Icom’s D-STAR (Digital Smart Technologies for Amateur Radio) Is a digital voice and data protocol specifically designed for amateur radio. It was one of the first digital modes developed for amateur radio, offering a range of features that enhance communication capabilities beyond what is possible with traditional analog FM systems.

Key Components and Features of D-STAR:

1. Digital Voice and Data Communication: DV (Digital Voice): This mode digitizes the voice signal using the AMBE (Advanced Multi-Band Excitation) vocoder, which compresses the voice into a smaller data stream, allowing for more efficient transmission. Alongside the voice, a small data stream (1200 bps) can also be transmitted, which can include things like GPS coordinates or text messages. DD (Digital Data): This mode is used for high-speed data transmission at 128 kbps, typically on the 1.2 GHz band. It’s similar to mobile internet and can be used for sending larger data files or accessing the internet.
2. Modulation: D-STAR uses GMSK (Gaussian Minimum Shift Keying) modulation, which is efficient and allows for the narrow bandwidth of 6.25 KHz per channel, doubling the capacity of the available spectrum compared to traditional 12.5 KHz FM channels.
3. D-STAR Repeater System: D-STAR repeaters work similarly to analog repeaters but with added capabilities. They can handle both local communication and link with other D-STAR repeaters around the world via the internet. This creates a vast network of linked repeaters, enabling global communication.
4. Call Sign Routing: One of the unique features of D-STAR is its ability to route calls by call sign. Auser can initiate a call to another operator by their call sign, and the system will automatically route the call through the necessary repeaters or gateways to reach the destination. This is useful for finding and contacting specific operators, no matter where they are in the world.
5. Reflectors and Linking: D-STAR uses “reflectors”, which are essentially virtual meeting rooms on the internet where multiple repeaters and users can connect simultaneously. This is similar to a conference call, allowing many users from different locations to communicate together. Users can also manually link their local repeater to another repeater or reflector, creating a temporary connection for a specific conversation or event.
6. D-PRS (Digital Position Reporting System): D-PRS is an adaptation of APRS (Automatic Packet Reporting System) For D-STAR. It allows users to transmit GPS coordinates over the D-STAR network. This is particularly useful for mobile operators or during search and rescue operation.
7. ID and Registration: To use D-STAR’s advanced features, such as call sign routing, users need to register their call sign on a D-STAR gateway. Once registered, they can access the global D-STAR network, allowing for international communication and call sign routing.
8. Gateway and Internet Linking: D-STAR repeaters are often connected to the internet via a gateway, which allows them to connect to the broader D-STAR netwok. This network linking is what enables D-STAR’s global communication capabilities, letting users talk to other operators around the world as if they were on the same local repeater.

How D-STAR Works in Practice: User Setup: An amateur radio operator programs their D-STAR radio with the appropriate settings, including their registered call sign, repeater information, and desired reflectors or destination call sign. Transmission: When the user transmits, their voice is digitized and sent as a digital signal to a local D-STAR repeater. The repeater can then repeat the signal locally or route it through the D-STAR network to a remote repeater or reflector. Reception: The target repeater or reflector receives the signal, and if it’s a voice transmission, the receiving user’s radio converts the digital signal back into an audible voice. If data is included, such as GPS information, the receiving radio can display this data or use it in applications like mapping. Global Communication: If a user wants to communicate with someone far away, they can use call sign routing or connect to a specific reflector that both users are linked to. This flexibility is one of D-STAR’s key advantages, enabling easy global communication.

Summary:

ICOM’s D-STAR system provides a modern, digital approach to amateur radio, offering clear voice communication, integrated data services, and global connectivity through the use of internet-linking repeaters and reflectors. Its ability to route calls by call sign and transmit data alongside voice makes it a powerful tool for amateur radio enthusiasts, especially those interested in long-distance communication and digital modes