Hi Andy, Ron,
Ron, good point to check the T/R switching, but check all switching diodes: the RX and TX.
My 50W (QCX) PA is also built with the 20m LPF.
I have just tried?quickly driving it with the QMX and the VSWR measured with the QMX was between 1.7:1 to 2.0:1 for 40m to 20m band. The driving RF power was around 4W.
However, when the PA is unkeyed, it means in RX position, than you should have the thru connection to the output so to the dummy load. The VSWR in this case is not 1:1 but it is not unbearable either. This is the R.L. what the receiver feels.
In addition the internal input 3dB attenuator is built as PI attenuator (330 | 22 | 330 Ohm) for 60 Ohm to 60 Ohm, so there are also some parts of a dB of inherent R.L. difference.
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73 Bojan S53DZ
