The next time it happens please start recording the audio on the bad and good instance.? Two minutes of audio should be fine.? Send the audio files to me.

Thanks.

Dave

On Mon, Feb 3, 2025 at 5:43?PM Jack Spitznagel (KD4IZ) via <kd4iz=[email protected]> wrote:

Hi Dave,

Thanks for responding on this issue.
I am running 3 instances of fldigi but have seen it with 2 or one in the past. I can't say that other audio apps were not running before.
I was not running a web browser or other audio stream app when I took those screen shots.?
Happened again last evening, this time all 3 instances showed the same effect. Re started the instances today and all has been fine.
Just now went back to make sure the webcam and conferencing apps and such were all unloaded. There should not be anything accessing the audio subsystem other than fldigi.

In response to the suggestion by James, WA9VEZ - no it was definitely not ionospheric multipath. All fldigi instances revert to clear trace immediately on a restart of each.
As a former electronics guy (ETN/crypto) Coastie, I had to deal with multipath and selective fade on fleet broadcast and ship to shore HF circuits all the time. I am familiar with what happens (including the doppler effect on timing) and love having the specrum scope features on the new generations of SDR based rigs. All amateurs should learn to use them properly and interpret thee pattern. IMO there would be much less QRM-ing going on as a result.

Thanks again and 73!

Jack Spitznagel
KD4IZ FM19oo
Parkton, MD

On 2/3/2025 6:56 AM, Dave via wrote:

I have only seen that once on Windows 11 Jack, but not when I was running multiple instances.? It occurred when the web browser was on line with media interface operating.? How many instances of fldigi and what other applications that might be using the audio stream?

David

On Fri, Jan 31, 2025 at 7:35?PM Jack Spitznagel (KD4IZ) via <kd4iz=[email protected]> wrote:

Dave W1HKJ, All,
Running multiple instances of fldigi version 4.2.06.20 on Win 11 very successfully, however when an instance is run for a long period of time I infrequently see some distortion creep in to the WF on one (sometimes 2) instances. When this happens, decode becomes degraded or stops only on the instance where I see the pattern like trace below:



From a concurrent iteration, that same signal looks like this:



Obviously it is not the rig or the OS audio system. It has happened for several versions back. It happens with fldigi using many different modems. Frustrating, because I have never been at the operating position when it does happen. It is always resolved by exiting the iterations that show the problem and restarting them. Everything seems to run fine for quite some time afterward.

1. Has anyone else seen this?

2. Any clue what might be happening?

Thanks and 73,

--
Jack Spitznagel
KD4IZ FM19oo
Parkton, MD