By Harry A. Jessell

TVNewsCheck

Following President Obama’s announcement last week that the White House would take up the cause of finding 500 MHz of additional spectrum from wireless broadband services, Larry Summers, director of the President’s National Economic Council, gave a speech in which he talked about how some of that spectrum could be gotten from broadcasting.

"New technologies can now support more than one high-quality signal in a space that previously could only fit one, enabling multiple stations to share a band of spectrum and free up an equal amount for other purposes," he said before the pro-broadband New America Foundation.

New technology can now support more than one high-quality signal in a space that previously could only fit one.

Really?

Not according to the Broadcasting Engineering Forum, an assemblage of mostly top broadcast engineers that the FCC convened on June 25 to address various technical issues surrounding the FCC’s (and now the president’s) plan to take back about a third of broadcast spectrum and auction it off for wireless broadband.

According to the forum’s panel on video compression and channel sharing, you really can’t put two "high-quality" signals on one broadcast channel, if by "high-quality" you mean high-definition and I don’t know how else you would define it in the second decade of the 21^st century.

Speaking for that panel, Andy Setos of Fox said that channel sharing is"not viable" because one or both of the signals would be "significantly degraded."

"Ultimately, when you are required to do this, you are forced to create a winner and loser in HD streams," he said.

Part of the problem is that the MPEG-2 compression scheme used by broadcasters is now almost 20 years old and unlikely to yield much more help in squeezing fat pictures through small spaces, he said. And moving to MPEG-4 compression is impractical since it would involve replacing the tens of millions of new digital TV sets that have been sold over the past decade, not to mention the 50 million digital-to-analog converters that were bought and painfully installed during the final DTV transition.

Of course, he said, you could put an HD and a degraded HD or an HD and an SD signal on one broadcast channels, but the owner of the inferior signal would not have much of a chance in a TV world that will soon be all HD. It would be like trying to make your way as a B&W TV service after color had taken over.

To sum up, the panel of experts represented by Setos severely undermined one of the cornerstones of the FCC’s plan to take back broadcast spectrum.

And so did the forum’s other three panels — on band repacking, cellularization of the broadcasting system and VHF propagation.

Speaking for the repacking panel, Bruce Franca of the Association for Maximum Service Television (MSTV) said recovering 120 MHz of broadcast spectrum as the FCC intends could not be done without a massive amount of channel sharing, something most broadcasters are loath to even consider. More than 700 TV stations in 85 heavily populated markets would have to share channels. In 21 of the markets, including New York and Chicago, every station would have to share. In 12, some stations would have to triple up.

Speaking for the VHF panel, Victor Tawil of MSTV and Kerry Cozad of Dielectric Communications said the FCC should forget about the idea of packing more TV stations into the VHF band, particularly the low end, chs. 2-6. Why? Because reception is lousy. To make low V effective, you would have to kick up the output power 100 times and it would it still wouldn’t be enough to overcome all the noise in the band and the limitation of antennas.

Speaking for the cellularization panel, Bob Seidel of CBS said distributed transmission systems, either of the single frequency or multiple frequency varieties, are not keys to recovering spectrum. They are expensive to implement and, for all the time and money, would produce little improvement in spectrum efficiency. To even consider such a system, he said, the country would have to adopt a new broadcast transmission scheme — COFDM — and that’s not going to happen for the same reason it’s not going to go to MPEG-4.

During this whole spectrum hoo-ha, FCC Chairman Julius Genachowski has run an open process, giving broadcasters ample opportunity to express their concerns with the broadband plan, even before it was put on paper.

In his speech at the NAB in April, he promised to hold an "engineers forum … to address concrete technical issues raised by the plan."

He delivered on that promise on June 25.

Now all he has to do is listen.