24 °C Malappuram, IN
November 12, 2019

D-STAR (Digital Smart Technology for Amateur Radio.)

THAJUDHEEN   VU2DJ – KD9JYD

It is an open protocol for digital communications established by JARL (Japan Amateur Radio League).
The biggest appeal of D-STAR is long distance communications over the Internet gateway through repeaters.Even with a handheld transceiver, you can communicate with a friend in another city or country with a clear audio. Call another station directly in simplex, not using a repeater.You can uplink to your local repeater and downlink from a remote repeater, even from the opposite side of the earth. D-Star is a digital operating mode connecting many repeaters and reflectors through VHF, UHF and the Internet. With D-Star it is possible at any given time to hear amateur radio operators from around the globe communicating through the D-Star system. D-Star is also a great mode for local and regional communication. Icom has an official D-Star page.

The use of D-STAR technology for Amateur Radio emergency communications provides a number of benefits augmenting traditional analog FM operations. Clear, crisp, noise-free communication is one of the most significant benefits of D-STAR. The ability to transmit simultaneous text along with voice increases the utility of Amateur Radio in emergency scenarios. Add the ability to link to remote stations via the internet and the capability to transmit high speed multi-media (HSMM) at 128 kbps and the true benefit of D-STAR can be seen. The narrow-band aspect of D-STAR (6.25 Khz) also conserves precious frequency spectrum.

Digital modulation equals Clear Audio

As the digital voice incorporates error correction and DSP technology, the result is clear and crisp audio. The concept is similar to conventional FM, but D-STAR DV mode provides clear intelligible audio without the noises associated with being on the fringes of the communication range. In addition to the clear audio, Icom transceivers automatically sense a FM signal while operating in DV mode, and temporary changes the operating mode to the FM mode.

How does it work?

D-Star refers to voice communication as “DV Mode” for Digital Voice Mode. Voice is converted to a digital format using a bit of computer code referred to as a CODEC. The CODEC code is embedded on a microchip which encodes and decodes the audio signals into and out of the AMBE (Advanced Multi-Band Excitation format). The CODEC that D-Star users is the only proprietary portion of the D-Star design.In Digital Voice (DV) mode, a D-Star transceiver employs circuitry that converts voice audio, using proprietary AMBE encoding, to data packets. The packets are transmitted at a rate of 4800 bps, with 3600 bps used for voice and error correction. The remaining 1200 bps are used for synchronization and general use, of which 900 bps are available for transmitting slow-speed text. Since voice packets and text packets each have a reserved space on the D-Star data stream, they can be sent simultaneously with no interference to each other. This capability has great utility in permitting short text messages to be transmitted while sending voice.

The D-Star data stream has space reserved for routing information. This data is used to direct signals to specific stations and to route signals through separate ports on different bands as well as internet linking to other repeater systems.

D STAR SIGNALS(F7W)

Band width

DD Mode Operation

In addition to DV mode, a high-speed Digital Data (DD) mode can be sent at 128 kbps only on the 23cm band. A higher-rate proprietary data protocol is used in 10GHz “link” radios for site-to-site linking.


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

DD mode is a 128kbps data mode in a 10 W mobile package on the 23cm band. This is perfect when you need network connectivity, at ranges your standard wireless network cannot reach. The ID-1becomes your wireless modem via your computer’s Ethernet port.

How is D-STAR applicable to emergency communication?

An 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 send e-mail or Microsoft Word files to someone. The quantity of data sent can be extremely high-volume compared to traditional amateur modes. Voice and even CW are capable of getting a message through, albeit slowly, but D-STAR can place documents, images, and spreadsheets into the hands of those who need them most.


D-RATS is an emerging D-STAR communications tool that supports text chat, TCP/IP forwarding, file transfers, and can act as an e-mail gateway. There is also the ability to map user’s positions using the DPRS function of D-STAR.

D-RATS

A multi-platform integrated tool for communication using D-STAR radios. With only a pair of radios (or an entire repeater stack) a variety of data transmission methods are supported, including:
• Instant-message chat
• Automatic beacon messages
• File transfers with error detection
• Structured forms
• GPS position reports
• Image and video transfers
• And much more


Developed for 1st responders Initially developed for the Washington County ARES/RACES group in Oregon, D-RATS quickly evolved into a full blown multi-platform EmComm software suite for data communications using D-STAR radios. Once you try it, D-RATS will become the most used tool in your EmComm tool box,
In time of emergency, message accuracy is vital. Don’t let a language barrier get in the way. If it is easier to show a data document than verbally describe something, then let D-RATS do it! You’ll get better EmComm efficiency, accuracy and accountability.


The D-RATS suite is powerful and can give you access to additional resources such as image transfer, custom communication forms, e-mail portals over several miles with the D-RATS e-mail gateway, as well as full asset tracking with multiple layer resource maps. In addition to accuracy, accountability and speed, simplicity ranks high on the 1st Responder Leader’s EmComm information wish list. But how can communications be simple during or after an emergency, when infrastructure support may be partially or completely compromised? The D-RATS suite is extremely scalable. It’s well suited to everyday communications, not just emergency situations. For example, say you need to send a few support messages during a civic marathon event, or during some field training exercises – the D-RATS software suite’s keyboard-to-keyboard text messaging, file transfers, and position reporting maps keep things basic. It’s much like the everyday communications we’re all now used to.

Routing and Linking

One of the great features of D-STAR is the user’s ability to talk anywhere they want via call sign commands. With the basic call sign routing, you can route your communications to a specific user or repeater. You are not required to know what repeater the person you want to communicate with is located. For those repeaters running the Dplus software, you have the capability of linking to another repeater or a group of repeaters via a reflector. The reflectors are a great way to meet new people and have communications with a group of users from all over the world at the same time.

Reflectors - what are they?

A reflector is software running on a computer with no radios attached to it that bridges communications between multiple repeaters or “hotspot” users. Think of a reflector as a teleconference bridge. Many of us call into telephone bridges at work that link multiple people together using a common number, a reflector is basically the same thing (even more basic, just like the old 3-way calls linked multiple phone calls together.) Each reflector has multiple modules designated by a letter code. There are 4 main types of reflectors: REF, XRF, DCS, and XLX. What’s the difference between them all? Really nothing. They all do the same basic thing, connect repeaters and hotspot users to each other on a common “bridge”.

  • REF – The first reflectors created were REF reflectors. REF reflectors use a protocol known as DPLUS and amateurs that wish to utilize those reflectors must register with a DSTAR gateway system. These are the most common type of reflectors and are natively supported for selection via most newer DSTAR radios using the DR (DSTAR Repeater) mode. It allows you to choose your repeater and link that repeater to reflectors using a menu instead of having to program channels.
  • XRF – Up next is XRF reflectors. These reflectors use a protocol known as D Extra. Again, they all do the same thing, just a different backend software.
  • DCS – Originating in Germany, it was ran by German amateur operators. Utilizing the DCS protocol, other hams have now taken over the DCS routing system and are now being used outside Germany but still mostly overseas.
  • XLX – Last but not least are the newest of the reflector types but it actually supports the 3 prior protocols, DPLUS, XRF, and DCS. XLX reflectors are primarily used to connect multiple reflectors together. One of the greatest benefits of XLX is that they can connect other digital radio protocols together such as DMR and Yaesu Fusion. A great example is the Quadnet Array which links all the digital modes together.

Share Pictures

Take pictures – including your shack, operating place in the field, rigs or friends – with your Android device and share them over D-STAR transceivers. Add to your ragchew with images and make QSO even more fun.

Text Messaging

Text messaging allows you to chat with other D-STAR users. Use texts when voice communications may not be appropriate. By using the Android devices, you can exchange a message by your preferred language

Export to the Android ApplicationIn

When connected with an Android device (through blutooth or data cable), received position information can be plotted on a Map Application.

D-PRS (Digital Packet Reporting System)

D-PRS converts the D-STAR GPS information to APRS compatible strings and presents it to the APRS-IS (APRS Internet Server) and other APRS clients. The APRS maps show real-time APRS information and tracks D-STAR stations on the Internet.

GPS Log Function

When receiving a call addressed to your call sign, this function automatically replies your current position information. Replied position information will pop up on the caller’s display.

Automatic Position Reply Function

The repeater search function assists you in accessing nearby repeaters, even in areas you are visiting for the first time. The function searches for a nearby repeater using the repeater memories with the GPS position information.

D-star radios

D-Star operations include an Icom IC-7100 all mode/all band transceiver (mobile and base),IC9700 all mode(VHF/UHF) Base transceiver , ID-5100 transceiver (VHF/UHF) and ID 4100A transceiver (VHF/UHF) mobile transceiver. I also use an Icom ID-51A Plus and KENWOOD TH74 HT for D-Star operation direct and through VHF and UHF DVAP devices.

From time to time I will also operate D-Star directly through my computer with a DV-Dongle. You can read about my experiences using the DVAP with a Raspberry Pi computer for portable and mobile operation

 

 

Raspberry Pi3 to get the most out of D-Star, hams communicate through the gateway system and through reflectors. The gateway system connects various D-Star repeaters through the Internet. Reflectors are hubs designed to allow numerous D-Star repeaters and individuals with DVAP devices and DV-Dongles to connect together through a common experience.


The Terminal mode and Access point mode enable you to make D-STAR calls through the Internet, even from areas where no D-STAR repeater is accessible by RF signal.

Terminal mode

Accesspoint mode

D-star satellite

D-Star ONE Sparrow (DP1GOS) halfduplex repeater & beacon frequencies

Uplink: 437,325MHz / Downlink: 435,525MHz RF-Power: 800-1200mW

D-Star One is the first communication & amateur radio satellite now in orbit. D-Star One is a 3U CubeSat which is equipped with four identical radio modules with D-Star capabilities, all being operated in a half-duplex mode.


Two modules are used for telemetry and telecomand and operate on identical frequencies. Telemetry can be received on 435,7 MHz, the format will be disclosed after launch. Both modules receive, and both modules answer. To prevent information loss, they answer after each other. So each telemetry frame is repeated twice. Both modules have a D-Star Voice-Message Beacon, but it is only activated for one module during LEOP. The Beacon is repeated once in a minute.


The other two modules are dedicated to the radio amateur community. Both modules have the same frequencies, so one of them will be powered down as long as the other one shows no degradation effects. The downlink frequency is 435.525 MHz and the uplink frequency is 437.325 MHz. Also here half-duplex mode is applied. The modules are configured to work as D-Star repeaters, so they retranslate the received d-star frames on the downlink frequency. They also have a D-Star voice beacon signal.


All modules are operated in a power save mode. This means that they are in idle for 40 seconds and then in receive mode for 20 seconds. Once a signal has been received, the modules switch to receive mode for five minutes. So it might be necessary to „ping“ the satellite a couple of times until an answer is received. The world’s first D-Star message from space was received on 29.12.2018 by DK3WN.The D-Star.ONE repeater function was tested and confirmed on 07.01.2019 by VK3VCL Wayne Bruce from Melbourne was the first who used the repeater of D-Star.ONE

D star repeater (DR)

A Dstar repeater comprise(up to) 5 connections,grouped as follows:

  • Rf voice ports used to receive and transmit voice communications with transceivers.
  • Rf data ports used to receive and transmit data communications with transceivers.
  • Network gateways that connect a repeater to the rest of the d-star network,

Not all repeaters have all ports but most repeaters have at least one rf port and a network gateway

PRABIN THOMAS – VU2POL & THAJ – VU2DJ (R) After the D-star Repeater installation for United Arab Emirates(A62A). This is first time in the middle East. Hope fully we have a new D-star repeater coming soon

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