[RTTY] List of Experimental Licenses Reveals Interesting HF Data Comm Experiments

[Eric Rosenberg]

I'm merely the messenger. Interpret this as you will...

73,
Eric W3DQ

On Fri, Jan 16, 2015 at 3:39 PM, wo4o - RiC <wo4o.radio at gmail.com> wrote:

> So ... experimenters could potentially 'interfere' with amateur radio
> communications between 1.800-2.000 MHz?  73, de ric, wo4o
>
> -----Original Message-----
> From: RTTY [mailto:rtty-bounces at contesting.com] On Behalf Of Eric
> Rosenberg
> Sent: Friday, January 16, 2015 3:27 PM
> To: rtty at contesting.com
> Subject: [RTTY] List of Experimental Licenses Reveals Interesting HF Data
> Comm Experiments
>
> Thought this item from TV Technology might interest this group...
>
> Enjoy!
> Eric W3DQ
>
> ---------------------
>
> 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.
>
> ----------------------------
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