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Date: Mon, 2 Jun 2014 21:40:29 -0400
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From: Warren Ziegler <wd2xgj@gmail.com>
To: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Subject: Re: VLF: W4DEX trans-Atlantic at 8971 Hz
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WOW
  I never thought that this would be possible!
73 Warren


On Mon, Jun 2, 2014 at 3:44 PM, Paul Nicholson <vlf0403@abelian.org> wrote:

>
> At 2014-06-01 10:00 UT W4DEX began a long transmission of GPS
> locked carrier at 8971.000 Hz from 35.273N,80.371W.
>
> Between 2014-06-02 00:00 and 06:00 a carrier was measured
> at that frequency here in Todmorden 53.703N,2.072W with flux
> density around  0.05fT.  It was not very significant so I
> combined the H-field and E-field receiver outputs (correcting
> for their known phase and amplitude response) to produce a
> uni-directional antenna response. This brought the signal up to
> a significant level.
>
> The signal bearing was roughly west.  W4DEX is bearing 285 deg
> from here.  The S/N is max on a bearing of 315 degrees which
> puts the prevailing south-westerly background nearer to the
> side of the antenna response.
>
> This gave the signal a respectable 12.5dB S/N in 46uHz bandwidth.
>
>  http://abelian.org/vlf/tmp/w4dex_140602a.gif
>
> This was the strongest peak in a span of over 6500 Fourier
> bins so is quite significant.
>
> The carrier was also visible during the daylight path in 23uHz
> bandwidth with average strength of around 0.02fT and with
> similar S/N thanks to the lower day time noise and reduced
> bandwidth.
>
> At 2014-06-02 12:00 Dex altered the TX frequency for a blind
> confirmation test. Six hours later the carrier (in 46uHz)
> had vanished and a new signal appeared at 8971.100 Hz with
> the same strength.
>
> An email response from Dex confirms 8971.1 as the new frequency.
>
> Range W4DEX to Todmorden UK is 6194 km.
>
> Ratio of day/night flux density agrees well with LWPC
> predictions for this path.  LWPC predicts strongest night
> signal between 00:30 and 04:30 and a sliding spectrum window
> agrees with this.
>
> LWPC requires ERP of 150uW to reproduce the observed flux
> density.  This is in the center of the ERP range estimated
> from W4DEX antenna dimensions and measured antenna current.
>
> --
> Paul Nicholson
> --
>
>


-- 
73 Warren K2ORS
                WD2XGJ
                WD2XSH/23
                WE2XEB/2
                WE2XGR/1

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<div dir=3D"ltr">WOW<div>=C2=A0 I never thought that this would be possible=
!</div><div>73 Warren</div><div><br></div></div><div class=3D"gmail_extra">=
<br><br><div class=3D"gmail_quote">On Mon, Jun 2, 2014 at 3:44 PM, Paul Nic=
holson <span dir=3D"ltr">&lt;<a href=3D"mailto:vlf0403@abelian.org" target=
=3D"_blank">vlf0403@abelian.org</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex"><br>
At 2014-06-01 10:00 UT W4DEX began a long transmission of GPS<br>
locked carrier at 8971.000 Hz from 35.273N,80.371W.<br>
<br>
Between 2014-06-02 00:00 and 06:00 a carrier was measured<br>
at that frequency here in Todmorden 53.703N,2.072W with flux<br>
density around =C2=A00.05fT. =C2=A0It was not very significant so I<br>
combined the H-field and E-field receiver outputs (correcting<br>
for their known phase and amplitude response) to produce a<br>
uni-directional antenna response. This brought the signal up to<br>
a significant level.<br>
<br>
The signal bearing was roughly west. =C2=A0W4DEX is bearing 285 deg<br>
from here. =C2=A0The S/N is max on a bearing of 315 degrees which<br>
puts the prevailing south-westerly background nearer to the<br>
side of the antenna response.<br>
<br>
This gave the signal a respectable 12.5dB S/N in 46uHz bandwidth.<br>
<br>
=C2=A0<a href=3D"http://abelian.org/vlf/tmp/w4dex_140602a.gif" target=3D"_b=
lank">http://abelian.org/vlf/tmp/<u></u>w4dex_140602a.gif</a><br>
<br>
This was the strongest peak in a span of over 6500 Fourier<br>
bins so is quite significant.<br>
<br>
The carrier was also visible during the daylight path in 23uHz<br>
bandwidth with average strength of around 0.02fT and with<br>
similar S/N thanks to the lower day time noise and reduced<br>
bandwidth.<br>
<br>
At 2014-06-02 12:00 Dex altered the TX frequency for a blind<br>
confirmation test. Six hours later the carrier (in 46uHz)<br>
had vanished and a new signal appeared at 8971.100 Hz with<br>
the same strength.<br>
<br>
An email response from Dex confirms 8971.1 as the new frequency.<br>
<br>
Range W4DEX to Todmorden UK is 6194 km.<br>
<br>
Ratio of day/night flux density agrees well with LWPC<br>
predictions for this path. =C2=A0LWPC predicts strongest night<br>
signal between 00:30 and 04:30 and a sliding spectrum window<br>
agrees with this.<br>
<br>
LWPC requires ERP of 150uW to reproduce the observed flux<br>
density. =C2=A0This is in the center of the ERP range estimated<br>
from W4DEX antenna dimensions and measured antenna current.<br>
<br>
--<br>
Paul Nicholson<br>
--<br>
<br>
</blockquote></div><br><br clear=3D"all"><div><br></div>-- <br>73 Warren K2=
ORS<br>=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 WD2XGJ <br>=
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 WD2XSH/23<br>=C2=A0=
 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 WE2XEB/2<br>=C2=A0 =C2=A0=
 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 WE2XGR/1<br><br>=C2=A0
</div>

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