Thanks Kevin! You are absolutely correct! It was RF getting into the computer/cable. After experimenting some more after my post, I realized that I failed to reconnect my station ground after field day. So the RF was going to ground via the PC's AC power cord. Before remembering that I failed to reattach the station ground, I was able to correct the 40 meter FT8 issue by...lowering the power output to 35%. I could go back to 100% power after just unplugging the PCs AC power cord...no more PC path to ground!
Thank you so much for your reply Kevin and best 73s!
