LF: DK7FC in Todmorden at 2970 Hz

[Paul Nicholson <vlf0403@abelian.org>]

Stefan wrote (10th March):

> Since 16:56 UTC  i'm running 180 mA antenna current
> on (2970 + 7/(24*3600)) Hz, i.e. on 2970.000081 Hz

After coherently stacking 13:00 to 00:00 for 9 days in a
bandwidth of 25.25 uHz I get a clear signal at significance
of around 5 sigma:

 http://abelian.org/vlf/tmp/170326a.png

The peak has S/N 14.0 dB in 25.25uHz, which is -66 dB in
2.5kHz bandwidth.   Signal azimuth is east with the expected
phase angle between E and H antennas.

The days used were 11th to 16th plus 18th to 20th.  Attempting
to include the 17th, or 21st to 23rd reduced the S/N.
Leaving out any of the nine stacks days also reduces the S/N.

The amplitude of each daily contribution is normalised by
the average power in a 20Hz bandwidth around the signal
frequency.

No other bandwidth or daily time range produces a stronger
peak.   14:00 to 19:00 in 55.5 uHz gives about 12dB S/N.

So far, no attempt has been made to compensate for night time
phase delay.

Distance is 881.2 km, approximately 8.7 wavelengths.

--
Paul Nicholson
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