After months of expressing concerns privately, ABC publicly declared its unhappiness with the U.S.'s current digital broadcast transmission standard. In a joint filing with NBC to the FCC, the network warns that the 8-VSB system provides poor indoor reception.
"Our real-world experience.is that this method of transmission does not provide reliable reception," the networks said.
ABC and NBC said they have little confidence that DTV receiver manufacturers will be able to make good on their promises to solve 8-VSB reception problems anytime soon and added that they will begin testing the rival European COFDM modulation standard next month.
Responding to criticism from a growing number of broadcasters, the FCC and the Advanced Television Systems Committee, a standards-setting body, are reexamining 8-VSB. They still hope the solution is in better receivers.
Sinclair Broadcast Group began questioning 8-VSB's efficacy two years ago and has been waging a campaign since last spring to get the FCC to reexamine the standard. Sinclair Vice President of New Technology Nat Ostroff, speaking at a BIA datacasting conference in Washington last Thursday, seemed buoyed by ABC and NBC's filing. "I think we've established that the concept of digital television that we had as broadcasters, that we were led to believe was available to us, is not being fulfilled," he said. "I'm pleased to say that today that knowledge is fairly well-disseminated, as networks like NBC and ABC have confirmed the results and demanded improvement."
Ostroff's viewpoint was countered by Richard Lewis, senior vice president of technology and research for Zenith Electronics, the patent-holder on the 8-VSB system. He released findings from a new engineering study of the New York market, commissioned by Zenith and conducted by respected engineer Jules Cohen, that indicates that COFDM would result in less coverage than 8-VSB and greater interference to co-channel and adjacent-channel DTV stations in surrounding markets.
The theoretical study looked at WNBC-DT, WABC-DT and WPIX-DT in New York, digital stations that have yet to go on the air. When asked why the COFDM/VSB study wasn't done with WCBS-DT or WNYW-DT, which are up and running in New York, a Zenith spokesman said the others were selected because of their adjacent-channel issues. He added that the results were not shared with either ABC or NBC.
As for 8-VSB reception difficulties now, Lewis said he is "very confident these issues will be resolved in the next two years."
Ostroff said that is too long to wait. He challenged set makers like Zenith to bring an 8-VSB receiver to the House hearings on DTV next month and demonstrate successful 8-VSB reception. "If they can show it inside the House hearing room, we will congratulate them on having solved the problem."
-Bill McConnell contributed to this report.