Message-ID: <5936A869.7070307@posteo.de>
Date: Tue, 06 Jun 2017 15:04:41 +0200
From: DK7FC <selberdenken@posteo.de>
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Subject: Re: VLF: New EbNaut announcement...
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Jacek, i confirm. Well done!

Markus, the same decode appeared when correcting the phase, as you say. 
But when the phase is not stable due to propagation, it could result in 
a phase pattern that can't be corrected, maybe? RN3AUS also reported 
about decodes after applying small frequency offsets.
Worth to investigate...

BTW yesterday i have ordered this octo-soundcard for the Raspi!

Luis/EA5DOM, what about your VLF RX improvements? :-)

73, Stefan

Am 06.06.2017 13:55, schrieb Markus Vester:
> Hi Stefan,
>
> your message was decoded well from DL0AO cardioid data.
>
> Initially, the best decode appeared with a phase slope, -30 0 0 30. 
> Entering a frequency offset of one FFT bin (+9.3 uHz), the blue peak 
> seems to be shifted slightly to the left as expected, but the same 
> best decode was achieved with flat phase.
>
> This seems to confirm your earlier observation of a one bin offset. 
> This is strange, as I've never observed such an offset in earlier 
> experiments based on shorter data with wider FFT resolution (31 uHz or 
> more), and I am lacking an explanation. I don't think we can blame 
> propagation because if there was any Doppler around sunset 
> this should be negative rather than positive.
>
> Best 73,
> Markus (DF6NM)
>
>
> -----Ursprüngliche Mitteilung-----
> Von: DK7FC <selberdenken@posteo.de>
> An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
> Verschickt: Mo, 5. Jun 2017 14:44
> Betreff: VLF: New EbNaut announcement...
>
> Hi VLF,
>
> For some local tests i like to transmit the 2 character message that i 
> already sent on 970 Hz 3 weeks ago. This time on 6470 Hz....
>
> Such a short message with sch long symbols may be interesting for 
> newcomers or various tests by the established VLF receivers...
>
>
> *f = 6470.100000 Hz
> Start time: 05.Jun.2017   13:00:00 UTC
> Symbol period: 60 s
> Characters: 2
> CRC bits: 3
> Coding 16K21A
> Duration: 9h, 20min
> Antenna current: ~ 460 mA*
>
> 73, Stefan

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Jacek, i confirm. Well done!<br>
<br>
Markus, the same decode appeared when correcting the phase, as you say.
But when the phase is not stable due to propagation, it could result in
a phase pattern that can't be corrected, maybe? RN3AUS also reported
about decodes after applying small frequency offsets.<br>
Worth to investigate...<br>
<br>
BTW yesterday i have ordered this octo-soundcard for the Raspi!<br>
<br>
Luis/EA5DOM, what about your VLF RX improvements? :-)<br>
<br>
73, Stefan<br>
<br>
Am 06.06.2017 13:55, schrieb Markus Vester:
<blockquote cite="mid:15c7d427aa5-45d-331e2@webprd-m61.mail.aol.com"
 type="cite">
  <div
 style="font-size: 10pt; font-family: arial,helvetica,sans-serif; color: black;">
  <div
 style="color: black; font-family: arial,helvetica,sans-serif; font-size: 10pt;">Hi
Stefan,</div>
  <div
 style="color: black; font-family: arial,helvetica,sans-serif; font-size: 10pt;"><br>
your message was decoded well from DL0AO cardioid data.</div>
  <div
 style="color: black; font-family: arial,helvetica,sans-serif; font-size: 10pt;"><br>
Initially, the best decode appeared with a phase slope, -30 0 0 30.
Entering a frequency offset of one FFT bin (+9.3 uHz), the blue peak
seems to be shifted slightly to the left as expected, but the same best
decode was achieved with flat phase. </div>
  <div
 style="color: black; font-family: arial,helvetica,sans-serif; font-size: 10pt;"><br>
This seems to confirm your earlier observation of a one bin offset.
This is strange, as I've never observed such an offset in earlier
experiments based on shorter data with wider FFT resolution (31 uHz or
more), and I am lacking an explanation. I don't think we can blame
propagation because if there was any Doppler around sunset
this should be negative rather than positive.  </div>
  <div
 style="color: black; font-family: arial,helvetica,sans-serif; font-size: 10pt;"><br>
Best 73,<br>
Markus (DF6NM)<br>
  </div>
  <div
 style="color: black; font-family: arial,helvetica,sans-serif; font-size: 10pt;"><br>
  <br>
-----Ursprüngliche Mitteilung----- <br>
Von: DK7FC <a class="moz-txt-link-rfc2396E" href="mailto:selberdenken@posteo.de">&lt;selberdenken@posteo.de&gt;</a><br>
An: rsgb_lf_group <a class="moz-txt-link-rfc2396E" href="mailto:rsgb_lf_group@blacksheep.org">&lt;rsgb_lf_group@blacksheep.org&gt;</a><br>
Verschickt: Mo, 5. Jun 2017 14:44<br>
Betreff: VLF: New EbNaut announcement...<br>
  <br>
  </div>
  <div id="AOLMsgPart_2_5db5e081-985c-4c00-b359-2027c514d35d">
  <div class="aolReplacedBody" text="#000000" bgcolor="#ffffff">Hi VLF,
  <br>
  <br>
For some local tests i like to transmit the 2 character message that i
already sent on 970 Hz 3 weeks ago. This time on 6470 Hz....<br>
  <br>
Such a short message with sch long symbols may be interesting for
newcomers or various tests by the established VLF receivers...<br>
  <br>
  <br>
  <b>f = 6470.100000 Hz<br>
Start time: 05.Jun.2017   13:00:00 UTC<br>
Symbol period: 60 s<br>
Characters: 2<br>
CRC bits: 3<br>
Coding 16K21A<br>
Duration: 9h, 20min<br>
Antenna current: ~ 460 mA</b><br>
  <br>
73, Stefan<br>
  </div>
  </div>
  </div>
</blockquote>
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