I don't know about high quality 40dB attenuator, but I quickly built the AE6PM power tap and additionally an attenuator of 20dB (68/270/68ohm). Total 60dB. And then I ran my 3 Watts through that setup. New shot is here:
Indeed it looks much nicer to the eye, but the verdict is about the same. 2nd harmonic about 40dB below the fundamental. That is not good enough, right? FCC says 43dB?
And of course I had to examine my QDX high band also with 30M added, see this one:
About 38dB below the fundamental.
Now, to make things realistic I added a Z-match inline with everything i.e. QMX 3W @ 30M > Z-match tuned to 50Ohms at 30M > 40dB power tap > 20dB attenuator > tinySA. And then I got this one:
52dBs difference between the fundamental and the worst harmonic. Is that good enough? I have two QDX:s and one QMX and each of them have their own dedicated Z-match. I never run them without.
If the Z-match will do the trick I'm happy! Should I be? Will FCC still come and knock on my door if I visit the US?
Anders
