“Superpower” WETA Asks for More Digital Power

It is an uncommon though not unique request
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Text has been updated with information about the number of other such requests.

WASHINGTON -- WETA(FM) is asking for permission to increase digital power beyond what would normally be allowed for an HD Radio station of its class.

Greater Washington Educational Telecommunications Association Inc., the licensee, asked the FCC for authority to operate the classical music station with its digital power in excess of �20 decibels below analog carrier power. When it modified the rules for digital power levels in 2010, the FCC established somewhat different digital ERP limits for �superpowered� stations like WETA compared to others; and it set out a process for such stations to request permission. Since the adoption of the 2010 Order in MM Docket No. 99-325, the Audio Division has granted 13 requests for increased FM digital power for superpowered FM stations.

The consulting engineer on this request is Joseph M. Davis of Chesapeake RF Consultants. The station is licensed for effective radiated power of 75 kW analog at antenna height above average terrain of 186 meters. �WETA is a so-called �superpower� station in that its licensed analog facility exceeds the maximum Class B parameters of 50 kW at 150 meters,� Davis wrote in the engineering exhibit. �GWETA seeks to operate WETA with a nominal digital power level of �13.7 dBc utilizing separate analog and digital transmitters (high-level combined system). At �13.7 dBc, the proposed nominal digital ERP is 3.2 kW. This matches the maximum digital ERP allowable for WETA of 3.2 kW ��

If you want to get really down and dirty with digital specifications, he explained further that WETA will operate in the MP3 service mode (extended hybrid) with symmetric digital sidebands, so the total digital sideband ERP is 0.8 dB higher than the nominal digital ERP. �The resulting proposed total digital ERP is 12.9 dBc at 3.8 kW. The total digital sideband ERP will be adjusted � should any other service modes be utilized in the future.�

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