Vertex Standard FT-2800M Dokumentacja Pobierz pdf (Strona 5)

September 2010 43

The QS1R, Contesters and Skimmer Server

Pete Smith, N4ZR

I suppose there may still be some

active Amateur Radio operators

who haven’t heard of CW Skim-

mer, the amazing, somewhat con-

troversial software written by Alex

Shovkoplyas,VE3NEA (www.dxatlas.

com). It decodes all the CW signals

across a wide slice of a band, decides

which ones are CQing and which are

answering CQs, and can, if asked, of-

fer “spots” via Telnet and the Internet.

DXers use it to find DX on a band,

and to figure out where to call in big

pile-ups by tracking the successful

callers. Contesters use it like tradi-

tional “packet clusters” to find people

to work and to catch band openings.

The QS1R, with its open software

architecture, offered Alex a tempt-

ing challenge. Instead of listening to

one band at a time, could the radio

be reprogrammed to listen to many

bands simultaneously? Well, it could,

and he did. The result was Skimmer

Server, software that offers Skimmer-

style decoding on up to seven bands

at once, and up to 192 kHz per band.

As a result, the QS1R/Skimmer

Server combination has captured the

attention of contesters and DXers

worldwide.

Reverse Beacon Network

I use my Skimmer Server/QS1R

combination both as a stand-alone

Telnet server, open to anyone who

wishes to log on, and also to contrib-

ute to the Reverse Beacon Network

(RBN), a worldwide network of Skim-

mer and Skimmer Server receiving

stations (reversebeacon.net). The

RBN collects Telnet spots from each

connected receiver and passes

them to the server, where they are

displayed on a constantly chang-

ing world map and also archived for

future analysis. The amount of infor-

mation collected is quite spectacular

— for example, in the 24 hours of the

Russian DX Contest, the RBN col-

lected over 545,000 spots from 34

“reverse beacons” on four continents.

So what? To begin with, you can

find out what stations or countries

have been spotted by the network,

when and on what frequencies —

like a constantly revised real-time

DX bulletin. Thanks to Rick Walker,

K4TD, spots from the RBN are also

available at telnet.reversebeacon.

net, port 7000. You can filter the spot

stream you receive, just as with a

DX Cluster node — only there are

many more spots.

In addition, a group led by Felipe

Ceglia, PY1NB, is hard at work

developing other new ways to use

the RBN’’s prodigious spot data-

base. The first of these is an online

Spot Analysis Tool, written by Nick

Sinanis, F5VIH/SV3SJ. Tell it a date,

the call signs of several stations to

compare and a reverse beacon’s call

sign, and it will quickly display com-

parative graphs of the stations’ sig-

nal strength (relative to local noise)

on every band. Although fading and

interference can invalidate any sin-

gle comparison, the graphs clearly

portray comparative performance

— you can use the data for bragging

rights, or to plan improvements for

“the next time.”

Using the Software

Back to Skimmer Server. In

Figure A, the left hand “pane” is the

aggregator, displaying the spots that

my station heard and reported (on

a simple vertical) in the few minutes

before the screen shot was taken.

The right-hand “pane” is the Skimmer

Server control panel, which I usually

keep on the STATUS tab, to tell me

how it’s doing in real time. In order to

reduce load on the host computer,

the Skimmer Server normally oper-

ates almost invisibly, as a simple icon

in the Windows System Tray, but you

can pop this window up to keep track

of what it is doing and to change set-

tings if you wish.

You’ll note that the control panel

tells me that both the Telnet server

and the link to the QS1R are working

normally, and also how many decod-

ers are currently operating on each

band. It reports how much computer

power is being used (this was on a

relatively quiet Monday morning at

96 kHz bandwidth on seven bands),

and other parameters of interest. By

the way, the computer on which I’m

running Skimmer Server is a rela-

tively basic dual-core Pentium, much

slower than the cheapest computers

currently on the market from major

manufacturers. A quad-core Godzilla

is not required.

Why are contesters so interested?

Well, Skimmer Server spots have

some unique advantages over spots

from traditional DX clusters. If you

connect to a Skimmer Server rela-

tively close to you, you will be able to

hear everything it can. It spots ev-

erything, not just rare stations, which

makes it ideal for contesting, though it

can occasionally get confused about

which stations are CQing (running

in contest parlance). The frequency

calibration is consistent, so that all

stations are heard at roughly the

same pitch as you jump up or down

the bandmap, and copy accuracy is

at least as good as the DX cluster

average. And finally, connecting to a

Skimmer Server off-site is an ideal

solution for multioperator stations,

avoiding the complex engineering

required if a CW Skimmer were used

in that RF-loaded environment.

The Skimmer Server software is

part of the CW Skimmer package,

available for download from Afreet

Software (www.dxatlas.com). The

package can be tried free for 30 days

and costs $75 to register for contin-

ued use thereafter.

Figure A — The Skimmer Server provides a wealth of information about

received stations. Information about software and computer parameters is

displayed on the right.

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