What is the approximate feed point impedance at the center of a two-wire half-wave folded dipole antenna?

Explanation

A folded dipole carries the same total power but divides the current between two parallel conductors, which steps the feed point impedance up by a factor of four. Four times the roughly 72 ohms of a plain half-wave dipole is about 300 ohms, which is why 300-ohm twinlead suits it.