OXCO precision clock

[Jammer]

I came across this today:


DuraTime HP Digtial Clock


It's a wall clock with an oven-controlled crystal oscillator. The manufacturer claims a 1 second per year accuracy. They are reasonably priced and accurate enough that ability to receive WWV or GPS signals would not be necessary. Something to consider if the talk of WWV being shut down materializes.

I just sent them a note asking whether the clocks can be readily adapted to 12v DC power. I also asked about power draw. Most OXCOs draw a watt or two, which is enough that they aren't practical to run from a battery in the clock, but not enough to have a significant effect on a boat's power budget.



I'll post any response I receive.

[transmitterdan]

A GPS receiver will provide very accurate time. It is not going away.

[Paul Elliott]

Modern wristwatches are also somewhat "ovenized" by virtue of being worn on your 98.6-degree wrist. Not as good as a proper ovenized xtal oscillator (or the rubidium standard in my garage/lab), but I've found that my cheapo Timex's rate is pretty constant. So don't take off your watch, log occasional time-comparisons to GPS or WWV for rate and time calibration, and you've got a reasonably good chronometer when the lights go out.

[BlueChicago]

If you can wait, this might be a bit more energy efficient, but likely to burn a hole in your pocket:


https://www.bloomberg.com/news/artic...-we-could-wear

[Jammer]

Originally Posted by transmitterdan

A GPS receiver will provide very accurate time. It is not going away.

You're probably right.


I'll start another thread on GPS/GLONASS system integrity.

[RaymondR]

A lot of us go live on boats to get away from the need for watches. What do you do that you need a watch which only has a one second error per million years?

[Paul Elliott]

Originally Posted by RaymondR

A lot of us go live on boats to get away from the need for watches. What do you do that you need a watch which only has a one second error per million years?

Some degree of precision is needed if you wish to do traditional celestial navigation. And that OCXO clock was spec'd at one second error per year (which is still better than required if you can get at least annual calibration).

[transmitterdan]

Originally Posted by Jammer

You're probably right.


I'll start another thread on GPS/GLONASS system integrity.

Please don't. The topic has been beaten literally to death. The folks that fear GPS will go away for days haven't a clue how it all works and are just engaged in mindless fear mongering or conspiracy theories. If GPS goes away it will be because WWIII has begun and knowing celestial nav will not help much then. So it's really a pointless topic IMO.

[barnakiel]

Not required. Plain USD 10,00 Casio does the job just as well.


Unless you can afford a mechanical chrono, do not waste your breath. Simply get spare gps and go.


b.

[RaymondR]

Originally Posted by Paul Elliott

Some degree of precision is needed if you wish to do traditional celestial navigation. And that OCXO clock was spec'd at one second error per year (which is still better than required if you can get at least annual calibration).

You can tune into the time signals on the HF radio and rate your crystal controlled wrist watch and get more than sufficient accuracy for celestial nav.

[Simi 60]

I saw a watch once.

[transmitterdan]

Originally Posted by RaymondR

You can tune into the time signals on the HF radio and rate your crystal controlled wrist watch and get more than sufficient accuracy for celestial nav.

Unfortunately the government of the US is recommending to stop all time broadcasting over radio including WWV, WWVH and WWVB. There is a petition you can sign to complain about this stupid idea.

https://petitions.whitehouse.gov/pet...tions-wwv-wwvh

[transmitterdan]

Originally Posted by transmitterdan

Unfortunately the government of the US is recommending to stop all time broadcasting over radio including WWV, WWVH and WWVB. There is a petition you can sign to complain about this stupid idea.

https://petitions.whitehouse.gov/pet...tions-wwv-wwvh

Unfortunately it is now closed for lack of sufficient interest.

[hellosailor]

I've had Big Red LED clocks before. After five years on "view it in a bright room" the LEDs usually get dim enough so you think about replacing them. Most of the makers run the LEDs at too high a power, to make them bright. And with commodity grade LED life expectancy being something like 20-50,000 hours...that could be as little as four or five years of running 24x7 anyway. Not the best choice for long-term use.

[Jammer]

Here's another interesting product. I inquired and was sent a quote of $1525 per unit for the high-stability version. More money but a better fit for onboard use:


* runs on 12-24vdc
* much smaller, about the size of a paperback book

* small display
* Typical accuracy within 1/4 second per year

* also an NTP server if you want that


https://www.masterclock.com/products...ers/ntp100-osc