The Alexandria Amateur Radio Club has begun to explore the use of D-STAR radio equipment and how this use of digital radio for the amateur service might be of interest to club members. "What's D-STAR?" you're probably asking. Well, D-STAR (Digital Smart Technology for Amateur Radio) is an open standard developed by the Japanese Amateur Radio League (JARL) over three years and published in 2001 that incorporates the use of digital technology in the transmission of signals between radios or repeaters. Currently, Icom is the sole manufacturer of radio products that implements the D-STAR protocol, although by being an open protocol, it is hoped that other manufacturers will begin to provide D-STAR compatible radio equipment as well.
As described on Icom's web page for D-STAR (http://www.icomamerica.com/amateur/dstar/) a D-STAR system "…supports two types of digital data streams. The Digital Voice (DV) stream used on 144 and 440 MHz contains both digitized voice (3600 bps including error correction) and digital data (1200 bps). Using a DV radio is like having both a packet link and FM voice operating simultaneously. The Digital Data (DD) stream, used only on 1.2 GHz, is entirely data with a bit rate of 128k bps. The data connection to a radio that uses DV is via an RS-232 interface or USB 1.0. An Ethernet connection is used for high-speed DD D-STAR data. Ordinary terminal emulation software (DV) or a Web browser (DD) will do just fine for exchanging data."
In August of this year, Icom re-instituted a special pricing deal that
they had done at Dayton for the purchase of a complete 2m/70cm/23cm repeater
"stack" system that implements D-STAR. A member of the club decided
to take advantage of this offer, and procured a complete system, which comprises
a controller module, 1.2 GHz data and voice modules, a 2m voice module,
and a 440 voice module. Initial shipment of the controller, 2m, and 440
modules were received in late August, with the 1.2 GHz modules arriving
in September. After all the modules were received, work began on assembling
the modules into a rack cabinet as efforts were underway in obtaining coordinated
repeater frequencies from T-MARC. This culminated in the D-STAR repeaters
being tested in mid-October and T-MARC providing the club with the following
frequency pairs for use with D-STAR on November 8:
|
Input
|
Output
|
Data
|
|
| 2 Meters |
144.780
|
145.380
|
|
| 440 Meters |
447.060
|
442.060
|
|
| 1.2 GHz |
1272.600
|
1284.600
|
1253.6000
|
Currently, as of mid-November, the appropriate antennas and a power supply have been ordered to make the site "live". Once the final location for the equipment is determined, the correct lengths of feed line will be ordered. One of the many interesting features of a D-STAR system is the ability to exchange "traffic" with other D-STAR users over the Internet. To do this, a computer acting as a traffic gateway to the Internet must be installed in the same location as the repeater stack. Several club members are currently engaged in this part of the project to see what will be involved in obtaining Internet access for the gateway computer at the proposed site. If all goes well, we hope to have the first active, complete D-STAR system in the state of Virginia and in the National Capitol area up and running by the end of the year. As the work continues to progress, this web page will be updated with new items and information. In the meantime, the following links are helpful for those who may want more information regarding D-STAR:
Icom
D-STAR information and background: http://www.icomamerica.com/amateur/dstar/
D-STAR online forum: http://www.icomamerica.com/support/forums/
K5TIT (Texas Interconnect Team)
Forum on D-STAR: http://www.k5tit.org/forum/default.asp
Ben Gelb's (KF4KJQ) D-STAR Wiki page
Marine Corps Marathon: http://d-star.mit.edu/index.php?title=Main_Page
D-STAR protocol documentation (PDF)
ARRL:
http://www.arrl.org/FandES/field/regulations/techchar/D-STAR.pdf