In an RF communication system, aspects of constant or proportional to absolute temperature biasing for minimizing transmitter output power variation may comprise configuring at least one current source to provide a temperature dependent current, where the current may be constant with temperature or vary proportionally to absolute temperature. The wear monitoring system may have at least a first radius sensor configured to generate a first signal indicative of a change in radius of at least one idler wheel, and a displacement sensor configured to generate a second signal indicative of a change in displacement of a track tensioning actuator. Canisters may also be removed from the front of the enclosure, thereby allowing dual access to a nonvolatile storage device. In addition to providing a wide variety of music, news and sports for drivers, the system provides a global listening audience for companies that wish to advertise to a broad spectrum of people. Furthermore the invention also concerns a method for diagnosing allergic hypersensitivity and for monitoring the response to a hyposensitization therapy.