Message-ID: <59144A6A.9030405@posteo.de>
Date: Thu, 11 May 2017 13:26:34 +0200
From: DK7FC <selberdenken@posteo.de>
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References: <1494434057.289033747@f20.i.mail.ru> <9ca738eb-6a64-a922-356a-6891cd122dc8@abelian.org>
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Subject: Re: LF: my results on VLF 05-08 May 2017
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Hi Paul, Alex, VLF,

Paul, thanks for working out the decode and timing problem, good work.

Alex, i don't know if this is just a PC time problem. At least what i 
can recommend is to control the PC clock by SpecLab! ...because there is 
no internet access in the garden. Not sure if you are already using this 
function.

Make a right click on the SpecLab icon, select properties and enable 
"start as administrator".
Disable the time sync (from a time server) function in windows.
Now when starting SpecLab, you need to confirm that the program will be 
started with admin privileges.
Since you are using a GPS module which provides PPS+NMEA, SpecLab knows 
the accurate time.
Open the GPS receiver function and enable the function "periodically 
synchronize PC's system date/time with data from GPS".
Before doing this, take a look on the value from "Current measured 
difference (System -GPS time): /w.xyz/ sec".
After enabling the function, this value should be in a range of 0.00x sec.

On the cope function of the Samlping rate Correction, what does the PC 
and EC show, or what is the ratio EC/PC? It should be less than 5% maybe.

Maybe it helps...

73, Stefan

Am 11.05.2017 09:02, schrieb Paul Nicholson:
>
> Alex wrote:
>
> > I think I have only false decodes of
> > {05 May 19:15 8270.1 4-char}
> > http://rn3aus.narod.ru/ebnaut-8270-05may2017-1915z.zip
>
> I got a successful genuine decode of the 4-char message
> from Alex's file
>
>  ebnaut06_MAY_0136_8270-1pps.wav
>
> Eb/N0 = 0.0 dB, constant reference phase
>
> carrier S/N: 13.62 dB in 31.2 uHz,
>             -31.43 dB in 1Hz,
>             -65.41 dB in 2.5kHz
>
> The decode needed a time offset of +1001 seconds
> which doesn't agree with difference between the WAV
> timestamp and the start of the message.  Something
> wrong with the clock at the RX site?
>
> Alex, try the decode again,
>
>  Symbols: 40.0
>  Message length: 4
>  Start offset: 1001
>  List length: 100
>
> Now I go look at the 2-char....
> -- 
> Paul Nicholson
> -- 
>
>
>

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Hi Paul, Alex, VLF, <br>
<br>
Paul, thanks for working out the decode and timing problem, good work.<br>
<br>
Alex, i don't know if this is just a PC time problem. At least what i
can recommend is to control the PC clock by SpecLab! ...because there
is no internet access in the garden. Not sure if you are already using
this function.<br>
<br>
Make a right click on the SpecLab icon, select properties and enable
"start as administrator". <br>
Disable the time sync (from a time server) function in windows.<br>
Now when starting SpecLab, you need to confirm that the program will be
started with admin privileges.<br>
Since you are using a GPS module which provides PPS+NMEA, SpecLab knows
the accurate time.<br>
Open the GPS receiver function and enable the function "periodically
synchronize PC's system date/time with data from GPS".<br>
Before doing this, take a look on the value from "Current measured
difference (System -GPS time): <i>w.xyz</i> sec".<br>
After enabling the function, this value should be in a range of 0.00x
sec.<br>
<br>
On the cope function of the Samlping rate Correction, what does the PC
and EC show, or what is the ratio EC/PC? It should be less than 5%
maybe.<br>
<br>
Maybe it helps...<br>
<br>
73, Stefan<br>
<br>
Am 11.05.2017 09:02, schrieb Paul Nicholson:
<blockquote cite="mid:9ca738eb-6a64-a922-356a-6891cd122dc8@abelian.org"
 type="cite"><br>
Alex wrote:
  <br>
  <br>
&gt; I think I have only false decodes of
  <br>
&gt; {05 May 19:15 8270.1 4-char}
  <br>
&gt; <a class="moz-txt-link-freetext" href="http://rn3aus.narod.ru/ebnaut-8270-05may2017-1915z.zip">http://rn3aus.narod.ru/ebnaut-8270-05may2017-1915z.zip</a>
  <br>
  <br>
I got a successful genuine decode of the 4-char message
  <br>
from Alex's file
  <br>
  <br>
 ebnaut06_MAY_0136_8270-1pps.wav
  <br>
  <br>
Eb/N0 = 0.0 dB, constant reference phase
  <br>
  <br>
carrier S/N: 13.62 dB in 31.2 uHz,
  <br>
            -31.43 dB in 1Hz,
  <br>
            -65.41 dB in 2.5kHz
  <br>
  <br>
The decode needed a time offset of +1001 seconds
  <br>
which doesn't agree with difference between the WAV
  <br>
timestamp and the start of the message.  Something
  <br>
wrong with the clock at the RX site?
  <br>
  <br>
Alex, try the decode again,
  <br>
  <br>
 Symbols: 40.0
  <br>
 Message length: 4
  <br>
 Start offset: 1001
  <br>
 List length: 100
  <br>
  <br>
Now I go look at the 2-char....
  <br>
--
  <br>
Paul Nicholson
  <br>
--
  <br>
  <br>
  <br>
  <br>
</blockquote>
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