Welcome to the new FlexRadio Community! Please review the new Community Rules and other important new Community information on the Message Board.
If you are having a problem, please check the Help Center for known solutions.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.

Transmit Issue with FT8

KF0X Member
edited October 2020 in SmartSDR for Mac
I have a Flex 6400 with the latest firmware. I have had Smart DSR for Mac for a couple months. All of a sudden, today my FT8 will not transmit. It receives just fine and works normally. I can key the transmitter normally and tune fine. However, no matter what I try, I am unable to push any audio through on FT8 to transmit. I even loaded and configured WSJT-X for Mac using Loopback. I am still unable to transmit. On WSJT-X, it works great until I try to transmit.

PLEASE NOTE: I am using SmartSDR for Mac 100% on SmartLink. The radio is located in a different location with both ends having a very solid Internet connection with low latency and low jitter. Each end is 100Mbps. Both ends are also on Comcast.

I am using a recent model MacMini. My external sound devices is M-Audio FastTrack which I know is working just fine too and doesn't have much to do with this issue anyway.

I am also using the latest version of macOS Catalina and the latest version of SmartSDR for Mac.

Any input would be greatly appreciated.


Randy, KF0X


  • Chip Swett
    Chip Swett Member ✭✭

    I’m having the same problem through SmartLink. When I was at my remote base last week running locally, it worked fine. Now that I am remote, it’s not working. Also no SSB output. Ft8 works normally on my windows client via SmartLink.

  • KF0X
    KF0X Member
    Chip, I just checked and SSB does not work on mine either. I can tune up and it works fine. My Windows version works just fine. Sounds like we have the exact same issue. I also remotely rebooted the 6400. That made no difference at all.
  • Chip Swett
    Chip Swett Member ✭✭


    Interesting. I'll keep digging and let you know if I come up with a solution.

  • Chip Swett
    Chip Swett Member ✭✭


    I got it working. After talking to Marcus, we figured out that SmartLink at the remote location was not setup properly. I had to do manual port forwarding. Now everything works properly. It didn't occur to me that SmartLink setup was a problem, because I was able to select the radio and SSDR/Mac looked like it was working...but with the limitations that you and I were experiencing. I hope this fixes your problem as well.



  • W1XYZ
    W1XYZ Member ✭✭
    I also have that problem through Smartlink and the fix is to disconnect and reconnect for me. It seems if I have had the 6400M operating locally at last shutdown, I need to do two disconnects and reconnects, then everything works. Is it my network? Maybe so, but why. Once it starts working it is stable and good. de W1XYZ
Sign In or Register to comment.