Dear Joe, LF Group
I monitored VO1NA over 11/12th and 13/14th - missed 12/13th due to "finger
trouble". On both nights I had good copy between 0100 and 0200utc, with
signal levels deteriorating towards dawn - the reverse of the situation
during the week, so it would certainly seem conditions have changed. Still
"O" copy for an hour or so each night though.
To investigate the effect of using different dot lengths, I made a .wav
file recording of the receiver audio during one of the better periods over
11/12th, and played it back through Spectrum Lab with different FFT
resolutions corresponding to 3s, 10s, and 30s dot lengths, but keeping the
scroll rate of the display the same. This gives a fairly good picture of
how the signal would look at these different speeds. In the attachment, the
top trace is "QRSS3", the middle trace "QRSS10", and the bottom trace is
how it actually was at QRSS30. The correspondence is not perfect because
the noise bursts are effectively compressed in time for the faster modes,
but it gives a pretty good idea. The QRSS3 trace is certainly visible, but
poor copy, but the QRSS10 trace is easily readable, so it looks like 10s
dots should be a good choice under reasonable conditions. increasing the
speed would certainly make life easier; a minimal QSO could be completed in
an hour or so.
Cheers, Jim Moritz
73 de M0BMU 
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