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Date: Wed, 23 Sep 2009 21:50:57 +0100
Message-ID: <fc7eccec0909231350y51645512ta48df1fd48f475f4@mail.gmail.com>
From: Andy Talbot <andy.g4jnt@googlemail.com>
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: s/n shown by wspr .... what is it actually showing ?
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Its normalised to 2500Hz banbdwidth - approximately an SSB filter's worth.

So +20dB in 100Hz   =   -3dB in 2500Hz.

Andy
www.g4jnt.com



On 23/09/2009, Graham <g8fzk@g8fzk.fsnet.co.uk> wrote:
>
>  Just watched Dave's G3YXM  wspr  signal on spec-lab ,
>
> Spec-lab showed the  signal to  be a constant  20 dB over the back ground
> noise floor  of the  rx
> so in my  book that's 20 dB  s/n
>
> The  wspr  decode is  showing -3 dB s/n ?
>
> What is it  actually  displaying ?
>
> G ..
>
>
>
>



-- 
Andy
www.g4jnt.com

this email has been scanned for political correctness by the nanny state

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<div>Its normalised to 2500Hz banbdwidth - approximately an SSB filter&#39=
;s worth.</div>
<div>=A0</div>
<div>So +20dB in 100Hz=A0=A0 =3D=A0 =A0-3dB in 2500Hz.=A0=A0 </div>
<div>=A0</div>
<div>Andy</div>
<div><a href=3D"http://www.g4jnt.com">www.g4jnt.com</a></div>
<div><br><br>=A0</div>
<div><span class=3D"gmail_quote">On 23/09/2009, <b class=3D"gmail_senderna=
me">Graham</b> &lt;<a href=3D"mailto:g8fzk@g8fzk.fsnet.co.uk">g8fzk@g8fzk.=
fsnet.co.uk</a>&gt; wrote:</span>
<blockquote class=3D"gmail_quote" style=3D"PADDING-LEFT: 1ex; MARGIN: 0px=
 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div style=3D"PADDING-RIGHT: 10px; PADDING-LEFT: 10px; PADDING-TOP: 15px"=
 name=3D"Compose message area">
<div><font face=3D"Arial" size=3D"2">Just watched Dave&#39;s G3YXM =A0wspr=
=A0 signal on spec-lab , </font></div>
<div><font face=3D"Arial" size=3D"2"></font>=A0</div>
<div><font face=3D"Arial" size=3D"2">Spec-lab showed the=A0 signal to=A0=
 be a constant=A0 20 dB over the back ground noise floor=A0 of the=A0 rx=
 </font></div>
<div><font face=3D"Arial" size=3D"2">so in my=A0 book that&#39;s 20 dB=A0=
 s/n=A0=A0 </font></div>
<div><font face=3D"Arial" size=3D"2"></font>=A0</div>
<div><font face=3D"Arial" size=3D"2">The=A0 wspr=A0 decode is=A0 showing=
 -3 dB s/n ?</font></div>
<div><font face=3D"Arial" size=3D"2"></font>=A0</div>
<div><font face=3D"Arial" size=3D"2">What is it=A0 actually=A0 displaying=
 ?</font></div>
<div><font face=3D"Arial" size=3D"2"></font>=A0</div>
<div><font face=3D"Arial" size=3D"2">G .. </font></div>
<div><font face=3D"Arial" size=3D"2"></font>=A0</div>
<div><font face=3D"Arial" size=3D"2"></font>=A0</div>
<div><font face=3D"Arial" size=3D"2"></font>=A0</div></div></blockquote></=
div><br><br clear=3D"all"><br>-- <br>Andy<br><a href=3D"http://www.g4jnt.c=
om">www.g4jnt.com</a><br><br>this email has been scanned for political cor=
rectness by the nanny state=20

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