@ Donald yes you are right, I used wrong description.
As for nanoVNA, you do not put power through it. S11 (source) goes into Input side of nanaVNA and S21 into output (ANT?) end. You should see classic curve for LPF filter. QMX is not connected to the power at that stage.
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73 de Marek SP9TKW
Marek SP9TKW