At Cumiana Italy 44.96N,7.42E run by Renato Romero IK1QFK:
Examining 9177Hz S/N and phase in 1 hour steps (278uHz)
20:00 2.9dB
20:30 3.2dB
transmission started around 21:20
21:30 6.2dB -102.3
22:00 1.8dB
22:30 6.1dB -159.4
23:00 5.3dB 155.1
23:30 4.1dB 172.9
00:00 6.4dB 151.8
00:30 6.4dB -173.8
01:00 4.4dB -174.5
01:30 6.2dB -174.0
02:00 8.9dB -165.6
02:30 8.1dB -161.3
03:00 6.8dB 151.3
03:30 9.8dB -178.6
transmission ended around 04:30
05:00 -1.2dB
06:00 -2.6dB
Undoubtedly a signal there. The steady phase tells us it is a
properly disciplined source, a spurious signal from an ordinary
xtal source would show lots of drift. A mains harmonic would
be invisible at this bandwidth (it would just add to background
noise as it drifted by).
So, is it W4DEX? A repeat test with a small frequency shift
would provide confirmation. S/N is about right given the
extra 1Mm beyond Todmorden. Frequency is exact which is
improbable otherwise. The signal vanishes after Dex switches
off. Signal not present before 21:30, therefore not a harmonic
of Renato's GPS timing system.
S/N is 13.7dB in this 4 hour spectrum:
http://abelian.org/vlf/tmp/141214f.gif
It is the strongest signal in 23000 neighbouring bins.
With the above, and this one by DL4YHF from the 2nd,
http://abelian.org/vlf/tmp/141202j.gif
we have two good candidate detections of W4DEX in Europe, awaiting
confirmation.
See Renato's website http://www.vlf.it/ for lots of articles
about VLF/ELF reception techniques.
--
Paul Nicholson
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