Dr. Slick wrote:
"What`s the definition of "surge impedance" versus regular old
"impedance"?"

Arnold B. Bailey treats this better than anybody I`ve seen. But, there
are many treatments. The regular old impedance of an antenna depends
upon its termination.

Surge impedance of an antenna depends on its conductor`s inductance per
unit length and capacitance per unit length. In the antenna these are
not uniform as they are in a transmission line, and average values have
been found useful.

Best regards, Richard Harrison, KB5WZI