Antenna technology developed for advanced U.S. military programs
is the key to hooking up super-mid and large jets to the Connexion
by Boeing network, according to Rockwell Collins. Collins subsidiary
Airshow "spent a truckload of money" to adapt that technology
to commercial use, says director of product management Chris Merry,
and the result is that the new Tailwind 500 antenna outperforms
anything else in the same size class.
Developed exclusively for Collins by Aerosat of Amherst, NH, the
Tailwind 500 hides a sophisticated horn array under its translucent
cover, and (like the folded optics of a reflector telescope) it
packs a lot of electron-sucking power into the 12-inch swept volume
limit of a fin-top radome. The antenna is 30% more efficient than
a conventional parabolic dish.
Aerosat also provided low-noise amplifiers-they boost the signal
power as it comes off the dish-that break a long-established noise
barrier by producing less than 1 dB of noise over the entire width
of the Ku-band. Innovative vibration isolators, servo motors and
an intricate chain-drive system keep the antenna pointed at the
satellite under the toughest conditions. Collins looked very hard
at real-world satellite footprints and "end of life power",
says Merry--communications satellite degrade throughout their lives
as solar radiation eats into their power cells--before writing the
specification for the new antenna.
The Tailwind 500 doesn't match the power of the big and expensive
fuselage-mounted antenna that Connexion by Boeing provides for airline
operators, but Rockwell Collins general aviation vp Denny Helgeson
argues that it doesn't have to. It delivers 5 Mb/sec on to the airplane-true
broadband-and up to 256 kB/sec off. (The antenna is actually good
for 1 Mb/sec-the restriction is a commercial one.) Combined with
the "managed network" features of Airshow 21, that is
enough to allow several users to access firewall-protected company
networks at the same time, and even to support videoconferencing.
Lufthansa Systems, meanwhile, is continuing to offer big-jet users
the option of the full-size Connexion by Boeing antenna, developed
by Mitsubishi. Its potential capacity is 30 Mb/sec on to the airplane
and 3 Mb/sec off. Mobile technologies product manager Andy Schweiger
points out that future business applications are likely to be tailored
to two-way broadband communications.
--Bill Sweetman
Collins offers an Ethernet-backbone
version of Airshow 21 for the Bombardier Global family, tailored
for office applications, and a FireWire version, better for
entertainment, in the Gulfstream G500 and G550.
