[Lowfer] Request for your frequency readout on my signal

[JD]

With 800 Hz audio representing 1838.230 kHz after scale correction, I read 
your frequency to be between the nominal value and 1 Hz below at any given 
moment during the time I watched.  That's at the bottom part of the picture. 
It does make it very rough on QRSS30, unfortunately. The secret of Argo's 
success is in its matched filter properties, which only help if the signal 
stays within the right number of FFT bins for the right amount of time.  It 
may work under other conditions, but Argo can't do its miracles as well (see 
my capture of XRS4 in a few minutes for more about this).

There was one "4" that was pretty stable, so I also did a practice run on it 
at QRSS10, to provide a simplified demonstration of the after-the-fact 
calibration technique.  Every month or so I check the sound card against WWV 
tones, of course, but there's seldom any correction needed there.  The 
daily--even hourly--concern is the radio.  Since all frequencies in the 
radio track the master oscillator, a check of WWV at 10 MHz makes it easy to 
find out how many parts per million I'm high or low.  Right after the "4" 
WWV was showing 29.1 Hz high, or 2.91 ppm.   That times 1.83823 MHz gave 
5.35 Hz as the receiver error for this signal at that particular time. 
Rather than play with Argo in the dark and mess everything up royally, I 
shift the scale graphically later.

Hope that helps, Andy.

John 
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