Roy Lewallen, W7EL wrote:
"Sorry. I take issue with this. The radiation resistance as universally
used in the professional literature "is" a distributed radiation
resistance---."

One definition, but not universal by any means.

Terman is as professional as needed for most purposes. Terman defines
radiation resistance and the custom for stating it on page 891 of his
1955 edition:
"Unless specifically stated to the contrary, it is customary to refer
the radiation resistance to a current maximum in the case of an
ungrounded antenna, and to the current at the base of the antenna when
the antenna is grounded."

Terman`s definition is unequivocal and useful. It is echoed by other
authors.

Kraus says on page 182 of his final 3rd edition:

"Ro = 60 times the intergral, zero to pi, of the square of Cos [(beta
L/2) cos theta] - cos(beta L/2) / sin theta, d theta

Where the radiation resistance Ro is referred to the current maximum.

In this case of a 1/2-wave antenna, this is at the center of the antenna
or at the terminals of the transmission line (see Fig. 6-7)."

The solution for a thin dipole yields 73 ohms.

Of course, the impedance of a standing-wave antenna varies continuously
along its length due to interaction of waves traveling in opposite
directions. For practical purposes, we can define Ro as the resistive
part and transform its value to the antenna input terminals if these
don`t correspond to a current maximum.

Best regards, Richard Harrison, KB5WZI