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Ssdr TX-Delay Video

Steve N4LQ
Steve N4LQ Member ✭✭
edited June 2020 in SmartSDR for Windows
This video shows the effect of TX-Delay on the transmitted signal https://www.youtube.com/watch?v=_B2S5pew0pg&feature=youtu.be

Comments

  • Paul Christensen, W9AC
    Paul Christensen, W9AC Member ✭✭
    edited February 2017

    It's more serious than shown on the video.  See photos below.  When the 6700 Tx Delay is set to the default 0 ms and CW Delay is 0 for full QSK, we now get the first waveform that shows hot-switching of the trailing edge.  This may be in the RF or DSP domain, but it's still a hot-switch timing error. 

    The second image shows CW delay at 17 ms and TX Delay staying the same at 0.  It did not look like this in prior SSDR releases.

     

    image
  • Paul Christensen, W9AC
    Paul Christensen, W9AC Member ✭✭
    edited February 2017

    Below with 17 ms of CW Delay added.  Blue trace in both screens is the key line.  The onset of the rising pulse is the key closure.  10ms horizontal divisions.

    Paul, W9AC

    image

  • Paul Christensen, W9AC
    Paul Christensen, W9AC Member ✭✭
    edited February 2017

    Next, for those thinking we need to have TX Delay higher than 0 ms, I set it to 15ms.  The keyed waveform is delayed by the proper amount of 15ms, but now "dit shortening" occurs and the trailing edge of the waveform is still cut. 

    The problem is not so much the dit shortening as that is discussed in the manual when Tx Delay is used.  The main problem is the truncated trailing edge that is causing severe key clicks.

    Paul, W9AC 


    Theoff.  image

  • Al_NN4ZZ
    Al_NN4ZZ Member ✭✭✭
    edited March 2017
    Paul,
    Thanks for the traces, they really help.  

    I'm trying to extrapolate for my settings using an amplifier TX Delay = 15 and CW Delay = 200 for semi-breakin.  It would seem that would avoid the hot switching problem and the element shortening problem also.  Do you agree?

    Regards, Al / NN4ZZ  
    al (at) nn4zz (dot) com


     
  • Ken - NM9P
    Ken - NM9P Member ✭✭✭
    edited June 2020
    Excellent, Paul.  
    I was getting ready to request that someone with a scope could make those exact tests!  
    Thanks.
    Can you run an additional few to document the changes made if TX Delay and CW Delay are both altered, as Al is suggesting?  What are the timing break-points.
    FOr now, I have been calling it a "timing inversion" where the cut-off time is not compensated with the TX Delay adjustment, especially if the CW Delay is shorter than the TX Delay.

    Thanks again,

    Ken - NM9P
  • Ken - NM9P
    Ken - NM9P Member ✭✭✭
    edited December 2016
    Also...
    Is there any difference in effect with the CW speed control setting at the three different "threshold" speeds that have been reported....?

    Ken - NM9P
  • Paul Christensen, W9AC
    Paul Christensen, W9AC Member ✭✭
    edited November 2016
    Ken,

    I tried to, but there are too many moving pieces between CW Speed, TX Delay, and CW Delay.  Also keep in mind there are three CW waveform "break points" that occur at 5-19 WPM, 20-29 WPM, and 30+ WPM.  The Delays affect these break points differently.

    The matrix just gets too big for the limited time I have. 

    Paul, W9AC
  • Paul Christensen, W9AC
    Paul Christensen, W9AC Member ✭✭
    edited November 2016
    Al,

    Those settings would normally be fine.  Using any any modern amp with either PIN or vacuum relay switching -- and/or perhaps a reed relay on the input, a TX Delay setting of 0 should work well.

    Based on what I'm seeing with v1.3 and my 6700, I would absolutely validate amp timing with a scope until we know more. 

    Paul, W9AC
  • Steve-N5AC
    Steve-N5AC Community Manager admin
    edited June 2020
    We reproduced and found the issue here are we are working to correct it.  We will release the fix in the upcoming 1.3.x point release as soon as we have it ready. 
  • np2g
    np2g Member ✭✭
    edited November 2015
    looking forward to this correction

    click click for now


  • Ken - NM9P
    Ken - NM9P Member ✭✭✭
    edited December 2016
    Wonderful! Thanks.
  • Brian - AE0P
    Brian - AE0P Member
    edited September 2014
    Steve,

    These timing issues are of a concern to many of us, but the "work-a-round" of proper settings are not well defined and clear for the variety of models, cw speed, amp delays, cw delay... etc.  
       
    1.  Please list for us the definitive, proper settings for release 1.3 so we can feel assured and confident at we are free of clicks, hot switching etc.  

    2. When will point release 1.3x be available that corrects these problems?

    Tnx es 73,

    Brian, AE0P



  • Paul Christensen, W9AC
    Paul Christensen, W9AC Member ✭✭
    edited November 2016

    I'm not Steve, but I've taken many measurements.   For now, I would ensure that CW Delay is set to 15 ms. to avoid key clicks and "hot switch" effects with SSDR V1.3. 

    Paul, W9AC

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