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Setting of TX delay is critical to good CW keying. It should not be!

K2CM
K2CM Member ✭✭
edited June 2020 in SmartSDR for Windows
SmartSDR v1.3, F6700, Windows 7, Intel Core i7.  

When incorrectly adjusted, the "TX Delay" on the setup screen, produces bad CW keying when using the internal keyer.

A "TX Delay" setting of 15 provides good keying with the internal keyer.  A setting of 100 produces strange output that does not match the sidetone.  As an example, a string of dashes produces a string of "K"s whereas the sidetone gives a series of dashes, with the setting of 100.

Either a bad setting should not be allowed, or a warning should be displayed on the screen that the setting may cause bad keying.


Comments

  • Steve N4LQ
    Steve N4LQ Member ✭✭
    edited September 2015
    No problem on the 6300.  I assume you were listening on another receiver. Keep in mind that the sidetone and the audio from another receiver are not in sync due to latency. Try turning off the sidetone on the 6700 and listen to the other receiver.
  • K2CM
    K2CM Member ✭✭
    edited September 2019
    I listen to my keying in my K3 with the F6.7K sidetone off.  A setting of 100 produces bad keying as heard in the K3 (and heard by several hams in Broome County, NY). A setting of 15 fixes the problem.
  • Steve N4LQ
    Steve N4LQ Member ✭✭
    edited September 2015
    Wow. That's strange. I wish some more 6700 owners would try and confirm this. 
  • Ken - NM9P
    Ken - NM9P Member ✭✭
    edited June 2020
    What keying speed and delay?  What band?  What power level?  I want to try and reproduce accurately.  Could you be getting RF back into your keying line?  Is the TX delay you are referring to the slider on the CW panel or the one in the Setup pull down tab?
  • K2CM
    K2CM Member ✭✭
    edited September 2019
    I am using my K3 to listen to my CW signal.

    The issue is with TX Delay in "Setup".

    "Radio Setup", "Setup", Transmit","TX Delay" - set value to 200 and listen in another receiver.
    Keying Speed=25WPM
    Power out is about a watt
    Also happens on high power
    Happens on 7.040, 14.020
    Delay on the Panadapter screen CW panel set to zero 
    Sidetone on or off, doesn't matter.
    Breakin, Iambic Selected (A or B....doesn't matter)


     A Value of "200"  - A single dash is not transmitted...its missing, and transmitter output does not match the sidetone.   My keying under these conditions is so bad that it is unintelligible.  

    A Value of "100" and the dashes sound like dots

    A Value of  "50"  and the dashes sound like poor quality "K"s.

    A Value of  "20"  the dits are shortened.


    If I set the Transmit Delay to zero, my keying is perfect as heard in my K3.  Since I can operate on high power with good keying with a TX Delay of zero, I doubt that the problem is RF feedback.

    I have removed all of the SmartSDR software and drivers and reloaded it.  No change.

    Changing the keying speed changes keying in various ways; but, its still bad.

    At a Value of 0, I get good keying.  Keying gets worse as I increase the delay.

    The delay in the CW panel does not appear to affect the keying.






  • Steve N4LQ
    Steve N4LQ Member ✭✭
    edited September 2015
    Oh...That delay! :*)

    According to the manual: 

    "The TX Delay will have a negative impact on QSK operation. If the intent is to operate QSK then Delay should be set to zero."
    So try adding some delay from the panandapter if you want to use TX delay in setup.
  • K2CM
    K2CM Member ✭✭
    edited September 2019
    Well that explains it! Problem solved, set to zero, all works well! Thanks!

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