I think most automatic clocks are setting themselves based on WWVB, not WWV. It broadcasts on longwave rather than shortwave and uses a different modulation.

I think most automatic clocks are setting themselves based on WWVB, not WWV. It broadcasts on longwave rather than shortwave and uses a different modulation. https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvb https://www.nist.gov/pml/time-and-frequency-division/time-di...