8-VSB: Almost just good enough
Industry expected to halt COFDM tests; broadcast wisdom says 2002 DTV conversion deadline has become unrealistic
By Paige Albiniak -- Broadcasting & Cable, 1/14/2001 7:00:00 PM
Test results on dueling digital-TV transmission standards 8-VSB and COFDM came in last week and the findings were neither pretty nor surprising: neither provides great indoor reception and that's a big problem.
"Neither system in its current implementation will meet all broadcasters' or viewers' need," said the report's executive summary.
The industry is expected to decide to stop running tests on COFDM and to push for more money, time and resources for 8-VSB. That word is expected to come out of a joint board meeting this Monday of the National Association of Broadcasters and the Association for Maximum Service Television in Carlsbad, Calif.
"To achieve what we all want to achieve, which is preserving an independent broadcast service, we need to have something that can get into the home on its own," said one broadcasting-industry executive who attended last week's summit. The tests showed conclusively that neither standard successfully and consistently brings a digital TV signal into the home without placing at least a 6-foot antenna-and preferably a 30-foot high rotating antenna-on the consumer's roof, something to which today's TV viewer is highly unlikely to be amenable.
"The tone and reaction of everyone at those meetings was that this is a major wake-up call," said one source. "This is a big damn deal."
How much more time and money it will take to get 8-VSB where the industry needs it to be is unclear, but summit panelists predicted that changing over to COFDM would stall the transition by as much as 10 years, and combining the two standards could delay the transition from four to 10 years. By sticking with 8-VSB, the industry can continue rolling out digital TV, and can add improvements as it goes without having to wholly change equipment.
Still, it's becoming more apparent that every commercial broadcaster is not going to be broadcasting digitally by May 2002. NAB sources won't even discuss the possibility of missing the FCC-imposed deadline, but with serious adjustments needed for the transmission standard, a very limited supply of tower crews and no money or motivation for TV stations in small markets to make the transition, 17 months just isn't that far away.
One broadcast attorney said that there are no plans to ask for an extension, but "I think it's possible and I think [NAB] could get it."
Another source said delay is not inevitable but "the further along we are, the easier it will be to convince Congress that we are moving in the right direction. Then they'll have more confidence about giving us relief in small markets."
Sources also say the tests' less-than-desirable results give broadcasters a stronger argument to take to the FCC to press for cable and satellite carriage of both their analog and digital signals during the transition.
The tests on the two standards were conducted at four UHF stations in the Washington/Baltimore area and at one low-power VHF station in Cleveland. Testers tried each standard three ways: with a 30-foot outdoor antenna, a 6-foot outdoor antenna and with indoor antennas alone. The study found that 8-VSB worked better than COFDM with a 30-foot antenna, COFDM worked better with the 6-foot antenna and neither worked very well indoors. The study accorded 8-VSB an edge because it also covered a wider signal area when 30-a foot antenna was used.
Still, the report's writers acknowledge that the poor indoor performance of both standards was "disappointing" and needs to be improved as quickly as possible.
"It is preferable to enhance performance and support new services through backward-compatible changes within the VSB family," says the report's executive summary. "However, it is essential that all testing and evaluation be conducted in a timely manner, since the impact of non-compatible approaches increases with time as the deployment of DTV rolls ahead."
For now, broadcasters are ahead of the FCC's timetable, with 173 stations in 61 markets having already converted to digital.
- Bill McConnell contributed to this story.
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