Flex RTTY mode TUNE & SDC Skimmer not working

[Eric Wagner]

It appears there is an interaction between Flex SmartSDR v4.1.3 (and likely 4.1.5) and SDC Skimmer software.  I'm still using an old version of SDC v17.34.

When SDC skimmer is running and connected to my Flex 8600, SmartSDR v4.1.3 in RTTY mode, pressing the TUNE button in SmartSDR will not generate a tuning carrier.  All other modes will generate the carrier with the TUNE button. 

With SDC skimmer not running, the TUNE button function works as expected.  I have filed a ticket with Flex and reporting the issue here.  

I am not certain if this worked with SmartSDR v4.0.1.  Flex fixed an issue in v4.0.1 listed in the release notes as follows:

SMART-11364 - Fixed RTTY showing no RF carrier when using the TUNE feature.

Eric - NR4O

[UT4LW Yuri Pavlov]

Eric, I haven't encountered this effect on my Flex-6400. SDC cannot prevent you from pressing the Tune button. There is no such command in SmartSDR-API.
This is a problem in SmartSDR, possibly in the firmware for Flex-8600 only.

пятница, 2 января 2026 г. в 22:45:50 UTC+2, ewp...@gmail.com:

[Andrew O'Brien]

SDC has worked well with my Flex 8400 , bothe SmartSDR 4.1.3 and 4.1.5 and the latest version of SDC. Tune button works fine.

Andy K3UK 

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[Miguel EC5W]

I encountered the same problem with my Flex 8600 during the last contest. I thought it was just a problem on my end, but I see it happens to other people too. I ran two different bands on SO2R, now I tried to rule it out with dual VFO on the same band and the same problem occurs.

SmartSDR 4.1.5 + SDC 19.041

[UT4LW Yuri Pavlov]

I'm not sure if the FleaxRadio developers are viewing this group. You need to contact them.

понедельник, 5 января 2026 г. в 13:20:41 UTC+2, Miguel EC5W:

[UT4LW Yuri Pavlov]

You can turn TUNE mode from the New QSO window: Ctrl+T

понедельник, 5 января 2026 г. в 13:53:39 UTC+2, UT4LW Yuri Pavlov:

[Eric Wagner]

It appears that Flex support believes the failure to enter TUNE mode is due to commands SDC is sending to the radio.  Here is their response for your review, followed by the last message I sent them with my testing process and the results.  

Clearly there is an interaction between SDC and Flex radios when 2 slices are active in a typical SO2R configuration and TUNE is attempted in RTTY mode.  Since 3rd Party SW is involved, they don't believe the problem is there's to resolve.  I hop you have a relationship with Flex's support or engineering team to arrange for further troubleshooting.  My suspicion is this is most likely an error in the SmartSDR software given their previous fix for a TUNE issue with RTTY in SmartSDR in v4.0.1.  

Let me know how I could help with isolating this issue.

Thanks,

Eric - NR4O

-------------------------------------------

----- Flex's last response ----
-------------------------------------------

Ken Wells

3 hours ago

Eric,
 
Since the radio works properly when you stop SDC, there is a strong probability that this is an issue with SDC and the commands it is sending to the radio.
 
I recommend that you contact the developer of SDC and explain the issue.
They will then need to contact the engineering team to coordinate with them to resolve the issue.
 
 
Since the issue related to this support ticket has been addressed, we are closing the ticket.
 
If you have any further questions or concerns regarding this support incident, please don’t hesitate to reach out. You can re-open the ticket at any time simply by replying to this message, and we’ll be happy to continue working with you.
 
Thank you for using the FlexRadio HelpDesk.
 
73

Ken Wells, NM9P

FlexRadio, Inc.
4616 W. Howard Lane
Suite 8-860
Austin, TX USA 7872

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
----- My test process and results sent to Flex after there recommendation to upgrade to latest SmartSDR ---------
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

• 

  Eric Wagner

  22 hours ago

  Ken,

  Here is the short update.  With 4.1.5 installed.  

  I am still seeing no carrier when pressing TUNE in RTTY mode with 2 slices open(my typical SO2R config) and SDC skimmer connected and running on separate computer.  

  If I close the SDC skimmer, TUNE in RTTY mode works as expected.  

  If I close slice B and leave SDC skimmer running, TUNE in RTTY mode works as expected.  

  Here are more details on my testing.

  Before installing 4.1.5 I thought it would be prudent to do a factory reset.

  Steps followed:
  1. Power down, remove remote power control, remove DC for ~3 minutes.
  2. Factory reset by holding power button until it turned white.
  3. Allow radio to fully reboot and stabilize for about 5 minutes.
  4. Did NOT import saved profiles.
  5. Launch SmartSDR for windows 4.1.3, set Slice A to 14.089, ANT1(rx)/ANT1(tx), select RTTY mode, select SO2R_TX1 profile, select RTTYDefault Mic profile.  This all factory standard stuff.
  6. Press TUNE - carrier generated as expected.
  7. Add second slice, set 21.085, ANT2(rx)/ANT2(tx), select RTTY, select SO2R_TX2, select RTTYDefault.
  8. Slice A TX - Press TUNE - carrier generated as expected.
  9. Slice B TX - Press TUNE - carrier generated as expected.
  10. Start SDC skimmer on other computer.
  11. Slice A TX - Press TUNE - radio switches to transmit, NO carrier.
  12. Slice B TX - Press TUNE - NO carrier.
  13. Stop SDC Skimmer - Press TUNE - carrier generated.
  14. Start SDC Skimmer - Press TUNE - NO carrier.
  15. Close Slice B - Press TUNE - carrier generated.
  16. Upgrade to 4.1.5 following standard procedure.
  17. Repeat steps 5 to 15 with exact same results. 

  --------------
  Summary:
  --------------

  It appears to me that this issue will be reproducible on models with more than 1 SCU, ie. 6600 and 8600 models.  This is consistent with the feedback I've gotten from my Flex Community and SDC Forum posts.  8400 and 6400 owners can't reproduce the problem.  At least 2 other 8600 owners operating SO2R see the same problem.  Hope this helps the engineering team to isolate the problem and get it resolved.

  Eric - NR4O

---------------------------------------

End my Flex submission

---------------------------------------

[UT4LW Yuri Pavlov]

Hi Eric.

There is no doubt that running two or more skimmers causes some kind of malfunction in the Flex-8600. Flex-6600/6400 users do not have this problem. 

There is also no problem with the Tone button in CW mode when connecting any number of skimmers.

I am trying to contact the FlexRadio developers; I have sent them a letter. I am awaiting a reply.

[Eric Wagner]

Flex has been very frustrating to deal with on these interaction problems.  

Appreciate your attempt to work with them. 

73,
Eric - NR4O

[Jiri Holy]

I did further experiment and found that whenever in SDC runs anything using IQstream from API (one or more skimmers or RTTY modem), the TUNE command in RTTY mode does not transmit carrier. It doesn't matter how is TUNE triggered, the same result with SmartSDR button, Ctrl-t from SDC or TUNE sent by my dialpad through TCP API. It seems that running IQstream affected the TUNE behavior in RTTY mode. In other modes It isn't affected.

I have not available another SW which utilize API IQstream to test if it will show the same problem. Applications using DAX audio does not affect it.

Flex-8400, latest FW and SmartSdr.

Regards

Jiri OK2WY

Dne středa 7. ledna 2026 v 23:18:27 UTC+1 uživatel ur4ix....@gmail.com napsal: