Radio frequency bandwidth from a far field transmitter of an implantable medical device is adjusted by controlling the data rate, the output power level, the transmitter supply voltage or combinations thereof. Adjustments are made on the basis of a sensed temperature, absence or presence of a lead or by way of wave shaping. A Surface Acoustic Wave (SAW) resonator based transmitter exhibits stable bandwidth in a temperature controlled operating environment. For temperatures outside of the range of human body temperature, the output of the SAW-based transmitter is adjusted to provide reduced bandwidth.