Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

Way back in 1960 something Braun in Germany made a little alarm clock using a 4.194304 MHz crystal which could reach this level of accuracy.  I had one and it certainly met the Harrison level of timekeeping when I used it for navigation.  I think that the crystal cut used had a temperature

Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

HI > On Apr 11, 2018, at 5:38 PM, Richard (Rick) Karlquist > wrote: > > The aging spec on the 10811 is 5 parts in 10^10 per day. > After 60 days, it could be off 30 ppb. So what we > have here is a non-ovenized AT cut that is better > than an ovenized SC cut. I'm sure.

Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

kb...@n1k.org said: > Before you say it can’t be done, the whole “average out” thing is how > time > pieces have been done for hundreds of years. The device may swing this way > and that …. done properly it eventually averages out. How well it works for > you … that depends. There

Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

I have a Citizen A660 movement which was spec’d at +/- 5 secs per year. I monitored it from when I bought it in December 2010 until its battery failed on 03/11/2012. It was in spec when both on and off the wrist (off the wrist it was in a drawer at a constant temperature and the accuracy was a

Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

The aging spec on the 10811 is 5 parts in 10^10 per day. After 60 days, it could be off 30 ppb. So what we have here is a non-ovenized AT cut that is better than an ovenized SC cut. I'm sure. I am reminded of the old Accutron ads. The headlines guaranteed so many seconds a day or whatever it

Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

Hi Guess at the aging Cut the crystal so it’s fairly flat at 25 to 35C Do a basic / simple temperature compensation (TCXO) …. and count on the errors to average out. The success of all that will depend a lot on how close your wrist is to the environment they used for their guesswork. Did

Re: [time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

In message <02d201d3d1b1$d7318640$859492c0$@joshreply.com>, tn...@joshreply.com writes: >That comes out to about 30ppb, and this is a pocket watch so they don't seem >to depend on the temp stabilization of being attached to a human wrist. For an application where neither phase noise

[time-nuts] Any guesses as to how Citizen is claiming ±1 second/year with using this AT-cut 8.4MHz XTAL?

That comes out to about 30ppb, and this is a pocket watch so they don’t seem to depend on the temp stabilization of being attached to a human wrist. https://www.ablogtowatch.com/wp-content/uploads/2018/03/Citizen-Cal-0100-Eco -Drive-Movement-04.jpg I’ve been reading about the new watch