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What is the cause of tuning noise with V3.3.29 and can it be stopped?

I recently installed V3.3.29 in my 6600M and Maestro and the installation went without problems.

However, I notice that now, whenever I turn the tuning knob (either slice), there is a light "crackling" noise that corresponds exactly with the rotation of the knob. It is not very loud and, if this were an analog radio, I'd attribute it to a dirty sliding contact on the tuning cap. That's approximately what it sounds like. It seems to be band and mode independent. It is not loud, but it is annoying.

My rig is a 6600M with a PGXL and TGXL and except for the noise, seems to work fine.



  • KD0RC
    KD0RC Broomfield, COMember, Super Elmer Moderator

    Hi Jim, I have heard this as well. It did not start with 3.3.29, it has been there all along. It seems to be related to network quality. Sometimes I run the VFO knob or mouse wheel really fast and there is no noise. Other times it is really noticeable even at slower speeds. I have not experimented to see what happens if I plug directly into the radio (link local), bypassing the router and switch. I suspect that there will be no noise when connected that way.

    You might want to do that experiment to see if it gets rid of the noise. If it does, then the likely culprit is the router and/or switch.

  • Sergey KN7K
    Sergey KN7K Member ✭✭

    Have the same issue. Open Support ticket and provided Video and other requested information. Nothing back yet.

    Last weekend I worked 7QP Contest and besides this cracking noise with VFO tuning, there is other annoyance that can be observed during transmit starting or switching to receive. It is not there all the time, but more than 70-80 of the time - something like "eating chips" noise.

    It is a "new feature of ver 3.3.29" :(


  • DL4RCE
    DL4RCE Member ✭✭

    Have had this for 3 years now, sometimes better, sometimes really worse!

    73, Volker

  • Sergey KN7K
    Sergey KN7K Member ✭✭

    Volker, True it was there before but not at as the same magnitude. I only noticed it before during tuning over loud stations and it was intermittent. Now it is much worse.


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

    I can share a bit on what I've seen on this (more unofficially than officially)

    It doesn't show up for everyone. As an example, I can't recreate it and that is likely due to the fact that I am not doing the right thing. I do hear it when a TCP command is sent to the radio (at times) from an external device. This is something we have mentioned before.

    It might be worth sharing the type of network switches are in play since we all use those, but not the same make/model and not all makes/models operate the same way.

    I have avoided anything 'Green' or power saving. TP-SG1024D is the model I am using and I have been very happy with it. You can't really do any testing with WiFi -- my MAC is terrible on Wifi and SmartSDR - almost unusable. That isn't an issue with SmartSDR but the MAC WiFi IP stack.

    I am just thinking out loud of how we can maybe look and see if something else is better or worse. Not to deflect from anything we are doing internally of course. But, to maybe come up with a possible workaround our understand some of the root cause as to 'way'.

    I have also spent time beating the **** out of networks using jPerf.

    73 for now

  • James Charlton
    James Charlton Member ✭✭

    Thanks for the comments, although they are not encouraging.

    I just tried again to provoke the noise and now everything is quiet, so, I guess it is intermittent. My router Is a Netgear (X10, I believe) with the 6600M, PGXL and TGXL cabled into it.

    I actually installed the TGXL at the same time I upgraded to V3.3.29 so I can't say which, if either, has anything to do with the noise. But the frequency indicator on the TGXL is continually updated as the radio is tuned and that is what got me thinking it has something to do with data transfer from the 6600M to the tuner.

    Now that I know this is a mystery, I'll try to trap a bit more data.

    Thanks for the update,

    Jim AD0AB

  • KD0RC
    KD0RC Broomfield, COMember, Super Elmer Moderator

    Hi Jim, I am very sure that it is caused by TCP data to and from the radio. I built a control box (TeensyMaestro) that communicates via the Flex API over TCP/IP.

    In my original design, I was polling the radio for changes every time through the main loop. Since I used a 600 MHz Teensy board (PJRC.com) it was flooding the network with API commands at a very high rate. Turning the VFO control fast caused the crackling sound.

    I eventually realized my poor design decision, and changed the code to only poll the rig every 20 ms. This helps, but does not completely eliminate the crackling while tuning. Like your experience, I don't hear it all the time. Other times it is fairly prominent.

    When tuning via the mouse wheel, I get the same effect, but at a lower level (can't turn the wheel that fast...).

    During normal VFO knob or mouse wheel tuning, I don't really notice the noise. When testing code changes in my control gizmo, I spin the tuning knobs as fast as I can to be sure that they behave properly. This is when the noise is most evident.

    Related to this noise (I think) is a tiny gap (click) in audio every time a client connects to the radio.

    To me, this noise should be near the bottom of the list of issues for Flex to look into. It only happens during tuning, and is not that loud. It was previously described on this thread as annoying - I concur with that description.

    I should probably do some tests without the router (link local) to see if that helps or hurts.

  • Alan
    Alan Member ✭✭✭

    Len - Question

    When you say you are polling the Flex, what do you mean by "polling"?

    In my Flex API experience, I found the audio would "crackle" when I sent subscription commands, and the Flex would send a large response message. Is this what you mean by "polling"? This seems less severe in v3.3, but still present.

    I now only subscribe to wanted Flex Status messages once on the start-up of a Radio, Client, or the non-GUI application.

    This way, no more "crackle" during the regular changing of parameters. The GUI client updates the Non-GUI client via status messages, with only the changed parameter, and no "Crackle". I see that "spinning" the VFO on the GUI Client can cause some faint crackling.

    When I command a change from the GUI client like a new VFO freq, the GUI-Client does not send an updated status message but sends a response message, confirming whether the command was good. Dan at Flex told me this is as per design. For these cases, I use the commanded parameter, frequency in this example, to update the parameter's indication on the Non-GUI Client. I store the parameter in context and update the context with either the Non-GUI or GUI client's last change, for that paramater.

    Alan. WA9WUD

  • KD0RC
    KD0RC Broomfield, COMember, Super Elmer Moderator

    Hi Alan, when I say polling, I just mean how often I send queued up commands to the radio. I really shouldn't use that term in this case as I am not asking the radio for info; I am sending API commands to it. I do subscribe to the radio, slice, TX, etc etc so that I get updates automagically. This is only done once at initialization time, so I don't notice any crackling from sub commands. I do notice that every client that connects (ACLog, SliceMaster, DDUtil, TeensyMaestro) causes a little click in the audio.

    Yes, Flex made some changes a while back (before I was learning about the API) to reduce network traffic by not echoing data sent to it. So, as you note above, for volume, frequency, AGC-T etc values, your program needs to keep track of them. What I do is parse any values that come from the radio and refresh my screen and control values (even if they haven't changed). That way, the TeensyMaestro stays in perfect sync with the radio, regardless of which client made the change.

  • James Charlton
    James Charlton Member ✭✭

    Thanks everyone for the comments.

    I agree that this is not a serious problem unless, it's an indication of something bigger. But it is a curious one.

    Assuming for a moment that the noise is related to some form of data communication, why does it show up in the audio? Maybe we are hearing RF leakage from the data stream or maybe something is interrupting the audio processing somehow.

    Although my noise was easily reproducible over the weekend, it seems to have stopped when I started this thread.


    Jim AD0AB

  • KD0RC
    KD0RC Broomfield, COMember, Super Elmer Moderator

    Hi Jim, no telling from our vantage point what exactly is happening. I have had it occur, then rebooted the computer and radio and it went away. Not sure if that is another clue or just a coincidence.

  • sschrack
    sschrack Member ✭✭

    Read this post earlier today and tonight I checked and yes, I hear the tuning noise very slightly.

    73 Steve N3MX

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