"George" wrote in message
...
On 10/30/2012 6:12 AM, Michael wrote:
I have two clock/radio television units. Both have battery backups.
I installed fresh 9 volt batteries and when power was restored last
night after a 3 hour outage, the clocks were 8-10 minutes fast. What
gives? I thought the batteries were supposed to maintain the time.
Just curious.


Normal operation uses the typically very accurate 60 Hz line frequency as
the time base.

At on time some clocked synced with the TV vidio. Don't know what happens
with the HDTV system.

Might check with you cell phone as those do sync with the system clocks.
Another option is one of the Atomic Clocks that sync with the WWVL signal.