Mal,
you and me are putting good signals in the air, for various reasons.
However, there are several others who are far below the noise level. If you
have look on my homepage (http:/www.qru.de/signals.htm), you will see a
graph, that shows the signal strenght in dBu vs. the distance in km. Most
of the German stations for example suffer from both: low power (20 Watt due
to the German regulations ... ) and bad antennas. The noise level at my qth
typically is in the -110 dBu range, sometimes moch worse (-90 to -100 dBu):
I had several contacts with stations on 136 kHz, that I could not hear
aurally, because their signals were 10 to 20 db below the current noise
level. With an "M", we still were able to manage a good QSO. Also on my
page you find a list of stations that I have worked so far on LF
(http://www.qru.de/stnhrd.htm). In the column "max . signal strength" you
find several stations without a signal report. Most of those stations were
far below the noise level, but readable in Slow-CW. For example, I would
not have been able to contact IK5ZPV in normal CW.
I made some experiement, injecting a signal generator into the normal
day-to-day noise. With my 25+ years of CW experiencs, I believe I can hear
CW signals well below the noise level. But with spectrogram in Slow-CW, I
am able to see (and read) signals that are 10 to 20 dB the lowest level my
ear is even able to detect the signal. Maybe it is a matter of the
Spectrogram settings.
I am sure, if we ever have a successful 2-way transatlantic QSO, it will be
in Slow CW!
Best 73
Geri, DK8KW (W1KW)
homepage: http://www.qru.de
"Longwave enthusiasts do it extremely slow!"
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