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FCC LPTV, Class A CP Proposed Grants Could Impact PSIP

Last Friday the FCC released Public Notice / Report PGL10-6 listing proposed low power/television translator and Class A television station construction permits.

Some of the proposed grants may be on frequencies previously used by full power TV stations for analog broadcasting. If the new low power or Class A TV stations use their RF channel number as their digital major channel number, it could cause problems for a full power station using the same virtual channel in that market.

As an example, a full power station may have previously operated in analog on Channel 22, but now transmits DTV on Channel 23 with a 22.1 major/minor Channel number. If an LPTV station files a displacement application and converts to digital on the full power station's old analog Channel 22 slot and also adopts a 22.1 major/minor Channel number, depending on the DTV tuner being used, the viewer's receiver will likely assign virtual Channel 22.1 to the first station it sees in the scan--the new low power station. The full power station operating with a virtual Channel 22 identification would either be stored as a duplicate virtual Channel 22.1 (not common) or would receive the station's RF Channel number; in this case, virtual Channel 22.1 would be saved as virtual Channel 23.1. Some DTV converter boxes may even place it on 70.1 to avoid conflict with other stations.

If viewers start complaining that your station has changed channels, this is one thing to check. Another would be to verify that your station's PSIP data is consistent across all tables. A common problem is the TSID will be correct in one tablet but not in another.

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.