[Skimmertalk] WSJT-X/FT8 skimming: high PC CPU utilization limiting count of spots

[Andy KU7T]

Hi,

I am using a single Z400 PC with the new RP 16 bit SDR to skim CW and FT8.

I made a few experiments. It seems if I run 8 bands FT8/WSJT-X, I often get time periods with no decodes. If I reduce the number of bands to 2 - 3, so that the CPU utilization spikes stay below 100%, I actually get more spots out.  Last night, my number of spots in 24 hours increased by 100% after I only skimmed 40,30,20 on FT8 (10 on CW).

So, it seems to me, WSJT-X is very time critical and if it cannot decode things in time, it just drops the data. That is unfortunate, as for skimming, I would not mind waiting 5 seconds to get the decodes out, as that would probably level the CPU util spikes more... Anyway, it is what it is, and I am not sure if the WSJT-X guys would be interested in looking into an optimization like that.

I am trying to evaluate my options. I list them here in case someone sees other options or errors in my thinking.


  1.  2nd PC: PC1 skims maybe 6 bands in CW and FT8 from first receiver, PC2 skims the rest from the 2nd receiver
  2.  2nd RP: Run all FT8 bands on an RP with the Linux skimmer (not WSJT-X) and use PC1 for CW (and maybe one or two bands of RTTY)

I believe the 2nd option is much cheaper on equipment and running costs. Comments? What do others do?

Thanks,
Andy
KU7T
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.contesting.com/pipermail/skimmertalk/attachments/20190727/be036648/attachment.html>