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Get the Most Out of Your Digital Signal

Check out the FCC ruling allowing increase in FM digital power

The map shows measured HD Radio coverage of FM station WKLB in Boston vs. predicted FCC protected contour with –14 dBc digital power.Credit: Courtesy Russ MundschenkWhen HD Radio was authorized a decade ago, it was immediately apparent that the coverage of the signal at 20 dB below the analog carrier did not come close to replicating the analog signal coverage in the real world. This problem became even more apparent when HD2 stations started popping up that had “nowhere to blend to” but instead just cut out abruptly.

In January 2010, the FCC produced a Report and Order allowing FM radio stations all over the country to increase their power levels for HD Radio broadcasts. Basically, it was a blanket authorization for virtually every FM station to increase the power level of the HD signal by 6 dB or, in other words, quadruple the existing power. Find the link to the R&O at (June 12, 2013, RWEE).

The great thing about this ruling is that it does not require any application but simply an electronic notification to the FCC within 10 days of commencing, using digital notification on the FCC’s Consolidated Database System; again find links to the CDBS at

The only exceptions are for “super-powered FM stations” that have different limitations; interested broadcasters in that category can determine their potential by using the Audio Division’s Digital ERP calculator, also listed at the above URL.

But wait, there’s more! Power level increases beyond –14 dBc are possible in many cases, and in some up to –10 dBc. This is a 10-fold increase in power, which has been shown in field studies to pretty much replicate your existing analog coverage. In order to obtain this authorization, stations must make a simple calculation to determine the station’s maximum digital ERP as detailed in the R&O, then submit an application to the FCC in the form of an informal request.

After much input from broadcasters and manufacturers, this ruling is the FCC’s best effort to help broadcasters make the most of their HD Radio signals while taking responsible and reasonable precautions to prevent new interference to adjacent channels.

If you are broadcasting HD Radio signals and have not taken advantage of this rule, you are not getting the most out of your license. Sure, upgrading your facility will cost money; but remember, this is our livelihood, it is what we do. Investing in HD Radio is investing in our future. Every other broadcast entertainment and information medium is digital, and radio must move forward with new technology to continue to compete. This rule allows us to do just that.

Paul Shulins is director of technical operations for Greater Media Boston.

Send your HD Radio tips or column suggestions to[email protected].