May 2019

May 2019

DEC Bulletin

Since Paul, AE5OJ and I gave a talk to the W5ES club on Friday, May 26, 2019 about introducing the digital modes I thought I would use this time to reiterate what was said about D-Star.

D-Star is the radio communications of the future and as ICOM states in their literature “for the second century of amateur radio”. D-Star stands for Digital Smart Technology for Amateur Radio. It was developed by the Japanese Amateur Radio League (JARL). D-Star is an open standard which means that anyone can build equipment that meets the standard. ICOM and Kenwood so far are the only manufactures that have taken advantage of this standard. There are some however, who have been successful in putting together some non-ICON equipment that works very well with D-Star. They have used a Yaesu radio and an interface box to achieve to this result. There are others that have homebrewed non-ICOM repeaters with great results as well. Check out KI6ZUM.com and VK5ZEA has some outstanding You Tube videos of his equipment.

D-Star uses a GMSK codec (Gaussian Mean Shift Keying encoder/decoder) at 4800 bps in digital voice mode. The codec is called Advanced Multiband Excitation (AMBE). AMBE is a product of Digital Voice Systems Incorporated (DVSI). It is similar but not the same as the APCO-25 IMBE digital voice used by Public Safety.

The D-Star modes are available with the following specs:

Digital Voice (DV)

            4800 bps GMSK data

            1200 bps forward error correction data

            1200 bps packet replacement/D-PRS (GPS tracking)

Digital Data (DD) can be used point-to-point or through a repeater. Data and voice are done on the same frequency simultaneously.

The ID-1 and ID-9700 radios are the only radios that can operate high speed data on the 23 cm band. They connect to the computer via a USB and Ethernet cables. The USB is for control and Ethernet is for data.

The 128-kbps data rate is near ISDN speed, and an Effective rate ~90 kbps

Low Speed Data can be done on the 2 m and 70 cm bands. It can be used to transmit position data like APRS.

It can be used for similar keyboard-keyboard applications such as D-Chat or D-Rats.

 

As far as D-Star vs Analog operations is concerned with the analog radios we need three settings, frequency, offset, and tone (pl). In the D-Star radios we need frequency, offset, DV mode, call-sign settings. With the D-Star radios it is a good idea to keep the manuals handy until you become familiar with the radio.

The D-Star system is a call-sign routed system. A station can be local or remote. The system routes the calls immediately. The call-sign entries are eight characters long. The eight character of a call-sign is reserved for the Terminal ID or Repeater ID.

We need to tell the D-Star system four things:

            MYCALL (who you are)

            URCALL (who you want to talk to)

            RPT1 (the repeater you are coming into)

            RPT2 (the repeater you are leaving from)

How you set up your call-sign entries tells the system where to route your transmissions. It could be locally on the same repeater. It could be on multiple repeater modules such as a crossband transmission, or it could be to another repeater module via the Internet gateway.

The D-Star repeater is a narrow band repeater. The D-Star voice and low-speed data repeater offers a significant improvement in spectrum efficiency. The repeater requires only a 6.25 kHz channel instead of the 15-30 kHz required by the analog repeater. We could replace one analog repeater and put three D-Star repeaters its place. D-Star repeaters could also be sandwiched in between two analog repeaters.

To see a list of the Last Heard stations on D-Star go to http://dstarusers.org/. This is a list of users worldwide. Another website to look at is http://www.dstarinfo.com. Here you can find many different features about D-Star.

We hope to have additional talks about the many other applications and capabilities of D-Star in the future. 

Questions and comments are welcome and encouraged regarding this article. Send an email to the address shown below.

Lew Maxwell, KB5HPT
DEC, District 6 – Far West Texas
Email: kb5hpt@arrl.net
Comments