D-Star was developed in Japan by the Japanese Amateur Radio League (JARL) 1999/2000
especially for ham radio and it became the leading system worldwide due to its clear and
relative simple user interface. Voice is being transformed by the AMBE Vocoder into a
compressed digital data stream of 3600 bits/s. In addition there is a data channel
with 1200 bits/s for a total data rate of 4800 bits/s. This data signal modulates a
carrier, so that a logical 0 is one frequency and a logical 1 a second frequency.
This is called 2FSK (two frequency shift keying) or GMSK (which is the same, however
the signal is modulated using a bell curve). This signal can be used to modulate most
FM transceivers (via the packet radio socket). This is the reason why there are many
home made D-Star solutions.
Three reflector systems are used for communication:
This is a slideshow presented by By John D. Hays, K7VE email@example.com presented at the
Digital Communications Conference in Vancouver, WA, USA 24-26 September 2010.
It is a quick overview of current development projects and building blocks for the D-STAR
experimenter or integrator. It gives a good overview of the D-Star devices and project developemnt as of 2010.
There is alot of material on d-star here:
The rocky road of software development is often difficult and fraught with perils,
but persistance often wins rich rewards. Maybe, not so much for the developer,
but certainly for the community of users. Here is an interesting account of such
a journay undertaken by Scott Lawson KI4LKF and his peers and his successors in the
developemt of Dextra, an open source D-Star protocol.
D-Star Open Source / Dextra project by Scott Lawson, KI4LKF