LF: Great LF prop died at 0015 UTC!

["Dexter McIntyre W4DEX" <dmcintyre@att.net>]

Starting before sunset here in NC Mal's signal was strong for several
hours.  See this screen shot:

http://www.qsl.net/w4dex/KEV29Dec01.jpg

At about 0015 UTC Mal's signal stopped.  Perhaps he went QRT.  But look
at the other signals.  Even the strong loran line at .921 went faint. 
Not sure who or what is at 922.75.  Check this screen shot:
http://www.qsl.net/w4dex/KEV30Dec01.jpg

KD4RLD was listening to a BC station on 163 kHz which was very strong
but also vanished about 0015UTC.  What happen to the great propagation?

Dexter