D-Star - Digital Smart Technologies for Amateur Radio
No Longer a Nay-sayer
I will be
the first one to admit that I dismissed D-Star from the day I first saw
it introduced by at the Dayton Hamvention. Every year after its
introduction I completely ignored the various Icom D-Star displays. My
thinking was FM was just fine, audio quality was usually good, and
there were plenty of FM repeaters all across the country. So how was
digital audio going to really improve the situation?
There
were hardly any repeaters available for the past several years. Sure I
read where you could access other D-Star users with a DV Dongle, but
that was through a computer and the Internet. Hardly amateur radio to
me.
So on a recent business trip, on the return trip home I
made a 28 hour stop in Atlanta to visit my daughter who currently lives
there. While she and her husband were at work the next afternoon, I
decide to make a trip to the Ham Radio Outlet store in North Atlanta.
After a few minutes to wandering the store, I was asked if I needed
help. I said "sure, I'd like to speak to someone about D-Star." I was
directed to the store manager, Mark KJ4VO who I was told was their
local D-Star expert.
Mark proceeded to explain just how D-Star
works. How most of the repeaters are linked. The fact that you can
carry on QSOs with hams throughout the world on just a handheld, or by
using the DV Dongle. I was shown a D-Star repeater system which is
installed in the store. Mark demonstrated linking and unlinking the
repeater to various "reflectors" to which various repeaters are
connected to throughout the world. We even made a few QSOs with three
of his fellow ham friends in different states.
All I can say is
after an hour, I was hooked. My first purchase while there was an Icom
IC-80AD dual-band handheld. I had it shipped since I did not want to
carry it back on the plane. Within a week of receiving it and playing
with it, I ordered an Icom ID-880H for use as a base radio in the
shack. Yes, I am totally and completely hooked on D-Star.
What is D-Star?
D-Star
offers digital voice and slow and high-speed data communications.
Slow-speed digital voice and data are transported at 4800 bps, of which
3600 bps is used for voice transmission and the remaining 1200 bps is
used for syncronization and general use. Of that 1200 bps, around 900
bps is available for the transmission of data.
High-Speed digital data communication is transported at 128kpbs and is
capable of supporting Ethernet packets and also is fast enough to use
for Internet applications such as displaying web pages.
D-Star is capable of connecting repeater sites using the Internet and
forms a world-wide radio network. This state-of-the-art system has a
tremendouse amount of functionality not available with less
sophisticated linking system like IRLP and Echolink.
The quality of the D-Star voice signal is very similar to that of FM
voice. Some say it sounds slightly inferior, but I think it is
equivalent and definitely has less noise - in fact no noise like you
will find with FM at times. The signal either makes it to the repeater
or receiver perfectly, or not at all. There is no in-between signal
quality that is found with traditional analog voice modes and no
squelch tail at the end of every transmission and the repeaters usually
do not have a courtesy beep. However, Icom has an ability to provide
that courtesy beep from within the radio to let you know when the other
party has turned the conversation over to you.
Unlike analog voice modes like FM, DV mode has the ability to transmit
1200 bps data simultaneously with the voice signal since they are both
digital signals and the "voice" and "data" portions of the signals do
not interfere with each other. While the data portion of this signal is
referred to as "slow-speed" data, it still is much faster than other
digital modes like PSK31. It is plenty fast for keyboard to keyboard
conversations, but not suitable to sending large files.
For the sending and receiving of greater volumes of data and large
files, D-Star has the "DD Mode" or Digital Data Mode. The DD mode is
only supported on the 1.2Ghz amateur band and is capable of sending a
receiving data at a 128kbps rate.
To send slow-speed data on D-Star, all that is required is connecting a
home-made serial cable or low cost commercially made serial cable from
your PC to the data port on the back of the radio. No special or
additional data modem is required. To send and receive high-speed data
on D-Star on a 1.2Ghz D-Star radio, all that is required is a standard
Ethernet cable connection.
The Practical Usage of D-Star
The
above are just some of the basics on D-Star. But now I will review the
value of D-Star and why every amateur should consider adopting this new
voice and data mode for the VHF and UHF bands (2M, 440Mhz, and 1.2Ghz).
One of the biggest benefits are that most repeaters are connected to
D-Star Reflectors. These are basically network servers. Once a ham is
registered with a repeater gateway, they can connect to D-Star users
beyond the local repeaters. You do not have to be registered with a
gateway to use a local repeater, only if you want to make use of the
D-Star network. If you do register with your local gateway, you only
have to register with one gateway as your registration information is
propagated to all other gateways and reflectors in the D-Star network.
This allows retired and older hams who have had to move into apartments
and retirement homes to still talk to their ham friends around the
world using only a D-Star capable handheld radio! No large special
antennas are required. If the ham does not have a D-Star capable
handheld, or does not have a local D-Star repeater yet, no worry,
several U.S. amateurs developed and manufacturer a little device known
as a DV Dongle. The DV-Dongle connects to a Personal Computer which
needs to be connected to the Internet with a high-speed DSL or Cable
Modem connection. Dial-up just does not cut it. Then with a standard
computer audio headset with microphone and headphones, the DV Dongle
allows the user to connect to any of the D-Star reflectors on the
network and carry on conversations with other DV Dongle users or radio
users through the repeaters connected to the various reflectors! This
allows every ham, no matter how they are housing and antenna
restricted, to again communicate with hams around the world.
Also, Technician licensees can experience international communication
with D-Star. Sure it is possible for Techicians to experience the
thrill of DX on 6 Meters and even some of the higher bands, or with
meteor scatter or moon bounce, that is not practical and available all
the time for the average Techician Class licensee. But with D-Star,
hams can talk to other hams around the world all the time. It's not
unusual for hams on the west coast getting ready for bed to talk with
hams in the United Kingdom who are on their daily commutes to work.
One of the features I really like is the ability to call another ham
without knowing his current location or what D-Star repeater he or she
is currently using. For example, I am in Cincinnati and a good friend
of mine WI0T, is usually in St. Charles, Missouri. If WI0T recently
used the K0MDG repeater in St. Louis, the D-Star network knows where he
is and what repeater is recently used. I program my radio to access my
local repeater, K8BIG C (the "C" means that it is the K8BIG 2 Meter
repeater). In the "URCALL" position, I enter "WI0T" which is Rod's
call. When I make a call to Rod on the K8BIG C repeater, the D-Star
network knows to route that transmission to the K0MDG repeater and Rod
will hear my call!
But let's say several days later, Rod goes on a business trip to Los
Angles and takes his D-Star capable radio with him and chats with some
of the local hams in Los Angeles on one of their D-Star repeaters. When
I use the same method to call Rod as before, this time the D-Star
network knows that WI0T is now in Los Angeles and routes my call
automatically to the Los Angeles area repeater that WI0T last used. All
this is accomplished automatically!
One of the best guides to providing an overview of D-Star, how to
program radios, using the repeaters, linking to reflectors, using the
DV Dongle, overview of third-party software programs to use with D-Star
such as D-RATS (RATS is STAR spelled backwards) and D-Chat, and how the
D-PRS capability of D-Star intergrates into the APRS network, can be
found in a book by Bernie Lafreniere, N6FN called the Nifty E-Z Guide to D-STAR Operation. This book can be order from www.niftyaccessories.com or from amazon.com.
If you would like to see if there are any D-Star repeaters in your area, you can check this constantly updated list here:
http://www.dstarusers.org/repeaters.php
This list only lists the U.S. based D-Star repeaters and not those
repeaters listed in other countries. Currently there are over 500
D-Star repeaters with more being added each month.
This listing does not show the hundreds and hundreds of D-Star Hotspots
and DV Access Points in operation. What are Hotspots and Access Points?
They are yet another way users can access the D-Star Network using
D-Star capable radios.
The
latest device to assist hams in connecting to the D-Star world-wide
network is the DV Access Point Dongle or "DVAP" for short. The DVAP was
introduced in January 2010 by Internet Labs the same people who created
the DV Dongle.
 DVAP Dongle
The DVAP can do two things. First, if you have a D-Star radio but no
local repeaters, it allows you to use your radio to connect to any
reflector in the D-Star network. How? The DVAP is actually a D-Star
voice encoder/decoder coupled with a micro two-meter transceiver that
can be set to any frequency in the two-meter amateur band. Let's say in
your area no one typically uses the 146.46 simplex frequency. So you
set the DVAP frequency to 146.46. You then connect the DVAP to the
D-Star network and desired reflector with the provided software. Now
you set your D-Star transceiver or handheld to 146.46 simplex using the
Digital Voice or DV setting. Now start talking! You control the DVAP
with the same commands that you would use for D-Star repeaters. This
allows you to unlink and link different relectors from your radio.
Since this particular device only has output power of around 10 mws,
its range is rather limited at about 100 yards. But that is perfect for
someone wanting to use their D-Star handheld around the house and yard.
You can also connect an external antenna to increase the range to maybe
around your neighborhood.
Coming Next - Hotspots
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