Hi Bryan,Of course the real question here is possibly why is there a mismatch  between the output of the qcx and the input of the amp? They are presumably notionally both 50 ohms. Is it really significant? Is there a fault somewhere?But... Depending on the tuner's construction and topology you may be able to get at the individual  components and measure them in place but I suspect the calibration error due to difficult connection into the tuner would be quite large.A more holistic approach would be to simply measure the effective complex impedance of the adjusted tuner as a whole. One way would be to put a 50 ohm dummy load on the output of the tuner and measure the impedance R+jX at the input. This will tell you that the output impedance of the QCX is R-jX (the complex conjugate). Now you can use any of the online pi, L or T match calculators to design a matching network that is the equivalent of the tuner.Hth.Andrew Sent from my Galaxy