Google Alleges Rigging of Wireless Microphone White Space Tests

Remember the white space device testing at FedEx field in August?

TV Technology covered it in the article Philips Disputes White Space Test 'Failures". This week, Google's Larry Page claimed the FedEx field tests were rigged.

The Google Public Policy Blog reports, "Larry addressed the ways in which TV broadcasters and wireless microphone companies have unfortunately injected politics into the FCC's testing process, referring to August tests at FedEx Field just outside of D.C. and at the Majestic Theater in New York City. Those tests were intended to assess whether white space device prototypes could sense the presence of wireless microphone signals. However actions suggest that wireless microphone operators actually transmitted not on their normal channels but instead on channels occupied by TV broadcast signals. For instance during the FedEx Field test, wireless microphones were improperly used on the very station that carried the broadcast of the game. As a result, the white spaces devices naturally could not detect the microphone signals, as they were hidden by the much more powerful TV signals."

It isn't clear exactly what part of the tests Larry Page is talking about, but if he is referring to the Philips white space device—which found few if any channels available at multiple test sites (wireless mics in use or not)—most engineers would say the device was either too sensitive or was acting in a random manner. In any event, if a full-power station was active on the channel and it was detected, the white space device is doing what it should do—block transmission on an occupied channel.

Should he be referring to the devices that failed to detect the wireless microphones, if they were transmitting on an "in use" TV channel, why didn't they detect the TV broadcast?

From the testing reports I saw, TV signals were very weak on the field. It isn't unusual, in such cases, for a broadcaster or other wireless microphone user to use those channels for wireless microphones. If it was an analog channel, as I suspect was the case, microphones that avoided transmitting on the visual, aural or chroma carriers could operate with little received interference.

Consequently, I don't see how Google can claim the tests were rigged by using wireless microphones on channels occupied by TV stations. In either case, the white space devices should have avoided the channel.

If anything, the presence of a full-power TV station should have made it easier to detect the channel was in use.

Of course, if the wireless microphones were using existing TV channels at FedEx field, white space device supporters can argue, with some validity, that "white space devices"—in this case the wireless microphones—are able to co-exist with TV broadcasting, even on the same channel! The difference, of course is that the wireless microphones were low-power narrowband short-range devices operating on the floor of a stadium. This is an area where it is unlikely anyone except for a fan in the stands with a portable TV set would be attempting to receive an off-air TV signal.

Doug Lung

Doug Lung is one of America's foremost authorities on broadcast RF technology. As vice president of Broadcast Technology for NBCUniversal Local, H. Douglas Lung leads NBC and Telemundo-owned stations’ RF and transmission affairs, including microwave, radars, satellite uplinks, and FCC technical filings. Beginning his career in 1976 at KSCI in Los Angeles, Lung has nearly 50 years of experience in broadcast television engineering. Beginning in 1985, he led the engineering department for what was to become the Telemundo network and station group, assisting in the design, construction and installation of the company’s broadcast and cable facilities. Other projects include work on the launch of Hawaii’s first UHF TV station, the rollout and testing of the ATSC mobile-handheld standard, and software development related to the incentive auction TV spectrum repack.
A longtime columnist for TV Technology, Doug is also a regular contributor to IEEE Broadcast Technology. He is the recipient of the 2023 NAB Television Engineering Award. He also received a Tech Leadership Award from TV Tech publisher Future plc in 2021 and is a member of the IEEE Broadcast Technology Society and the Society of Broadcast Engineers.