O.T. Timers



#6

- I have a digital watch that not only sets itself from WWWB time station but takes more than one reading and digitally corrects it's own rate. Here's one reference to it. http://atomicelmer.topcities.com/clocks/sports.html I had it in Europe for 15 days and it was spot on with the BBC time ticks, then the battery failed. I had a similar watch destroyed by someone who insisted he had to set it after he changed the cell. I found a dressy watch by Casio that had a solar rechargeable cell. http://www.casio.com/products/Timepiece/Waveceptor/WV300DA-7A/ Both watches have a ready time zone change and a display of GMT. I use wall and bedside clocks set by WWWB time. I enjoyed showing the unannounced timer in the HP45 and it was great for short
time splits from 0-9, just press the number keys. Sam


#7

Here in Germany, rado controlled clocks are quite common. I have several analog ones in my home and a digital clock near my bed. The signal comes from Darmstadt and is known to be very accurate.

My computers set their time from the 'net.

Edit: See Walter's post for a more accurate description where the signal comes from. Or look here. You can search for DCF77 in Google Maps or Google Earth.


Edited: 14 Sept 2009, 3:40 p.m. after one or more responses were posted


#8

Like in other countries, the time signal here comes from an atomic clock. Ours is Cs AFAIK and is located at PTB (Physikalisch-Technische Bundesanstalt = German Weights and Measures at Braunschweig, an institute like NIST in the USA). The signal is DCF77, long wave, broadcasted from Mainflingen (some 50 km east of Frankfurt). You can receive it within 1500 km radius, provided you are not behind concrete walls or similar obstacles for electromagnetic radiation.

Way back, I took part in production of radio controlled clocks, so this is what I recall.


#9

Thanks for the clarification, I've updated my post with a Link to Google Maps.

Edited: 14 Sept 2009, 3:41 p.m.

#10

Quote:
I enjoyed showing the unannounced timer in the HP45 and it was great for short time splits from 0-9, just press the number keys. Sam

The HP-45 is not very accurate as a timer. The timing is controlled by a simple LC circuit - a capacitor and an inductor creating a sine wave at about 800 kHz. But it varies from calculator to calculator because of part tolerances and may vary with temperature.

The HP-55 replaces the LC parts with a quartz crystal at 784 kHz. According to the owner's handbook it is accurate to 0.01%, or 1.5 seconds in 8 hours.

I enjoy using my HP-55 but I haven't found any real use for the timer.

I have a Waveceptor watch and also a digital wall clock that syncs to the WWWB time station. In previous days I would tune a shortwave radio to the time station to sync my watches.


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