Two major broadcasting associations continue to press the Federal Communications Commission not to fast track unlicensed personal, portable devices that tap into "white space"—unused analog TV channels.

The analog-to-digital television transition "will be seriously jeopardized" if the FCC lets such devices access TV spectrum "without being accompanied by proper protections," argue reps from the National Association of Broadcasters (NAB) and the Association for Maximum Service Television (MSTV).

Top TV station owning groups sit on the board of MSTV, as do the presidents of Hearst-Argyle Television and Tribune Broadcasting. They're locked in a proceeding dogfight with members of the "White Space Coalition"—Microsoft, Google, Hewlett-Packard, Intel, and Philips Electronics North America.

The white spacers won a victory in October of 2006 when the FCC gave the go-ahead to technologies that can take advantage of temporarily unused TV spectrum, more of which will become available thanks to the digital TV (DTV) transition, scheduled to finish in February of 2009.

Sensor devices using geo-location and other techniques can detect such temporarily unused TV frequencies, or "white space," and route them to home entertainment systems, local area networks (LANs), and "community mesh networks" linking neighborhood LANs together.

In February of this year Microsoft submitted specs to the FCC for a small white space receiver, able to access signals for a UHF radio, a CR scanner, and a laptop computer attached to a network processor through an ethernet interface.

But NAB and MSTV's April 20th FCC statement, part of a long string of he said/she said filings, says that the White Space Coalition has not demonstrated that these receivers will easily coexist with TV signals.

"We urge the Commission to see past the [white space] Coalitions rhetoric and give attention to the technical analysis and data in the record—all of which suggests that personal/portable devices will cause interference and should not be permitted," MSTV/NAB charge.

They argue that:

• The White Space Coalition has not demonstrated that their safeguards for unlicensed devices will prevent signal interference, even within a family home. Thus their safeguards may be "ineffective to prevent interference to nearby neighbors," MSTV/NAB claim. "One can easily imagine this same situation occurring in an apartment, condominium or town home environment."
• The coalition has not submitted data that refutes MSTV/NAB assertions that portable devices "would pose a threat to broadcasters." MSTV/NAB says that the FCC has recently released studies that confirm their fears "that TV receivers can have worse performance when multiple interfering signals are present."
• Reliance upon spectrum sensing technology alone will not prevent TV band devices from intruding on occupied television channels. The signal power limits that the White Space Coalition recommends for its spectrum detecting devices may not be sufficient to prevent such intrusion.
• NAB/AMST also charges that white space device interference ranges are comparable to the signal power of cell phones that communicate with towers miles away, "not merely the same home or next door as suggested by the Coalition and others."

The tone of MSTV/NAB's conclusion suggests that the last word on this debate is far off.

"While the [White Space] Coalition has claimed that it supports a robust technical debate on this issue," the two groups contend, "its response to MSTV/NAB suggest that it wants this debate to be devoid of facts, measurements and data."