National Free WiFi Too Impractical to Ever Come to Your Community
NEWS ANALYSIS: The much ballyhooed stories about a free national WiFi network using 5GHz spectrum and white space ignore technical reality to create confusion and raise false hopes.
Worse, it's unlikely that these white spaces will be useful for devices such as phones. The reason is that the frequencies available in the white spaces vary by locality, and they cover a wide range of frequencies in the UHF television band. Those frequencies range from 470MHz through 700MHz. Frequencies above that have already been—or are about to be—auctioned off for mobile carrier use. If you've been around long enough to remember the old days of UHF television, you'll recall that getting a good signal at any distance was problematic. For a television signal to get to you, the broadcaster had to transmit using power in the tens to hundreds of thousands of watts of what's called effective radiated power. While it's certainly possible to send out data at those power levels, remember that data communications is a two-way process. And your phone typically puts out less than one watt of power, usually a lot less. What this means is that you might be able to receive data, but unless you're next to the transmitter, it'll never be a two-way conversation. One way to overcome this is to place thousands of hotspots in a community as some cities do with municipal WiFi. This works, although with WiFi it really only works well if you're not inside a building. With the proposed UHF solution, it will work inside buildings, but only to a certain extent. As you'll also remember from the days of UHF television, signals didn't go over hills, around trees or through thick concrete walls. This was one of the biggest problems suffered by UHF broadcasters. The only thing that really kept them alive was cable television. UHF data communications won't work any better, but if thousands of local hotspots are available, that won't matter.






















