Skip to main content

White Space: NAB Fine With Geolocation Concept

White space device (WSD) proponents like to portray broadcasters as dinosaurs attempting to protect their business from competition.

NAB President and CEO David Rehr countered those claims in a letter to FCC Chairman Kevin Martin in which he states, "Broadcasters again want to emphasize that we do not oppose the use of vacant channels in the television broadcast bands. We support the concept of geolocation in combination with an accurate database as a method of avoiding interference with television broadcasts and wireless microphones."

Rehr pointed out, however, "Spectrum sensing alone, as the data within the OET report actually show, does not provide adequate interference protection."

The letter also questions why, if geolocation "is a potentially workable basis of white space device rules, why use geolocation-plus-sensing capability in lieu of the simpler geolocation technique alone?" The letter asks the FCC to consider how a 40 mW power limit is consistent with evidence in the technical record showing that operation on adjacent channels should be at much lower power levels and "in fact should not be allowed at all in order to fully protect television service."

The letter also asks whether the proposed power limits for unlicensed devices will cause interference to cable television service, based on the results of the OET field tests. "There is no justification in the technical record or the OET report for the FCC basing rules on the general assumption that interference from an unlicensed white space device to a digital television (DTV) receiver at 10 meters or closer can be disregarded," NAB argues.

In summary, the letter states: "Given these omissions and unanswered questions, the Commission should not proceed on November 4 to adopt final rules authorizing white space devices. Before approving these devices that would have a profound impact on the public's access to television broadcasts, both over-the-air and on cable, the Commission must pause to ensure that it acts only on the basis of reliable and properly peer-reviewed and vetted technical evidence."

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.