The U.S. Federal Communications Commission (FCC) Office of Engineering Technology recently issued the results of a study it conducted as to whether unlicensed portable devices operating over unused TV analog channels cause interference with existing television broadcast signals. The conclusion of the FCC: yes, they do cause television interference.

This ruling supports the traditional positions taken by TV broadcasters, wireless microphone manufacturers and sports leagues. Microsoft does not agree with this finding and reportedly plans to file an objection to the FCC ruling with the hope of putting unused television airwaves, or “white space” to work as high-speed Internet access at a cost it says can be far lower than is currently available.

As we reported in an earlier story, television broadcasting signals have historically been analog signals; these analog signals will soon be converted to digital signals in 2009, leaving a vast amount of open analog “white space” available for use. Microsoft has developed a prototype device that it claims can carry high-speed Internet services using open white space frequencies without creating interference, and recently tested it before the FCC.

Unfortunately, the first prototype failed the initial tests, according to the FCC. Microsoft claims that its newest prototype will pass the tests and is appealing to the FCC to allow another demonstration.

The FCC claims to be interested in investigating the potential performance capabilities of devices in white-space frequencies and has invited “interested parties” to visit the FCC laboratory in Columbia, Maryland, to observe and discuss the test setup and procedures for performance evaluation of portable devices using open analog airwaves.

The FCC is accepting comments about its denial of the Microsoft device for use in open white space until August 15th. But the National Association of Broadcasters has dug its heels in, and insists that the FCC initial tests of Microsoft’s prototype device were complete and accurate. They maintain that allowing Microsoft to use this space will result in television reception that is marred by interference.