DPRG
DPRG List  



[DPRG] Long Distance Data Transmission (Off Topic)

Subject: [DPRG] Long Distance Data Transmission (Off Topic)
From: Kipton Moravec kip at kdream.com
Date: Sat May 19 20:18:27 CDT 2007

In my capacity as a Amateur Radio Operator, I was helping with
communications for the Wild Ride, which is a bicycle rally from
Richardson, to Plano, Murphy, Wylie, Lavon, and Nevada and back. There
were 16, 40, and 64 mile routes. I was at "Rest Stop 2" on the Lavon
side of the Lake Lavon Dam. http://www.wildridebikerally.com 

Besides the normal voice communications, we had digital communications
(successful for the first time) this year.

There is a relatively new technology called D-Star (which is one way of
many) to transmit digital data. We used 10 Watt D-Star 128K baud radios
in the 1.2 GHz band to connect to a repeater on the top of the Bank of
America Plaza, in Dallas (tallest building downtown). The repeater
routed the data to the Internet, and to a server where we dumped
photographs. I took pictures, loaded them to my laptop, the D-Star radio
attached to the Ethernet port of my laptop, and used FTP to transfer the
pictures to the server.  The D-Star looked like a slow Ethernet
connection with full TCP/IP to my laptop. 

The server took the latest picture in my FTP directory, and inserted it
into the web page for Rest Stop 2, which was part of a automatically
rotating web page slide show. 

Then in Richardson, they set up a WiFi link from the roof of Nortel
building to the Start and Finish of the Rally. There we had a wide
screen TV showing the web page slide show so everybody could see what
was going on on the course many miles away. Within 2 minutes of me
transferring the data from Lake Lavon Dam, it was on the screen in
Richardson. It was pretty cool.

Rest Stop 3 was farther out, a little north of Nevada. The rest stop was
in a valley and they could not get enough antenna height to make it to
Dallas. So they set up the D-Star radio on the closest hill that could
make it, and routed about 300 feet of Ethernet cable to a Linksys WiFi
router, with a directional antenna on a portable mast that could reach
Rest Stop 3.

The Amateur Radio Clubs do these exercises to practice for Emergency
Communications to be able to transmit voice and data when some kind of
emergency happens like Katrina, or the tornado in Greenburg, Kansas.
(http://www.kansas.com/static/slides/050507tornadoaerials/)

Voice has been going well for a long time, and slow data (1200) has been
around awhile. Faster data rates like 2400, - 9600 baud are becoming
more common, but the D-Star is the first one at 128K baud, and it is
nice that we can send TCP/IP packets through it.

By the way, you need an Amateur Radio license to operate D-Star. But it
is pretty easy to get your license. I did it in a weekend class.

-- 
Kipton Moravec KE5NGX
"Always do right; this will gratify some people and astonish the rest."
--Mark Twain


More information about the DPRG mailing list