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D-STAR

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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 amateur 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.

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.

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

Unknown Date – The conclusion of all this work is the digital technology for amateur radio called D-Star.[1]

February, 1 2008: Icom announces the availability of Gateway 2.0 software.

April 23, 2008: 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 2 m (VHF), 70 cm (UHF), and 23 cm (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 AMBE 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 used in the 10 GHz "link" radios for site-to-site links.

Radios providing DV data service within the low-speed voice protocol variant typically use an RS-232 or USB connection for low speed data (1200 bit/s), while the Icom ID-1 23 cm band radio offers a standard Ethernet connection for high speed (128 kbit/s) connections, to allow easy interfacing with computer equipment.[2]

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.[3]

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). [4] 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.

Bruce Perens, K6BP, amateur radio and open source advocate, has announced that he will investigate the development of an alternative codec.[5]

Gateway server

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 and -recommended configuration is CentOS 5.1 on a Pentium IV 2.4 GHz or faster machine.

The recommended configuration uses 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 2.4 GHz or faster and the memory should at least be 512 MB or greater. There should be two network interface cards and at least 10 GB 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.

How Gateway 2.0 works

Each participating amateur station wanting to use repeaters/gateways attached to a particular trust server domain must "register" with a gateway as their "home" system, which also populates their information into the trust server a specialized central gateway system—which allows for lookups across a particular trust server domain. Only one "registration" per trust domain is required. Each amateur is set aside eight 10.x.x.x internal IP addresses for use with their callsign or radios, and various naming conventions are available to utilize these addresses if needed for specialized callsign routing. Most amateurs will need only a handful of these "registered" IP addresses, because the system maps these to callsigns, and the callsign can be entered into multiple radios.

The gateway machine controls two NICs, the "external" one being on a real 10.x.x.x network behind a router. A router that can NAT a single public IP address (can be static or dynamic in Gateway 2.0 systems) to a full 10.x.x.x/24 subnet mask is required. From there, the Gateway has another NIC connected directly to the D-Star repeater controller via 10BaseT and the typical configuration is a 172.16.x.x pair of addresses between the gateway and the controller.

Differences between Gateway 2.0 and Gateway 1.0

The main differences between Gateway 1.0 and 2.0 are the addition of a relational database (PostgreSQL) for more flexibility and control of updates, versus the previous use of only BIND for "database" activities, the addition of both an administrative and end-user Web interface for registration which was previously handled via command-line commands by the Gateway 1.0 system administrators, dropping the requirement for static public IP addresses for gateways, and the ability of the software to use a DNS FQDN to find and communicate with the trust server, allowing for redundancy/failover options for the trust server administrators. Finally, a feature called "multicast" has been added for administrators to be able to provide users with a special "name" they can route calls to which will send their transmissions to up to ten other D-Star repeaters at the same time. With cooperation between administrators a "multicast group" can be created for multiple repeater networks or other events.

Another additional feature of Gateway 2.0 is the ability to use callsign "suffixes" appended to the user's callsign in a similar fashion to the repeaters and gateways in the original system, which allow for direct routing to a particular user's radio or between two user radios with the same base callsign, by utilizing the 8th most significant field of the callsign and adding a letter to that location, both in the gateway registration process on the Web interface, and in the radios themselves.

Gateway 1.0 control software

The Gateway 1.0 software was similar to Gateway 2.0, and utilized Fedora Core 2+ or Red Hat Linux 9+ OS on a Pentium-grade 2.4 GHz or faster machine and Icom has announced a shut-down date for the U.S. Gateway 1.0 Trust Server, see "History" section.

Add-on software

Various projects exist for gateway administrators to add "add-on" software to their gateways, including the most popular package called "dplus" created by Robin Cutshaw AA4RC. A large number of Gateway 2.0 systems are offering services added by this software package to their end-users, and users are getting used to having these features.[1] Features include the ability to link systems directly, "voice mail" (a single inbox today), ability to play/record audio to and from the repeaters connected to the Gateway and the most important, the ability for DV-Dongle [2] users to communicate from the Internet to the radio users on the repeaters.

There is often a misconception by users and system administrators alike that the Gateway 2.0 systems have these add-on features from dplus by default, a testament to the popularity of this add-on software. Software development on dplus is very active right now, and features such as multiple repeater/system connections similar to the type of linking done by other popular repeater-linking systems (IRLP and EchoLink) are being worked on.

Manufacturers of D-STAR equipment

Manufacturer Radio(s) Repeater(s) More Information
Icom Yes Yes (http://en.wikipedia.org/wiki/Image:D-STAR_equipment.pdf)
Kenwood No No (Kenwood "re-badges" an Icom radio in Japan which is not for sale outside Japan.)
Moetronix DV Dongle No (http://www.moetronix.com/dvdongle/) (Available through multiple amateur radio dealers.)

Equipment

  • Icom D-STAR equipment[6]
    • Transceivers:
    • Icom ID-1: 23 cm digital voice and digital data mobile transceiver. Power is selectable at 1 W or 10 W. USB control port and Ethernet connection for data.
    • Icom IC-2820H/IC-E2820: 2 m / 70 cm twin band digital voice mobile transceiver. Power up to 50 W on each band. May be purchased with or without D-STAR module. The D-STAR module includes a built-in GPS receiver with accompanying antenna.
    • Icom ID-800H: 2 m / 70 cm dual band digital voice mobile transceiver. Power up to 55 W on 2 m and 50 W on 70 cm.
    • Icom IC-92AD: 2 m / 70 cm twin band digital voice hand held transceiver. Four power settings up to 5 W on each band. Rugged and submersible design, optional microphone with embedded GPS.
    • Icom IC-91AD/IC-E91 + D-STAR: 2 m / 70 cm twin band digital voice hand held transceiver. Power is selectable at 0.5 W or 5 W on each band.
    • Icom IC-2200H: 2 m single band digital voice mobile transceiver. Power up to 65 W. Must purchase optional D-STAR module.
    • Icom IC-V82: 2 m single band digital voice hand held transceiver. Power up to 7 W. Must purchase optional D-STAR module.
    • Icom IC-U82: 70 cm single band digital voice hand held transceiver. Power up to 5 W. Must purchase optional D-STAR module.

    Note: All mobile (including hand-held) radios may also be used on conventional analog FM.
    Repeater equipment:

    • Icom ID-RP2000V: 2 m digital voice repeater.
    • Icom ID-RP4000V: 70 cm digital voice repeater.
    • Icom ID-RP2V: 23 cm digital voice repeater.
    • Icom ID-RP2D: 23 cm digital data access point.
    • Icom ID-RP2C: Repeater controller. Can support up to four digital voice repeaters and digital data access points. Required to operate any Icom D-STAR digital voice repeater or digital data access point.
  • Kenwood D-STAR equipment[7]
    • Transceivers:
    • Kenwood TMW-706S: 2 m / 70 cm dual band digital voice mobile transceiver. Power up to 50 W.
    • Kenwood TMW-706: 2 m / 70 cm dual band digital voice mobile transceiver. Power up to 20 W.

    Note: These transceivers are not available in North America and appear to be OEM versions of the Icom ID-800H

  • Inet Labs
    • Computer accessory:
    • DV-Dongle[8]: USB device with AMBE codec, which can be used to generate D-STAR packets over the Internet through applications such as DVTOOL[9].
      • Note: Available only through Ham Radio Outlet[3] (search for model DV-DONGLE) or by homebrew using documentation at Moetronix[10].

Compatible programs and online projects

D-StarLet (Open source, client-server, Win98, Linux, Mac)

Interface D-PRS Interface (Open source, GPS)

DStarMonitor, DStarQuery, d*Chat, D-RATS (open source)

D-StarLet

A Web-based text messaging application using D-Star digital data technology[11][12]

D-StarLet is an open source client-server solution that allows content creation and modification from certain persons. D-StarLet interfaces with a D-Star radio through the serial port. It works with Windows (98+), Linux (Red Hat 7.3+), Apple Mac OS X, and others.

D-PRS interface

D-PRS is GPS for ham radio. Includes DStarTNC2, javAPRSSrvr, DStarInterface, and TNC-X[11]

DStarMonitor

A Java application run on the repeater gateway PC which logs activity on the attached repeaters. Additional features include APRS object representation of each repeater.[11]

DStarQuery

DStarQuery monitors the low-speed data stream of a D-STAR radio looking queries sent from a remote station. When a valid query is received, a predefined sequence is executed and the results transmitted from the station running DStarQuery. For example, a station transmits "?D*rptrs?" and it is received by a DStarQuery station which responds with a list of local repeaters.[11]

The program D-PRS Interface includes a "Query" entry field that streamlines this process allowing the user to simply enter the desired command. Most DStarQuery systems will respond with a list of available commands when "?D*info?" is received.

d*Chat

A simple "instant message" or keyboard-to-keyboard chat application for DV mode.[11]http://nj6n.com/dstar/dstar_chat.html

D-TERM

A simple "instant message" or keyboard-to-keyboard chat application for DV mode.[11] http://www.d-term.de

D-RATS

An emerging D-STAR communications tool that supports text chat, file transfers, and more. Written in Python to be cross-platform. Runs on Windows, Mac OS X, and Linux.

Dstar Comms

An advanced software application for use with DStar enabled radios. Supports advanced text chat, personal messaging with auto-reply and inbox, e-mail gateway and a beacon mode. GPS Tracking / Logging and a GPS Beacon emulator and Internet linking. New features are added weekly and users can suggest new features through the Dstar Comms forum. www.dstarcomms.com[4]

DSTARSWITCH

An open source project (under the GNU Lesser General Public License) geared towards allowing multiple applications to communicate through one D-STAR radio at the same time. Anyone may contribute to this project and will receive credit for doing so. DSTAR SWITCH is an open collaborated project for creating base libraries and applications to allow the passing of information from the host computer to the D-STAR radio and vice versa.

A Web-based search for worldwide D-Star repeaters and D-Star stations that appear on the D-StarUsers.org site. It links to the jFindu locator site information. http://dstarsearch.org

DStar TV

Slow Scan TV for DStar radios and video streaming for Icom ID-1 by GM7HHB. Runs on Windows XP and Vista. http://www.dstartv.com

Home-brew D-Star radio

The first presumed D-Star radio including pictures and diagrams can be found at Moetronix.com's Digital Voice Transceiver Project. This page includes the schematic, source, and whitepaper.

Another project is Satoshi Yasuda's (7M3TJZ/AD6GZ) experiments with a UT-118 DV adapter. This project involves interfacing Icom's UT-118 with other manufacturer's amateur radio tranceivers. With this project some VHF/UHF/SHF amateur radio tranceivers are capable of being adapted for D-STAR operation. This requires access to the receiver's discriminator and to the direct FM modulator of the radio, sometimes available at a 9600 bit/s packet interface. See "Make the DV adapter using UT-118" for details.

EA3CNO also has designed another interface based on a PIC microprocessor and UT-118 module see: "MODEM ADAPTADOR PARA DV" for details.

References

  1. ^ "Amateur Equipment". Icom America.
  2. ^ "What is D-Star?". Icom America.
  3. ^ "About K5TIT - The Texas Interconnect Team". Texas Interconnect Team.
  4. ^ "DStar- is anybody else worried about this?".
  5. ^ Bruce Perens. "The Codec2 Project: Next-Generation Audio Codecs and Vocoders for Two-Way Radio". Retrieved 2008-07-20.
  6. ^ "Amateur Equipment". Icom Worldwide.
  7. ^ "Amateur Equipment". Kenwood (Google Translation).
  8. ^ "DV Dongle Homepage". AA4RC.
  9. ^ "DVTool Software Download (Zipped)". AA4RC.
  10. ^ "Amateur Equipment". Moetronix.
  11. ^ a b c d e f "3rd party". Icom America.
  12. ^ AE7Q. "3rd party sub: D-StarLet". Icom America.{{cite web}}: CS1 maint: numeric names: authors list (link)

Journal

Journals with D-STAR relevant information and a brief description

  • ARRL: QST Special Emergency Communications Issue Vol 91 No 9 September 2007 Page 30, by Gary Pearce, KN4AQ talks about his experience using D-STAR followed by his comparison of the radio and conclusion. Page 109, by Icom describes D-Star used in EmComm.
  • ARRL: QST Icom IC 2820H Dual Band FM Transceiver Vol 91 No 11 November 2007 Page 74, by Steve Ford, WB8IMY does a review on the IC 2820H Dual Band FM Transceiver.
  • RSGB: RadCom March 2008 (Vol 83 No 03) review of Icom IC-E2820 transceiver and overview of D-Star.
  • CQ-VHF: D-STAR in the Southeastern U.S., Greg Sarratt, W4OZK, (partial), http://www.cq-vhf.com/D-StarWin08.html

Media

Media with D-STAR relevant information and a brief description

  • The Rain Report The Rain Report September 2007, by J. Maynard, k5zc The Rain Report discuss major concern in the D-STAR community

See also

Retrieved from "https://en.wikipedia.org/w/index.php?title=D-STAR&oldid=246995009"