On Sat, 03 Nov 2012 12:27:20 +0000, Ed Cryer wrote:

Gene E. Bloch wrote:
On Fri, 02 Nov 2012 18:59:39 +0000, Ed Cryer wrote:

Paul wrote:
Ed Cryer wrote:
Drew wrote:
On 11/1/2012 12:04 PM, Ed Cryer wrote:
In our local sports centre swimming pool there's a clock on the
wall. It
keeps good time. I've relied on it for years to time myself.
However, every day at 4-00pm exactly it goes into overdrive, and sweeps
round covering many hours in a few seconds. Then it resets at just
after
4-00pm, and continues normally.

I've pointed it out to many fellow swimmers; and they stare in
amazement, raised eyebrows and a dim expression over the facial
features
and say they don't know.

The other day I finally gave in and asked at Reception what it was all
about. She told me that that was the only clock in the Centre that did
that, that they weren't interconnected and that she didn't know why.

My best guess is that it's a radio clock, and it self-adjust every day
at 4-00pm. But I've googled for "clock speeds up at 4-00pm" and the
like
and haven't found the answer.

Some one here must have met one of these things. If so then let me know
more.

Ed

Possible atomic clock of some kind?

I have a strong suspicion you're right here. Everybody else seems to
have gone for radio-control (I did myself as first guess), but look
what googling has produced.

It looks just like this;
http://www.walmart.com/ip/14-Analog-...Pearl/13443480

And then take a look at these hits for images on "Analog Atomic Wall
Clock"; there are zillions.
http://tinyurl.com/bt95lv3

There must be quite a lot of these things in use around the world. The
write-up says;
Radio-Controlled Atomic Time
Automatically sets to exact time
Accurate to the second
Automatically updates for daylight saving time (on/off option)
4 time zone settings
14'' Plastic Frame
Simple Operation: Insert One AA Alkaline Battery (not included)
After signal is received, press Time Zone button to set
Four Time Zone Settings
Daylight Saving Time Option On/Off
Manual Reset Button

Ed

According to this, that product uses WWVB.

http://www.lacrosse-clock.com/lacrosse_technology.htm

The signal strength varies through the day. So if it
was having a reception problem, you'd wait until the
signal reached peak strength, to see if the clock could
pick it up.

http://www.nist.gov/pml/div688/grp40/radioclocks.cfm

( http://en.wikipedia.org/wiki/WWVB )

Amazing it runs off one AA alkaline cell. So while
you don't have to set the time, the battery is still
going to need changing.

Paul



I find that hard to believe, too. My little Acctim digital radio clock
needs two AAs. But it also displays date, temp and phase of moon. Mind
you, I can't recall having ever changed the batts since I got the thing.

Ed

Clearly the second battery is for the moon phase :-)

Imagine the battery situation if these things had to use vacuum tubes
(valves).


I've been looking for a use for that moon phase display.
I thought it might come in useful if I ever become a Moslem or a Jew,
when it would indicate approaching Ramadan or Passover. But I had a
near-death experience some years back, and no religious awakening at all
in my narrow little life.
Maybe now, however, when the skies have been so cloud-covered for months
that it's nice to know what would be visible without them.

:-)
Ed

I thought my comment about vacuum tubes might have been enough to out
the fear of god into you :-)

The reason there are no atheists in fox holes is that they all left.

--
Gene E. Bloch (Stumbling Bloch)