Tuesday, June 05, 2007

KXTO QRSS Sample File

For those who wish to experiment with receiving QRSS (slow speed Morse Code) transmissions prior to the KXTO Test, Brandon Jordan who runs the very informative www.dxtests.info web site has posted a sample file that will closely match the actual file for the test. It's available at:

KXTO 10 Minute File.wav

You can download a free Spectrum Analyzer called "Argo" at:

www.weaksignals.com

Keep in mind, that what you're really looking at is a audio frequency spectrum analyzer, not RF. You're feeding an audio signal from your radio (headphone jack, or other output) into one of the inputs on your computer soundcard (MIc, Line, etc.) and then viewing what that audio looks like.

Using this technique it's possible to detect slow speed Morse Code signals well below the noise, sometimes as much as -20db! Using this technique, world wide reception of the KXTO DX test may be possible.

In advance of the test, I'd concentrate on looking at the carrier signals of various AM stations using USB, LSB, and CW modes. Adjust levels on the receiver output, soundcard input, etc. until you get nice, clean images that are free of distortion. It's easy to overdrive the soundcard with too "hot" of a signal.

The actual transmission will be at 2.5khz and you should be able to literally "read" the dots and dashs of the QRSS transmission spelling out, K-X-T-O.

In Morse that looks like-

K= Dash Dot Dash
X= Dash Dot Dot Dash
T= Dash
O= Dash Dash Dash

It's a great mode, and potentially a nighttime IBOC-Beater! You can learn lots more at:

http://www.w0ch.net/qrss/qrss.htm

http://www.ussc.com/~turner/qrss1.html

73,
Les Rayburn, N1LF

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