Date: Sun, 26 Mar 2017 17:43:40 -0400
From: Markus Vester <markusvester@aol.com>
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: DK7FC in Todmorden at 2970 Hz
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Congratulations Paul and Stefan, that is a very nice confirmation!

> stacking 13:00 to 00:00=20
Interesting that this worked well, as it includes the sunset terminator, an=
d would typically be the time of highest QRN background on higher frequenci=
es.  =20

> is normalised by the average power in a 20Hz bandwidth=20
I would think that a little more benefit could be achieved by further downw=
eighting the days with higher noise (gain factor -2 dB / 1 dB ).

Still wondering who of you has spent more Joules on this, the transmitter o=
r the data processing on the receive side ;-)

All the best,
Markus

-----Urspr=C3=BCngliche Mitteilung-----=20
Von: Paul Nicholson <vlf0403@abelian.org>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: So, 26. Mrz 2017 22:43
Betreff: LF: DK7FC in Todmorden at 2970 Hz


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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<div style=3D"font-size:10pt;font-family:arial,helvetica,sans-serif;color:b=
lack;"><div style=3D"color: black; font-family: arial,helvetica,sans-serif;=
 font-size: 10pt;">Congratulations Paul and Stefan, that is a very nice con=
firmation!<br><br>&gt; stacking 13:00 to 00:00 <br>Interesting that this wo=
rked&nbsp;well, as&nbsp;it&nbsp;includes&nbsp;the sunset terminator, and wo=
uld typically be the time&nbsp;of&nbsp;highest QRN background on higher fre=
quencies.&nbsp;&nbsp;&nbsp;<br><br>&gt; is normalised by the average power =
in a 20Hz bandwidth <br>I would think that a little&nbsp;more benefit could=
 be achieved by further downweighting the days with higher noise (gain fact=
or -2 dB&nbsp;/ 1 dB ).<br><br>Still wondering who of you has spent more Jo=
ules on this, the transmitter or the data processing&nbsp;on the receive si=
de ;-)<br><br>All the best,<br>Markus<br><br>-----Urspr=C3=BCngliche Mittei=
lung----- <br>Von: Paul Nicholson &lt;vlf0403@abelian.org&gt;<br>An: rsgb_l=
f_group &lt;rsgb_lf_group@blacksheep.org&gt;<br>Verschickt: So, 26. Mrz 201=
7 22:43<br>Betreff: LF: DK7FC in Todmorden at 2970 Hz<br><br></div><br>Stef=
an wrote (10th March):<br><br> &gt; Since 16:56 UTC  i'm running 180 mA ant=
enna current<br> &gt; on (2970 + 7/(24*3600)) Hz, i.e. on 2970.000081 Hz<br=
><br>After coherently stacking 13:00 to 00:00 for 9 days in a<br>bandwidth =
of 25.25 uHz I get a clear signal at significance<br>of around 5 sigma:<br>=
<br>  <a href=3D"http://abelian.org/vlf/tmp/170326a.png" target=3D"_blank">=
http://abelian.org/vlf/tmp/170326a.png</a><br><br>The peak has S/N 14.0 dB =
in 25.25uHz, which is -66 dB in<br>2.5kHz bandwidth.   Signal azimuth is ea=
st with the expected<br>phase angle between E and H antennas.<br><br>The da=
ys used were 11th to 16th plus 18th to 20th.  Attempting<br>to include the =
17th, or 21st to 23rd reduced the S/N.<br>Leaving out any of the nine stack=
s days also reduces the S/N.<br><br>The amplitude of each daily contributio=
n is normalised by<br>the average power in a 20Hz bandwidth around the sign=
al<br>frequency.<br><br>No other bandwidth or daily time range produces a s=
tronger<br>peak.   14:00 to 19:00 in 55.5 uHz gives about 12dB S/N.<br><br>=
So far, no attempt has been made to compensate for night time<br>phase dela=
y.<br><br>Distance is 881.2 km, approximately 8.7 wavelengths.<br><br>--<br=
>Paul Nicholson<br>--<br><br></div>
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