I am experimenting with various forms of matching network to go between my 
136kHz antenna and the transmitter. It would be very handy if I had a fairly 
simple circuit analysis program with which to do the following:

Having measured the input impedance to the combined matching unit and antenna, 
then “subtract” the components of the matching network, see what I get and 
compare it with what I actually measure. I'm not always convinced that what I 
measure is what I think I'm measuring.

Platforms available: XP, Linux and MacOs X.

Yes, I could write something, but somebody must have done this and there is no 
point in reinventing the wheel.

Any suggestions, please?

Regards
John F5VLF