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Smartlink on MacOS drop / Local operation "stuttering" issue

Smartlink is currently unusable on my Flex-6400 system for remote operation, local operation is possible but experiences a "stuttering" issue making SSB transmit audio intermittent, it is ok with CW/FT8, has issues with CAT/DAX clients.


  • Flex-6400 connected to my home network via TP-Link Wifi Client
  • SmartSDR MacOS version 2.0.19 used for radio control, CAT/DAX not enabled, Rogue Amoeba Loopback not enabled
  • 2021 Macbook Pro 16 inch, M1-Max, 32 Gig Ram, MacOS Version 12.2.1 (Monterey), location services off, with only SmartSDR running
  • SmartLink on a variety of Wifi systems
  • Home network is 1 gig symmetrical in/out of house

Description of the issue:

Whenever I try to use Smartlink for remote operation the radio is discoverable, will initially connect, will usually show the SmartSDR waterfall, but shortly after will drop the connection to the radio altogether. I am able to reconnect to the radio as many times as I want, sometimes the first connection is still registered as active by Smartlink and I terminate it via the Smartlink login process so that I always have only one login active on the 6400.

During local network operation on the 6400, the connection to the radio is moderately consistent but does periodically "stutter", losing audio. SSB Mic operation is not consistently usable with transmit audio intermittent probably due to Mac network issues. Generally CW and FT8 work, CAT/DAX have been intermittent seemingly due to issues with Loopback and/or OS inability to keep up.

My Theory on the problem:

My theory on why this is happening is that perhaps once Smartlink connects SmartSDR directly to my 6400 after login/connection, the local Wifi "stuttering" issue is seen as a network drop - disconnecting the radio and requiring a complete re-login/reconnect. Alternately, perhaps this is a MacOS SmartSDR problem between the application and MacOS?

I suspect the CAT/DAX/Loopback issues are another problem so prefer to keep them out of the picture until the SmartSDR/Smartlink issues are sorted - unless someone disagrees.

Debugging steps so far:

I am about to provide direct CAT6 cable connection to the radio instead of using the TP-Link wifi client on the theory that the issue is with using WiFi locally. This will take some time to install unfortunately. In the meantime, I would welcome any ideas on other causes and/or MacOS debugging procedures that might help me locate the issue/s.

Thanks in advance for any guidance,

73, Scott, W1MVY


  • KD0RC
    KD0RC Broomfield, COMember, Super Elmer Moderator

    Hi Scott, I think you are on the right track. WiFi is notoriously bad for the real-time needs of radio (as opposed to buffered video streaming that works well).

    One thing to try that may validate your thoughts on the WiFi, is to directly plug a computer into the radio. The local stuttering should stop completely. This won't work for testing SmartLink, of course, but could give you some insight into the WiFi issue.

  • snacey0103
    snacey0103 Member ✭✭

    @KD0RC Thanks for the quick reply. Yeah, direct connecting the the Mac to the radio sounds like a good step. The issue preventing that for the very near term is that Mac's don't have hardware network connectors anymore. I have to purchase a dongle. Ugh :)


    Scott, W1MVY

  • Ted  VE3TRQ
    Ted VE3TRQ Member ✭✭✭

    Scott, if you have a choice of WiFi frequency, use 5Gig, not 2.4Gig. I find 5G very usable, but 2.4G totally unusable. Of course this will vary on your neighbors’ use of WiFi :-(

  • Alan
    Alan Member ✭✭✭✭


    I too, use a M2 MacBook Pro. However, I use a Thunderbolt hub with a hardwired ethernet connection. I agree, your use of WiFi, may be an issue.

    Tell us more how you have your audio path set up, starting at the microphone. Have you ruled out it may be an audio processing issue within your Mac? I ask, because you report digital audio is working OK, which uses the same bandwidth, from the Mac, as does SSB audio, over your same WiFI LAN. That may isolate the issue to your Mac Audio.

    How do you know about the SSB phone is stuttering? That could also be a sign you are clipping the audio, either in the Mac or in Smart SDR. Are you getting reports? Or how are you monitoring your SSB transmission, such as using the FDX, two slice, method.

    You could configure loopback to "hijack" your Microphone, and then send the the audio to both the Mac SDR and another audio sources, such as your headphones. This gives you a way to hear exactly what your Mac Audio sounds like at the input of Smart SDR.

    Alan. WA9WUD

  • snacey0103
    snacey0103 Member ✭✭

    Hi all,

    Ok. Here is my debug status today.

    I directly connected locally to the 6400, all stuttering issues disappeared. So the Wifi is the problem for sure.

    I reconfigured the TP-Link client to connect via 5 Gig wifi and am testing that locally now. It still hiccups periodically, but as Ted, VE3TRQ stated it does seem a lot better.

    Alan WA9WUD, I know that the audio was stuttering from signal reports. I have played with audio drive levels but it seemed to be inter-related to the Wifi drops... I still have more testing and playing to do with SSB. I will play with the FDX monitoring approach this week too. I'm still learning all the capabilities of the Flex rigs...

    If things go well with the 5 gig Wifi in the next few days I may call off the installation of CAT-6, but I suspect that in the end the hardware connect method will be more reliable.... I'll let you all know.


    Scott, W1MVY

  • snacey0103
    snacey0103 Member ✭✭

    Update - I just complete 2 SSB QSO's on 40M with great audio reports. I believe that the 5 gig (802.11n) wifi recommendation was the secret for local Flexradio use. For anyone else who tries wifi connection - don't use 2.4 gig wifi to connect a Flex SDR into your local network. Thanks Ted, VE3TRQ.

    I will test out Smartlink remote connection with the 6400 connected to my LAN via wifi to see if that also works. Stay tuned.

    -- Scott, W1MVY

  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin


    As others have said, WiFi is a great tool, but it is really broken for real time streaming applications such as your radio.

    I have done the exact test you did with the TP-Link Mesh. It 'works', but it isn't usable. The WiFi bandwidth is very fractional.

    There are many ways to hardwire a radio from using CAT5e, 'PowerlIne' which sends IP stuff over the AC power line and MoCA which uses RG6 type cable which is good if you have a house already wired with Cable TV cable. In fact, a lot of Cable TV modes support it already.


  • snacey0103
    snacey0103 Member ✭✭

    Update for Monday - I have now tested Smartlink remote operation as well as JS8Call and WSJT using CAT/DAX locally all with the 6400 connected via an 802.11n 5 Gig link into my router.

    As for Smartlink remote, it no longer drops the connection - which is good. Receive is solid. Transmit, however, seems to be intermittent using the SmartSDR/MacOS FT8 application. Remote transmit seems to key the 6400 okay, but does not always record any power output - an interesting behavior. It seems that the audio to drive the rig comes from the Mac using the SmartSDR/MacOS FT8 application and is sent over the network to the 6400 - if so, then this may indicate that audio output from the Mac to the 6400 is still questionable when running remote. I need to experiment with this more.

    Local use of CAT/DAX clients is now solid too. So I feel that the 802.11n 5 Gig radio to Mac is sufficiently performant for local operation with my installation. I plan to hold off on the CAT-6 installation as that is either a lot of dirty work under my house or quite expensive to get someone else to do it for me :)

    I am wondering if part of the 2.4 Gig to 5 Gig local problem may be within my ARRIS BGW210-700 network router supplied by AT&T - perhaps the connectivity between the 2.4 and 5 gig radios/network hardware within the router is insufficient. Now that I run exclusively 5 Gig between my 6400 and my Mac things are fine. Live and learn.

    Still some more debugging needed for remote operation but this is progress.


    Scott, W1MVY

  • Ted  VE3TRQ
    Ted VE3TRQ Member ✭✭✭

    The problem with 2.4G is the fact there are only 3 clear channels out of the 11 in NA: 1, 6, and 11. All the others leak into one of those, so if at least three of your neighbors are using 2.4, it is absolute that they will hold off your signal at some time, no matter the channel you use (it is, after all, a "party line"). The WiFi protocol demands that it stop and listen in order to not interfere with others, so it is inherently intermittent - isochronous it ain't :-)

    5G has many more channels available to choose from, and they are discrete, so even though the reach is lesser, it most often works better in that shared WiFi spectrum. I also agree with Mike - if you can, use a wire!

  • John KB4DU
    John KB4DU Member ✭✭✭✭

    Per Mikes recommendation a few years ago, I installed a pair of TP-Link power wiring adapters. One is connected to the router at the cable modem location and the other one at the shack. I can access the radio using smartlink, which goes through the adapters from the router to the shack without issue.

  • Hal Massey
    Hal Massey Member ✭✭

    Once you cable your Flex Radio up you can probably get away with WiFi on your MacBook Pro. I have three remote Flexes (one is at home, one is at a commercial repeater site in the Rocky Mountains, and the other is on a farm in the Northern Colorado prairie).

    I'm on 15M right now with the Rocky Mtn remote via MacSDR, a 2019 PowerBookPro using wireless. No issues. Also 1GB sym here at the house.

    Best wishes and best regards / WB6NNR

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