Subject: [NEXTEL-1] Beaming TV to Cars, via Satellite

From: Marcelrf <[email-masked]>
Date: Thu, 26 Feb 2004 03:03:35 -0500

February 23, 2004

TECHNOLOGY
Beaming TV to Cars, via Satellite
By IVAN BERGER

VIDEO systems in today's minivans and sport utility vehicles help to
keep the peace in millions of back seats, entertaining
young passengers with the huge selection of movies available on DVD and
videocassette. But what the video systems
rarely show are television programs. Reception of local TV broadcasts is
marginal even when parked, and there are definite limits to how far you
can stretch the cable TV connection you have at home.

But the prospects for mobile TV are looking up - about 25,000 miles up,
in fact - to where the satellites are. Newly developed rooftop mobile
antennas are designed to pull in signals better from direct broadcast
satellite systems like the Dish Network and DirecTV, and at the same
time cut a lower profile on the vehicle's roof.

Simpler and less costly methods of bringing TV to the car are coming,
too, from Sirius and XM, two satellite radio companies that currently
offer dozens of audio channels to mobile customers. At the Consumer
Electronics Show in Las Vegas last month, both companies demonstrated
how TV could be integrated into their existing systems using small
antennas like the ones now used to receive radio signals.

With the addition of a video data stream to today's audio service, the
amount of entertainment available to subscribers of satellite services
will certainly increase. But more practical uses of the satellite's
capacity are coming, too: delivery of traffic and weather data. Sirius
is working with Delphi, a supplier of automotive electronics, to develop
a system that will display the location of accidents and road
construction on the car's in-dash G.P.S. navigation screen, alerting the
driver to possible delays and offering alternate routes.

The new services mean an increased workload for satellites, which are
ideal for transmitting mobile programming: they are high enough for
their signals to clear earthly obstructions and their coverage is broad
enough that even fast-moving cars will not drive out of range in
mid-program.

The shortcoming, until now, has been the receiving antenna. Satellites
broadcast with far lower power than earthbound television stations, and
if the antenna's base - your vehicle - is turning and jouncing around,
it has to be constantly re-aimed to stay on target. Conventional TV
dishes, though practical when parked, are too hard to keep aimed. Dome
antennas bulge prominently from the roof.

One possible solution is to use a phased-array design, in which the
signals received by clusters of identical antennas are combined in
different ways - concentrating the signals from some directions while
reducing the reception from others."We'd like to do it that way," said
Robert W. Schumacher, director of mobile multimedia for Delphi, "but if
we did it the brute-force military way, the antenna would cost so much
that you'd buy that and they'd throw in the car."

Instead, the newest low-profile vehicle antennas are hybrids, combining
physical and phased-array aiming techniques: a flat multi-element
antenna is mounted on a turntable that keeps it aimed at the satellite's
compass direction, while the pattern in which the elements' signals are
combined tilts the pickup pattern toward the satellite's vertical
position in space.
Tilting the antenna's pattern, not the antenna itself, keeps the unit
thin: less than 5 inches for the KVH TracVision A5, which mounts on
vehicle roof racks, and about half that for the Motia Cross Country,
which can be built into a car's roof.
Even these hybrid systems are far from cheap. The KVH A5 is about
$3,500, plus installation, much of that cost related to keeping the
antenna aimed. Future systems may link to the car's navigation system,
predicting a car's path even before it enters a turn, Dr. Schumacher
said.

For many car owners, though, cost and size will rule out systems like
these, despite high picture quality and a wide choice of channels. The
systems shown by XM and Sirius offer a lower-cost - but more limited -
approach to in-car TV. For cars that already have satellite radio,
adding television service would only require installing screens and
video decoders.
The trade-off is bandwidth: the radio satellites will carry far fewer TV
channels, probably three to six apiece. The picture will not be
living-room quality, either. Without enough data space for full
frame-by-frame video like broadcast TV, the radio satellites will carry
streaming video, highly compressed like Internet video clips.

Fortunately, the relatively small screens in cars do not reveal a lot of
detail anyway. Both Sirius and XM mentioned cartoons prominently among
their program options. Sirius says it hopes to have its video service
operating in 15 to 18 months, but XM has not announced its schedule.

 http://www.nytimes.com/2004/02/23/automobiles/23CARS.html
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