Will Feds Grab DTV Spectrum?

A clash is shaping up between DTV broadcasters and other potential users of their spectrum. Broadcasters are getting ready to defend the spectrum they received in the DTV transition which concluded in 2009. But some in the federal government say much of that spectrum that would be better used for expanded cellphone networks and a new generation of wireless internet service.

What The New York Times describes as "an old media vs. new media lobbying battle" is now underway.

Exactly how much spectrum does broadcast TV use? Check out the U.S. Dept. of Commerce spectrum map. The answer is three out of the four large blue blocks in the middle row.

DTV, like analog TV before it, requires blank spaces in the spectrum between channels to prevent interference. This, critics say, is an inefficient use of spectrum that is needed to make mobile devices work better and promote the growth of wireless internet.

The Federal Communications Commission, under relatively new chair Julius Genachowski, wants to reclaim some of that spectrum and auction it off to the highest bidder. He says the process would be "voluntary," but adds, "voluntary can't mean...giving every broadcasters a new and unprecedented right to keep their exact channel location."

Broadcasters and their allies don't like the sound of that, the Times reports. "We are not going to volunteer," said CBS CEO Les Moonves flatly. Said Rep. John Dingell (D-MI): "You hold a gun at the teller's head and say, 'We know you are going to voluntarily give me this money. If you don't, I'm going to shoot you'."

At stake is free HDTV delivered to 11 million households, a number that may grow if the economy worsens and more people cancel cable and satellite service. However, defenders of the spectrum grab say it will promote economic growth and make the U.S. competitive with the worldwide pace of technological change.

See The New York Times.

WiWavelength's picture


You did not read the frequency allocation table very clearly. Starting with the second row, each subsequent row displays ten times the bandwidth of the previous row. In other words, it follows a logarithmic scale (as do your loudspeaker frequency response graphs).

So, while AM radio appears to cover a very wide swath of spectrum, it actually occupies little more than 1 MHz total bandwidth. In comparison, VHF/UHF TV requires 6 MHz bandwidth per channel for nearly 300 MHz total bandwidth.

Also, AM radio spectrum is not under consideration for conversion to mobile use because frequencies under 2 MHz have wavelengths several hundred feet long -- much too long for mobile use.


Mark Fleischmann's picture
Thanks for your correction. I'll remove the part about AM from the story.