D-STAR

Lore & Background

In 1998, an investigation into bringing digital technology to amateur radio was started, funded by the Japanese Ministry of Posts and Telecommunications and administered by the Japan Amateur Radio League. The result was published in 2001 as D-STAR. In September 2003, Icom named Matt Yellen, KB7TSE (now K7DN), to lead its US D-STAR development program. Starting in April 2004, Icom began releasing D-STAR optional hardware, beginning with the 2-meter mobile unit IC-2200H, followed by handheld transceivers the next year. The UT-118 add-on card was required for these early radios to operate in D-STAR mode. JARL released changes to the standard in late 2004, and Icom delayed hardware release in anticipation. The Icom ID-1 1.3 GHz mobile radio, released in late 2004, was the first D-STAR radio to provide digital data (DD) mode operation at 128 kbit/s. The first D-STAR satellite QSO occurred in 2007 via AMSAT's AO-27 microsatellite, with minor difficulty from doppler shift. The first D-STAR capable microsatellite, OUFTI-1, a 1 kg CubeSat built by Belgian students, was launched in early 2016. In 2015, FlexRadio Systems added D-STAR support to their HF transceivers via a software upgrade, requiring the ThumbDV device from NW Digital Radio.

Reader's Guide

D-STAR's significance lies in being the first digital mode purpose-built for amateur radio, establishing a framework for digital voice and data that later modes would build upon. Its integration of Internet connectivity through gateway servers allowed amateur radio operators to link repeaters globally using callsign routing, expanding the reach of local systems. The protocol's use of proprietary AMBE encoding for voice at 3,600 bit/s, with 1,200 bit/s for additional data, demonstrated a practical balance between audio quality and bandwidth efficiency. The system's ability to operate on HF, VHF, UHF, and microwave bands, along with its dedicated 10 GHz interlinking radio for emergency communications, showed versatility. The development of the G2 gateway software, running on CentOS Linux with a mix of open-source and proprietary components, created a trust-server environment for user registration and traffic routing. The introduction of DD mode at 128 kbit/s on the 23 cm band provided a high-speed data capability unique among amateur digital modes at the time. D-STAR's legacy includes influencing subsequent digital voice standards and demonstrating that amateur radio could effectively integrate with IP networks while maintaining its own identity.

Did You Know?

• D-STAR was developed in the late 1990s by the Japan Amateur Radio League and funded by the Japanese Ministry of Posts and Telecommunications.
• D-STAR-compatible radios are manufactured by Icom, Kenwood, and FlexRadio Systems.
• The Icom ID-1 was the only D-STAR radio to provide 128 kbit/s digital data mode until the release of the IC-9700 in 2019.