Take the question of spectral availability. While this might seem one of the easiest to settle-is more than half of US TV spectrum lying fallow or is it not?—the answer isn't obvious. The New America Foundation, a think tank that supports white space devices, claims that 25 to 80 percent of TV bandwidth is unused, depending on where you look. When the group hosted Google co-founder Larry Page at a DC event a few months back, Page also spoke of all that prime spectral real estate that was being "wasted..."

And Sascha Meinrath of the New America Foundation calls the entire spectrum availability issue "absolutely ridiculous." The spectrum is only booked up, he notes, if the FCC rules out sticking a white space device on an empty channel adjacent to a TV channel. In fact, so concerned is the broadcasting industry about interference that it has asked for a "third adjacent" rule on white space devices, should they be allowed; a device would need two empty channels on either side of its transmission channel before it could broadcast (for a total of five empty channels).

The issue is tremendously important. If white space devices truly need to find three (next adjacent) or five (third adjacent) available channels before transmitting, their usefulness would be curtailed dramatically. LINK