ARRL Experimenting with Icom D-Star Digital System:

Thanks to the generosity of Icom, MFJ and NCG (Comet), the ARRL has embarked on a project to learn firsthand what D-Star http://www.arrl.org/FandES/field/regulations/techchar/ digital technology has to offer and to assess its capabilities in a real-world Amateur Radio environment. Icom, so far the only ham radio manufacturer offering D-Star equipment, has donated a D-Star voice repeater, data repeater and controller to W1AW. Eight model ID-1 D-Star 10 W mobile transceivers are on loan from the manufacturer.

"We appreciate Icom's cooperation and support as we explore D-Star's capabilities and learn more about digital radio systems," ARRL CEO David Sumner, K1ZZ, said in expressing the League's gratitude.

MFJ donated an MFJ-1532N Pulsar, which is serving as the transmitting antenna, while NCG contributed a pair of Comet GP21 antennas to receive digital data and voice for the 1.2 GHz (23 cm) multipurpose D-Star system. The antennas have been installed on two of the W1AW antenna support structures.

Although still in the early phase, the project plans to exercise the technology's digital voice and data capabilities as well as its capability to become part of a wider D-Star digital repeater network via an Internet gateway.

Icom Amateur Products Division Manager Ray Novak, N9JA, says the D-Star standard, first published four years ago, resulted from government-funded research in Japan administered by the Japan Amateur Radio League (JARL) to investigate Amateur Radio digital technologies. Novak emphasizes that D-Star is an open protocol that's available for implementation by anyone, and Icom is working with other manufacturers to get more D-Star compatible gear on the market.

"Amateur Radio is again out there in the forefront of technology," Novak says. Although he concedes there's a steep learning curve ahead, he predicts Amateur Radio users will invent new ways to put D-Star technology to work as they get better acquainted with its possibilities.

At this stage, the D-Star 23-cm repeater is up and running in digital voice mode, and W1AW Station Manager Joe Carcia, NJ1Q, and ARRL Web and Software Development Manager Jon Bloom, KE3Z, enjoyed the first contact through the repeater on November 30. In the meantime, Bloom has been working to interface the D-Star system with a Linux server, which will serve as an Internet gateway, to check out that aspect of the system.

Novak says the digital voice stream can simultaneously handle voice at 3600 bps with error correction and data at up to 1200 bps. Since a D-Star voice signal occupies only 6.25 kHz, Novak says, the potential is there to make more efficient use of available spectrum on 2 meters by squeezing up to four D-Star repeaters into the same space as two analog channels. New repeater modules are in development for 2 meters and 70 cm.

Working through a D-Star repeater is a bit different than using an analog repeater. Your call sign is the key to a D-Star system, since it's incorporated into every transmission you make. "Because of D-Star's call sign-routed system," Novak explained, "registered users are able to cross-communicate with stations registered on another network's D-Star repeater, wherever it may be."

Novak says the 1.2 GHz D-Star system's high-speed (128 kbps) data capability is another exciting feature. With the Ethernet jack on the Icom ID-1 transceiver, you now have the functionality of an ISDN (integrated services digital network) line available in your vehicle," Novak said.

"We'll have to find new ways of using this technology," he continued. "That will be where ham radio changes. This opens up an unbelievable array of features for repeater systems--including graphics, schedules, tables, photos, you name it!"

A D-Star Last Heard Report Web page http://www.dstarusers.org/ lists stations heard, their location and the date and time and, sometimes, type of transmission. The K5TIT Dallas D-Star Web site http://www.k5tit.org/ includes a repeater listing and a discussion forum, and a promise of more to come.

Source:

The ARRL Letter Vol. 24, No. 49 December 16, 2005

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