To: rsgb_lf_group@blacksheep.org
References: <5667438E.50200@virginbroadband.com.au>
From: =?UTF-8?Q?Wolfgang_B=c3=bcscher?= <dl4yhf@freenet.de>
Message-ID: <56674B3F.4060301@freenet.de>
Date: Tue, 8 Dec 2015 22:27:27 +0100
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Subject: Re: LF: VO1NA - carrier
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Hello Edgar and all,

Interesting animated GIF - wonder how you create those :-)

One suggestion: Even though it's incoherent averaging, a curve with the 
long-term average spectrum plotted along with the recent spectrum 
(graph) sometimes helps to identify very weak peaks, because in the 
average of all amplitude spectra, 'sigma' (the standard deviation) will 
gradually drop, the noise in the spectrum will be ironed out making weak 
peaks easier to spot. At least, a 'long term average' doesn't hurt. You 
could reset the averages (accumulators) once per day or so.

A very long FFT, covering an entire day, may be even more useful 
(coherent, more 'FFT gain' than with incoherent averaging). But in the 
recent version of SL there is no such feature. Possibly easier to do 
this in the post-processing, using the decimated I/Q wave files for 
input, and an FFT with arbitrary length (SL's FFT is the normal 
implementation, which needs a power of two for the FFT length).

All the best,
   Wolf .


Am 08.12.2015 um 21:54 schrieb edgar:
> Hi Joe,
>
> Result from last night.
>
> https://dl.dropboxusercontent.com/u/101251787/VO1NA/VO1NA.gif
>
> Some adjustment in Spectrum Lab settings still required.
>
> Regards, Edgar
> Moonah, Tasmania.


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    Hello Edgar and all,<br>
    <br>
    Interesting animated GIF - wonder how you create those :-)<br>
    <br>
    One suggestion: Even though it's incoherent averaging, a curve with
    the long-term average spectrum plotted along with the recent
    spectrum (graph) sometimes helps to identify very weak peaks,
    because in the average of all amplitude spectra, 'sigma' (the
    standard deviation) will gradually drop, the noise in the spectrum
    will be ironed out making weak peaks easier to spot. At least, a
    'long term average' doesn't hurt. You could reset the averages
    (accumulators) once per day or so.<br>
    <br>
    A very long FFT, covering an entire day, may be even more useful
    (coherent, more 'FFT gain' than with incoherent averaging). But in
    the recent version of SL there is no such feature. Possibly easier
    to do this in the post-processing, using the decimated I/Q wave
    files for input, and an FFT with arbitrary length (SL's FFT is the
    normal implementation, which needs a power of two for the FFT
    length).<br>
    <br>
    All the best,<br>
      Wolf .<br>
    <br>
    <br>
    <div class="moz-cite-prefix">Am 08.12.2015 um 21:54 schrieb edgar:<br>
    </div>
    <blockquote cite="mid:5667438E.50200@virginbroadband.com.au"
      type="cite">
      <meta http-equiv="content-type" content="text/html; charset=utf-8">
      <font face="Arial">Hi Joe,<br>
        <br>
        Result from last night.<br>
        <br>
        <a moz-do-not-send="true" class="moz-txt-link-freetext"
          href="https://dl.dropboxusercontent.com/u/101251787/VO1NA/VO1NA.gif">https://dl.dropboxusercontent.com/u/101251787/VO1NA/VO1NA.gif</a><br>
        <br>
        Some adjustment in Spectrum Lab settings still required.<br>
        <br>
        Regards, Edgar<br>
        Moonah, Tasmania.<br>
      </font> </blockquote>
    <br>
  </body>
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