# Atomic Clock Opinions Wanted

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#### Ken1

##### Member
Hi, I am interested in purchasing an atomic clock to get away from the nuisance of incorrect time (or blinking time when the 9v backup battery dies) displayed by conventional led bedroom clocks after power outages. I have looked at various atomic clocks available online but have noticed a lot of negative reviews about the clocks failing to set the time accurately as well as taking a long time to light up the time after the power comes back on after a power outage. I would like to hear from anyone who has had experience with these clocks and especially recommendations for a make/model that reliably displays correct time and also displays the time as soon as power is restored after an outage.

#### Ian Rogers

##### User Extraordinaire
Forum Supporter
I know a friend who has two atomic clocks, one in the kitchen and one in the living room.. He lives in Berkshire.

Both are always different by up to 2 minutes...

My DAB radio always displays the correct ( internet ) time...

#### ericgibbs

##### Well-Known Member
hi Ken,
What is you location.?
E

#### Externet

##### Active Member
Are you talking about atomic clocks or about radio controlled clocks ? An atomic clock will seriously upset your wallet. A radio controlled clock receives the time from a remotely located real atomic clock. A trickle charged rechargeable backup battery for the latter should bring the latter to negligible error.

#### MikeMl

##### Well-Known Member
I have a couple of self-setting, ceiling projection clocks here in Arizona. They receive standard time signals from WWVB in Ft. Collins, Colorado, and re-sync automatically after power outage.

Wouldn't have to play 20 questions with you if you had simply put in your location when you registered for this web site!

#### AnalogKid

##### Well-Known Member
The radio controlled clocks are very sensitive to position - antenna position and the location of the clock in the US. In Ohio, my Radio Shack clock (60 kHz) will not set no matter what floor or window direction, but my decades-old Heathkit (10 MHz) works perfectly anywhere on the second floor. OTOH, my Casio radio *watch* sets correctly every morning at 3 am while on my desk in the basement.

There are web sites detailing active antennae design and construction to help improve reception.

Because they are so finicky, I recommend buying locally if possible.

ak

#### jpanhalt

##### Well-Known Member
I got this one in 2016:

eBay at $5.00 It is accurate to within a second compared to NIST time. PC time (Internet time?) as I write this is about 2 seconds faster. It just sits in a first floor window and hasn't been touched. Seller was "coolproducts4u15" but he has not been active recently. No brand on the clock. Dimensions are roughly 72 mm X 107 mm X 16 mm. There are so many offerings that purchase is probably a hit or miss proposition. My criteria were good looks, size, and cost. John #### audioguru ##### Well-Known Member Most Helpful Member The electricity in my city fails only occasionally. When it does fail then everybody cheers. #### Tony Stewart ##### Well-Known Member Most Helpful Member 10MHz OCXO's are << 1 e-10 and tuned to a <<1e-11 to 1e-12 reference while there are roughly 3 x10 e7 seconds per year.$400 new EBay ? cheap Usually come in counters with this option

my VLF Rx design back then verified this which was cesium sync'd to US Navy VLF transmitters.

#### Externet

##### Active Member
Or, can't you use a GPS receiver for its time ?

#### dr pepper

##### Well-Known Member
I have 2 or 3 here at home and another at work, all operate very well, but then I'm less than 50 miles from the transmitter in anthorn.
You can get wifi enabled clocks these days if you have wifi, these are pretty good too (as post 2).

#### Ken1

##### Member
I am located in southern Manitoba Canada approximately 100 miles north of the Manitoba North Dakota border.
I am looking for a relatively inexpensive digital timepiece that will provide more accurate time than the old technology I have. I looked at some WWVB radio controlled clocks (atomic clocks as the sellers like to call them) but I am not particular as to what type of technology used to automatically set the time, just as long as it works at my location. Here in my rural location power outages are getting more common with Manitoba Hydro closing rural offices. Repair crews now have to travel 1 hour to get here to fix an outage; the closest office used to be 10 minutes away. This has resulted in a lot less line maintenance especially regarding tree pruning and now every time a strong wind comes up a tree falls on the line somewhere and the power goes out.

#### crutschow

##### Well-Known Member
I have a Sony ICFC218 Dream Machine Autoset Clock Radio which has a CR2032 lithium battery backup.
I've had it for about 10 years and have never replaced the battery.
If the power fails for any length of time, even days, it will come back with the correct time when power returns, no blinking display.
It even autosets for daylight time.
It's not radio controlled, I think it is just crystal controlled like a standard battery clock, since it does gain a few minutes a year, but that's acceptable to me.
That model appears to be no longer made but they may build an updated version.

#### jpanhalt

##### Well-Known Member
Assuming you need battery back-up for extended periods:

1) According to WWVB reception maps (http://tf.nist.gov/stations/wwvbcoverage.htm ), you should be able to get that station as well as I get it in Cleveland. That will give you the greatest accuracy. A "pure" atomic clock will have lapses when reception is poor, so they usually include another method to keep time during those periods (see #2).

2) A crystal controlled clock, often called a Real Time Clock (RTC), will be pretty good. In fact, many (most) atomic clocks include an RTC for time keeping that is reset to WWVB when reception is good.

LaCrosse Technology (http://www.lacrossetechnology.com/products/time/digital-wall-clocks ) is a common brand in the US. I have taken a couple apart and the insides are pretty similar to each other and to direct imports from China. If you get that brand, it may cost a little more than the least expensive direct import from China, but you might also get customer service should it stop working. My personal experience with a La Crosse wrist watch was poor. It worked for about a year and then developed a constant error of about 12 minutes and could not be reset. La Crosse was not helpful.

The choice is yours. With so many varieties of clocks being made, it is impossible to tell you a specific model that is cheap and works well. The model I described above works well, was cheap, but was not branded. A branded clock will likely cost more.

John

#### OBW0549

##### Active Member
Another thing to keep in mind regarding these "atomic" clocks which synchronize with VLF time stations such as WWVB (broadcasting at 60 kHz): their performance can be very dependent on their immediate electrical environment.

The VLF spectrum has become increasingly noisy in recent years due to the proliferation of electronic devices containing switching-type voltage regulators which produce significant amounts of EMI, and this noise interferes with reception of the time station signal. Laptop computers, desktop computers, "wall wart" DC supplies such as smart phone chargers, compact fluorescent lights and LED lamp bulbs all emit interference that can ruin reception.

If I shut down all electronic devices at my place, my LaCrosse clock re-synchronizes every night without fail; if I leave anything on, it never syncs and the time gradually drifts off at the rate of several seconds per day.

#### schmitt trigger

##### Well-Known Member
OBW0549:
I imagine that when Karl Benz, Henry Ford and other automotive pioneers looked at the then wide open blue skies, they never thought that their inventions would someday in the future, choke with smoke vast swaths of humanity.

Same with EMI pollution.

#### BobW

##### Active Member
For the ultimate coolness factor, you don't want a so-called atomic clock that's nothing more than a radio receiver synced to WWV. You need a rubidium frequency standard—a genuine atomic clock. You can get them used on Ebay for under \$200.
Search Ebay for "Rubidium Frequency Standard"
You'll get lots of hits.

#### Ken1

##### Member
I have one more question regarding radio controlled clocks. Is there a difference between the WWVB time signal here in North America and the NPL time signal in the UK? I found a clock on Ebay which I like, however it's sold by a seller in the UK and I would like to know if the radio control electronics will work here. The clock is a model PREC0019 made by precision timekeeping.

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