Message-ID: <577C17E1.5080802@posteo.de>
Date: Tue, 05 Jul 2016 22:26:09 +0200
From: DK7FC <selberdenken@posteo.de>
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Subject: Re: LF: Portable VLF/ULF recording system with PPS+NMEA
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Hi Michel,

I'm using this soundcard: http://www.ebay.de/itm/121666143901

Best 73, Stefan

Am 05.07.2016 17:23, schrieb Michel Brunel:
> Hallo Stefan,
>
> Looks promising, what sound card are you using and if you can read it, 
> what is the audio codec chip ?
> I recently tried to replace the 12 MHz crystal of a CUA-202, but the 
> onchip PLL of the PCM2902 ruined my effort (too bad a jitter)
>
> For my future Ebnaut operation,  I just set up a "Stratum 1 time box" 
> with a Raspberry PI2 and a tiny GPS receiver (VK16E)
> The 1PPS is directly sent to a GPIO and managed by the kernel 
> (Raspbian Jessie) NTPQ reports an accuracy of 2E-19 which
> translates to 2 ms
> Ah, Wolf's ntp client works like a charm with the Rpi ntp server ! 
>  That's a great internet free solution.
>
> 73,
>
> Michel - f5wk
>
>
>
> Le mardi 5 juillet 2016 à 16:45:52, DK7FC écrivait :
>
> *> Hi all,
>
> > I've completed my portable VLF/ULF(audio) recording system.
> > See:
> *> 
> https://dl.dropboxusercontent.com/u/19882028/ULF/VLFesULF%20portable%20recording.jpg
>
>
> *> The system consists out of a:
> > - Raspberry Pi 2B
> > - DC/DC converter with a 5.0V output (80% efficiency)
> > - 7 Ah lead acid battery
> > - Stereo input soundcard
> > - 32 GB USB stick
> > - NEO-6M GPS module (including antenna)
> > - (shut down button)
> > - (switch for starting/stopping a recording)
>
> > The latest add-on, the GPS module now allows to record 1PPS impulses and
> > NMEA data for most accurate and glitch-free(corrected) recordings,
> > absolute timestamps as well as location data.
> > The recording is stred as a wav file to the USB stick directly.
> > It consumes 160 mA at 12V during a record. With the battery it should be
> > no problem to record for nearly 2 days.
> > Future ULF reception tests can now be done with this improved 
> technique...
>
> > 73, Stefan
>
>
>
>
>
>
> */-- /

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Hi Michel,<br>
<br>
I'm using this soundcard: <a class="moz-txt-link-freetext" href="http://www.ebay.de/itm/121666143901">http://www.ebay.de/itm/121666143901</a><br>
<br>
Best 73, Stefan<br>
<br>
Am 05.07.2016 17:23, schrieb Michel Brunel:
<blockquote cite="mid:1172051038.20160705172345@mterrier.net"
 type="cite">
  <title>Re: LF: Portable VLF/ULF recording system with PPS+NMEA</title>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  <span style="font-family: 'Calibri'; font-size: 12pt;">Hallo Stefan,<br>
  <br>
Looks promising, what sound card are you using and if you can read it,
what is the audio codec chip ?  <br>
I recently tried to replace the 12 MHz crystal of a CUA-202, but the
onchip PLL of the PCM2902 ruined my effort (too bad a jitter)<br>
  <br>
For my future Ebnaut operation,  I just set up a "Stratum 1 time box"
with a Raspberry PI2 and a tiny GPS receiver (VK16E)<br>
The 1PPS is directly sent to a GPIO and managed by the kernel (Raspbian
Jessie) NTPQ reports an accuracy of 2E-19 which<br>
translates to 2 ms <br>
Ah, Wolf's ntp client works like a charm with the Rpi ntp server !
 That's a great internet free solution.<br>
  <br>
73,<br>
  <br>
Michel - f5wk<br>
  <br>
  <br>
  <br>
Le mardi 5 juillet 2016 à 16:45:52, DK7FC écrivait :<br>
  <br>
  <span
 style="font-family: 'courier new'; font-size: 9pt; color: rgb(128, 0, 0);"><b>&gt;
Hi all,<br>
  <br>
&gt; I've completed my portable VLF/ULF(audio) recording system.<br>
&gt; See: <br>
  </b></span></span><a moz-do-not-send="true"
 style="font-family: 'courier new'; font-size: 9pt;"
 href="https://dl.dropboxusercontent.com/u/19882028/ULF/VLFesULF%20portable%20recording.jpg">&gt;
https://dl.dropboxusercontent.com/u/19882028/ULF/VLFesULF%20portable%20recording.jpg</a><br>
  <br>
  <br>
  <span
 style="font-family: 'courier new'; font-size: 9pt; color: rgb(128, 0, 0);"><b>&gt;
The system consists out of a:<br>
&gt; - Raspberry Pi 2B<br>
&gt; - DC/DC converter with a 5.0V output (80% efficiency)<br>
&gt; - 7 Ah lead acid battery<br>
&gt; - Stereo input soundcard<br>
&gt; - 32 GB USB stick<br>
&gt; - NEO-6M GPS module (including antenna)<br>
&gt; - (shut down button)<br>
&gt; - (switch for starting/stopping a recording)<br>
  <br>
&gt; The latest add-on, the GPS module now allows to record 1PPS
impulses and <br>
&gt; NMEA data for most accurate and glitch-free(corrected) recordings, <br>
&gt; absolute timestamps as well as location data.<br>
&gt; The recording is stred as a wav file to the USB stick directly.<br>
&gt; It consumes 160 mA at 12V during a record. With the battery it
should be <br>
&gt; no problem to record for nearly 2 days.<br>
&gt; Future ULF reception tests can now be done with this improved
technique...<br>
  <br>
&gt; 73, Stefan<br>
  <br>
  <br>
  <br>
  <br>
  <br>
  <br>
  </b><span
 style="font-family: 'arial'; font-size: 8pt; color: rgb(192, 192, 192);"><i>-- </i></span></span></blockquote>
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