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( D-Star stands for    D.igital - S.mart Technologies for A.mateur R.adio  a open protocol developed for amateur use)

D-STAR (Digital Smart Technologies for Amateur Radio) is a digital voice and data protocol specification developed as the result of research by the Japan Amateur Radio League to investigate digital technologies for Ham Radio. While there are other digital on-air technologies being used by Amateurs that have come from other services, D-Star is one of the first on-air standards to be widely deployed and sold by a major radio manufacturer that is designed specifically for Amateur service use.

D-Star compatible radios are available on VHF and UHF and microwave amateur radio bands. In addition to the over-the-air protocol, D-Star also provides specifications for network connectivity, enabling D-Star radios to be connected to the Internet or other networks and provisions for routing data streams of voice or packet data via Amateur Radio callsigns.

The first manufacturer to offer D-Star compatible radios is ICOM, and no other amateur radio equipment manufacturer has chosen to include D-Star technology in their radios, yet. Kenwood re-brands an ICOM radio and distributes it in Japan only.

This has given us more tools that make us more valuable in government agencies minds.  This allows us to pass more information in a more secure way, while maintaining interoperablility.  D-Star has gained a lot of popularity in the US, even though it is currently offered only by one major manufacturor.  Other companys may soon follow if it continues to take off.

icomic92ad.jpg

Icom IC-92 AD
D-Star + APRS VHF/UHF HT with optional hand-mic that has a built in GPS.

icomid1.1200mhz.jpg

Icom ID-1  1200Mhz
One of the firtst D-Star radios made by Icom.  Boasts many useful features listed on Icoms website.

Icom D-Star

Independent R.C (D-Star)

D-Star users

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Icom IC2820-H  VHF/UHF D-Star
 

Single repeater

The D-STAR repeater operates similar to existing analog repeater. That is a simple relay of transmit and receive communication in 1.2GHz band.

Simngle Repeater Diagram

Microwave link

When D-STAR repeaters are connected via 10GHz microwave, the D-STAR system transfers a received data to another repeater site. You can also make a CQ call to a specified repeater area.

Microwave Link Diagram

Internet gateway relay

When D-STAR repeaters are connected with the Internet gateway, the D-STAR system relays the received data over the Internet. Microwave links and Internet gateways can be combined even during one contact. So your message will get through virtually to anywhere in the D-STAR system.

Internet Gateway Relay Diagram

Above information from Icom Website, I do not take any credit for it.

For information purposes only.

History

1999 – Funded by the Japanese government and administrated by the JARL, investigation was put into finding a new way of bringing digital technology to amateur radio.

2001 – D-Star is published as the result of the research.

 Icom enters the construction of the new digital technology by offering the hardware necessary to create this technology.

 The conclusion of all this work is the digital technology for amateur radio called D-Star.

Icom announces the availability of Gateway 2.0 software.

 Icom and US Trust Server administration announce the shutdown of the Gateway 1.0 U.S. Trust Server will occur at 00:00 UTC on June 1, 2008, at which time all systems should have transitioned to Gateway 2.0 software and the new U.S. Trust Server.

Technical details

D-STAR transfers both voice and data via digital encoding over the  (VHF), (UHF), and  (1.2 GHz) amateur radio bands. There is also an interlinking radio system for creating links between systems in a local area on 10 GHz.

Within the D-Star Digital Voice protocol standards (DV), voice audio is encoded as a 3600 bit/s data stream using proprietary  encoding, with 1200 bit/s FEC, leaving 1200 bit/s for an additional data "path" between radios utilizing DV mode. On air bit rates for DV mode are 4800 bit/s over the 2 m, 70 cm and 23 cm bands.

In addition to DV mode, a high speed Digital Data (DD) Mode can be sent at 128 kbit/s only on the 23 cm band. A higher rate proprietary data protocol, currently believed to be much like ATM, is utilized in the 10 GHz "link" radios for site-to-site inter-linking.

Radios providing DV data service within the low-speed voice protocol variant typically use an RS232 or USB connection for low speed data (1200 bit/s), while the Icom ID-1 23cm band radio offers a standard Ethernet connection for high speed (128 kbit/s) connections, to allow easy interfacing with computer equipment.

Importance of Digital Technology and D-STAR

As long as the signal strength is above a minimum threshold, and no multi-path is occurring, the quality of the data received is better than an analog signal at the same strength.

The system today is capable of linking repeaters together locally and through the Internet utilizing callsigns for routing of traffic. Servers are linked via TCP/IP utilizing proprietary "Gateway" software, available from Icom. This allows Amateur Radio operators to talk to any other Amateurs participating in a particular gateway "trust" environment. The current master gateway in the United States is operated by the K5TIT group, in Texas, who were the first to install a D-Star repeater system in the U.S.

Another important aspect of D-STAR technology is its ability to send large quantities of data to emergency responders in the event of a disaster. Served agencies can instantly relate to sending "email" or a "word files" to someone. The data sent can be high-volume, where traditional amateur radio "modes" are capable of getting a message through albeit slowly, D-STAR can place documents into the hands of those that need them most - fast image, text and document data exchanges.

Criticism

D-STAR has been criticized for its use of a patented, closed-source proprietary voice codec (AMBE).  Hams do not have access to the detailed specification of this codec or the rights to implement it on their own without buying a licensed product. Hams have a long tradition of building, improving upon and experimenting with their own radio designs. The modern digital age equivalent of this would be designing and/or implementing codecs in software. Critics say the proprietary nature of AMBE and its availability only in hardware form (as ICs) discourages innovation. Even critics praise the openness of the rest of the D-STAR standard which can be implemented freely. An open-source replacement for the AMBE codec would resolve this issue. Gateway Server Information

The current gateway control software rs-rp2c Version 2.0, more commonly called "Gateway 2.0", runs on virtually any Linux, but the Icom supported/recommended configuration is CentOS 5.1 on a Pentium IV 2.4 GHz or faster machine.

Recommended Configuration utilizes Linux CentOS 5.1 with the latest updates, typically running Kernel 2.4.20. glibc 2.3.2 and BIND 9.2.1. The CPU should be 2.4GHz or faster and the memory should at least be 512MB or greater. There should be 2 network interface cards and at least 10GB free of hard drive space which includes the OS install. Finally for middleware, Apache 2.0.59, Tomcat 5.5.20, mod_jk2 2.0.4, OpenSSL 0.9.8d, J2SE 5.0 and postgreSQL 8.2.3 are utilized, but these can be different as updates occur.

Along with the open-source tools, the Icom proprietary dsipsvd or "D-Star IP Service Daemon" and a variety of crontab entries utilize a mixture of the local PostgreSQL and BIND servers to look up callsigns and "pcname" fields (stored in BIND) which are mapped to individual 10.x.x.x internal-only addresses for routing of both voice and data traffic between participating gateways.

During installation, the Gateway 2.0 software installation script builds most of the web-based open-source tools from source for standardization purposes, while utilizing some of the packages of the host Linux OS, thus making CentOS 5.1 the common way to deploy a system, to keep incompatibilities from occurring in both package versions and configuration.

Additionally, Gateways operating on the U.S. Trust server are asked during initial setup to install DStarMonitor which is an add-on tool that allows the overall system administrators to see the status of each Gateway's local clock and other processes and PIDs needed for normal system operation, and also sends traffic and other data to servers operated under the domain name of "dstarusers.org". Installation of this software also includes JavaAPRSd, a Java-based APRS interface which is utilized on Gateway 2.0 systems to interface between the Icom/D-Star GPS tracking system called DPRS to the more widely known and utilized Amateur Radio APRS system.