dansawyeror wrote:
Roy,

Thank you. My first objective is hopefully relatively simple. I would
like to determine resonance and measure Z. In order to do that I will
use an HP 8405A and directional couplers. Your suggestion is to practice
that on known antennas. That makes sense. Given that I have relatively
good generators and can measure forward and reflected signals at the
antenna, is that sufficient to measure model impedance?

Provided that you can measure phase as well as amplitude, both with
adequate accuracy, and know how to establish a reference plane by either
calibration or calculation. It's not simple.

Roy Lewallen, W7EL