The rigorous formula for the input impedance of a symmetrical, cylindrical antenna as derived by Hallén is used to obtain complete tables and curves for the input resistance, reactance, impedance-magnitude, and phase angle as functions of the variables h/λ and a/λ. Here h is the half length and a the radius of the center-fed antenna. Expressions are derived for the maximum input resistance and for the resonant and antiresonant lengths. Curves are shown for the input resistance of resonant and antiresonant antennas as functions of a/λ.