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Problems while transmitting Digimodes

AWeAWe Member ✭✭
has anybody else problems while transmitting over DAX/WJST-X with ticking/cracking sound? I´m using Loopback to transfer audio from WSJT-X to SmartSDR and i´m out of ideas how to solve these ticking sound while transmitting. I tried changing buffer size, LAN adjustments and many other.
I tried also a install on my second Mac but the same, both are on Catalina 10.15.6
With DogparkSDR is everything smooth.
Any ideas?

73 Al


  • K3DCWK3DCW Member ✭✭

    Would check it out, Al, but I just had a ceiling collapse that took my shack off-the-air for the time being. Perhaps someone else can offer some observations.

  • George KF2TGeorge KF2T Member ✭✭✭

    Al, I see similar results. Marcus’ DAX is apparently somewhat different than Don’s implementation. He is looking into a batch of tweaks for us all.

  • ConnyConny Member ✭✭

    I can confirm that any audio sent to my 6600M from SmartSDR MacOS DAX (using Rouge Amoeba Loopback 2.1.4) and running on a MacMini (Catlina 10.15.6) have interruptions and wide band clicks on transmission.

    Tested with the following as audio source:

    JTDX, WSJTX and "Tone generator" from NCH Software.

    Currently it's not usable for me for TX modulation.

    I'm curious to know if anyone have SmartSDR (MacOS) DAX TX modulation working.

  • George KF2TGeorge KF2T Member ✭✭✭
    edited September 2020

    I'm seeing similar effects - not to the point of unusability, but noticeable. Same setup as Conny (except 6600, not M).

    One other thing I notice is that DAX levels seem to change occasionally on startup (compared to previous shutdown).

    How is your network connection?

    I have had a good exchange with Marcus about DAX - he is using a different approach that includes I/Q signals, so it may need some fine tuning.


  • ConnyConny Member ✭✭

    I'm on a local 1Gbit/s Ethernet local /24 subnet.

    When I check the Ethernet frames I noticed DAX sent "IF" VITA frames to the radio.

    But I also noticed that the SmartSDR DAX periodically stops transmitting VITA "IF" frames to the radio. It's normally fraction of ms between these frames but then it stops periodiaclly for 200-300 ms. This seems to correlate with the drops in audio modulation. During this interruption the radio is sending VITA frames to the SmartSDR Mac OS application. Then the DAX continues sending "IF" frames to the radio.

    If it's of interest I can attach the WireShark capture.

    It's unusable to me because the modulation have audio drops every second. Once or twice an hour would be acceptable, until its corrected, but drops every second is not.

  • AWeAWe Member ✭✭
    Thanks @all for the comments. I´m also in contact with Marcus but he cannot determine this problem. No other complaints this problem, until now i´m the only one.
    @Geo, network is excellent with short cat6 cable. My Flex is beside the desk.

    73 Al
  • ConnyConny Member ✭✭

    For now, as a work around, I'm using xDAX 2.0 (10) from Mario Illgen DL3LSM.

    I use the built in CAT and xDAX seems to work fine with SmartSDR MacOS 1.3.10 (40)

  • George KF2TGeorge KF2T Member ✭✭✭

    If Marcus is watching this group - using Mario's xDAX works markedly better. More reliable, cleaner streaming.

  • AWeAWe Member ✭✭
    Using now DL3LSM´s "xDAX", for now it works very smooth, clean audio and low delay. Thanks for the great tip! 73´Al
  • K3DCWK3DCW Member ✭✭

    Check out the new update, v1.4.1, to see if it solves your sound issues. It is now available in the App Store.

  • AWeAWe Member ✭✭
    The actual update doesn´t fix it because Marcus cannot find a problem on his setup. 100% fix is using xDAX, no cracks, no ticking, little delay, very good app.
  • K3DCWK3DCW Member ✭✭

    Another update is available (v1.4.4), including fixes for DAX. Hopefully it will solve your audio issues.

  • AWeAWe Member ✭✭

    I can say this problem is fixed in 1.4.4. Great job by Marcus.

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