The association of television broadcasters launched a campaign on Monday designed to persuade the Federal Communications Commission not to allow portable wireless Internet services in the so-called "white spaces" of TV spectrum.

The move pits powerful broadcasters against some of the biggest names in technology, including Microsoft, Google, Intel, and Dell.

The broadcasters said they began airing a television advertisement as well as print ads in several Capital Hill publications on Monday. They also planned to send a letter to the FCC arguing that enabling portable wireless Internet services in the white spaces will degrade TV service for consumers just as they spend billions of dollars buying new digital TV sets. "This investment should not be jeopardized by the introduction of unlicensed personal and portable devices that are sure to interfere with television reception," the letter reads.

The campaign from the National Association of Broadcasters and the Association for Maximum Service Television comes in response to an FCC report detailing its testing of prototype devices from the technology giants, which are working together as the White Space Coalition.

The companies, also including Hewlett-Packard, EarthLink, and Philips Electronics North America, had submitted prototypes of products that could operate in the portion of a spectrum band that a TV broadcaster doesn't use, known as white space. The devices were designed to look for broadcasts in the spectrum and then transmit only if the spectrum was free. But the FCC found that the devices didn't consistently detect the signals and could sometimes cause interference.

The FCC has already approved transmission in the spectrum for fixed devices. The prototypes submitted by the technology companies were of portable products.

However, two weeks after the FCC released its report, Microsoft filed a letter with the FCC explaining that the device it submitted was badly damaged and that's why it failed to adequately detect broadcast signals.

The broadcasters say that even if the devices work as designed, they won't protect digital TV sets from "devastating interference." That interference would cause an unacceptable hit on quality, they say. "While our friends at Intel, Google and Microsoft may find system errors, computer glitches and dropped calls tolerable, broadcasters do not," Alan Frank, NAB's chairman, said in a press release.

Even though the FCC found that the prototype devices don't consistently work properly, the agency said it is open to the possibility that future devices could perform better.