Distorted signal

AH0U

My 6700 seems fine when I click on test in SSDR but when I transmit in WSJT I get a different pattern on the screen and stations report I am distorted....Level is in the yellow at -10 or so power output is at 40 watts but something does not seem right...See the screen shots attached ,one is when I use the test button the other is when it is transmitting at 35 watts out in FT8

SSDR POWER out.jpg

SDR output.jpg

Tim K9WX

What happens if you close SSDR and restart immediately? Is your transmitted signal still distorted? I suspect your may be suffering from the the latency issue described here: https://helpdesk.flexradio.com/hc/en-us/articles/202118698-Using-LatencyMon-to-collect-DPC-Latency-Data I occasionally see a similar distortion on my setup, with my transmitted signal looking like this:

If I close SSDR and restart, my signal then looks like this and everything functions normally:

Note that my horizontal scale is much different than yours.

I have used LatencyMon in an effort to identify a responsible driver but, unfortunately, it tells me that I have multiple drivers at issue. And, I have seen the defective waveform on a virtually new, home-built PC where I know all the drivers and the BIOS are as up to date as they can be. So I just live with it; quitting and restarting SSDR always resolves the issue.

Tim K9WX

Tim K9WX

There was also a recent post here which seems to deal with this issue, but the solution suggested there is not applicable in my case as I typically don't have multiple, unused DAX channels open. See https://community.flexradio.com/discussion/8026674/dax-corruption

Tim K9WX

Bob K8RC

I have had this happen also.

Stop DAX and then restart it and it goes away for me.

The clue is when the transmit spectrum looks like SSB transmitting white noise in addition to the to "spike" of the desired signal.

bahillen

I have had this problem for years. It is a known problem and it is easy to resolve for a few days. It is an TX overflow in the DAX driver. Most users don’t see the problem because they don’t leave their radio SSDR on 24/7. I run 4 wsjt instances. It takes about 2 - 3 days for the problem to appear. Also you have to be monitoring your TX In the waterfall to see it start to appear with an increasing number of noise bursts on the waterfall. Shortly thereafter you get the picture shown above. You can hear the distortion in the monitor if checked. You can call and call, no one will respond. I have seen a couple times another station transmitting that distorted interference across the band.

You do not have to close DAX or SSDR. Just click on the DAX TX button to disable then click again DAX TX to enable. I have a process that if I haven’t operated for a day I just click DAX TX off and back on while receiving and the problem is resolved. Restarting SSDR or DAX, you lose your wsjt station information that is a real **** me off.

I was told a couple years ago that DAX was not developed by a Flex employee but developed by a provider. I don’t know if the was true or is still true.

I always keep my DAX app visible on the screen just to monitor the status of the interface. If something occurs to the audio stream TX or RX. It is quick to resolve. I keep monitor on so I can hear the distortion and monitor the waterfall in TX. I hate calling an important contact and not getting a reply because of a problem on my end.

73

Bill

W9JJB

bahillen

I don’t know if this problem affects CW or SSB but will affect 3 rd party audio interfaces. In other words digital may create a lot of load on the DAX Driver that is not seen otherwise. If anyone has seen this in other modes it would be informative.

73

Bill

W9JJB

AH0U

Tnx.... Ill keep an eye on it and do the restart process