What transformer turns ratio matches an antenna’s 600-ohm feed point impedance to a 50-ohm coaxial cable?
Explication
Impedance transforms as the square of the turns ratio, so the turns ratio is √(600 / 50) = √(12) = 3.46, which rounds to 3.5 to 1. The 12 to 1 distractor is the impedance ratio itself, before taking the square root.