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White Space: More Tests Could Have Caused TV, Cable Interference

As I reported last week, a careful reading of the TV White Space Phase II Test Report shows the WSD transmitter caused interference to both over-the-air and cable TV reception.

If the FCC had done more transmitter tests at multiple locations, the results of the limited field-testing in the Report indicates there would have been interference to over the air TV reception and, depending on the transmitter location, cable TV reception.

While I applaud the FCC's desire to protect TV viewers from interference, had the transmitter been tested outside the laboratory facility and viewers complained of interference, it is unlikely the commission would be moving as fast as it is on this proceeding. I hope the transmitter testing at multiple locations was scratched because of concern for interference to viewers and not because of concern for interference to WSD proponents' political agendas.

Tuesday the FCC released the peer review panel's report on the FCC Office of Engineering and Technology's testing of prototype TV white space devices. Comments on the review are due today.

The panel that reviewed the testing consisted of FCC staff members and as expected generally found the testing was appropriate, stating it "believes the testing was well done and thorough." However, the panel suggested that the tests could have included more laboratory testing for multiple signals types and wondered if tests could have been performed to investigate the potential causes of excessive false detections.

In a Memorandum on the Peer Review of Prototype TV White Space Phase II Study, OET chief Julius Knapp responded to the panels comments regarding additional transmitter tests.

Broadcasters and TV viewers concerned about white space devices interfering with TV reception will find Knapp's response ironic considering what appears to be a rush by the FCC chairman and commissioners to approve these devices: "We acknowledge that this single device could have been utilized in tests performed at multiple locations to produce a larger data set, but sensitivities regarding the potential for producing interference to the OTA reception of TV signals made us reluctant to activate the transmitter beyond the confines of the laboratory facility."

The FCC Office of Engineering and Technology home page has links to the Peer Review, the Memorandums, and the test reports.

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.