Why did the FCC give a failing grade to a controversial Microsoft prototype that sends high-speed Internet signals over unused television airwaves? It was broken. At least, that's the word from Microsoft.

As we reported earlier today, on July 31 the Federal Communications Commission released an 85-page report saying that Microsoft's "white space" prototype was unable to detect unused TV spectrum and that it interfered with other wireless devices. But after discussions with the commission, Redmond is now claiming that the device tested by the FCC was defective. As if we didn't already know that.

"During meetings with FCC engineers last week, Microsoft determined that the prototype device tested by the Commission was working improperly and an internal component was broken. This accounted for the FCC's aberrant test results," said Jack Krumholtz, Microsoft's managing director for federal government affairs. "We remain confident that the unused channels in the television spectrum band can successfully be used without harmful interference to incumbent licensees such as television and wireless microphone services."

When contacted, the FCC declined to comment - that's typically way it works with ongoing investigations like this one - but Chairman Kevin Martin is on record as saying the commission hopes to find a way of transmitting Internet service over "white spaces," portions of television spectrum that go unused by local TV channels. Just this afternoon, the commission's office of engineering announced that it plans to discuss the matter with "interested parties" on Thursday. Microsoft's prototype is also backed by big-name tech companies like Dell, Google, Intel, and Philips. (Yes, Microsoft and Google are working together.)

Meanwhile, the National Association of Broadcasters (NAB), the trade association that serves more than 8,300 local radio and television stations, was more than happy to toss us a comment. Spokesman Dennis Wharton believes that Microsoft's prototype - broken or not - deserves no airtime. "The FCC performed rigorous tests on the Microsoft devices," he said, "and we are confident that its finding that these devices cause interference to television reception is accurate."

By definition, Redmond's prototype would use local television spectrum that stations do not use, but the NAB still sees Microsoft as a gun-wielding egocentric: "Nearly a decade ago, broadcasters and government launched the historic public-private partnership that is bringing the next generation of television to American consumers. Now that the [digital TV] transition is near completion, up steps Microsoft and its allies to jeopardize all that has been accomplished. By continuing to press its self-serving agenda, Microsoft is playing Russian Roulette with America's access to interference free TV reception."

As you might have noticed from Google's efforts to convince the FCC that it should give consumers open access to the 700-MHz band, the portion of the wireless band no longer used by TV stations who've made the switch to digital transmission, the big web players hope to establish a means of broadband access that's outside the control of big telcos like AT&T and Verizon. If approved by the FCC, mobile devices such as the Microsoft white-space prototype would enable consumers to connect directly to the net - without an OK from wireless carriers. That's pretty much what the commission has allowed with a portion of the 700-MHz band, but white spaces represent a much larger chunk of bandwidth.

Evidently, Microsoft had submitted two white-space prototypes to the FCC for testing: the one that failed the FCC's test, and a "spare" that was never used. According to Microsoft, once they got the spare back into their own lab, it worked pretty well - but it seems that certain functions needed a little tweaking.

"Microsoft's testing of the spare prototype device it had previously submitted to the FCC revealed that in the FCC's laboratory, the spare device was able to detect digital television signals at the power level that we had stated," Krumholtz said. "And with some adjustments, this device detected wireless microphone signals as we had indicated that it would."

The company also wants it known that one of its partners, Philips, submitted a second white-space prototype and that it worked just fine. Of course, Microsoft failing a test is bigger news that Philips passing one. ®