Message-ID: <D511D3CBA16848DF932F206B55484DD2@White>
From: "Markus Vester" <markusvester@aol.com>
To: <rsgb_lf_group@blacksheep.org>
References: <B642235FE9444C2A85F37190C576DEB3@malcoHP>
Date: Sun, 15 Nov 2015 12:53:52 +0100
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Subject: Re: LF: WSPR DECODES - and Opera
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QRSS better than WSPR? Almost, but not quite... see Rik's evaluation:
 http://on7yd.strobbe.eu/QRSS/
The SNR threshold 50% successful WSPR decodes is between -29 and -30 dB =
(2.5 kHz), wheras the QRSS messages required a couple of dB more (-27 to =
-28 dB). In Rik's challenge, completely random messages were used, and =
only completely correct readings were counted as success. Due to the =
structure of Morse code (dashes are better visible than dots), partial =
"decodes" are often possible at lower SNR, which often allow conducting =
a QSO using some a-priori information and guesswork.   =20

Rik also looked at Opera versus WSPR, and found a 6 dB deficit for Opera =
at same peak power. That was probably still in an early stage of Opera =
development, and the decoding abilities have been improved since then. =
My own tests with Opera v1.5.6  =20
 http://df6nm.bplaced.net/opera/Success_rate.png
got 50% successful Op-32 decodes at -40 dB average SNR. This scales to =
-28 dB (av) or -25 dB (PEP) at Op-2 speed, i.e. a 1.5 dB improvement =
since Rik's blue curve. However, at same average power, Opera-2 is still =
1.5 dB weaker than WSPR-2 (or 4.5 dB weaker at same peak power).=20

Including the volume of conveyed information, WSPR wins another 2.52 dB =
(50 bits versus 28 bits), and it is also slightly shorter than Op-2 =
(110.6 vs 122.4 s, another 0.44 dB). Thus alltogether the difference is =
4.5 dB at same average power (i.e. Op needs 2.8 times the energy per =
bit), or 7.5 dB at same PEP (with a given TX, Opera needs 5.6 times as =
long to send the same amount of information). Minimum Eb/N0 values are =
about +7.9 dB for WSPR and +12.4 dB for Opera.

Regarding correlation detections, my measurements using coherent signals =
showed that opds can go about 8 dB lower than the Opera decoder. For =
comparison, Opera's Dynamic Deep-Search believably claims to go 5 dB =
below the decoder.

Sorry for reiterating this topic again...

Best 73,
Markus (DF6NM) =20



From: mal hamilton=20
Sent: Sunday, November 15, 2015 10:37 AM
To: rsgb_lf_group@blacksheep.org=20
Subject: LF: WSPR DECODES


MF
I have been observing WSPR signals this past couple of days on 474.2 Khz =
and although most are Decoding there are a number of weak signals =
visible on the  waterfall that do not decode. I am in a quiet location =
so noise is not a problem. My clock and input are set up as specified.
Had these station been using QRSS the copy would be perfect.=20
also
the same applies to Opera signals visible on the waterfall but do not =
decode, usually weak.
QRSS has the advantage that the raw signal observed is immediately =
readable on the screen even the barely visible.

G3KEV

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content=3Dtext/html;charset=3Diso-8859-1 =
http-equiv=3DContent-Type>
<META name=3DGENERATOR content=3D"MSHTML 8.00.6001.23588"></HEAD>
<BODY style=3D"PADDING-LEFT: 10px; PADDING-RIGHT: 10px; PADDING-TOP: =
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id=3DMailContainerBody leftMargin=3D0 topMargin=3D0 bgColor=3D#ffffff=20
CanvasTabStop=3D"true" name=3D"Compose message area">
<DIV><FONT size=3D2 face=3DArial>QRSS better than WSPR? Almost, but not =
quite... see=20
Rik's evaluation:<BR>&nbsp;<A=20
title=3D"http://on7yd.strobbe.eu/QRSS/&#10;STRG + Klicken, um =
Verkn=FCpfung zu folgen"=20
href=3D"http://on7yd.strobbe.eu/QRSS/">http://on7yd.strobbe.eu/QRSS/</A><=
/FONT></DIV>
<DIV><FONT size=3D2 face=3DArial>The SNR threshold 50% successful WSPR =
decodes is=20
between -29 and -30 dB (2.5 kHz), wheras the QRSS messages required a =
couple of=20
dB more (-27 to -28 dB). In&nbsp;Rik's challenge, completely random =
messages=20
were used, and only completely correct readings were counted as success. =
Due to=20
the structure of Morse code (dashes are better visible than dots), =
partial=20
"decodes" are often possible at lower SNR, which often allow conducting =
a QSO=20
using some a-priori information and guesswork.&nbsp;&nbsp;&nbsp; =
</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial></FONT>&nbsp;</DIV>
<DIV><FONT size=3D2 face=3DArial>Rik also looked at Opera versus WSPR, =
and found a 6=20
dB deficit for Opera at same peak power. That was probably still in an =
early=20
stage of Opera development, and the decoding abilities have been =
improved since=20
then. My own tests with Opera v1.5.6&nbsp;&nbsp; <BR>&nbsp;<A=20
title=3D"http://df6nm.bplaced.net/opera/Success_rate.png&#10;STRG + =
Klicken, um Verkn=FCpfung zu folgen"=20
href=3D"http://df6nm.bplaced.net/opera/Success_rate.png">http://df6nm.bpl=
aced.net/opera/Success_rate.png</A><BR>got=20
50% successful Op-32 decodes at -40 dB average SNR. This scales to -28 =
dB (av)=20
or -25 dB (PEP) at Op-2 speed, i.e. a 1.5 dB improvement since Rik's =
blue curve.=20
However, at <STRONG>same average power, Opera-2 is still 1.5 dB weaker =
than=20
WSPR-2</STRONG> (or 4.5 dB weaker at same peak power). </FONT></DIV>
<DIV><FONT size=3D2 face=3DArial></FONT>&nbsp;</DIV>
<DIV><FONT size=3D2 face=3DArial>Including the volume of conveyed =
information, WSPR=20
wins another 2.52 dB (50 bits versus 28 bits), and it is also slightly =
shorter=20
than Op-2 (110.6 vs 122.4 s, another 0.44 dB). Thus alltogether the =
difference=20
is 4.5 dB at same average power (i.e. Op needs 2.8 times the energy per =
bit), or=20
7.5 dB at same PEP (with a given TX, Opera needs 5.6 times as long to =
send the=20
same amount of information). Minimum Eb/N0 values are about +7.9 dB for =
WSPR and=20
+12.4 dB for Opera.</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial></FONT>&nbsp;</DIV>
<DIV><FONT size=3D2 face=3DArial>Regarding correlation detections, my =
measurements=20
using coherent signals showed that opds can go about 8 dB lower than the =
Opera=20
decoder. For comparison, Opera's Dynamic Deep-Search believably claims =
to go 5=20
dB below the decoder.</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial></FONT>&nbsp;</DIV>
<DIV><FONT size=3D2 face=3DArial>Sorry for reiterating this topic=20
again...</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=3D2 face=3DArial>Best 73,<BR>Markus (DF6NM)&nbsp; =
<BR></FONT></DIV>
<DIV style=3D"FONT: 10pt Tahoma">
<DIV><BR></DIV>
<DIV style=3D"BACKGROUND: #f5f5f5">
<DIV style=3D"font-color: black"><B>From:</B> <A =
title=3Dg3kevmal@talktalk.net=20
href=3D"mailto:g3kevmal@talktalk.net">mal hamilton</A> </DIV>
<DIV><B>Sent:</B> Sunday, November 15, 2015 10:37 AM</DIV>
<DIV><B>To:</B> <A=20
title=3D"mailto:rsgb_lf_group@blacksheep.org&#10;STRG + Klicken, um =
Verkn=FCpfung zu folgen"=20
href=3D"mailto:rsgb_lf_group@blacksheep.org">rsgb_lf_group@blacksheep.org=
</A>=20
</DIV>
<DIV><B>Subject:</B> LF: WSPR DECODES</DIV></DIV></DIV>
<DIV><BR></DIV>
<DIV dir=3Dltr>
<DIV style=3D"FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: 12pt">
<DIV>MF</DIV>
<DIV>I have been observing WSPR signals this past couple of days on =
474.2 Khz=20
and although most are Decoding there are a number of weak signals =
visible on=20
the&nbsp; waterfall that do not decode. I am in a quiet location so =
noise is not=20
a problem. My clock and input are set up as specified.</DIV>
<DIV>Had these station been using QRSS the copy would be perfect. </DIV>
<DIV>also</DIV>
<DIV>the same applies to Opera signals visible on the waterfall but do =
not=20
decode, usually weak.</DIV>
<DIV>QRSS has the advantage that the raw signal observed is immediately =
readable=20
on the screen even the barely visible.</DIV>
<DIV>&nbsp;</DIV>
<DIV>G3KEV</DIV>
<DIV>&nbsp;</DIV></DIV></DIV></BODY></HTML>

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