Sunday, July 28, 2019

Flex vs. Apache Labs with Windows update 1903

Posts to the Flex forum had me dreading the newest update for Windows 10. Other major Windows updates have caused problems requiring owners to uninstall and then reinstall SmartSDR, the software that runs Flex transceivers.

Not as simple as it sounds but not too difficult, this procedure is a 10 or 12 step process that takes 30 minutes or so. I've had to do it before and don't mind the process.

But this time, with update 1903 from Microsoft, other Flex owners are reporting that they've had to reinstall a fresh version of Windows 10, then install SmartSDR after all Windows updates have completed. And then reinstall all the other programs that had been on the computer.

The problem, specifically, is that the DAX drivers (digital audio from the Flex - ie, the virtual audio cables built into Flex software) get renamed and or conflicted and, either fixable or not, from one user to the next without having to reinstall Windows.

I have two separate SDR set-ups and decided to do the Windows update to each of them. The desktop PC runs the Flex and the laptop is for my Apache Labs transceiver, running OpenHDSDR mRX (with Virtual Audio Cables) to operate that rig.

Over the years, with numerous Windows updates, I've never had the least little problem post-update with the Apache Labs rig. So I updated that PC first, then started OpenHDSDR mRX. It connected with the rig, no problem. Opening WSJT-X to test digital audio between the two programs proved that everything was working properly.

On to the Flex computer...

This is where the good news ends. Evidently, the drivers for DAX audio get renamed during the W1903 update. This should be an easy fix, albeit a PITA. I'll tinker with that tomorrow and, if I can't get it all to play nicely, will open a help ticket with Flex support.

Two things bother me:

  • At least one Flex owner had to reinstall Windows, even with support from Flex.
  • Why does my Apache Labs software come through these updates without a problem, yet Flex's SmartSDR almost always has issues?

I get that Flex can't control what Microsoft does, but OpenHDSDR mRX is unaffected - isn't there a way to mimic the immunity of OpenHDSDR mRX's virtual audio cables into Flex's DAX?

Hopefully, my fix will be easy and I'll be able to accomplish it myself via Device Manager. If not, I'll let Flex TeamView into my PC and fix it remotely as they've done for others.

Part of my reason for having gone the SDR route in 80% of my station is because it is a learning opportunity and one that I wanted. I find the technology interesting - more so than standard QSO-making much of the time, even when that QSO-making involves working new DXCC entities.

New developments are happening all the time and the price of admission is dropping lower and lower. Look at SDRplay for an example of the seemingly endless applications of a radio available for less than $150 - and with performance specs that, until recently, were associated only with rigs costing 10X as much.

However, if a Windows reinstallation will be required to make my Flex work, it'll be time to find a new home for it and look at Apache Labs for a non-QRP replacement. No radio is worth a potential PC refresh just because a Windows update was initiated.


  1. Like you, it seems likely far-fetched that a clean install of Windows would really be necessary to fix a driver issue. Seems like a re-installation is the refuge for tech support that can't really help someone with a proper fix. Windows may be a complex platform, but a true root cause determination should produce a procedure that can be followed to restore proper functioning without resorting to just pulling the plug and re-loading everything.

    I agree that's a frightening thing to contemplate, and should never be the solution, unless the system has been hopelessly scrambled. Never to fix an application installation issue.

    Please keep us updated on this.

  2. Keep us all appraised.

    Can Flex comment on the issue?
    I wonder if the Flex software creates the virtual audio cables in the user space as well as the system profile. This would cause the software to be modified by admin or elevated users, but not a regular user. I have witnessed this with software that requires system resources that are supposed to be duplicated in the Users Virtual Store, but are deleted as part of the update/upgrade.


    John McGrath

  3. The problem is fixed. It turns out that several of the audio devices (DAX drivers included among them) get renamed with the 1903 update. So there are two solutions: either uninstall SmartSDR (including DAX drivers) and reinstall or go into Settings> Control Panel> Sound and rename the drivers to their original names. Here is a before and after photo:

    Everything is working properly now.

    I was on the verge of doing a fresh Windows install with the idea that it would clean up all the fragments left of other programs after uninstalling them, clean up the registry, etc. Then I found the photo above posted by K6LJ.

    Some further info FWIW: both my RSPduo and the mcHF continued to perform normally (with WSJT-X, etc) after the update. Only the Flex DAX drivers were affected.

    I wonder if it's good PC practice to do a fresh Windows installation every 2 or 3 years?

    73 - John

  4. From Joe N3HEE:

    I just updated one of my Windows 10 machines to 1903. Had same issue with DAX IQ drivers. It was a simple task of renaming the mislabeled DAX IQ devices in the Sound Control Panel as shown above.

    For example I saw this in the Sound Control Panel after Windows 1903 update ....

    DAX Reserved Audio RX 1
    FlexRadio Systems DAX IQ

    It should be renamed to ...

    DAX Reserved IQ RX 1
    FlexRadio Systems DAX IQ

    In other words all (DAX Reserved IQ RX #) and (DAX IQ RX #) labels in the Sound Control Panel need to be paired with (FlexRadio Systems DAX IQ). Whereas (DAX Reserved Audio RX #) and (DAX Audio RX #) needs to paired with (FlexRadio Systems DAX Audio).

    Just look for the mismatches and rename accordingly.

  5. One thing that is really a mystery to me is why some of these types of driver problems are so inconsistent. One Windows 10 installation will have lots of issues but another will update perfectly fine. If the update begins with an otherwise up to date Windows installation and the current DAX drivers then it seems like every update should either fail or succeed. Just not some of each!

    I have been fortunate I suppose. Since getting my Flex 6400M last fall I've gone through a couple of Windows 10 updates and the Flex 2.x to 3.x SmartSDR update and everything has gone smoothly.

    Tim N9PUZ

    1. Yes, why the inconsistency? I thought I would be one of those who got away with not having any problems with this update since that was usually the case before...but not this time. Fortunately, the fix was easy although not provided by Flex tech support but rather by a forum participant.

      73 - John