 
 <prompt> If you multiply di radius of one circle by two, wetin you go get? Given di last question, write one context wey contain di answer. E fit be 1 - 20 sentences. Context: <response>: Instead, e dey often better make person get antenna wey e impedance no dey change too much over certain bandwidth. E come be say the amount of reactance wey person go see for the terminals of a resonant antenna when the frequency dey shift, like say, by 5%, e dey depend well well on the diameter of the conductor wey dem use. A long thin wire wey dem use as half-wave dipole (or quarter wave monopole) go get reactance wey dey significantly pass the resistive impedance wey e get for resonance, wey go cause poor match and generally unacceptable performance. If person use tube wey diameter be like 1/50 of e length for the element, e go reduce the reactance for the altered frequency wey no go too much, and the mismatch go dey small wey go just small-small affect the antenna's net performance. So, dem dey use thick tubes for the solid elements of antennas like Yagi-Uda arrays. 