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Internet dropouts when the DAX is running

Wolfgang Member ✭✭
edited March 2020 in SmartSDR for Windows
When I stream the DAX (just one slice), there are short interruptions (small black lines) in the scope. As soon as I deactivate the DAX stream again, the interruption is over. Does the DAX cause an huge Internet load that is too large or is this a latency problem? But that doesn't always happen.
73 de HB9RYZ, Wolfgang


  • Dudley  WA5QPZ
    Dudley WA5QPZ Member ✭✭
    edited March 2020

    If you are running on a slow network,  or via Smartlink.     I have run with DAX down to 800 KBit,  but any slower than that,  there is just not enough bandwidth..   If this is on your local LAN, and through wireless,   you need to diagnose your wireless really close.. 


  • Ted  VE3TRQ
    Ted VE3TRQ Member ✭✭✭
    edited December 2019
    It might be useful for those trying to give advice if you would describe your network. How is the radio connected? How is the PC connected? Do you use WiFi, and if so, what frequency band? What is using your DAX stream?
  • Mike-VA3MW
    Mike-VA3MW FlexRadio Employee, Community Manager admin
    edited December 2019

    How much upload speed do you have?  If you are unsure, run a speedtest and let us know the number.


    It sounds like you are exceeding all your upload bandwidth.  You can reduce your upload bandwidth by reducing the FPS and RATE settings on the client that you are using.

    We need some more data in order to give you a better answer.


  • Wolfgang
    Wolfgang Member ✭✭
    edited December 2019
    Hi All
    Your are right. Here some more information.
    It's our remote DX Station and we are using Smartlink with our Flex 6500.
    The Downlink speed at the remote site is 25 MBits/s and the Uplink is 5 MBit/s

  • Kevin - K4KWB
    Kevin - K4KWB Member
    edited December 2019
    Wolfgang, I had a similar issue and am running a new Netgear Orbi mesh, 230meg pipe coming in etc. but was still getting that line. I rebooted everything, tried new cat5 cables etc. the thing that helped me is that I loaded an older version of the software to my 6600. After that I reloaded 3.1.8, now my rtt is 1 to 6 ms. No more black lines. Kevin
  • N2WQ
    N2WQ Member
    edited December 2019
    You have the Flex, another SDR, and a webcam (plus others). How do you manage how much network traffic each device is allowed to generate and push over the internet?
  • Dave KØKQ
    Dave KØKQ Member
    edited December 2019

    I have witnessed just what you described and concur with what others have said. In my case, the black lines of dropout were caused by asking too much of the available remote site uplink bandwidth.

    Here are some ideas.
    First, in windows find a blank space in the taskbar, right click. Select Task Manager /  Performance /  Your internet connection. Mine is WiFi.

    You'll see a nice real time graph of your internet connection. 

    DAX is very bandwidth intense for my limited uplink connection at the remote site.

    The graph demonstrated this.  Alternately, I have found that VBaudio is reliable when used with WSJT-X and takes much less bandwidth, enough to make the connection usable. 

    Next, watching the graph, go into SSDR / Display /  and slide the FPS and Rate down to one. In my case the graph went from 600k uplink from remote site to 200k with VBAaudio. 

    The black lines of dropout you described went away. When on FT8 I use the graph in WSJT-X instead of SSDR graphic.

    Someone suggested testing your uplink bandwidth, you would need to be at the remote site to do that. 


  • Wolfgang
    Wolfgang Member ✭✭
    edited December 2019
    Hi All
    Thank you very much for your tips. It seems to be a Uplink-Issue, at least then, when the SmartLink bandwith indicator in the lower right corner shows red or yellow. And I got now the evidence that DAX needs a lot of bandwith.

    So I know now where to tweak.

    So I will close this "ticket" :-)

    73 de HB9RYZ

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