[cctalk] WWVB

This is kind computer related but maybe more ham radio related but I figure if anywhere, here is the place to find an answer. I have a SkyScan ATOMIC CLOCK. It is supposed to get its time from WWVB. The antenna icon that is supposed to mean it is receiving WWVB is on. Your probably wondering why I keep saying "supposed to". The clock is always wrong. Slow by about 2 minutes. Is there a known problem with WWVB? bill