Distorted Wave Form on Transmit

Steve W6SDM

Intermittently, when I transmit I get an even, perfect peak on my panadapter, equal on both sides. Other times I get a distorted shape. I notice this particularly on CW and on DIGU mode running FT8. Is this indicative of a bad audio setting? I have changed settings on WSJT-X and on the Flex but the pattern remains the same.

I am completing QSOs and have had good reports. When I have a distorted shape, it's the same from band to band. I have a Flex 6300.

Steve, W6SDM

Tim K9WX

My typical FT8 waveform looks like this:

Every now and then, it will look like this:

There have been a number of threads in the Community in the past few years on this issue. My recollection is that the response from Flex has been to consider this: https://helpdesk.flexradio.com/hc/en-us/articles/202118698-Using-LatencyMon-to-collect-DPC-Latency-Data

I have run Latency Monitor but have been unable to identify a single driver or even a small group of drivers that might be at fault in my situation. I've had the problem for most of the 3+ years I have had my 6600 and I saw it a year ago on a brand new computer I built myself, where I was reasonably confident all of my drivers and my BIOS were up to date.

So, this is a problem I have learned to live with. When I see the distorted waveform on either a wav file playback or FT8, I quit SSDR and restart it immediately. That has always solved my problem. I have never seen the distorted waveform on CW where I use an external Winkey.

KD0RC

Hi Tim, have you tried closing just DAX and restarting it instead of closing all of SmartSDR? If just restarting DAX resolves the issue, then that helps to narrow down the source of the problem.

I haven't come across this issue, so I can't do the experiment myself.

Neil D Friedman N3DF

I have seen this using SDR for Mac. I assumed it resulted from rfi.

Tim K9WX

Len: the answer to your question is yes, I have tried restarting just DAX, which sometimes works and sometimes doesn't. Restarting SSDR always works and is just as easy.

Tim K9WX

KD0RC

Ah, ok. Well I guess that is a good data point. Might be good to submit a helpdesk ticket with the info you presented here.

Steve W6SDM

Thanks for all the info and the reference to the article. It's good to know that I am not the only one to experience this. I am going to do some checking on the drivers and see what happens. From what I can tell, it doesn't affect my transmitted signal.