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Date: Thu, 13 Feb 2014 00:03:30 +0100
From: wolf_dl4yhf <dl4yhf@freenet.de>
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Subject: Re: LF: CQ CQ DL4YHF WSQ2
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Hi Nicolas,

Am 12.02.2014 23:52, schrieb F4DTL@aol.com:
> quick brown fox jumps over the lazy dog
>
> dl4yhf
> ...-.-
> cq cq ddl4yhfd4yh e k
> *F4DTL Nicolas*

*Ok, I was inspired for that sentence when reading the WSQ help pages :-)*

btw Murray ZL1BPU has answered my questions regarding notch filter, 
guess he won't mind relaying his entire message here.
Note the last sentence.

Cheers,
   Wolf.

-----

Wolf,
I can read the rsgb_lf_group reflector, but not post to it (problem 
getting them to change my login). I am pleased to note your interest in 
WSQ2. I can hopefully answer your questions about it works.
First, there is no notch filter, so if there are interfering carriers, 
you'll need to QSY. Not ideal, I know, but with no error correction with 
a puncturing function there would still be no way to recover from all 
the errors. The source code is available, so if you want to try, you 
could add a notch filter.
The important reason behind not using FEC is TYPING SPEED. We designed 
it for 5WPM. WSQ2 is intended to be a QSO mode, like CW. If there are 
errors, you ask for repeats. In our experience (we also tested WSQ with 
FEC), for the same text speed, there is little difference between 
reception quality of 0.5 baud with no FEC, and 0.25 baud with standard 
NASA convolutional coding FEC. The big difference was that the FEC 
version was of course much slower. Yes, the FEC version had slightly 
fewer errors at around --24dB SNR, but it dropped out at --25 just like 
the non-FEC version.
Exactly the same situation applies when you compare DominoEX4 with 
THOR8. Similar sensitivity, but double the speed. It's all about the 
integration time -- the slower symbol rate has an impulse noise 
rejection advantage as well as a sensitivity advantage.
You have to realize that WSQ2 is designed as a real-time QSO mode, it is 
not for beaconing or propagation measurement. Sure, you need slightly 
more signal than for WSPR, but you can have a real QSO with a real 
person. FEC, and especially block modes, don't lend themselves to this 
level of operating freedom.
If anyone on the rsgb reflector has any questions about the mode, please 
point them in my direction.
73,
Murray ZL1BPU


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    <div class="moz-cite-prefix">Hi Nicolas,<br>
      <br>
      Am 12.02.2014 23:52, schrieb <a class="moz-txt-link-abbreviated" href="mailto:F4DTL@aol.com">F4DTL@aol.com</a>:<br>
    </div>
    <blockquote cite="mid:728ab.22f842d6.402d5511@aol.com" type="cite">
      <meta content="text/html; charset=ISO-8859-1"
        http-equiv="Content-Type">
      <meta name="GENERATOR" content="MSHTML 8.00.6001.23543">
      <font id="role_document" face="Arial" size="2" color="#000000">
        <div>quick brown fox jumps over the lazy dog <br>
          &nbsp;<br>
          dl4yhf&nbsp; <br>
          ...-.- </div>
        <div>&nbsp;</div>
        <div>cq cq ddl4yhfd4yh e k <br>
        </div>
        <div>&nbsp;</div>
        <div><strong>F4DTL Nicolas</strong></div>
      </font></blockquote>
    <br>
    <strong><font size="2"><font face="Arial">Ok, I was inspi<font
            size="2">red for that <font size="2">sentence when</font>
            reading the <font size="2">WSQ help pages :-<font size="2">)</font></font></font></font></font></strong><br>
    <br>
    btw Murray ZL1BPU has answered my questions regarding notch filter,
    guess he won't mind relaying his entire message here.<br>
    Note the last sentence.<br>
    <br>
    Cheers,<br>
    &nbsp; Wolf.<br>
    <br>
    -----<br>
    <br>
    <div>Wolf,</div>
    <div>I can read the rsgb_lf_group reflector, but not post to it
      (problem getting them to change my login). I am pleased to note
      your interest in WSQ2. I can hopefully answer your questions about
      it works.</div>
    <div>&nbsp;</div>
    <div>First, there is no notch filter, so if there are interfering
      carriers, you&#8217;ll need to QSY. Not ideal, I know, but with no error
      correction with a puncturing function there would still be no way
      to recover from all the errors. The source code is available, so
      if you want to try, you could add a notch filter.</div>
    <div>&nbsp;</div>
    <div>The important reason behind not using FEC is TYPING SPEED. We
      designed it for 5WPM. WSQ2 is intended to be a QSO mode, like CW.
      If there are errors, you ask for repeats. In our experience (we
      also tested WSQ with FEC), for the same text speed, there is
      little difference between reception quality of 0.5 baud with no
      FEC, and 0.25 baud with standard NASA convolutional coding FEC.
      The big difference was that the FEC version was of course much
      slower. Yes, the FEC version had slightly fewer errors at around
      &#8211;24dB SNR, but it dropped out at &#8211;25 just like the non-FEC
      version.</div>
    <div>&nbsp;</div>
    <div>Exactly the same situation applies when you compare DominoEX4
      with THOR8. Similar sensitivity, but double the speed. It&#8217;s all
      about the integration time &#8211; the slower symbol rate has an impulse
      noise rejection advantage as well as a sensitivity advantage.</div>
    <div>&nbsp;</div>
    <div>You have to realize that WSQ2 is designed as a real-time QSO
      mode, it is not for beaconing or propagation measurement. Sure,
      you need slightly more signal than for WSPR, but you can have a
      real QSO with a real person. FEC, and especially block modes,
      don&#8217;t lend themselves to this level of operating freedom.</div>
    <div>&nbsp;</div>
    <div>If anyone on the rsgb reflector has any questions about the
      mode, please point them in my direction.</div>
    <div>&nbsp;</div>
    <div>73,</div>
    <div>Murray ZL1BPU</div>
    <br>
    <br>
    <br>
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