What is a beta or hairpin match?

A beta match, commonly referred to as a hairpin match due to its physical U-shape resembling a hairpin, is essentially a shorted transmission line stub used for impedance matching. It is typically attached at the feed point of a Yagi antenna. When a Yagi is optimized for maximum forward gain, its feed point impedance often drops below 50 ohms and becomes slightly capacitive. The hairpin match acts as a parallel inductor across the feed point. This cancels out the capacitive reactance and steps up the resistive portion of the impedance to match a standard 50-ohm coaxial cable. The distractors describe other matching methods. For instance, a 1/4 wavelength section of 75-ohm coax describes a Q-section (or quarter-wave matching transformer), not a hairpin match.