Subject: [NEXTEL-1] Technology Gets in Its Own Way

From: [email-masked]
Date: Wed, 05 Nov 2003 00:28:40 -0500

Technology Gets in Its Own Way

Radio signals from myriad devices such as cellphones and garage door
openers clash in an annoying and, at times, hazardous competition.

By Jube Shiver Jr., Times Staff Writer

Alvin Cowans spent nearly $1 million for a house sporting all the
technological conveniences — from a stereo system that piped music to
every room to telephone caller ID that flashed on the big-screen TV.
He had barely plugged everything in when the ghosts appeared.

Cowans heard them over his cordless phone, chattering like a fax machine
even though he didn't own one. And they played with the automatic garage
door, sending it up and down when no one was home.
"I'll go outside and see the door open and I'll call my wife and she
swears she closed it when she left," said Cowans, a former defensive
back for the Pittsburgh Steelers who now runs an Orlando, Fla., credit
union.  "It's like some of these things have a mind of their own."

Digital poltergeists are afoot these days as an explosion of garage door
openers, television remotes, cellular phones and other wireless devices
create quirky and potentially dangerous interference in the increasingly
crowded airwaves.
So-called signal leakage ranges from the mundane — like TV static when
the vacuum cleaner runs — to the serious — like baby monitors
interfering with airplane navigation equipment. The latter happened in
May when pilots flying into London's Luton airport heard cries broadcast
by a baby monitor on the ground that drowned out communications from air
traffic controllers.

The Federal Communications Commission, which polices airwaves in the
United States, has seen the number of complaints about interference jump
to more than half a dozen a day from almost none in the 1970s. Over the
last two years the agency has boosted its engineering staff by 15% and
spent $5 million on new gear to test products for interference.

"We are seeing — with the expansion of wireless products — the potential
for a lot more interference," said Jack Black, business development
manager for DLS Electronic Systems Inc., in Wheeling, Ill., one of the
largest electronic testing labs.  "If we don't do [something] you are
going to see more electromagnetic interference."

But FCC Chairman Michael K. Powell has proposed less, not more,
government regulation of the publicly owned radio spectrum. His bet: The
same companies that spend billions of dollars to lease parts of the
spectrum will find ways to minimize interference.

Most interference problems are caused by transistors. They act as small
radios inside electronic products, sending and receiving signals that
travel in limited frequencies on the radio spectrum, like cars driving
side-by-side on a multi-lane highway.
The lanes on the electronic freeway can be very close together, however.
Garage door remotes operate at around 40 megahertz while some cordless
phones use the band between 40 and 50 MHz. Baby monitors broadcast coos
and whines at 49 MHz. Mobile phone operators occupy parts of the 800-MHz
band as well as from 1,850 to 1,990 MHz.

The FCC tries to impose lane discipline. But when signals leak outside
their frequency, or when two devices share the same frequency or
broadcast with too much power, the results can be unpredictable. And
because all electrical devices leak tiny amounts of electromagnetic
radiation, virtually any modern gadget has the potential to interfere
with anything around it.
That's why the airlines are so strict about passengers not playing a
Game Boy or listening to a Walkman during takeoff and landing, when
electronic navigation and communication gear in the cockpit is most
crucial.

German scientist Peter B. Ladkin, who studies electronic interference,
said mobile phones are particularly prodigious producers of
interference. "As far as I am concerned, cellphones have to be turned
off, not on standby but turned off, from the moment the aircraft is
anywhere near the runway environment until the aircraft leaves the
runway environment on landing," said Ladkin, a computer science
professor at the University of Bielefeld. "No exceptions."

Ladkin took an interest in interference in the early 1980s, when he was
living near Oakland International Airport. He noticed that on rainy days
when airport controllers used certain frequencies, his garage door would
open on its own.
Although the FCC runs a program to certify that electronic equipment
sold in the United States will not emit harmful electromagnetic
interference, the agency concedes it can test only a fraction of the
electronic gear. Instead, it depends on tests manufacturers submit.

Those are far from foolproof, as the agency found after allegedly "FCC
certified" television antennas designed for recreational vehicles
interfered with the Coast Guard's global positioning systems, said
Edmond J. Thomas, chief of the FCC's Office of Engineering and
Technology.

The problem was underscored five years ago in Dallas, shortly after the
nation's first digital television station went on the air. Broadcasts by
WFAA-TV immediately began interfering with about 60 wireless heart
monitors at Baylor University Medical Center.

No one died or was injured, but the hospital had to buy $200,000 of new
equipment.
As in the Dallas case, it is often the introduction of new technology
that triggers airwave interference.
"Cellular was really the major change," said the FCC's Thomas. Before
the arrival of mobile phones, Thomas said, airwave interference was
easily detected and fixed. But today, "new capabilities are being
brought to the marketplace that require state of the art technologies"
to detect and troubleshoot.

"A lot of this wireless stuff is not ready for prime time," said Richard
Rose, chief executive of the Atlanta computer consulting firm Practical
Solutions. "I tell my corporate folks, 'Don't install a wireless
network. Go wired.' There are too many interference and security
issues."

Most interference is just inconvenient. Rose once stalked around his
office looking for intruders after he heard people talking. He later
determined that the voices were broadcast over his computer speakers by
two-way radios used by workers at a different company.

Jennifer Anderson Smith, a Havertown, Pa., mother of four, has gone
through four baby monitors in four years in an unsuccessful search for
an interference-free device.

Smith said that instead of hearing her infant son over the monitor, "I
would
sometimes hear my neighbors' phone conversations, and I said to myself,
'Hey,
that isn't David. He can't even talk yet.' "

Although interference is a minor annoyance to most, it can be costly to
commercial users who depend on the airwaves for their livelihood. And
because the spectrum is finite, they don't want newcomers encroaching on
their valuable turf.
Broadcasters are organizing against an FCC proposal that would allow
wireless computers and other devices to use a portion of the spectrum
assigned to television broadcasts. Similarly, public safety officials
want the FCC to evict cellphone carriers from certain frequencies to
minimize interference with police and firefighter radios.

Although the federal government has more than doubled the amount of
airwaves devoted to carrying wireless phone calls, the industry's
appetite is taxing even that. And while most countries boast a single
technology standard for cellphone transmissions, there are three major
standards in the U.S., making it hard for the wireless industry to use
the spectrum efficiently.

To free up more airwaves, FCC Chairman Powell proposes a radical idea
called "interference temperature." The concept would allow more users to
share the airwaves by using transceivers that shut off or skip to
another frequency when they encounter a conflict.

"The time has come to consider an entirely new paradigm for interference
protection," Powell declared in a speech last year at the University of
Colorado at Boulder. "Transmitters would be required to ensure that the
interference level —or interference temperature — is not exceeded.
Receivers would be required to tolerate an interference level."
The idea has shown some promise. Last year, the Pentagon objected to
allowing the fast-growing market for wireless computing equipment to use
the 5-gigahertz frequency band, saying the technology, known as Wi-Fi,
would interfere with military missile radar. After testing the claim,
FCC engineers brokered a solution that requires Wi-Fi devices on the
5-GHz band to use dynamic frequency selection and shut down when they
sense competing military use of the airwaves.
"The Wi-Fi device looks for the radar signal," the FCC's Thomas said.
"If it detects it, it moves to another part of the band."
But some experts say frequency hopping is not a long-term solution. For
starters, it makes tracking interference more difficult. Some cordless
and cellular phones already do not confine themselves to easily
identified frequencies and instead hopscotch all over to find unused
channels.

"The problem is that beyond a certain number of users in a given band,
these technologies tend to fall apart," said John K. Daher, a research
engineer at the Georgia Tech Research Institute. "A handful of these
devices is fine. But beyond a certain point they start to conflict with
each other."
http://www.latimes.com/business/la-fi-interference4nov04,1,7936987.story?coll=la-home-leftrail

------------------------ Yahoo! Groups Sponsor ---------------------~-->
Buy Ink Cartridges or Refill Kits for your HP, Epson, Canon or Lexmark
Printer at MyInks.com. Free s/h on orders $50 or more to the US & Canada.
http://www.c1tracking.com/l.asp?cid=5511
http://us.click.yahoo.com/mOAaAA/3exGAA/qnsNAA/61FxlB/TM
---------------------------------------------------------------------~->

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/