A radio antenna comprising a tuning component, such as a transmission line, coupled to the radiating element for providing a frequency shift from the resonant frequency, and an adjustment mechanism for adjusting the frequency shift by effectively changing the length of the transmission line. The adjustment mechanism comprises one or more extension lines, and a switching mechanism, which can be closed to couple one or more of the extension lines to the transmission line. The tuning component can also be one or more lumped reactive elements.