Pushing back on the PR onslaught by Google and its cohorts
in the White Spaces Coalition—Google said the FCC rigged the wireless mic tests
at FedEx Field outside Washington—ESPN
has released some details of its observation of the tests.
Before Google charged that the FCC rigged its own tests, the
White Spaces Coalition claimed it was pleased that at the same tests, a
spectrum-sensing device from Philips Research successfully detected TV signals.
Yes, ESPN said, the Philips device found TV signals—even
where there were none, such as on Channel 37, reserved for medical telemetry,
with no TV use.
“With regard to the test results, the device provided by
Philips did not generate data
at FedEx Field that demonstrates sensing technology is mature or will offer
meaningful protection for incumbents in the VHF and UHF bands,” ESPN wrote in a
Sept. 26 letter to the commission. “On 7 out of 8 scans conducted at FedEx
field, the Philips device incorrectly determined that all UHF channels were
occupied. The Philips device appeared to automatically ‘rubber stamp’ channels
as occupied, including channels that were clearly vacant.”
Advocates of nearly unfettered white space usage have tried
to use the fact that wireless mics sometimes operate on occupied TV channels as
an indication that the mic makers and users are being disingenuous in their
claims that white space devices might cause interference to TV and mic signals.
TV Technology columnist
Doug Lung addresses those claims in his current issue of RF Report, and can’t find any scenario under which the coalition’s
argument makes any sense.
A report from the FCC Office of Engineering and Technology
could settle some of the argument when it issues its report on its tests,
probably this fall.
ESPN also urged the FCC to thoroughly test beacon
technology. Both Motorola and Silicon Valley
startup Adaptrum have submitted beacon devices and strategies for using the
beacons to protect against interference. But ESPN maintains the technology
remains unproven and would only exacerbate the problem of available spectrum at
RF-rich events such as NFL games.