This read-write TruthValue, when set to true, configures the wireless radio to use a 10MHz external reference clock instead of its internal timing source. An admin sets this when the deployment requires the radio to be frequency-synchronized to an external, more precise timing reference, such as a GPS-derived clock. For example, in a network where multiple radios must stay tightly frequency-aligned, an admin would set cwrClockRefExt to true and feed each radio the same external 10MHz reference.