A patient monitoring device incorporates a receiver capable of single-antenna or multi-antenna operation. Multi-antenna operation permits the monitoring device to take advantage of spatial diversity for improved communication with an implantable medical device in the presence of fading. However, the small size of many patient monitoring devices can make the incorporation of multiple antennas difficult. To permit spatial diversity operation, a base station includes at least a second antenna that can be coupled to the patient monitoring device. Alternatively, the base station may have one or more high quality antennas that are used by patient monitoring device instead of the antenna in the patient monitoring device when the patient monitoring device is coupled to the base station.