[Lowfer] 74.5495 QRSS 60 as usual till at least 0600...

[Bob Raide]

JD;
Interesting findings!  I am glad your trying all these things and coming up with results.  This is real "experimentation"-Bob
 
From: listread at lwca.org
To: lowfer at mailman.qth.net
Date: Wed, 9 Oct 2013 01:34:52 -0500
Subject: Re: [Lowfer] 74.5495 QRSS 60 as usual till at least 0600...

Bob, Argo, and the spirit of Christmas be praised!  (To paraphrase Ebeneezer 
Scrooge.)
 
This is something of a miracle capture.  It was made with the sound 
completely turned down on the radio.  I use the auxiliary speaker output for 
the soundcard feed, not the headphone jack, so I have ample power to drive 
the clipper when needed.  I switch the speaker back in parallel whenever I 
want to listen.  The leakage through the audio amplifier was so low, 
however, that I couldn't hear anything at all when I went back to 
speaker--not even a peep of static, which was quite formidable on 74 kHz 
tonight, with frequent peaks at 50-60 dB above signal in a 250 Hz bandwidth. 
But Argo saw XRS4 anyway!
 
By the time I realized I had turned down the volume knob in the dark by 
mistake, Argo was reporting the signal at -112 dB to -114, and the 
background (in however many millihertz a bin is at QRSS30) as -120.  Try 
THAT with all your phony-baloney SNR numbers, WSPR!
 
I went to correct the audio level at the start of the second "4" but quickly 
realized that wasn't helping, so I put it back the way it was.
 
I'm always amazed at what Argo does, but this is a great demonstration of 
what it's capable of when everything falls into place to let you use its 
matched-filter characteristics to the fullest.  Bob's signal had the right 
element timings in the proper ratios, and by a miracle my radio was stable 
enough for a while that the signal apparently never drifted more than +/- 1 
bin width during the capture.  Argo was thus able to work with almost no 
energy being received, in the presence of truly intimidating noise.
 

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