D-STAR

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D-STAR (Digital Smart Technologies for Amateur Radio ) is a digital transmission standard with which voice ( DV digital voice mode ) and data ( DD digital data mode ) can be transmitted over narrowband radio links. This standard was developed between 1999 and 2001 by the Japanese amateur radio association Japan Amateur Radio League . At the request of JARL, only the ICOM company accepted this protocol and developed and sold relay radio stations, end devices and software on a commercial basis. It was only in mid-2016 that Kenwood was the second manufacturer to introduce a device for D-STAR, the TH-D74 .

Possible uses

Within a D-STAR network, communication can take place directly between the end devices or via relay stations and the Internet. The DD mode (= Digital Data Mode) only takes place via the 23 cm band . The following options are implemented in DV mode (= Digital Voice Mode):

  • digitized speech with 2.4 kBit / s plus forward error correction (FEC) with 1.2 kBit / s,
  • Short text messages parallel to voice transmission,
  • Data transmission via the 1.2 kBit / s data channel parallel to voice transmission,
  • GPS tracking via the 1.2 kBit / s data channel (however not isolated as with APRS , but parallel to the voice transmission; sending pure GPS data via repeaters - especially automatically - is undesirable, as this disrupts voice communication; in some cases it is GPS transmissions without voice part suppressed),
  • automatic routing in connection with manual roaming,
  • Linking relay stations to one another,
  • Linking by means of conference servers,
  • experimental linking with Echolink and APCO P25 as well as DMR (Hytera) via special conference rooms (see section DCS ).

With the appearance of the Icom ID-51E PLUS handheld radio at the beginning of 2015, a "faster" DV data operating mode is being advertised under the name DV Fast Data Mode:

  • 3480 bps transfer rate
  • no voice channel
  • incompatible with low-speed data communication in DV mode

The following options are implemented in DD mode:

  • 128 kBit / s IP data channel in which the radio device and the relay radio station work in bridge mode,
  • any IP-based protocol possible,
  • Internet access (similar to WLAN) in accordance with national regulations.

technology

IC-E91AD, the first dual-band handheld radio available in Germany with optional D-STAR functionality

D-STAR uses an open protocol. With D-STAR, all information is digitally transmitted using GMSK frequency shift keying. The 4.8 kbit / s data stream is made up of the voice channel (2.4 kbit / s), the FEC (1.2 kbit / s) and the data channel (1.2 kbit / s). This then results in the channel bandwidth of 6 kHz. A channel bandwidth of 150 kHz is provided for broadband data connections with 128 kbit / s and a bandwidth of 10.5 MHz for backbone connections with 10 Mbit / s.

Speech coding

In DV mode, the speech is first digitized and then compressed using the proprietary AMBE speech codec with regard to the required data rate of 2.4 kbit / s.

APCO P25 , TETRA , DMR , as well as the digital transmission standard from Alinco and the digital devices sold by Yaesu based on Continuous 4 level FM (C4FM) are not compatible with D-STAR.

Legal situation in Germany

Encrypted transmission methods are prohibited in international radio traffic in accordance with the Radio Regulations (Art. 25.2A) and in Germany in accordance with the Amateur Radio Ordinance ( Section 16, Paragraphs 7 and 8 ). Therefore, there were initially concerns as to whether the use of the proprietary codec would have to be assessed as encryption.

According to the authority responsible for amateur radio services in Germany , the Federal Network Agency , dated April 30, 2008, there are no legal objections to the use of DV mode in Germany despite the proprietary nature of the codec. The AMBE + process produces a data stream , the content of which cannot be evaluated without resorting to proprietary processes. The documentation available to the authority is sufficient for this.

User software

There are various programs for data transmission via the data channel transmitted parallel to the voice, such as

  • D-StarLet (text chat)
  • Dstar Comms PRO (SMS, email)
  • DStar TV (still image transmission)
  • D-Term (text chat)
  • D-RATS (text chat, file transfer, position transfer, e-mail (including WinLink connection)).

Infrastructure software

The Internet gateways for D-STAR initially only ran under Linux with proprietary gateway software from the manufacturer ICOM.

However, the gateway software lacks some features such as conference calls, callsign lists on the Internet, etc. These functions are supplemented by the additional software packages "DSM" (D-STAR Monitor) for web-based activity display and "dplus" with its reflector systems REFnnn with virtual conference rooms. These software packages (closed source) were written by radio amateurs. However, the additions were noticeable due to deficiencies and problems in the area of data protection .

Privacy concerns

The working group future amateur radio service has published a declaration that was reproduced in the radio telegram 8/2009. It was seen as problematic which data was sent to the trust server in the USA: A gateway operator would therefore have no control over which services were running on his gateway server and which data would be transmitted via his Internet connection. A strange, anonymous US trust server team would have de facto root access to the research.

Therefore, free and partly free software solutions were gradually developed. The best known were:

  • ircDDBGateway - based on the ircDDB network, but not to be equated with it, this software enables the operation of relay radio stations with the ICOM hardware as well as free developments such as the DVRPTR modem board and the operation of a hotspot, a kind of miniature relay radio station in the simplex Business. Integration in the ircDDB network is possible, but not absolutely necessary. There are ready-made packages for Linux and Windows, as well as the source code to compile yourself.
  • ControlCenter - a development by the DVRPTR developers for operating relay stations, hotspots, etc. v. m. with the DVRPTR boards. It runs on Windows and the Windows binary with the help of Mono also on Linux.

ircDDB network

In order to be able to do without a trust server, the routing information is distributed in parallel to the conventional methods by a system based on IRC technology. Since February 20, 2011, the data has only been displayed in the ircDDB Live Log and the LastHeard list if the user has expressly enabled this by sending the destination callsign "VIS ON". To deactivate, the target call sign "VIS OFF" is sent once. Until then - even without the explicit consent of the user - the connection data was also stored by at least one server operator in the USA and made available via a web interface.

xReflector

The interconnection of several relays to form a conference is not provided for in the original D-STAR protocol. To make this possible, the xReflector system was designed as an alternative to the dplus reflectors already mentioned. However, this turned out to be prone to failure - connections could be interrupted by short carriers (e.g. also by an automatic transmission of a GPS beacon) - so that it has now been replaced by the DCS system.

DCS (Digital Call Server)

The X reflectors were replaced by the DCS system from mid-2012. The so-called digital call server can be used to interconnect several relay radio stations to form conferences, similar to the previous X reflectors. The servers themselves are numbered. In Germany, the server is DCS001. Each server is divided into 26 conference rooms from A to Z. The conference rooms A of all DCS servers are interconnected worldwide (name of the conference room "worldwide radio traffic"). Room Z corresponds to the echo function. This leaves 24 rooms to which functions can be assigned.

With DCS, the routing information is not only transmitted at the beginning of a transmission, but repeatedly at intervals of 20 ms (according to another source every 200 ms), which means that the system is less susceptible to brief interference than the X reflector network.

In the DCS system, callsigns that are not registered via DTMF IDs are currently excluded from the use of the DCS reflectors in order - according to the operator - to restrict the abuse of callsigns to local repeaters or, in the event of abuse, to take legal action in the event of such incidents Kind of to have. It is not documented whether this registration remains valid even if the DCS identifier expires. ( see CCS (Call Connection Service))

Switching on a repeater is possible, as with X reflectors, by entering the reflector with seven digits and L (for left) in the URCALL field; ie " DCS001CL " to connect to conference room C (conference room Germany) of DCS server number 1 . The separation by " U " in the 8th position of the URCALL field is also designed.

In addition, it is now also possible to transmit control commands - such as connecting and disconnecting - via DTMF tones. With most of the devices on the market, this is easier than adapting the URCALL field (unless you occupy individual memory locations with the corresponding commands, in which case, however, you have to assign several memory locations with the respective commands for each repeater). To connect to a conference room, send D plus number of the server (one-digit) + number of the conference room (two-digit; A = 01, B = 02 ... Z = 26) through DTMF, i.e. D103, to connect to conference room C of the server DCS001 connect. A status query is made by transmitting the 0 (zero), the # (hash) is used to separate.

For the experimental connection with Echolink, conference room V of the Swiss DCS server DCS003 was switched to the Echolink node 8008 HB9DR-R. Echolink can currently be reached from the D-Star network using the DTMF identifier 0000 . Room "M" on the Austrian reflector DCS009 - accessible from the D-STAR network via DTMF D913 - is connected to the Hytera DMR network.

CCS (Call Connection Service)

As the next expansion stage of DCS, the CCS system combines the properties of the original callsign routing, IrcDDB, D-Plus and StarNET.

With callsign routing, the repeaters are automatically linked temporarily here, so that a direct response (without programming the receiver in the URCALL field) is necessary and monitoring on the addressed repeater is also possible. With the original callsign routing, in contrast, you cannot overhear on the target repeater; A response as to whether the target repeater was occupied or not available was only given via a cryptic text message in the display; The person addressed had to program the callsign routing to the caller before answering, and the forwarding would break down even with brief disruptions.

In contrast to the DCS system, callsign routing is now also possible using DTMF commands. For this, personal DTMF IDs must be assigned (compare Echolink). To end the link established via CCS callsign routing, the DTMF tone "A" is sent - in contrast to Echolink and the conference room link.

Since the system was dimensioned with only a four-digit address space, the available IDs were no longer sufficient due to the large number of registrations for the CCS system at the beginning of 2015. Therefore, the users who had not used D-Star for several months were deleted from the CCS database without prior notice. A new registration via the Internet is possible at any time.

Stations that can be reached via CCS callsign routing via DTMF command ideally use the four-digit suffix field of the Mycall entry to send their CCS number.

CCS7 (Call Connection Service)

This is an extension of the CCS system to 7 digits, whereby the first three digits consist of the Mobile Country Code (MCC). The identifiers are merged with the DMR system. For routing within your own country, it is sufficient to use the last 4 digits for addressing. A test operation has been taking place on isolated servers since 2015.

DIY projects

A kit to expand standard FM radios was available from an amateur radio magazine. Wireless telephones from the former C network (e.g. Siemens C5) can also be retrofitted with a DV modem. There are also various software projects that deal with the decoding of D-Star.

  1. Integration of the ICOM board UT-118DV with AMBE 2020 chip for retrofitting analog radios by Satoshi Yasuda (7M3TJZ / AD6GZ),
  2. Self-construction project with AMBE2020 chip from AE4JV / Moetronix,
  3. Self-construction project with AMBE2020 chip for pure coding of the NF
  4. Extension board for a converted C5 telephone from DO1FJN
  5. DVRPTR board for use as a dongle, hotspot or full duplex relay or DV transceiver (connection to 9k6-capable radio)
  6. UP4DAR board as an open source Universal Platform for Digital Amateur Radio
  7. Reception via SDR and decoding of the D-Star header information by the dstar.exe program
  8. Reception via SDR and speech decoding by the program DSD 1.7 (Digital Speech Decoder)

Distribution and network development in Germany, Austria and Switzerland

The "Taunus Relay Group" has been operating a D-STAR relay station on the Großer Feldberg in the Taunus 881  m above sea level since January 2007 NHN with the transmission frequency 439.450 MHz and the reception frequency 431.850 MHz. The amateur radio call sign was initially DB0DFT B. After moving from the telecommunications tower to the observation tower opposite in the operating rooms of the Hessian Broadcasting Corporation in May 2007, the call sign was changed to DB0HRF B. A gateway connection to the global D-STAR network has existed since October 2007.

Over the years, the number of relay radio stations has grown steadily and various networks have developed (see above), some of which also allow cross-network connections. As of January 2014, there are over 1600 registered gateways worldwide with one or more connected relays. The ircDDB network has around 110 gateways in Germany, 13 in Austria and 21 in Switzerland. In addition, there is an unknown number of hotspots, which as a rule do not have their own registration and therefore cannot be statistically recorded.

Web links

Commons : D-STAR  - collection of images, videos and audio files

Individual evidence

  1. http://www.jarl.com/d-star/
  2. English operating instructions for the IC-E92, page 53 (as well as the same for the IC-E91 and IC-E2828 except for the device name): “Only 1 message can be stored in the IC-E92. The received message is cleared by turning power OFF, or overwritten when another message is received. A transmitted message that includes lower case characters from the IC-E92 may not be decoded and displayed correctly by the ID-800H, IC-V82 / U82, etc. " - " Only one message can be stored in the IC-E92. The received message will be deleted when switched off or overwritten when another message is received. A sent message containing lowercase letters from the IC-E92 will be recognized by the ID-800H, IC-V82 / U82 and the like. s. w. not correctly decoded and displayed. "
  3. http://www.darc.de/uploads/media/Heru_21-12_v._29.08.2012_01.pdf Section “Radio data operation and automatic GPS beacons via D-Star relays”, printed on page 5 of Hessenrundspruch no. 21 / 12 of August 29, 2012, accessed December 7, 2012
  4. http://www.jarl.com/d-star/shogen.pdf
  5. http://www.agz-ev.de/hamradio2day/lösungen/2008_290.html
  6. http://www.arrl.org/files/file/D-STAR.pdf
  7. D-TERM. Retrieved January 3, 2014.
  8. ^ D-RATS. A Communications Tool For D-STAR. ( Memento of the original from August 25, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved January 3, 2014.  @1@ 2Template: Webachiv / IABot / www.d-rats.com
  9. http://www.dstarusers.org/ Tabular display of the US Trust-linked relay stations
  10. http://www.opendstar.org/tools/CHANGELOG-dplus.txt Change history of the dplus versions with syntax descriptions
  11. http://www.dstarinfo.com/reflectors.aspx List of dplus reflectors
  12. Dr. Ralph P. Schorn, DC5JQ: Issue 321 . In: ArbeitsGemeinschaft Zukunft Amateurfunkdienst eV (Ed.): HamRadio 2day . No. 321 , June 14, 2009, data protection in amateur radio and especially with D-STAR. , S. 1–5 ( online [accessed February 1, 2015]).
  13. http://www.amateurfunk-wiki.de/index.php/D-STAR#ircDDB_Netz Section ircDDB-Netz in the Amateurfunk-Wiki, accessed June 10, 2012
  14. http://ircddb.net/live-vis-deu.html Information on ircddb.net, accessed June 10, 2012
  15. http://www.dstardb.com/Privacy.php/ Information on dstardb.com, accessed June 10, 2012 (English)
  16. Archive link ( Memento of the original from July 28, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Information on DJ1WHV's website, accessed December 4, 2012  @1@ 2Template: Webachiv / IABot / www.qslnet.de
  17. Harald Kaufmann, DL2HCK: Blocking in the D-Star DCS system; published in CQDL 8/2014
  18. http://dl4ah.beepworld.de/index.htm Information on the D-Star repeater DB0SHA, accessed December 15, 2012
  19. a b http://db0ulm.wordpress.com/2012/10/01/vom-dcs-zum-ccs-d-star-callsign-routing-wird-zum-kinderspiel/ Thomas Grassmann: From DCS to CCS - D - Star callsign routing becomes a breeze, accessed December 28, 2012
  20. Info at dstar.ch: Call sign abuse in the DCS system , accessed on May 18, 2014.
  21. Message in the DARC's Germany slogan : Use of D-Star reflector DCS001 requires registration , accessed on May 18, 2014.
  22. D-STAR use in the amateur radio wiki of the German Amateur Radio Club and the Adacom professional association for amateur data radio e. V.
  23. Torsten Schultze, Sven Mewes: DCS: Replacement for xReflectoren . In: Funkamateur (magazine) . No. 6/2012 , June 2012, ISSN  0016-2833 , p. 660 .
  24. D-Star HB9HD ( Memento from March 27, 2013 in the Internet Archive )
  25. Info page of the xReflector network , accessed on May 18, 2014.
  26. Bob Kolator (OE1KBS): Bridges between D-Star, Motorola, Hytera; published in CQDL 5/2015, page 50
  27. CCS operation - A note from OM Sven DO5SL on the homepage of the Spessart Relay Group, accessed on December 24, 2013.
  28. CCS - Call Connection Service - User Manual on the homepage of the Spessart Relay Group, accessed December 24, 2013.
  29. Information page from Thomas Mansch (DL2MT) at qrz.com
  30. Hans-Jürgen Barthen, Jochen Berns: Clean-up actions at D-STAR . In: Funkamateur (magazine) . No. 5/2015 , May 2015, ISSN  0016-2833 , p. 570 .
  31. Call Connection Service - Basics and Hints ( Memento of March 3, 2017 in the Internet Archive ) on the pages of the Cwmbran and District Amateur Radio Society : “It is common practice now for CCS capable stations to use the four digit suffix field to store and display their CCS number (and no longer the type of radio you are using or your name) This also makes it easy for someone else to find you and call you without having to look you up in the database. "
  32. User Register ( Memento of the original from March 28, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved March 28, 2016. @1@ 2Template: Webachiv / IABot / dmr.ham-digital.net
  33. "CCS7 - what is that?" At ham-digital.net/ . Retrieved July 28, 2015.
  34. http://www.d-star.asia/
  35. http://www.digisolutions.de/
  36. Archived copy ( memento of the original from January 15, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved December 29, 2012 @1@ 2Template: Webachiv / IABot / www.up4dar.de
  37. http://www.rtl-sdr.com/decoding-d-star-headers-rtl-sdr/
  38. http://www.rtl-sdr.com/receiving-dstar-voice-dsd-1-7-windows/