Message-ID: <5D0A2650.3050800@posteo.de>
Date: Wed, 19 Jun 2019 14:10:56 +0200
From: DK7FC <selberdenken@posteo.de>
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To: rsgb_lf_group@blacksheep.org
References: <5D090874.4070805@posteo.de> <1661234464.2572111.1560890591920@mail.yahoo.com>
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Subject: Re: SLF: Sidebands arround ZEVS in 1 mHz
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Hi Markus,

Thanks. Seems you are right. The problem seemed to occur when generating 
the spectrogram from a stream. But now i've extracted the same time 
period from the database and produced the spectrogram from a 
(timestamped) .wav file. Fortunately it looks perfectly sharp!
I'll investigate... I'm trying if a stage  'vttime -m none'  stage will 
help...

73, Stefan


Am 18.06.2019 22:43, schrieb Markus Vester:
> Hi Stefan,
>
> it seems these sidelines are about 10 dB down at +- 6 mHz. If they 
> were real, we'd surely see them in 424 uHz at DL0AO, but there's 
> nothing there.
>
> What is strange ist that the main carrier is shown 2 mHz below the 82 
> Hz tick, wheras in reality ZEVS is only 10 uHz below nominal. So I 
> suspect that the real input samplerate is around 24 ppm higher than 
> what SpecLab thinks it is. This may cause periodic buffer overflows, 
> where samples are lost and phasejumps occurs. The sideline spacing 
> indicates that this is happening every 1000/6 seconds (~ 3 minutes).
>
> 73, Markus
>
> -----Ursprüngliche Mitteilung-----
> Von: DK7FC <selberdenken@posteo.de>
> An: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>
> Verschickt: Di, 18. Jun. 2019 17:53
> Betreff: SLF: Sidebands arround ZEVS in 1 mHz
>
> These days i'm calibrating the colours and angles in my ELF...VLF
> spectrograms. The colour of ZEVS is now calibrated to deviate less than
> 3 deg. However producing a spectrogram in 1 mHZ FFT bin width, i can see
> sidebands of ZEVS.
> Did someone else observe a similar effect?
> In a first thought i would assume it is my timing system that causes the
> problem. But maybe it is ZEVS itselfe? Or even propagation?
>
> 73, Stefan
>
> PS: Capture attached.
>

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Hi Markus, <br>
<br>
Thanks. Seems you are right. The problem seemed to occur when
generating the spectrogram from a stream. But now i've extracted the
same time period from the database and produced the spectrogram from a
(timestamped) .wav file. Fortunately it looks perfectly sharp!<br>
I'll investigate... I'm trying if a stage  'vttime -m none'  stage will
help...<br>
<br>
73, Stefan<br>
<br>
<br>
Am 18.06.2019 22:43, schrieb Markus Vester:
<blockquote cite="mid:1661234464.2572111.1560890591920@mail.yahoo.com"
 type="cite">
  <div
 style="font-size: 10pt; font-family: arial,helvetica,sans-serif; color: black;">
  <div
 style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: black;"
 data-mce-style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: black;">Hi
Stefan,</div>
  <div
 style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: black;"
 data-mce-style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: black;"><br>
  </div>
  <div
 style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: black;"
 data-mce-style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: black;">it
seems these sidelines are about 10 dB down at +- 6 mHz. If they were
real, we'd surely see them in 424 uHz at DL0AO, but there's nothing
there.</div>
  <div
 style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: black;"
 data-mce-style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: black;"><br>
  </div>
  <div
 style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: black;"
 data-mce-style="font-family: arial,helvetica,sans-serif; font-size: 10pt; color: black;">What
is strange ist that the main carrier is shown 2 mHz below the 82 Hz
tick, wheras in reality ZEVS is only 10 uHz below nominal. So I suspect
that the real input samplerate is around 24 ppm higher than what
SpecLab thinks it is. This may cause periodic buffer overflows, where
samples are lost and phasejumps occurs. The sideline spacing indicates
that this is happening every 1000/6 seconds (~ 3 minutes). <br>
  <br>
73, Markus<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: <a class="moz-txt-link-abbreviated" href="mailto:rsgb_lf_group@blacksheep.org">rsgb_lf_group@blacksheep.org</a> <a class="moz-txt-link-rfc2396E" href="mailto:rsgb_lf_group@blacksheep.org">&lt;rsgb_lf_group@blacksheep.org&gt;</a><br>
Verschickt: Di, 18. Jun. 2019 17:53<br>
Betreff: SLF: Sidebands arround ZEVS in 1 mHz<br>
  <br>
  </div>
  <div dir="ltr">These days i'm calibrating the colours and angles in
my ELF...VLF <br>
  </div>
  <div dir="ltr">spectrograms. The colour of ZEVS is now calibrated to
deviate less than <br>
  </div>
  <div dir="ltr">3 deg. However producing a spectrogram in 1 mHZ FFT
bin width, i can see <br>
  </div>
  <div dir="ltr">sidebands of ZEVS.<br>
  </div>
  <div dir="ltr">Did someone else observe a similar effect?<br>
  </div>
  <div dir="ltr">In a first thought i would assume it is my timing
system that causes the <br>
  </div>
  <div dir="ltr">problem. But maybe it is ZEVS itselfe? Or even
propagation?<br>
  </div>
  <div dir="ltr"><br>
  </div>
  <div dir="ltr">73, Stefan<br>
  </div>
  <div dir="ltr"><br>
  </div>
  <div dir="ltr">PS: Capture attached.<br>
  </div>
  <br>
  </div>
</blockquote>
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