From: "Mike Dennison" <mike.dennison@rsgb.org.uk>
To: rsgb_lf_group@blacksheep.org
Date: Fri, 12 May 2000 10:27:40 +0100
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Subject: LF: QRSS and QRN
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> >From Dave G3YMC
> If Spectran and the other programs offer the capability to copy stations
> 20dB below noise, in these circumstances this would only take you to s9,
> which was certainly copyable with normal CW.  I admit the static levels
> recently have been much higher than usual, and would not expect anyone to
> attempt to work transatlantic under such conditions (or to even ragchew!) 
> I have two weakish carriers on the band, 136.7 and 137.8 which are
> normally just above the noise.  I wonder how copy of these is on Spectran
> with 20dB over heavy static - I can just about copy traces here in the
> crashes.

This misses the point. Spectrogram etc can copy CW up to 20db 
below 'normal' noise. But the duty cycle of static is much lower 
than noise, therefore there is a =much= greater advantage than 
20dB. Using Spectrogram and QRSS, I can receive signals 100% 
in heavy static that would be impossible to read using normal CW 
at whatever speed. 

But in any case it is really up to the individual operator to use 
whatever technique he feels happiest with, and regardless of what 
technique is used, S9+ QRN is going to degrade it. Also QRSS is 
no good for ragchews, no matter how good the S/N is.

I will try to demonstrate the advantage of QRSS in static by 
providing a WAV recording and Spectrogram plot on my web site 
(which make me the only LF operator hoping there's QRN tonight!).


Mike, G3XDV (IO91VT)
http://www.dennison.demon.co.uk/activity.htm