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Re: [dxsoft] CwGet "accuracy"

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  • nharvey113@aol.com
    Hi Mark, CwGet is ok, but try MRP40.? It s the best CW copier around. Neil? AC6YO ... From: Mark Amos To: dxsoft@yahoogroups.com Sent:
    Message 1 of 43 , May 1 12:31 PM
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      Hi Mark,

      CwGet is ok, but try MRP40.? It's the best CW copier around.

      Neil? AC6YO


      -----Original Message-----
      From: Mark Amos <mark@...>
      To: dxsoft@yahoogroups.com
      Sent: Thu, 30 Apr 2009 5:16 pm
      Subject: [dxsoft] CwGet "accuracy"








      All,

      I did a completely unscientific measurement of CwGet "accuracy" and thought
      I'd share my results here. Overall, the results were about 98% accurate
      copy.

      I copied W1AW code practice at 20 WPM (maybe 18?) and compared the results
      to CwGet and have detailed the results below. Also, at the bottom is the
      text I copied and the text copied by CwGet.

      For the "test", the radio I used was an HPSDR and a 1/4 wave vertical on 40
      meters running PowerSDR software feeding the audio to CwGet. The signal
      strength varied from S5 to S9+10 over an S2 noise floor (on a calibrated S
      meter.) The missed characters were during dips in the signal. In all
      fairness, I had trouble with them too (in two of the drop outs), but could
      guess the words based on context. There were only three of these during the
      test.

      I was using a 25Hz filter (in the Radio) and a 140Hz filter in CwGet with a
      500 lpm burst filter.

      By my count (which is probably off - I didn't count punctuation errors,
      since I don't generally include punctuation in my copy) it appears that
      there were 3 word mistakes out of 105 words. The letter error rate was about
      9 characters mistaken out of 550 characters. I didn't bother calculating the
      element/bit error rate - but I suspect it was less than 1%. Obviously there
      is no error correction with CW so you get what you get...

      This is an insufficient test to conclude much about the accuracy of CwGet
      (an N of 550 is pretty small and the conditions were good.) With fading,
      QRM, a bad fist, etc., etc. the accuracy of the program would suffer (as
      would mine.) I have a better processing engine for syntax and grammar and
      error "correction" (my brain) which gives me an advantage in filling in
      missing letters/words. On the other hand, CwGet can copy accurately at 50
      WPM (at that speed my accuracy is about 20% comprehension - I can't copy
      accurately over 30 WPM no matter how good the conditions...)

      In any case, I think it's a pretty good tool. I've tried a few others and
      CwGet seems to be head-and-shoulders above the others I've used.

      FYI, there's a neat article in HAM-MAG this month on a "hardware" decoder
      (uses PIC software) that looks like it would be fun to play with. I haven't
      looked at the code, but I suspect it won't be much competition to CwGet. I
      wrote some CW software in 8080 assembler back in the 80s and while it copied
      machine sent code (via a keyer) at 100%, it could only do it at 12 WPM and
      it barely worked at all on-the-air...

      Anyway, I just thought some of you might be interested in my "unscientific"
      test.

      Mark
      W8XR

      county search and rescue in washington state I didnt have their number so I
      called my local 911 dispatcher all they had was the info for king county in
      washington so I called them and they gave me the number for snohomish. when
      I got hold of snohomish county search and rescue they asked me to obtain
      additional info from russ such as the color of his tent and if he was in a
      clear or wooded area and remain in contact with him as long as possible
      williams said russ and I were able to maintain contact until about 8 pm on
      sunday

      county search and rescue in washington state. i didnt have their number, so
      i called my local 911 dispatcher. all they had was the info for king county
      in washington, so i called them and they ga e t me the number for snohomish.
      when i got a hold of snohomish county search and rescue, n e tw asked me to
      obtain additional info from russ, such as the color of his tent e nd if he
      was in a clear or wooded area, and remain in contact with him as long as
      possible, williams said. russ and i were able to maintain contact until
      about 8 pm on sunday,








      [Non-text portions of this message have been removed]
    • Palle A. Andersen
      Mr. Afzal! I have used CWGET for the last 8 years. Before that I have try d my selv to make a decoding program for CW. I have bin teaching other HAMs CW for
      Message 43 of 43 , May 7 2:34 AM
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        Mr. Afzal!
        I have used CWGET for the last 8 years.
        Before that I have try'd my selv to make a decoding program for CW.
        I have bin teaching other HAMs CW for many years, so I know the nature of CW, and I know how different a singel letter could be, depending on, who is sending the letters.
        You must know the nature of CW, before asking this question.

        No program can to day or EVER in the future decode CW 100 %, because of this nature.
        You will experience, that sometime, where the sender is trained and good with his key, or if he use a computer keyboard to transmit, and with signalstringht over S5, a program to recive CW works 100 % perfect, but then som noise arive and spoil the signal, or the signal is faiding down in the noise, then the perfection disapeare, and the recivibng goes down to 80 % or less.

        That nature is impossible for a programmer to overcome.

        The conclution must be, that CW-decoding can work 100 % if the condition is right.

        You must make your own expirience.

        Vy 73 de OZ6YM, Palle

        --- In dxsoft@yahoogroups.com, afzal talib <afz_632007@...> wrote:
        >
        >     I just want to know that cw get receives cw signals perfectly and from where i will get it
        >  
        >                     afzal
        >
        >
        >
        >
        > [Non-text portions of this message have been removed]
        >
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