Unlicensed TV band devices threaten DTV investment

The FCC must require that adequate protections be put in place before any unlicensed TV band device is allowed to operate in television spectrum, the NAB and the Association for Maximum Service Television told the commission May 15 in jointly filed comments.

The trade associations told the commission that tests conducted by the FCC’s own Office of Engineering & Technology and subsequent report show that the commission must “exercise caution and establish baseline protections in order to prevent interference to television service.”

The trade groups are concerned that any move by the FCC to allow unlicensed TV band devices to operate in TV spectrum prior to establishment of sufficient protections will threaten the successful completion of the transition to DTV, putting the billions of dollars consumers and broadcasters have spent so far in jeopardy.

The issue of unlicensed TV band devices also potentially impacts wireless mics and other wireless communications devices commonly used in ENG because they operate on certain UHF and VHF channels as well.

According to the filing, the OET record confirms that the commission must account for several facts in any action it takes. Namely, it must take into account that:

• DTV receivers are at their most vulnerable to interference when operating at low signal levels and that 84 percentof the coverage area of a broadcast station may experience low signal levels;
• Interfering signals from multiple devices can be significantly more severe than a single interfering signal;
• There is wide variance of DTV interference rejection performance among DTV receivers.

For more information, visit www.nab.org/xert/corpcomm/pressrel/releases/051607_NABMSTV_TVBandDevices.pd.