Which of the following is used to shunt feed a grounded tower at its base?

الشرح

A grounded tower has no insulated feed point, so it is fed by running a wire up alongside it, bonding that wire to the tower some distance up, and driving the wire at the bottom through a series capacitor — the same topology as a gamma match on a Yagi. Beta/hairpin and double-bazooka matches both need a driven element with two isolated terminals, which a grounded tower does not have.