Roy Lewallen wrote:

C = 160 * pi^2 ~ 1579.

This is exactly 4 times the radiation resistance of a short dipole with
linear current distribution (i.e., one without a top hat), since the
average current is twice the amount for the same radiated power.

Since the resistance is inversely proportional to the current,
shouldn't you have divided by 4 instead of multiplying by 4?
--
73, Cecil http://www.qsl.net/w5dxp