Bzzarre DAX issue

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  • Problem
  • Updated 2 years ago
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I am running two instances of WSJT-X and started having some issues were the instance on Slice A and  DAX channel 1 was having a hard time decoding.  I could restart everything and it would work fine briefly and then stop decoding. I think on the second or third 15 second interval.   The signal showed on the waterfall but the Band Activity window would stop having new stations added.

After looking closely the signals got fuzzy on the waterfall. Compare the working decode below dotted line in picture to fuzzy non decoding above dotted line in the picture below.

I could put the second instance which was on slice B on the same frequency and it looked fine.

In the end I moved Slice A to DAX channel 3 and am running 2 and 3 now instead of 1 and 2.

I have switched everything around and the levels are fine. Its definitely an issue with DAX channel 1.

So before I strip it off the machine, delete the DAX channels from the device manager and start over I thought I would put a post here to see if anyone has had similar issues and an easier fix.

Rich


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Rich McCabe

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Posted 2 years ago

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Tim - W4TME, Customer Experience Manager

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Stop and restart just DAX to see if that cleans up the fuzziness.
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Rich McCabe

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Yes, it does.

(Edited)
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Bill W2PKY

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Please post your PC specs and O/S. Have you looked at the Task Manager Performance tab to see if your CPU is overloaded? It's common for individual DAX channels to become corrupt due to CPU stress. What other apps are you running on this PC?
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Rich McCabe

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Bill, too many apps to list.  CPU is far from overloaded and its about 25% with everything running including mail, browsers, etc.

But in a nutshell its an i7-4790 processor, 32 GIG of memory, SSD drives, etc.

Did not know it was "common" for DAX channels to become corrupt because of high CPU usage.  That seems odd. This is fist DAX issue I have encountered since owning a 6000 series.

Rich
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Michael Coslo

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Is one of the programs by any chance FireFox? I stopped using it after it regularly enfrf up at over 100 percent CPU Sy thst point it's frozen, but plays havoc with everything else as you can imagine. 
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Rich McCabe

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My default browser is firefox. But still only running 25 to 30% CPU total and Firefox is 2 to 4% of that.

I am trying to kill as many thing as I can.

Oddly enough it just stopped decoding on both WSJT instances and they were on channel 2 and 4. I closed DAX, reopened and it took right off.

I think I am going to remove DAX and start over.
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Ria - N2RJ, Elmer

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I suspect this is the known DAX corruption issue that some of us run into. 
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Rich McCabe

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So what is the fix?  I was planning on stripping it off, making sure the device manager is clean and reinstalling.
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Rich McCabe

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Tim - W4TME, Customer Experience Manager

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Reinstalling software will be a wasted exercise.

The DAX issue appears to be driver related in that the internal buffers suffer some type of corruption.  The working theory is that this is DPC related.  So the first thing I'd do is check your DPCs when you have all of your software running.  Ideally, you start monitoring before the corruption and then stop after it happens/  You can use LatencyMon to determine if your PC is suitable for running real-time audio processing software 

 https://helpdesk.flexradio.com/hc/en-us/articles/202118698-Using-LatencyMon-to-collect-DPC-Latency-D...
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Bill W2PKY

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My ASUS Z97A I7 4790 4Ghz will not run Win10 and DAX reliably, however, Win7 is solid. I have also found it necessary to off load Browser apps to another PC. DAX data streams must be serviced with no delay otherwise the decoding becomes corrupt. It's possible one or more of your apps are hogging the CPU now and then interfering with the servicing of DAX.
Your CPU has 8 execution units and CPU0 most likely services all HW interrupts. Take a look at CPU0 in the task manager and see if it's spiking up now and then.
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Rich McCabe

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Tim help ticket started with TXT file attached. I did it on a working DAX. Should I do it on the failing DAX?

Screenshot from program below

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Tim - W4TME, Customer Experience Manager

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The distortion started only after 3 minutes?
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Rich McCabe

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Tim, the distortion often starts after 3 decodes (45 seconds)
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Tim - W4TME, Customer Experience Manager

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Interesting.  Do you see the same behavior with other digital mode apps?  Just trying to change some variables and see if the behavior changes.
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Rich McCabe

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Tim, seemed OK with FLDigi. That is all I tried.

The Camera app is history and moved on to something else.  It  was using minimal resources so never thought about it being an issue.

The program is "AnyCam".

Working perfect now.
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Tim - W4TME, Customer Experience Manager

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Excellent.  Thanks for the update.
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Rich McCabe

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Yea could not be happier with it. Thanks for your help Tim.

Merry Christmas

73

Rich

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Dave - G3SBP

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Rich,  I have the same problem which occurs occasionally and can be on either slice.  Only cure is to shut down the Flex and re-boot! The key is the signals look flattened and then will not decode.

Dave. G3SBP.
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Cal Spreitzer

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That is bzzarre!  I've had DAX corruption issues but only on Transmit,  never on receive.  Rx still works fine and decodes are normal but TX is distorted.   When I run Latency Monitor I find there are no DPC issues.  Closing DAX and restarting fixes problem. 

Rich,  what does your TX signal look like?  is it distorted as well?

Cal/N3CAL
(Edited)
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Rich McCabe

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Official Response
I worked with Flex support with no resolution. They thought maybe a failing hard drive.

I ended up killing every non crucial application and then starting bringing them back one at a time.

Long story short, I have been running an app that monitors a couple IP cameras around my house and that is not playing well with DAX.

I am running three instances of WSJT-X and working fine.