|
 |
| |
| The following
table compares D-STAR capabilities and costs with those of VHF
packet for both low-speed and high-speed systems. (Costs are
based on equipment MSRP.) You can see that low-speed D-STAR
links, which support simultaneous voice and data, cost no more
than low-speed packet and are cost-competitive with even high-speed
packet. High-speed D-STAR links provide approximately 10 times
the performance of high-speed packet at less than three times
the price. |
| |
| |
D-STAR |
PACKET |
| VOICE CODEC
|
3600
bps AMBE® |
None |
| DATA
SPEED |
DV:
1200 bps (net 950 bps)
DD: 128k bps (net 90k bps) |
LS:
1200 bps
HS: 9600 bps |
| BANDWIDTH |
DV:
6kHz
DD: 150kHz |
20
kHz |
| FREQUENCY |
DV:
Any VHF/UHF band
DD: 1.2 GHz |
Any
VHF/UHF band |
|
|
Software
and system developers want to know the detailed technical specifications
and the following table illustrates the main points of the D-STAR
system.
DV: Digital Voice
+ Data DD:
High Speed Data LS:
Low Speed Data HS:
High Speed Data |
| |
| |
D-STAR |
PACKET |
| DATA
INTERFACE |
DV:
RS-232 or USB 1.0
DD: Ethernet |
RS-232 |
| DATA
FORMAT |
Same
as Ethernet |
7-bit
ASCII text |
| AIR
LINK |
D-STAR
packet format and 0.5GMSK
modulation |
LS:
AX.25 using Bell 202 modulation
HS: AX.25 using K9NG Bell 212A |
NETWORK &
TRANSPORT |
DV:
Transparent point-to-point
DD: TCP/IP |
AX.25
of TCP/IP |
|
| |
 |
| For low-speed
DV D-STAR links (1200 bps), the data interface to your laptop
or terminal is a familiar RS-232, three-wire connection (Rx
data, Tx data, and signal ground) or a USB 1.0 interface, depending
on the radio. For high-speed D-STAR (128k bps), the data interface
is an Ethernet connection with the customary RJ-45 jack |
|
 |
| Over the
air, packet signals use FSK protocols originally designed for
land-line applications and adapted to amateur radio. D-STAR
uses the up-to-date modulation method of 0.5GMSK--Gaussian Minimum
Shift Keying. GMSK provides improved performance over packet
because it is designed for wireless links. Data is sent using
the D-STAR packet format, which includes FEC (Forward Error
Correction) and routing information. The data itself is encapsulated
within the D-STAR packet as an Ethernet packet. |
|
 |
Low-speed
DV D-STAR data is a “keyboard-to-keyboard” mode.
The D-STAR system provides reliable, transparent transport from
user to user by using CRC error detection. High-speed DD D-STAR
data appears at the data interface as an Ethernet packet suitable
for encapsulation by the TCP/IP protocol stack. The Ethernet
connection is a bridged, point-to-point connection between static
IP addresses so that standard Internet application software
can be used to transfer data across the D-STAR system. You may
download your own copy of the JARL’s D-STAR Technical
Specification at
D
-STAR Specification
*All
information, including pricing, is subject to change without
notice or obligation.
|
