The design of a digitally switched mobile radio transmitter cavity resonator operating at 909 MHz is presented. By using only two loop transitions between the cavity and two switchable TEM coaxial resonators mounted external to the cavity, a total of ten different frequencies has been selected over a bandwidth of 2.5 MHz. Cavity unloadedQwas optimised for a value greater than 13000 over the bandwidth. This was found to be sufficient for the intended applications. Switching speeds of 1.53μs and 0.8μs have been measured for the turn ‘on’ and turn ‘off’ transients, respectively. Measured and theoretical results show reasonable agreement.