Audio issue on SDR Console

Ken Sejkora

Hello all,


I’m perplexed.  Ever since updating Windows-10 (latest feature update) about 10-days ago, I’ve been hearing some intermittent “pops” and “cracks” on the audio stream from SDRC connected to an Airspy Discovery HF+.   When listening, it’s not troublesome, and only slightly noticeable, but it is there.  Platform is Win-10, X64, 32 GB RAM, 4200 MHz Intel processor.  Although not a huge issue with casual listening, it is causing problems with decoding various digital modes.  The attached image shows a WEFAX (weather FAX) session with MultiPSK from a US Coast Guard transmitter about 10-miles away.  The upper slice of the FAX image shows the reception with SDRC, and the lower half show MultiPSK processing the audio from SDRSharp.  Running the audio through WEFAX mode on a parallel session of  fldigi yields similar results when comparing SDRC with SDRSharp.  I confirmed the volume setting, filter settings, audio buffer settings, CPU usage, etc. within SDRC, and nothing seems to be amiss.


I also have SDR++ and HDSDR on my PC, and they produce similar successful decodes  to SDRSharp.  Audio levels, mode (USB, 2.6 kHz), and filter settings are all the same across all four SDR software packages.  Considering the physical SDR connections (antenna, USB cable) were not changed between software swaps, I don’t think it’s any kind of RF or AF overload issue. I even tried an SDRPlay RSP1 with all four programs, and get identical results, that is – successful decodes with SDRSharp, HDSRR, and SDR++, but illegible FAX with SDRC.  I’ve tried reinstalling the latest beta version of SDRC, as well as the last stable version, but neither version makes any difference.  Again, SDRSharp, HDSDR, and SDR++ all produce successful decodes with both the Airspy Discovery HF+ and  SDRPlay RSP1.


I’ve also tried uninstalling and reinstalling my hardware audio drivers and virtual audio cables (VB-Audio Voicemeeter), and shut down the computer and swapped the Airspy Discovery HF+ to a different USB port, but nothing resolves the noise issue within SDRC.


Considering that the current configuration of hardware audio driver, virtual audio cable, etc. still work with SDRSharp, HDSDR, and SDR++, I have to ‘conclude’ the problem being an issue with SDRC.  I had been using SDRC successfully with fldigi and MultiPSK a few months ago, well before the recent Windows update.


I’m open to any suggestions for a solution to my problem.  Again, I’ve reinstalled/overwritten the ‘old’ installations of SDRC, but I haven’t actually uninstalled the program, rebooted the PC, and reinstalled a “clean” instance of SDRC.  I guess I’ll try that next.


Thanks – Ken, WBØOCV


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