[Elecraft] When Transmitting on FT8 - KPA500 has issues - KD8ZYD

[Fred]

I’m going to try and answer all the questions that have shown up in this
thread.  I really appreciate all the ideas and things to check.  I do have
a day job (7 years to go) so I only have time to play with this at night
and try and debug.



I drive my KPA 500 with somewhere between 20 and 25 watts from the K3
depending on the band



I do not get any faults on the KPA 500 or KAT 500.



The fault log on the KPA 500 was clean



I will test with WSJTx in the Tune mode and report back.  I will check the
sound card settings to make sure they are correct



My computer is home built, i5-4590 CPU @ 3.3 GHz, 16 GB Memory, SSD Drive,
decent graphics card



Andy, K3WYC posted - I have not looked at the video but this sounds very
similar to a problem I have seen.   In my case HDSDR sound output had
spontaneously changed to TS-590 TX CODEC creating a feedback loop through
the PC.  Break the loop and all is normal.  – Question, how do you break
the loop?



All connections are good.  When I built the K-Line, I made all new Co-ax
cables with Amphenol connectors.  All Elecraft cables are less than 2 years
old.



I need to add a ground from my MFJ Anderson Power Poll connection strip.
Everything else is grounded to a ground bar, to a 10 foot copper rod
outside the house, connected to another 10 foot copper rod at my tower and
so on.



I have not tried to see if this happens at 200 watts.  I need to pay
attention to see if it happens just on certain bands, or only on my Mosley
or my wire dipole.  It never happens if I am not using the KPA 500.



Jack, W6FB if I let this go and check things as it is happening, do you
think I could damage my equipment?  That is one thing that worries me so
when it happens, I kill the transmit ASAP



I want to thank everyone in the Elecraft community for all the replies!!
Thanks a lot!!



Please let me know if anyone has any other questions.



Fred, KD8ZYD

-- 
Thanks,

Fred