BC-DX 841 04 Jan 2008 Private Verwendung der Meldun

era Over the Horizon Radar, located in Delta Junction. The radar system
bounced shortwave signals off the ionosphere to detect aerial targets,
such as Soviet bombers, at ranges up to 1,800 miles.
Digital Aurora provided numerous details in its filing about its broadcast
operations, but offered no information on its tests for the Joint
Electromagnetic Technologies program. The company said the purpose of the
project is to provide a terrestrial digital radio service for the citizens
of Alaska, and if digital transmission proves reliable, it will seek
partnerships with content providers with priority given to nonprofit
organizations.
Whit Hicks, Digital Aurora's president who also is the chief executive
officer of the Delta Mine Training Center in Delta Junction, declined to
identify the military purposes of the DRM shortwave test in an e- mail
response to a query from Government Executive.
"We are still in the planning stage for our project and don't have much to
talk about now," he said. "Our project is fairly basic at this point. We
are just trying to determine if the theoretical propagation predictions
hold up. If they do, we will see where it takes us. Until then its just
basic research. Give us a year to see how things work."
Digital Aurora did not did not indicate in its filing whether it intended
to broadcast programming during its two-year test. The company said it
intends to broadcast unspecified types of digital audio during testing to
determine the power levels needed to provide an adequate signal so that
DRM receivers can decode the signal with high reliability throughout the
state.
DRM easily can be adapted to fit the requirements of Special Forces, said
Bennett Kobb, who runs a Web site advocating the use of DRM technology for
development of a low-power broadcasting service in the United States in
the 26 megahertz wave band. He said because DRM is a digital technology,
it could be used to transmit data, imagery and maps to deployed forces.
But the narrowband high-frequency channels DRM operates at frequencies
between 4.4 megahertz and 10 megahertz limit throughput. DRM transmits at
a rate between 3,600 and 5,400 bits per second, according to industry
estimates. That's far below high-speed Internet connections, which provide
throughput in megabits per second.
Eric Johnson, professor of electrical and computer engineering at New
Mexico State University in Las Cruces, N.M., said DRM could be used as a
one way broadcast medium to support military operations. Johnson, who has
helped develop high-frequency data standards for NATO, said there have
been demonstrations using DRM to send charts to a ship sailing around
Europe.
DRM could be used to send "change orders [and] map overlays to a team in
the field," he said. "It would be hard to disguise a high-power, encrypted
high-frequency broadcast, but with high-grade crypto, no one could read it
so all they would get is that we're sending data. [And there is] no way to
tell where it's going."
Johnson said DRM is not as robust as the Navy's High-Frequency Internet
Protocol system, which supports two-way transmissions at 9.6 kilobits per
second. "But DRM isn't bad, and the receivers are getting really
inexpensive," he said.
(via Benn Kobb, ibid., dxld July 18)