WASHINGTON, D.C. — The Media Bureau of the FCC has formally modified its rules as it pertains to FM terrestrial digital audio broadcasting systems, a change that is designed to give Xperi Corp.’s HD Radio a bigger signal contour.
At present, HD multicast channels are victim to the “digital cliff,” as the signal contours for all-digital FM signals are smaller than that of analog signals. While HD1 digital signal contours are exactly the same as digital multicast siblings, the synchronous analog signal associated with the main HD1 channel prevents sudden drops of a station.
To give digital signals, HD1 through HD4 and beyond, the FCC on September 24, 2024 adopted a “First Report and Order in Modifying Rules for FM Terrestrial Digital Audio Broadcasting Systems.” This saw the revision of broadcast radio procedures and rules, including sections 73.404 and 73.406 of the rules, to allow digital FM station operation with asymmetric power on the digital sidebands.
On Friday (5/23), the Media Bureau confirmed that the R&O was published in the Federal Register that day. As such, the amendments became effective.
And, as such, digital FM stations must now use FCC Form 2100, Schedule 335-FM to notify the Commission of asymmetric power operations.
Who will be the first operator to file is now likely the subject of industry speculation.
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