Repeaters and repeater systems

D-STAR gateway protocols and software support linking repeater systems over a few miles or around the world. A regional group of repeaters create a D-STAR zone, shown in figure 4, working together and addressable in the D-STAR system as a unit. Whether you live in the wide-open spaces or a densely populated area, D-STAR repeaters can be tied together to make up the repeater system you want using either Internet or microwave links.

Repeaters linked with D-STAR can also share information using the same D-STAR link. This information includes repeater operating information and statistics. System designers can add entirely new functions, sharing weather and control information, for example. Another possibility is “smart systems” that track interference or user location.

If you’ve tried to coordinate a repeater channel on 2-meters or 440 MHz in any metropolitan area, you know how crowded the bands are! The D-STAR voice and low-speed data signal offers a significant improvement in spectrum efficiency, requiring only a 6 kHz channel instead of the 20, 25, or even 30 kHz of analog wide-band FM. As shown in figure 5, D-STAR repeaters can be interleaved between existing channels or multiple repeaters deployed in the spectrum of only one analog FM repeater.

As authorized users make their initial transmission to a D-STAR system, the call sign information attached to the digitized voice packets is recorded by the repeater controller. The controller then shares the information with other D-STAR systems through the D-STAR gateway registry. The registry is maintained on gateway servers located around the world as shown in figure 6 -- currently Japan, the United States, and the UK. When an authorized D-STAR user makes a call to a call sign not currently registered on that repeater system, the registry allows the repeater controller to route the call to the repeater on which the targeted user was last registered.