Narrow-Bandwidth Television Association

1 second in 100 days, that is a crystal of 10 MHz within 1 Hz. Because 100 days is 8 640 000 sec. That is for a crystal already a chalenge, without an oven this is impossible and even then.

I wonder how the clock maker tuned his clock, because to make something like that you must have a reference, time or frequency. I know, I made a precise 60 Hz "artificial mains" for the mechanical, synchronous motor driven clock in my SB-630 station console. And then you realise how precise the running speed of a clock must be, to keep it on time during a longer period of time. In the USA the mains frequency is corrected over longer times, just as the 50Hz in Europe. Never the less the time of a mains driven clock can be about 1 minute late or too early. But I did not like that.

To have a good reference I built a GPS-controlled 10 MHz oscillator. With that I can see how precise the time base of my digital frequency counter is. Well, 1 Hz precision on 10 MHz, 10^-7, is too difficult for the built-in TCXO.

True, the best reference that us mortals have for timekeeping is GPS, both long and short-term for frequency and UTC for driving a real (visible) clock. Add or subtract to/from the UTC time to get local time as well as adjusting for daylight saving time, where used.

Most GPS 'bare bones' modules output NMEA ASCII data with the time, and a whole lot of satellite data plus a separate 1PPS (One pulse per second), it's the latter you use to lock a GPSDO (Global Positioning System Disciplined Oscillator) to what is effectively an atomic level reference.

The most important factor is the GPS receiver/module has a good view of the sky, not so easy if you live in an apartment, but even just half the sky (on a balcony) will generally work well. However, if you live in the northern hemisphere it's better that you have a clear view to the south for as you get further away from the equator the less coverage there is to the north. The opposite in the southern hemisphere. The best location would be Singapore, only one degree north of the equator - if you can afford to live there!

Steve A.

At first i was thinking is this mechanical related and if to do with crystals and other precise clocks a dead yes .
It is funny and i would not of picked it that the most precise clocks in the universe are mechanical ...rotating pulsars .
Atomic clock better ?

lol Harry! You need a hug?

FlyMario wrote:lol Harry! You need a hug?

???

Thats ok i am good Peter ; )

So I found out that my Leonardo Micro Arduinos actually do have a crystal in them so I switched to that.

Now my clocks are measuring between 80,000 and 80,004. Absolutely perfect!

Thanks for your comments guys!