Message-ID: <5A2D886D.5060109@posteo.de>
Date: Sun, 10 Dec 2017 20:18:05 +0100
From: DK7FC <selberdenken@posteo.de>
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To: rsgb_lf_group@blacksheep.org, Michael Smith <mike@unixnut.net>
CC: Vasily Savchenko <ua0snv@yahoo.com>
References: <2dbcd2a8-0109-41e4-c0ca-aada17f54de8@abelian.org>
In-Reply-To: <2dbcd2a8-0109-41e4-c0ca-aada17f54de8@abelian.org>
Subject: Re: VLF: Transatlantic success East to West
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Hello Paul, Mike, VLF,

What an exciting achievement. My congrats to Mike for his sensitive well 
working VLF RX. I guess it is his best DX of a man made signal :-)
Also big thanks to Paul, without his contribution we woudn't be there 
now, apart from all the software tools! It is always a cooperative 
success! That's what we need in this world!

What next?
A longer message should be tried. Since i'd like to continue on 5170 Hz 
with RN3AUS, i just try a 3 character message next on 17470.1 Hz. I'll 
stay at 16K21A, so that people with an older PC also have a chance to 
decode the message.

When east-to-west is 20 dB harder than the other direction, how far 
could we go towards the east? Does someone from *JAPAN* read this email 
and likes to try a serious attempt to detect a short message over the 
9000 km land path?
And what about stations in *VK* or/and *ZL*? There is no impossible and 
this is a total new territory for us. There is a lot to discover.

BTW i am in contact with UA0SNV. Yesterday he told me he was outside and 
installed a 120m long wire while it was -30 C outside :-) Heroic!

Currently i'm playing a bit in QRSS-600, see the grabbers. If someone 
likes to detect it...

For tonite i would start the new 3 charcter message on the TA path. With 
3 good days we could make it!:

*f = 17470.1000 Hz
Start time: 10.Dec.2017  22:00:00 UTC
Symbol period: 40 s
Characters: 3
CRC bits: 16
Coding 16K21A
Duration: 09:36 [hh:mm]
Antenna current: 1.2 A*


73, Stefan


Am 10.12.2017 16:22, schrieb Paul Nicholson:
>
> Stefan wrote:
>
> > f = 17470.1000 Hz
> > Start time: 07.Dec.2017  21:30:00 UTC
> > Symbol period: 60 s
> > Characters: 1
> > CRC bits: 10
> > Coding 16K21A
>
> and
>
> > I transmitted the message last night again [9th]
>
> A good signal at Forest, VA, from the overnight transmission
> 9th/10th, via Mike Smith's VLF receiver at 37.35348N,79.19450W,
> near Lynchburg.
>
> Decoded 'T' with Eb/N0 = +1.5 dB, BER 42.5%, rank 9;
>
> S/N was -36.29 dB in 1Hz;
>
> Reference phase 120,135,120,135;
>
> Congratulations to Stefan DK7FC and Mike KE4RJQ for the
> first VLF east-to-west transatlantic message.  Distance
> is 6817.7 km.
>
> This is a most significant achievement. East to west is some
> 20dB harder than the other direction!
>
> You can run the decode yourself from the 'vt' file at
>
>  http://abelian.org/vlf/dk7fc.171209f4.vt
>
> The file is 4.2 Mbyte, 2 I/Q sample pairs/second.
> It was extracted from Mike's raw recording with
>
>  vtread -T2017-12-09_21:30,+34590 /data/raw-fb |
>     vtfilter -h bp,f=17470,w=3000 -h bs,f=16400,w=600 -h 
> bs,f=18300,w=800 |
>     vtblank -a13 -d0 -t100 -v | vtmult -f 17470.1 |
>     vtresample -r480 |
>     vtresample -r2 > dk7fc.171209f4.vt
>
> Decode with:
>
>  vtraw -oa dk7fc.171209f4.vt |
>     ebnaut -dp16K21A -r2 -S60 -k10 -N1 -PS15 -L800 -v -c8 -a50
>
> This was a clean decode with no false detects to get in the
> way.  The signal is extremely weak but gives an unambiguous
> decode.
>
> Please CC Mike in any replies, as he is not on the RSGB
> mailing list.
>
> -- 
> Paul Nicholson
> -- 
>
>

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Hello Paul, Mike, VLF,<br>
<br>
What an exciting achievement. My congrats to Mike for his sensitive
well working VLF RX. I guess it is his best DX of a man made signal :-)<br>
Also big thanks to Paul, without his contribution we woudn't be there
now, apart from all the software tools! It is always a cooperative
success! That's what we need in this world!<br>
<br>
What next? <br>
A longer message should be tried. Since i'd like to continue on 5170 Hz
with RN3AUS, i just try a 3 character message next on 17470.1 Hz. I'll
stay at 16K21A, so that people with an older PC also have a chance to
decode the message.<br>
<br>
When east-to-west is 20 dB harder than the other direction, how far
could we go towards the east? Does someone from <b>JAPAN</b> read this
email and likes to try a serious attempt to detect a short message over
the 9000 km land path?<br>
And what about stations in <b>VK</b> or/and <b>ZL</b>? There is no
impossible and this is a total new territory for us. There is a lot to
discover.<br>
<br>
BTW i am in contact with UA0SNV. Yesterday he told me he was outside
and installed a 120m long wire while it was -30 C outside :-) Heroic!<br>
<br>
Currently i'm playing a bit in QRSS-600, see the grabbers. If someone
likes to detect it...<br>
<br>
For tonite i would start the new 3 charcter message on the TA path.
With 3 good days we could make it!:<br>
<br>
<b>f = 17470.1000 Hz<br>
Start time: 10.Dec.2017  22:00:00 UTC<br>
Symbol period: 40 s<br>
Characters: 3<br>
CRC bits: 16<br>
Coding 16K21A<br>
Duration: 09:36 [hh:mm] <br>
Antenna current: 1.2 A</b><br>
<br>
<br>
73, Stefan<br>
<br>
<br>
<br>
Am 10.12.2017 16:22, schrieb Paul Nicholson:
<blockquote cite="mid:2dbcd2a8-0109-41e4-c0ca-aada17f54de8@abelian.org"
 type="cite"><br>
Stefan wrote:
  <br>
  <br>
&gt; f = 17470.1000 Hz
  <br>
&gt; Start time: 07.Dec.2017  21:30:00 UTC
  <br>
&gt; Symbol period: 60 s
  <br>
&gt; Characters: 1
  <br>
&gt; CRC bits: 10
  <br>
&gt; Coding 16K21A
  <br>
  <br>
and
  <br>
  <br>
&gt; I transmitted the message last night again [9th]
  <br>
  <br>
A good signal at Forest, VA, from the overnight transmission
  <br>
9th/10th, via Mike Smith's VLF receiver at 37.35348N,79.19450W,
  <br>
near Lynchburg.
  <br>
  <br>
Decoded 'T' with Eb/N0 = +1.5 dB, BER 42.5%, rank 9;
  <br>
  <br>
S/N was -36.29 dB in 1Hz;
  <br>
  <br>
Reference phase 120,135,120,135;
  <br>
  <br>
Congratulations to Stefan DK7FC and Mike KE4RJQ for the
  <br>
first VLF east-to-west transatlantic message.  Distance
  <br>
is 6817.7 km.
  <br>
  <br>
This is a most significant achievement. East to west is some
  <br>
20dB harder than the other direction!
  <br>
  <br>
You can run the decode yourself from the 'vt' file at
  <br>
  <br>
 <a class="moz-txt-link-freetext" href="http://abelian.org/vlf/dk7fc.171209f4.vt">http://abelian.org/vlf/dk7fc.171209f4.vt</a>
  <br>
  <br>
The file is 4.2 Mbyte, 2 I/Q sample pairs/second.
  <br>
It was extracted from Mike's raw recording with
  <br>
  <br>
 vtread -T2017-12-09_21:30,+34590 /data/raw-fb |
  <br>
    vtfilter -h bp,f=17470,w=3000 -h bs,f=16400,w=600 -h
bs,f=18300,w=800 |
  <br>
    vtblank -a13 -d0 -t100 -v | vtmult -f 17470.1 |
  <br>
    vtresample -r480 |
  <br>
    vtresample -r2 &gt; dk7fc.171209f4.vt
  <br>
  <br>
Decode with:
  <br>
  <br>
 vtraw -oa dk7fc.171209f4.vt |
  <br>
    ebnaut -dp16K21A -r2 -S60 -k10 -N1 -PS15 -L800 -v -c8 -a50
  <br>
  <br>
This was a clean decode with no false detects to get in the
  <br>
way.  The signal is extremely weak but gives an unambiguous
  <br>
decode.
  <br>
  <br>
Please CC Mike in any replies, as he is not on the RSGB
  <br>
mailing list.
  <br>
  <br>
--
  <br>
Paul Nicholson
  <br>
--
  <br>
  <br>
  <br>
</blockquote>
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