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Audio crackling and popping


I operated CQWW CW remotely this weekend and noticed a significant audio popping and crackling. My remote internet service is rock solid. I even noticed the popping when testing the system at home (over a wireless hotspot) before deployment.

My setup:

Flex 6600 (v3.3.32), PGXL, SmartSDR for Mac on the remote MacBookPro; N1MM+ running local to the Flex on an i5 8th gen NUC running Windows 10. I connected to the remote directly via VPN (SoftEther) AND non-VPN using SmartLink. Results were the same either way.

The crackling and popping made CW copy difficult. I've operated remote many times and have not experienced the cracks and pops to this degree. Could this be related to the (significantly high) number of spots on the panadapter?

Thanks in advance.

Rusty - W3US


  • Martin_G4ENZ
    Martin_G4ENZ Member ✭✭

    Hi Rusty,

    My experience in CQWW CW was similar to yours, a crackling sound. I have a 6400 running v3.3.33 and I was using N1MM, SO2R with two slices. Spot timeout was set to 3 minutes and a couple of local skimmers were generating around 200 spots per minute. I had no other clients attached to the 6400.

    The crackling seemed to occur whenever "old" spots were being removed. If I halted the feed of spots, the crackling would continue whilst the current spots timed out and then everything would be quiet again. I checked the network quality during this and had had only a few (<10) dropped packets out of >2,000,000.

    In periods when the spot rate decreased, there was no crackling. There definitely seems to be a performance constraint somewhere in how the software/firmware is managing spots on the panadapter. My workaround is to "sensibly" manage the number of spots.

    73 Martin - G4ENZ

  • Tim K9WX
    Tim K9WX Member ✭✭✭

    I recently upgraded to SSDR 2.8.1 from 2.4.10 and noticed this same thing, a popping or crackling sound on CW. Although in my case remote operation is not involved. I tested and eliminated network performance and RFI as possible causes.

    I opened a Help Desk ticket, describing my experience. I received this reply:

    "We are aware of an issue with the recent version of SmartSDR where this specific behavior has been reported. Our sustaining engineering team has been investigating and working on a fix. The fix is slated for SmartSDR v3.4 that should be released before the end of the year if testing continues to progress successfully."

    I replied back, asking if there were any currently supported version of SSDR that did not show this behavior. I received this reply:

    "Yes, but the recent V2 versions (last 2 years) have a variety of software defects (some critical) that can result is the inability to create slice receivers or corrupt the SD card. We do not recommend downgrading unless it is absolutely necessary."

    I then asked if there were any V3 versions of SSDR that did not show the noisy CW behavior and which are safe with regard to SD card integrity. I received this reply:

    "Unfortunately, SmartSDR v3 is not any better in this regard; there are no previous versions of SmartSDR v3 I can recommend. If you want to downgrade, I would only suggest using v2.4.10."

    My upgrade to 2.8.1 from 2.4.10 was because of SD card corruption. So I won't go back to 2.4.10 and am holding at 2.8.1 until the promised fix is available.

    Tim K9WX

  • w7ii
    w7ii Member
    I started noticing the audio pop and crackle during CQWW CW also. It almost got to the point that listening was unbearable. I am running 6600 with a Maestro, V3.3.33. Nothing is remote, it is all sitting in front of me.
    The problem is only noticeable during the big contests when the display is full of spots and many large signals. The display will become sluggish and I hear a pop as I tune across large signals. I use N1MM to import the spots and if I turn off the telnet window the pops are still there but begin to dissipate as time goes on.
    I questioned the quality of my small network and I made a few adjustments before the ARRL 160 contest and the clicks and pops seemed to lessen. But this weekend the cracks and pops were back with the high activity for the ARRL 10m contest. This time I tried using two Maestros on the network and at times the system was nearly unusable. I use N1MM to play WAV files for CQ and the playback audio was so chopped that it was unusable. Panning across the band was extremely sluggish and as the display would **** along, the audio would click and pop.
    Today, without all the contest spotting activity, everything is fine. This is all very disappointing and I don't remember noticing any of this behavior before V3.3.33. I'm glad I'm not the only one experiencing these issues. Let's hope V3.4 comes soon with a fix otherwise I will have to go to the mall and ask Santa for a K4.

    Bill W7ii