In article , tommyknocker
writes:

Yes, that's the impression I got too. Somewhere on the net I saw a
diagram of WWVB's coverage area-it covers all of North America at night
and just a little area of the Rockies during the day.

One can find out just about anything about WWVB by going to:

http://www.bldrdoc.gov/timefreq/stations/wwvb.htm

Once there, click on the yellow buttons below the photo of WWVB
towers against an awesomely forbidding dark sky. Click COVERAGE
for the best signal strength around the clock...which is 0600 to 0800
UTC. Lots of other fascinating information under those buttons,
especially on metrology of time and frequency...plus one 1.15 MB
paper from 2003 on Radio Clocks under the Publications for Time
and Frequency page.

Note: NIST must have played with their website since I was there
last in 2003. Getting to the time-frequency stations takes more
button guessing and pushing since then from the main one. :-)
I was just at the link above and it worked on 12 Mar 04.

Len Anderson
retired (from regular hours) electronic engineer person