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Date: Sun, 7 Feb 2010 21:09:54 +0000
Message-ID: <fc7eccec1002071309j70cf7527ncdf577a0cd4e9cd9@mail.gmail.com>
From: Andy Talbot <andy.g4jnt@googlemail.com>
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: Re: WSPR S/N Tests
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Yes.
Odd that.
Increased spectrogram noise reading when it ought to be filtered out

I suspect the spectrogram is not a simple power level indication.   SpecJT
appears to be more of a CFAR indication and the WSPR one may be
not-dissimilar in concept.

Andy
www.g4jnt.com

> Doing this also produces a lot of false decodes - the spectrogram display
> in WSPR shows a couple of broad, bright, noise-like bands where the
> passband-stopband transitions of the audio filter occur, with assorted
> spectral lines that are probably low-level noise from one PC or another. I
> have often noticed the number of false decodes goes up when there are
> narrow-

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<div>Yes. </div>
<div>Odd that.</div>
<div>Increased spectrogram noise reading when it ought to be filtered out<=
/div>
<div>=A0</div>
<div>I suspect the spectrogram is not a simple=A0power level indication.=
=A0=A0 SpecJT appears to be more of a CFAR indication and the WSPR one may=
 be not-dissimilar in concept.</div>
<div><br clear=3D"all">Andy<br><a href=3D"http://www.g4jnt.com">www.g4jnt.=
com</a><br></div>
<div class=3D"gmail_quote">
<blockquote style=3D"BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8e=
x; PADDING-LEFT: 1ex" class=3D"gmail_quote">Doing this also produces a lot=
 of false decodes - the spectrogram display in WSPR shows a couple of broa=
d, bright, noise-like bands where the passband-stopband transitions of the=
 audio filter occur, with assorted spectral lines that are probably low-le=
vel noise from one PC or another. I have often noticed the number of false=
 decodes goes up when there are narrow-</blockquote>
</div>

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