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WSJT-X, Splatter, 6400

New user here. I have successfully setup WSJT-X for FT-4 and FT-8 and it is working well.

I leave my rig on 24x7 if that makes any difference.

After a number of days (2-7 days, etc.) I get reports of splatter and my TX signal is indeed very wide above the waterfall. I'm switching between 80, 60, 40, 30, 20 and 17 mostly. It happens suddenly and is not gradual at all. A power-cycle of the 6400 restores the TX signal to normal.

No amp and a simple wire antenna at this point with an MFJ-993B tuner.

Any ideas?

73 Mitch NB6Q


  • Ted  VE3TRQ
    Ted VE3TRQ Member ✭✭✭

    Might be useful to know the versions of the software involved, both SmartSDR version number and Windows version (and maybe network details also, i.e. WiFi, Ethernet, direct connect, etc).

    Some combinations of Windows and SSDR have resulted in DAX corruption. Usually it is adequate to stop and restart DAX. I'm sure others will add more information and ideas. Personally, I tend to at least restart SSDR and DAX daily - never have issues (except for those times my network acts up).

  • Bob N7ZO
    Bob N7ZO Member ✭✭

    Hi Mitch,

    It sounds like the DAX buffer corruption bug, which has been in DAX for many years and remains unfixed. A search here will produce many discussions on the subject.

    Try restarting just DAX to see if this is the problem. I also run my 6700 24/7 and have gotten into the habit of restarting DAX before every operating session. I wrote a batch file to make the restart easier.

    73, Bob, N7ZO

  • NB6Q
    NB6Q Member ✭✭

    Thank you for the quick responses. This is very helpful for my troubleshooting and reassuring that I'm not hallucinating. I check the articles about the DAX buffer corruption.

    SmartSDR version v3.1.12, Windows 10 Home on i7 dedicated to ham radio (no other apps running, no general browsing, etc.) with latest Microsoft updates

    Being a new user I have a question. How best to restart DAX when this happens again? Does just clicking on "X" on the DAX control panel achieve this?

  • Bob N7ZO
    Bob N7ZO Member ✭✭

    Clicking on the X and then restarting from the desktop icon works, but a batch file makes it a bit easier.

    See here: https://community.flexradio.com/discussion/comment/20508607#Comment_20508607

    73, Bob, N7ZO

  • NB6Q
    NB6Q Member ✭✭

    Thank you, Bob. This is great. I'm an old UNIX/Linux guy so I'll port the bat file to a cygwin bash script and it should work well. I didn't know the paths or binary layout so the batch file clarifies all of that.

    73 -mitch NB6Q

  • Bob N7ZO
    Bob N7ZO Member ✭✭
    edited April 18

    Hi Mitch,

    I just noticed the editor stripped some of the backslashes last time I posted the batch file. The correct batch file is:

    taskkill /f /im DAX.exe

    timeout 2

    start "" /d "C:\Program Files\FlexRadio Systems\SmartSDR v3.1.12\DAX" /b DAX.exe

    73, Bob, N7ZO

  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin


    When this happens, you can always listen to yourself with a 2nd slice while transmitting just to be sure you are hearing what you are being told. This is the FDX mode.

    While you could be seeing some DAX corruption, you also want to make sure your audio Level in SmartSDR is no higher than -5dbm. This is where a screen shot of SmartSDR while in TX and failure is so helpful to help diagnose.

    Also, what version of SmartSDR are you using?


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