Test for Technical Amendments and Preclusion Showings with proposed transmitter 
site locations within 39 km of Spectrum Limited Market Grids.
An applicant filing a Technical Amendment or Preclusion Showing proposing a transmitter site 
within 39 km of a Spectrum Limited Market Grid is required to submit a Grid Test.  When determining 
available LPFM channel/point combinations in Spectrum Limited Market Grids, the Preclusion Showing 
must include an LPFM spectrum availability study, whichmust protect all authorizations and 
applications on co- and first-adjacent channels.  The study should assume the dismissal of all 
pending Auction 83 Applications.
3
  The study must ignore LPFM second-adjacent and intermediate-
frequency protection requirements but otherwise apply all other LPFM spacing requirements.  The study 
must include all Spectrum Limited Market Grids that are within 39 km of the proposed transmitter site 
location.
                                                     
1
Thirty-nine kilometers is the largest LPFM to FM translator spacing requirement specified in 47 C.F.R. § 
73.807(d)(1).
2
Media Bureau Releases Updated Low Power FM Spectrum Availability Data Files, DA 12-1987, Public Notice, 27 
FCC Rcd 15256 (MB 2012) (http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-12-1987A1.docx).
3
Fourth Report and Order, 27 FCC Rcd at 3387-88 (explaining the exclusion of pending Auction 83 Applications 
from this type of preclusion study).
An amendment fails this test if it would preclude an identified LPFM channel/point licensing 
opportunity within any Spectrum Limited Market Grid.
C.  Grid Test for Technical Amendments with proposed transmitter site locations within 39 km 
of Spectrum Available Market Grids.
An applicant filing a Technical Amendment proposing a transmitter site within 39 km of a 
Spectrum Available Market is required to submit a Grid Test.  When determining available LPFM 
channel/point combinations in Spectrum Available markets, the LPFM spectrum availability studymust 
protect all authorizations and applications on co-, first-, and second-adjacent channels, including all 
pending Auction 83 Applications.
4
  The study must ignore LPFM intermediate-frequency protection 
requirements but otherwise apply all other LPFM spacing requirements.  The study must include all 
Spectrum Available market grids that are within 39 km of the proposed transmitter site location.
An amendment fails this test if it would preclude an identified LPFM channel/point licensing 
opportunity within any Spectrum Available Market Grid.  
D. Top-50 Transmitter Site Test for Technical Amendments and Preclusion Showings with 
proposed transmitter site locations within Top-50 Spectrum Limited markets but outside the 
Market Grids.
An applicant filing a Technical Amendment or Preclusion Showings proposing a transmitter site 
outside the Market Grid in a Top-50 Spectrum Limited market is required to submit a Top-50 Transmitter 
Site Test.  In order to submit a successful test, the applicant must show – assuming the dismissal of all 
pending Auction 83 translator applications in the market – that no LPFM channel is available or –
assuming the grant of the subject application – that at least one LPFM channel remains available at the 
out-of-grid transmitter site location proposed in the application.  Studies must protect all authorizations 
and applications on co- and first-adjacent channels.  The study must ignore LPFM second-adjacent and 
intermediate-frequency protection requirements but otherwise apply all other LPFM spacing 
requirements.
5
  
An amendment fails this test if there would be only one LPFM channel available at the specified 
transmitter site location and it is precluded by the subject application.
                                                     
4
Fourth Report and Order, 27 FCC Rcd at 3387-88.
5
Id.