Google now has a Wireless Spectrum Database
What are TV white spaces?
One important form of unlicensed spectrum is TV white spaces, unused channels in the broadcast television spectrum band. Many parts of the world have dozens of open TV channels, especially in rural areas, that can travel distances up to 10 miles. The FCC, Ofcom, and other regulators are providing a path to allow Wi-Fi to broadcast over unused TV channels. White spaces could help bridge the digital divide by providing wireless internet to rural areas and help enable technology innovation.
Google – continuing to do the opposite of evil things (most of the time).