Interference to NCE-FM Stations from Channel 6 DTV

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The FCC is proposing a large increase in transmission power for low-VHF DTV stations, including channel 6, which is adjacent to the NCE-FM band.  NPR Labs conducted a study of all NCE-FM stations, which finds that interference could affect substantial numbers of FM listeners.

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The Commission’s current Notice of Proposed Rulemaking (EM Docket No. 10-235, adopted November 30, 2010), proposes to increase the maximum transmitted power of digital television stations on channels 2 to 6 (“low-VHF”) from 10 kW to 40 kW, referenced to a height above average terrain of 305 meters.  NPR Labs prepared this study to determine whether, and to what extent, the blanket increase in power proposed by the Commission may increase the interference to reception of existing NCE-FM stations.

Download the March 18, 2011 engineering report (PDF)

The map in Figure 1 shows the locations of NCE-FM stations in the continental United States on channels 201 through 205 (88.1 to 88.9 MHz), which are potentially the most-affected because of closer frequency-adjacency to channel 6 spectrum.  Including all NCE-FM stations would have produced a denser display of dots, but a display of many overlapping dots that would not have revealed the numbers of stations geographically.  This illustrates that NCE-FM stations are distributed widely across the U.S., and are potentially subject to any new channel 6 DTV stations, if authorized.

Download the NCE-FM station map (PDF)
 

 

Posted March 2011