The long road toward deployment of high-definition
television appears to be hitting new technical potholes, as broadcasters are facing a
flock of new troubling questions about interference, poor reception and tower problems.
The two issues in the immediate spotlight pertain to
interference with unlicensed wireless gear used in hospitals and to instances of poor
reception of digital TV signals over in-home TV antennas. Most executives questioned last
week, however, downplayed any problems on those matters.
But the transmitter problem and how quickly broadcasters
can move to support digital TV delivery over new channels allocated by the Federal
Communications Commission could be another matter.
While some broadcasters said they'll meet their
construction deadlines this year and beyond, others, speaking privately, were concerned.
They pointed to obstacles such as local resistance to tower siting, difficult negotiations
with site providers and a shortage of suppliers and contractors as factors that could add
long delays to the digital rollout.
"This was seen as a problem a year ago, and it's
still with us," said one broadcast executive, asking not to be named.
While he acknowledged that many stations will be able to
use existing facilities, he said many others will either have to build new towers or
extend the ones that they already have to new heights in order to accommodate the new
digital transmitters.
In the past year, "the problem has gotten worse,"
said Ron Gibbs, president of Lodestar Towers Inc., a subsidiary of LeBlanc & Royle
Enterprises, a supplier of communications facilities in the broadcast and wireless
industries.
He termed as "pure fantasy" administration plans
of taking back and auctioning off the analog broadcast channels by 2006.
Public resistance to wireless towers has grown so strong
that informal talks have begun in Congress to limit localities' prerogatives in
dealing with tower building, said Gibbs, who chairs a committee on the matter within the
Personal Communications Industry Association.
The broadcast and wireless industries, Gibbs said, have
failed to persuade Congress to intervene against the nationwide surge in tower-site
moratoriums.
"When you say to the local zoning authority that
you're going to build a 1,500-foot tower, you're going to draw a real
crowd," Gibbs said, noting that mobile wireless towers drawing flack today are
typically only 150 feet high or so.
Further exacerbating the situation is the fact that there
were three major broadcast-tower collapses over a one-year period ending last fall that
resulted in a total of seven deaths in Cedar Hill, Texas; Jackson, Miss.; and Monroe, La.,
Gibbs said.
He noted that these failures -- all resulting from efforts
to extend towers to support digital TV transmitters -- raised concerns about the
availability of qualified people to meet broadcast construction deadlines and about the
costs of insurance, which have already been affected by the recent disasters.
Gibbs said he was worried that the industry will "end
up in a situation where only those who can afford to self-insure themselves will be able
to supply services."
As for the immediate issues of interference problems
associated with digital TV signals, industry executives said none of the news was really
new.
For example, said National Association of Broadcasters
spokesman Dennis Wharton, broadcast engineers put the FCC on notice several years ago that
unlicensed wireless devices operating over broadcast spectrum that was to be used for
digital TV might suffer interference.
That happened at Baylor University Medical Center Feb. 27,
when Dallas station WFAA-TV became the first to launch HDTV service on an ongoing basis.
The failure of wireless heart monitors at the hospital triggered alarms across the medical
and broadcast sectors, putting unlicensed users of the frequencies on notice that they
would have to upgrade their gear or risk similar outages.
The NAB was working with hospital trade associations and
broadcasters to get the message out, Wharton said, stressing, "This is spectrum that
has been reserved for broadcasters."
The other technical issue was interference related to
digital TV's modulation system. Here, image ghosting has resulted from signals being
received over multiple paths by antennas mounted on TV sets.
Sinclair Broadcast Group CEO David Smith wrote to House
Telecommunications Subcommittee chairman Billy Tauzin (R-La.) to suggest that the
multipath problem might require a re-evaluation of the choice of modulation systems used
in digital TV.
Tauzin spokesman Ken Johnson, noting that Smith had made
"a very powerful, persuasive argument," said Tauzin would raise the issue with
FCC chairman William Kennard, but he added that Tauzin was not taking sides yet.
Sinclair's action came as some industry sources
pointed to poor results of indoor-reception tests by Maximum Service Television (MSTV), a
broadcast-industry technical group, at an experimental NBC station in Washington, D.C.
"The tests are showing that a very large number of
sites don't work, in some cases even for rooftop reception," said a senior
engineering executive who has had a lead role in preparing for HDTV.
This source complained that previous testing on HDTV
standards had been cut back from six locations to one unrepresentative city: Charlotte,
N.C.
Problems over indoor antenna reception came to light after
the FCC agreed to give UHF stations more power to work with, said Sinclair vice president
Nat Ostroff, who wants the tests made public.
Broadcast executives close to the tests disagreed that
there was a problem, saying that the tests in Washington involved "worst-case"
conditions.
"If you're getting very poor NTSC [National
Television System Committee] reception, you're not going to get good DTV [digital TV]
reception," said Victor Tawil, vice president for technology at MSTV.
Sinclair officials suggested that the modulation problems
might require a change from the VSB (vestigial sideband) system to a technique used in
Japan and Europe known as COFDM, but other executives last week voiced little support for
this move.
