Digital Modes; D­star; Dmr - DV Development Group DV4mini D-STAR User Manual

Digital Modes:
The DV4mini can handle five digital modes:
D­Star:
D-Star was developed in Japan 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. DCS (most common),
D-Plus, REF reflectors (mostly in English speaking countries), and the
x-Reflector system which plays a minor role. DV4mini enables
communication on all these systems.
DMR:
DMR was originally designed by ETSI for commercial applications. This is
evident in the user interface where numbers are used in lieu of call signs.
DMR modulates with 4FSK, indicating that it uses 4 frequencies (compared to
D-Star with 2 frequencies). This allows to double the data rate to 9600 bit/s.
The higher rate allows the transmission of 2 channels at the same time (2
time slots). The DV4mini always works in simplex mode in DMR.
If you use time slot one (TS1) you have to set your radio to color code 1 (CC1)
and the talkgroup you want to use, i.e TG311 or TG262 etc. ​
have to enter the talkgroup number into the receive group list of your radio
too, or your squelch will not open. This is a common error made by first time
users and it is very frustrating.
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