DAX distortion or computer problem?

N4AB

I usually leave my 6700 on all day when I'm home, and it is usually set to JT65/JT9 digital mode. Every so often when I check the radio, to see what is going on the bands, I find that the signal video display shows the extreme distortion shown in the attached screen dump, the program is still working and decoding signals OK when this happens.

Sometimes I can "Fix" the problem by just clicking the DAX control panel, channel receive button "Off" then back "On", but most of the time I have to "Exit" the DAX program and restart the program. This is shown on the screen dump at 1330 utc (the row of red stripes). The distortion started at 1321 and the signals were cleaned up after the DAX restart at 1331.

I don't know if this is a DAX problem or a computer problem. I am not even sure where to start looking for the answer to the title question (DAX or PC).

Does anyone else see this problem? If not then the answer would have to be the PC, which is a HP I7 machine with a NVIDIA GTX745 video card.

Any input would be appreciated ,Thanks.

Al, N4AB

Tim - W4TME

Run LatencyMon (http://www.resplendence.com/latencymon) until you see the problem.  I suspect you have a DPC or other issue that is preventing the PC from being able to process real-time audio.

Cedric HB9HFN

I had the same kind of problem. Be sure to install the latest driver for your video card. Also set the power management settings of your PC to maximum performance. It disables CPU throttling. See here for an explanation: http://isboxer.com/wiki/HOWTO:Disable_CPU_Throttling_in_Windows

73, Cedric HB9HFN

Andrew VK5CV

I have had this with 1.3.8 on DAX1 only.

It can result in a whole bunch of WSPR decodes on a strong signal.

Not seen on 1.4 yet.

Andrew VK5CV