Loading ...
Sorry, an error occurred while loading the content.

Re: [V4Protocol] What's happened

Expand Messages
  • charles standlee
    More than likely it s just the holiday s, The same thing happended last year with Winmor and a few other new modes.  73, Chuck AC5PW
    Message 1 of 8 , Jan 2, 2011
    • 0 Attachment
      More than likely it's just the holiday's, The same thing happended last year with Winmor and a few other new modes.
       
      73, Chuck AC5PW



      From: "kirkharding@..." <kirk.harding@...>
      To: V4Protocol@yahoogroups.com
      Sent: Sun, January 2, 2011 8:55:47 AM
      Subject: [V4Protocol] What's happened

       

      I've noticed as of late that emails from the group have dropped to 0. Not sure if the problems are my email settings (they look OK to me), or interest in the group has subsided. In any case, I'm interested in what's going on, if anything? I'm continuing to enjoy the mode but am not hearing as many users. Maybe it's the time of year with holidays and all.
      Happy New Year.

      Kirk, K6KAR
      Niceville, FL


    • Rick Muething
      All, The current version appears pretty stable. I have been working on the ARQ mode and had to make some significant changes there. Of course the standard
      Message 2 of 8 , Jan 2, 2011
      • 0 Attachment

        All,

        The current version appears pretty stable. I have been working on the ARQ mode and had to make some significant changes there. Of course the standard holiday, parties etc.   Hope to have a rev out this week with ARQ enabled.

         

        Rick KN6KB

        No virus found in this incoming message.
        Checked by AVG - www.avg.com
        Version: 9.0.872 / Virus Database: 271.1.1/3259 - Release Date: 01/01/11 14:34:00

      • John Hirth
        Happy New Year, Rick. I m sure I speak for all of us when I convey my thanks for another year of your hard work programming for the benefit the digital
        Message 3 of 8 , Jan 2, 2011
        • 0 Attachment
          Happy New Year, Rick. I'm sure I speak for all of us when I convey my
          thanks for another year of your hard work programming for the benefit
          the digital community of Amateur Radio.

          I've been and am a strong supporter, but at the risk of irritating those
          who have been excitedly waiting for the release of ARQ functionality, I
          going to be bold enough to ask tha instead of diverting focus at this
          point toward another set of issues, might it be worth a bit more time to
          tweak FEC mode's performance a bit more in weak signal and poor band
          conditions?

          I've been monitoring (and working) more often lately, and even with
          version 0170 I just can't rid myself of the impression that in poor band
          conditions I could be easily making good QSOs with any of a few other
          modes, when with V4FEC I get little more than sporadic decodes. With
          several of the other soundcard modes when I can just barely hear that
          there's a signal on frequency I know I can get usable (often 100%) text,
          but in those same conditions I struggle with V4FEC to get frames decoded.

          Have we reach the point of diminishing returns with effort on the
          performance of V4FEC?

          But then again, perhaps I should just quietly wait and see.

          73 and thanks again,
          John W2KI
        • Rick Muething
          John, There are several issues here.... For one thing it is literally impossible to tweak, tune or even accurately evaluate the performance of ANY digital mode
          Message 4 of 8 , Jan 2, 2011
          • 0 Attachment
            John,
             
            There are several issues here.... For one thing it is literally impossible to tweak, tune or even accurately evaluate the performance of ANY digital mode without  a controlled environment such as those on a HF simulator of some type.  e.g.  Many casually associate the “quality” of the signal with its strength....one factor but path distortions (multipath, doppler etc) are actually more critical than just signal strength.   For example I have run both PSK (31, 63 etc), WINMOR and V4 through various channels and PSK modes (including those PSK modes in WINMOR) do not fare well in poor multipath environments such as NVIS, aurora etc.  Though most narrow band slow modes (e.g. PSK31) can be made to perform well in weak signal (white Gaussian noise) environments.
             
            Optimizing a protocol for general usage environment entails repeated optimizations for factors such as error correction coding, automatic tuning, ARQ reliability (protocol robustness), poor multipath propagation as well as weak signal. For example it is possible to get another 1.7 dB or so weak signal performance by doubling the sound card sample rate and FFT sizes (at the expense of CPU loading)  and I will look into that at some time in the future. But I want to get the basic protocol functionally working which includes ARQ before launching off into some of these optimization efforts.  One thing ARQ will allow is to lower the detection thresholds (those magic constants inside the program no one sees!) that determine for example if and when a frame sync is detected.  For true ARQ the thresholds can be set more aggressively since the ARQ protocol protects against any bad data getting through. This for example will allow better weak signal net throughput yet still allow the 100 % copy that ARQ allows.
             
            To put it in perspective...The WINMOR protocol (more complex for sure than V4) took over 2 years to develop and optimize. Pactor 3 (with the PTC II’s massive DSP power) was optimized for over 10 years.  These things all take time, real engineering effort and controlled methodical testing.  Surely over the air rag chews are fun and provide good feedback on functionality  and desired functions but when it comes to really MEASURING performance (error rates vs. S/N over standardized CCIR channels) there is no  substitute for using the HF channel simulator and performing hours of testing and statistic collections.
             
            The theory and initial tests I have run with V4 suggest it can be made very robust and still fit in a narrow 200 Hz channel and deliver modest 50+wpm typing speeds.  It will however always be possible to design and field modes that offer better weak signal performances by using slower throughput (e.g. PSK31, JT65 etc) and/or wide bandwidth (e.g. Domino/Olivia).
             
            Rick KN6KB
             
             
             
            Sent: Sunday, January 02, 2011 10:45 AM
            Subject: Re: [V4Protocol] What's happened
             
             

            Happy New Year, Rick. I'm sure I speak for all of us when I convey my
            thanks for another year of your hard work programming for the benefit
            the digital community of Amateur Radio.

            I've been and am a strong supporter, but at the risk of irritating those
            who have been excitedly waiting for the release of ARQ functionality, I
            going to be bold enough to ask tha instead of diverting focus at this
            point toward another set of issues, might it be worth a bit more time to
            tweak FEC mode's performance a bit more in weak signal and poor band
            conditions?

            I've been monitoring (and working) more often lately, and even with
            version 0170 I just can't rid myself of the impression that in poor band
            conditions I could be easily making good QSOs with any of a few other
            modes, when with V4FEC I get little more than sporadic decodes. With
            several of the other soundcard modes when I can just barely hear that
            there's a signal on frequency I know I can get usable (often 100%) text,
            but in those same conditions I struggle with V4FEC to get frames decoded.

            Have we reach the point of diminishing returns with effort on the
            performance of V4FEC?

            But then again, perhaps I should just quietly wait and see.

            73 and thanks again,
            John W2KI

          • Phil Williams
            Many casually associate the “quality” of the signal with its strength....one factor but path distortions (multipath, doppler etc) are actually more
            Message 5 of 8 , Jan 2, 2011
            • 0 Attachment
              "Many casually associate the “quality” of the signal with its strength....one factor but path distortions (multipath, doppler etc) are actually more critical than just signal strength."

              Could not have said the above better myself.  Everyone to burn the above in to the middle of their forehead.

              Then....go buy a mirror from the local market...philw de ka1gmn


            • John Hirth
              Thanks for again sharing your plans for FEC and ARQ. As I said in closing, I ll quietly (and gladly) stand by as we try to help your efforts, however
              Message 6 of 8 , Jan 2, 2011
              • 0 Attachment
                Thanks for again sharing your plans for FEC and ARQ. As I said in
                closing, I'll quietly (and gladly) stand by as we try to help your
                efforts, however meagerly.

                73, John W2KI
              • W6IDS
                Happy New Year Rick, to you and yours. Yes, the chat FEC seems quite stable to me per se. You don t need to wrap the ARQ in ribbons or wrap or anything. Just
                Message 7 of 8 , Jan 2, 2011
                • 0 Attachment
                  Happy New Year Rick, to you and yours.
                   
                  Yes, the chat FEC seems quite stable to me per se.  You don't need to wrap
                  the ARQ in ribbons or wrap or anything.  Just put it where the tree was and
                  then step back out of the way.
                   
                  Howard W6IDS
                  Richmond, IN Em79NV
                   
                  <tapping fingers, glancing at watch - AGAIN!>
                  ----- Original Message -----
                  Sent: Sunday, January 02, 2011 10:10 AM
                  Subject: RE: [V4Protocol] What's happened

                  All,

                  The current version appears pretty stable. I have been working on the ARQ mode and had to make some significant changes there. Of course the standard holiday, parties etc.   Hope to have a rev out this week with ARQ enabled.

                   Rick KN6KB


                Your message has been successfully submitted and would be delivered to recipients shortly.