[GreenKeys] faster HF datacom rates expermental lic. for MITRE etc.. granted

[Ed Sharpe Archivist for SMECC via GreenKeys]

from the rtty  board-
 
>From TV Technology
Doug Lung's RF Report
1/16/2015

List of  Experimental Licenses Reveals Interesting HF Data Comm Experiments

Ham  radio operators have been using the shortwave ("high-frequency" or HF)
bands  for data communications for over 50 years, but the data rates are
much less  than those available with dial-up modems. HF communications have
the  advantage that they don't depend on vulnerable satellites, don't
require  line-of-sight, and can cover huge distances under the  right
conditions.

The FCC recently granted two companies experimental  licenses to use HF
bands for data communications at far greater bandwidths  and data rates than
have been used by amateur radio operators. While these  communication
systems are being developed for the military, it's possible  some of the
techniques developed could be used for digital broadcasting in  the AM band,
or more likely for shortwave broadcasting where sky wave  propagation is
important.

According to the commission's Office of  Engineering and Technology
Experimental Licensing Branch's list of  experimental applications between
10/1/14 to 10/31/14, license WH2XCI was  granted to The MITRE Corporation to
operate in the 2505.00 - 4100.00, 4210.00  - 4995.00, 5005.00 - 6210.00,
6320.0 - 8250.00, 8450.00 - 9995.00, 10005.00 -  12200.00, 13500.00 -
14990.00 and 15010.00 - 16000.00 kHz bands to test HF  communications at
fixed locations in Bedford and Worcester in Massachusetts  and Oneida and
Rome in New York.

MITRE's application states, "While  satellite communication provides high
data rate connectivity, there are  vulnerabilities that include degradation
and disruption of service. HF radio  communication generally are limited to
narrower bandwidths and lower data  rates than satellite communications. To
ensure critical communications are  maintained, we are investigating the
capability of higher bandwidth and  higher data rate communications in the
HF band applying polarization  diversity MIMO concepts."

The goal, according to the application, is to  obtain reliable
communications at a data rate between 1 and 4 bits/Hz/s.  MITRE said it will
develop a 100 kHz bandwidth waveform that can achieve  approximately 256
kbps with forward error correction (FEC) coding. MITRE will  attempt to use
both X and O modes to carry independent communications  channels. PA0SIM has
an excellent description of the X and O modes at XO  propagation web page.

In addition to the 100 kHz bandwidth, MITRE's  license allows bandwidths up
to 1 MHz. MITRE states, "A stretch goal is to  extend to wider bandwidth
waveforms, up to 1 MHz." The researchers' note: "we  understand that this
wideband waveform may run up against other users and  possibly cause
interference. We plan to transmit at as low a power as  possible and on a
not-to-interfere basis."

According to the license,  MITRE will use emissions with the designators
5K00Q3N, 500KD7D, 500Q3N,  500W7D, 1M00D7D, 1M00Q3N and 1M00D7W. These
designators imply maximum  bandwidths of 5 kHz, 500 kHz and 1 MHz. The
authorized effective radiated  power ranges from 6 W to 122 W, depending on
frequency and bandwidth. The  license includes a condition stating "Licensee
should be aware that other  stations may be licensed on these frequencies
and if any interference occurs,  the licensee of this authorization will be
subject to immediate shut down."  MITRE application shows the equipment
being used includes nine Ettus N210  software defined radios, six
Minicircuits ZHL-5W-1 and six BAE Australia "TBD  - 50 W unit". Apparently
these are the power amplifiers.

MITRE's  application describes the antennas - crossed dipoles and verticals
- that  will be used in testing to isolate the X and O propagation modes.
You find  the application, associated exhibits, and the grant using the
Experimental  Licensing System Call Sign Search and entering callsign
WH2XCI. MITRE will be  using

Another interesting grant is WG2XZF to TrellisWare Technologies,  Inc.. It
is an experimental license to operate between 1.800 and 12.00 MHz  "to
implement and field test the design of an advanced hf waveform" mobile  in
Julian, CA. The application shows the emission type as  30K0D7D,
significantly narrower than the MITRE filing, utilizing QPSK to  64QAM
modulation. I did not find any data rate specification.

Even if  these communications technologies never find their way to AM or
shortwave  broadcasting, it is encouraging to see how HF communications is
continuing to  evolve.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20150117/73b2fd64/attachment.html>