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CTIA and Rural Cellular Association Ask FCC to Limit Ch. 51 TV Use

The FCC is seeking comments on a Petition for Rulemaking and Request for: Licensing Freezes that was filed on March 15, 2011 by the CTIA--The Wireless Association, along with the Rural Cellular Association.

These groups want the FCC to revise its rules to prohibit future licensing of TV broadcast stations on Channel 51, and to freeze acceptance, processing and granting of applications for new or modified broadcast facilities on Channel 51, and also to accelerate clearance of the channel "where incumbent Channel 51 broadcasters reach voluntary agreements to relocate to an alternate channel."

The Petition and Request states:

"Petitioners do not ask the Commission to disturb existing operations on Channel 51. Rather, we urge the Commission to take action to prevent additional stations from commencing operation in this channel in the future and to accelerate clearance of the channel by broadcasters who voluntary agree to do so."

The CTIA and the Rural Cellular Association say that these requests will provide "A Block" licensees a clear picture of the interference environment in the band and enable them to deploy their networks. (The 700 MHz "A" Block is adjacent to Channel 51.)

"A Block" licensees are required to protect existing broadcasters, as well as potential future broadcasters, on Channel 51, but the petitioners' main concern is about interference from TV's Channel 51 into "A Block" base station receivers. Manufacturers have warned Cellular South, an "A Block" licensee, about disruptive interference from TV stations operating on Channel 51.

It's easy to understand why CTIA and the Rural Cellular Association want to limit broadcasting on the channel, but it's also clear that this is only an interim step.

With the purported spectrum "crisis," Channel 51 (692-698 MHz) is unlikely to remain unused when broadcasters move off it. Under some yet-to-be-defined mechanism, the FCC and wireless carriers are looking to take over half the UHF spectrum from broadcasters, but it isn't clear how long this will take or even whether Congress will permit it. The interference problems with high-power broadcast transmissions on channels adjacent to wireless communications spectrum will remain.

A search of the FCC TV Engineering Database spreadsheet dated March 21, 2011 showed only 25 licensed full power commercial and educational TV stations on Channel 51. The database showed 88 licensed low-power TV, Class A TV, and TV translator stations licensed on Channel 51.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.