A Good Week for U.S. DTV Broadcasters

The last two weeks have been filled with good news for terrestrial DTV in the U.S. For many broadcasters who have been following the problems with the ATSC 8VSB transmission system, perhaps the best news of the week was Mark Schubin's special mid-week memo "Thundering Thursday Thanks - SPECIAL! DTT in the U.S. Works!"
Author:
Publish date:

The last two weeks have been filled with good news for terrestrial DTV in the U.S. For many broadcasters who have been following the problems with the ATSC 8VSB transmission system, perhaps the best news of the week was Mark Schubin's special mid-week memo "Thundering Thursday Thanks - SPECIAL! DTT in the U.S. Works!" Many manufacturers' hopes for breakthrough DTV reception have been dashed over the years after testing in Mark Schubin's New York apartment. The test that led to Mark's special memo used the LG/Zenith LST-3100A DTV receiver that included LG/Zenith's 5th generation 8VSB demodulator chip. Mark's memo reported, "With a simple loop antenna, with NO care in the positioning, we were able to pull in seven DTT stations reliably. When I say 'reliably,' I mean not only that the pictures and sound were okay but that people could move around the room and I could move the antenna around without causing any breakup. It WAS possible for me to find an orientation where I could make it fail, but I really had to try, even on WNYW-DT, which could previously be received only with the antenna on the floor."

He noted, "For the first time, I could receive signals (six channels) from an antenna atop my TV, where I normally get analog channels. I received three channels reliably from New Jersey. We got the same results with the classic Radio Shack dual bow-tie with reflector, but other (fancier) antennas did not work as well." I suspect that the reason the fancier antennas did not work as well was because the new Zenith chip was actually combining multiple signal echoes to achieve a better final carrier to noise ratio that was possible on any individual signal path.

Mark continued, "The only channel I have previously received that I could not get this morning was (which we confirmed with a spectrum analyzer) off the air. Two of the other channels I could not receive are operating at very low power, and one has its transmissions beamed away from me."

Based on this test, Mark said, "I now believe that any shmo with reception conditions similar to mine can simply take the receiver out of the box, connect a cheap loop antenna, stick it wherever it looks good, and start to receive ATSC signals from all full-power, full-pattern stations."

For more information on Mark's test, including a list of the stations he did receive, see his Mark's Monday Memo Web page and select July 22nd from the menu on the left.

Other good news for broadcasters was that distant network DTV stations cannot be offered by DBS providers to households in markets where local network DTV stations are eligible for coverage. See the article elsewhere in this week's RF Report for the details, including a requirement the FCC adopt rules for DTV translators.

As noted in last week's RF Report, the ATSC has approved the enhanced 8-VSB (E-VSB) standard and posted the revised Standard A/53C with Amendment 1, Annex C, on its Web site. See this week's article for more information the new standard.

The final "good news" last week was the announcement of an RF tuner chip from LSI Logic that meets the performance standards required for DTV reception. Over the last few months I've seen an increase in manufacturers' announcements of new components for DTV sets.

In other news, the House Subcommittee on Telecommunications and the Internet considered Berlin's shutdown of analog TV and its implications for the U.S. DTV transition. While testimony from the hearing had not been posted on the Subcommittee's web site as of July 25, the testimony of LIN Television VP New Development and General Counsel Greg Schmidt on behalf of broadcasters was posted on the NAB Web site. See TV Technology News Bytes article Hard-date Makes Pols Equivocate for more information on the hearing. .