So long everyone, it's been fun riding the C-Dog, but I'm out for now. Good luck to all the longs-keep the faith-I'll be back when my money's free again! Bill.
Ooops........................................
HDTV: Not Heart-Stopping, but a Bit Too Close
By PETER H. LEWIS
hen engineers at WFAA-TV in Dallas recently flipped a switch to become one of the nation's
first regular digital broadcasters, a dozen wireless heart monitors stopped working at the
heart-surgery recovery center at the Baylor University Medical Center. When the problems
vanished suddenly, clinical engineers were baffled - it turns out that all was well as soon as WFAA
turned off its transmitters for the night.
When the broadcast tests resumed the next day, the heart
monitors went on the blink again.
No one was harmed, and the hospital brought in auxiliary bedside
monitors to insure reliable monitoring of the patients. But it took
nearly two days before hospital technicians identified the source of
the interference as the digital television tests run by WFAA on
Feb. 27, said Scott Juett, a senior clinical engineer at the Baylor
Health Care System in Dallas. The hospital's wireless heart
monitors had been using part of the Channel 9 broadcast spectrum,
but the Federal Communications Commission had granted that
band to WFAA-TV for its high-definition, or HDTV, broadcasts.
Baylor made some changes to its equipment, and WFAA rescheduled its digital debut for Monday. A
station spokesman said WFAA notified all local hospitals that the system would be retested over the
weekend. But as soon as the second test began, on March 7, another large hospital, Methodist Medical
Center near downtown Dallas, reported disruptions in some of its 55 wireless heart monitors. Again, no
heart patients were harmed, said Sam Lopez, a hospital spokesman.
WFAA stopped its testing again, and Methodist Medical Center technicians scrambled to switch its
telemetry system to a new frequency.
The interrupted broadcasts suggest that the imminent
arrival of a new generation of digital television broadcast
stations across the country may mean more than just
brilliant pictures for those who can get an HDTV set (not
yet on the market). Government and medical officials
acknowledge that digital broadcasts have the potential to
disrupt important medical monitoring equipment at nearby
hospitals.
FCC officials were aware of the possible problem and
warned hospitals last October that the new generation of
digital television stations, scheduled to begin broadcasting
on or before Nov. 1 in at least 10 major cities, including
New York, could interfere with some types of wireless
heart, blood pressure and respiratory monitors and
"endanger the health and safety of the patients." The FCC
advised hospitals and medical equipment manufacturers to
"avoid operating on occupied broadcast channels."
But medical, broadcast and regulatory officials conceded
this week that the warnings had gone largely unheeded or
unheard. Some hospitals are continuing to use already
allocated portions of the television broadcast spectrum for
medical devices that send a patient's vital signs through the airwaves to a nurse's monitoring station.
The broadcasters have the stronger claim to the wavelengths in question. All pieces of medical
telemetry equipment are classified as "secondary devices" that must yield to licensed broadcasters in a
given broadcast spectrum.
The incidents in Dallas were not the first time broadcast technologies have affected medical
equipment. Things like cellular telephones, microwaves, two-way radios, cordless phones, video games
and even laptop computers can interfere with hospital devices.
The broadcast interference conflict is relatively simple and inexpensive to avoid. The Baylor medical
center officials decided to accelerate the planned purchase of new medical telemetry equipment that
will reduce the risk; there are areas of unused broadcast spectrum where the medical devices can
operate without HDTV interference.
In response to the Dallas interference problems, the National Association of Broadcasters sent a fax
Tuesday alerting its 1,200 station members that "difficulties may arise in other markets as stations begin
to make the transition to digital television."
The association's bulletin said, "The inception of digital television will increase the use of the TV
spectrum during the digital transmission, making it harder to find vacant channels that can be used by
low-power, unlicensed devices (such as heart monitors) without interference."
The Food and Drug Administration had an emergency meeting Wednesday to discuss the problem.
"Now that the problem has been identified, we hope it won't occur again and blindside anybody," said a
spokesman for the FCC.
In Dallas, David Muscari, director of creative services for WFAA's parent company, A.H. Belo Corp.,
said the station was planning to try to begin digital broadcasts on Channel 9 on Friday or Saturday,
depending on how quickly the hospitals adapted their equipment.
If the tests are successful this time, WFAA will become the first commercial station in the country to
begin regular HDTV broadcasts on the VHF spectrum (channels from 2 to 13). WRAL-HD in
Raleigh, N.C., has been broadcasting HDTV signals since July 1996 on the UHF frequencies
(channels 14 to 51) without incident, said John Greene, vice president for special projects for WRAL's
owner, Capitol Broadcasting. |
