So, for fun, I entered the circuit for the bidirectional amplifier used in the BitX20, and did some basic simulation. You can see it in the image linked below. I was trying to figure out how to instrument the schematic so I could determine the input and output impedance (and eventually things like return loss as well). Still puzzling over stuff like this. But the circuit is pretty straightfoward. I may have to build this amplifier, just for amusement.
Addendum: If you don't know what a BitX-20 is, you can find out lots by googling around, perhaps beginning with Farhan's original page. If you check out his schematic, you'll find three copies of this bidirectional amplifier.
Well, I spent the morning raking leaves in my front yard, and then went over to Target and got some new LED lights for our Christmas tree, and also got a new wreath. In keeping with our desire to decorate, I've changed the theme of my blog from its normal spartan whiteness to this holiday monstrosity of cheer. Enjoy it while it lasts, and best wishes to you all this holiday season.