Amateur Extra › E9 Antennas and Transmission Lines › E9E05
E9E05
What Yagi driven element feed point impedance is required to use a beta or hairpin matching system?
Pick an answer to check it.
Answer: A. Capacitive (driven element electrically shorter than 1/2 wavelength)
The hairpin acts as an inductor across the feed point. It needs a capacitive feed point, so the driven element is made a little shorter than a half wavelength.
Tip: Hairpin needs a slightly short, capacitive element.