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6000 TX audio distorted after being on for a few days.

Hugh - VA3TO
Hugh - VA3TO Member ✭✭
edited November 2020 in FLEX-6000 Signature Series

I have a Flex 6300 running SmartSDR v3.18 that I mostly use for remote operation on digital modes (FT8, MSK144) so I leave it on 24-7. After a few days I have to reboot the radio because the TX audio becomes distorted just from sitting there being on. This isn't a new problem, I've been putting up with it since I got the radio 3 years ago (even under v1 & v2 software) and but it has become annoying enough that I would now like to resolve it.

FTR the radio was sent to Flex about a year and a half ago so it has been through their tests with no faults found.

Has anyone else observed this ? Try leaving your radio on unused for a few days then attempt to use it on a digital mode while paying attention to the TX audio.

I know enough about software to be dangerous and this seems like a stack or other buffer overflow to me. Is Flex aware of the problem and are they working on a fix ?



  • Walt
    Walt Member ✭✭

    I have experienced the same thing for the same amount of time. Finally sent in a trouble report over a year ago along with some on-air WSPR results showing that when it went distorted, remote stations would report me two or three times in the same time segment with carrier frequencies about 30 cycles apart. Flex gave me a ticket number starting with a 7xxx that I long ago threw away since I got tired of the 'reboot' solution and have moved on. I now use the 6500 I bought in 2014 only as a spare receiver.

    Good luck


  • bahillen
    bahillen Member ✭✭✭

    I have the same problem. DAX is the culprit in my case. 6600 using SmartSDR 3.1.12.

    AfterFT8 running for several days the TX audio starts to see a few pops on the waterfall. It gets more frequent over the next 30 minutes when it fills up the transmitted spectrum.

    it can be immediately resolved in the DAX window by clicking the TX button OFF and ON. It is then good for a couple days. I have established a procedure of clicking it off and on every day or two and don’t have issues. also I usually use the TX monitor and can hear the distortion when it occurs

    I also submitted a help desk ticket a couple years ago and it was on the backlog list. I was told that DAX was written by an outside software company.

    I can’t say it is not affected by 3 rd party software like wsjt or SliceMaster but doubt it. Behaves like a memory leak




  • Patrick
    Patrick Member ✭✭✭

    I have experienced this also. Over time DAX gets corrupted in some way. Could be memory leaks, or buffer over right runs based on time without a reset. Not sure why Flex does not see this. I now shut down every nite after end of operation and do not experience this problem. There are other problems that result from long term on operation, such as complete lock up, requiring a crash down, then a factory reset and restoration of profiles. I wish Flex would take this seriously. Yes, the software runs great as far as what it was designed for, but there are issues with reliability.

  • bahillen
    bahillen Member ✭✭✭


    are you monitoring this thread? What is planned for DAX?


  • Patrick
    Patrick Member ✭✭✭

    This problem has continued to occur even with the replacement of my computer and upgrade from 6500 to 6700. It is not Ethernet related as latency and errors are none existent. Only dropped packets happen on band change or mode changes. Only long term operation, and not operating for 4 + hours causes this problem. As I stated only solution for reliability is doing a shutdown. Power remains on to the radio to keep the clock and GPSDO up 24x7. Premium radios should have premium reliability.

  • Bob N7ZO
    Bob N7ZO Member ✭✭
    edited November 2020

    Although Flex has made some slight improvements to DAX reliability over the years, I still see this problem frequently here. I have gotten into the habit of restarting DAX daily or every time I sit down at the radio. This is a problem well known in the Flex community and it is a shame that Flex doesn't fix this.

    To make restarting DAX easier, I use a batch file. See here: https://community.flexradio.com/discussion/comment/20508607#Comment_20508607

    73, Bob, N7ZO

  • In terms of distortion on transmit audio... I have it in general and can't get rid of it..... Try some hard "E" 's .... Distortion is wicked. That's on my Flex 6400. A friend of mine runs a Flex 6700, and another a 6400, all with the same distortion issues. I just shake my head, be the last Flex I ever own. Not sure if it's an Algorithm issue, or a hardware issue in these radios, but throw on a pair of headphones and listen closely to the sizzle/cracks in the audio, not broadcast quality that's for sure.

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