Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-13 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 13 Sep 2014 01:23, Alexander Pummer alex...@ieee.org wrote: just open the box, look for the wires which going to the magnet which drives the minute hand and measure the period time -- not the frequency, it is to low yes analog quarz clock slows down as the battery get old, you will be

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-13 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 13 Sep 2014 04:39, David McGaw n1...@dartmouth.edu wrote: The battery probably was going weak and the oscillator coming out of full control by the crystal. The tuning-fork crystal used in RTCs is not as high-Q as a MHz crystal. I have noticed clocks using these can go quite slow at low

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-13 Thread Tim Shoppa
On Sat, Sep 13, 2014 at 8:08 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: So if it the mechanics skips a pulse, one really needs some method of measuring the position of the hands and recording that. Better modern quartz movements, have circuitry in the

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-13 Thread Bob Camp
Hi In this era of “everything runs at GHz” it’s a bit tough to reach back to the sort of process used for watch IC’s. The idea is to optimize for low power / low leakage. They make enough of them that an application specific process can be used. The divide side of the chip may have an Fmax of

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-13 Thread Alexander Pummer
there is only one magnet, which drives the fastest moving arm -- the pointer for the seconds -- the other arms are connected via gears, by the way that case with the weak periodically recovering battery is an observed one, I connected a paper chart recorder to the clock and recorded the

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-13 Thread Lee Mushel
Interesting topic! Of course I no longer wear a watch since such a habit after advancing well into retirement seems pointless but I did want to point out that perhaps you could include the Bulova Accutron in your studies. Long ago I fell on ice and landed on my wrist with the result that my

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-12 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 12 Sep 2014 03:35, Alex Pummer a...@pcscons.com wrote: No that is to much, except if you overdrive it and you are so lucky that after it broke it is still working on a different frequency, but I would suggest check your frequency counter too, because 3% off of a clock frequency wold make the

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-12 Thread Bob Camp
Hi If this is an RTC, it’s probably running off of a battery when the machine is powered down. It is far more likely that the oscillator is dropping out (stopping) rather than shifting frequency. One way it might do this is to stop for a relatively brief period, battery recovers, and then

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-12 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
Dr David Kirkby Managing Director Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT, United Kingdom Registered in England and Wales as company number 08914892 http://www.kirkbymicrowave.co.uk/ Tel 07910 441670 / +44 7910 441670 (0900-2100 GMT) On 12

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-12 Thread Alexander Pummer
just open the box, look for the wires which going to the magnet which drives the minute hand and measure the period time -- not the frequency, it is to low yes analog quarz clock slows down as the battery get old, you will be surprised, that the driver pulse's period time dos not change, but

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-12 Thread David McGaw
The battery probably was going weak and the oscillator coming out of full control by the crystal. The tuning-fork crystal used in RTCs is not as high-Q as a MHz crystal. I have noticed clocks using these can go quite slow at low voltage. The crystal acts more like an inductor in this case

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-11 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 26 Nov 2012 14:12, David Kirkby david.kir...@onetel.net wrote: I've got an HP 8720D VNA. This has been out of support from Agilent for 8 years, so its getting on a bit. There's a clock in the instrument which keeps the date and time. This is losing about 1 day per month (rough guess), so

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2014-09-11 Thread Alex Pummer
No that is to much, except if you overdrive it and you are so lucky that after it broke it is still working on a different frequency, but I would suggest check your frequency counter too, because 3% off of a clock frequency wold make the clock almost unusable not just for time nuts... 73

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2012-11-26 Thread GandalfG8
David Try here, they have the service guide but no component level info available that I can see. _http://na.tm.agilent.com/8720/document.htm_ (http://na.tm.agilent.com/8720/document.htm) Regards Nigel GM8PZR In a message dated 26/11/2012 14:12:55 GMT Standard Time,

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2012-11-26 Thread Bob Camp
Hi Simple answer - no. More complicated answer - you can see a crystal jump to a spur, but they are going to be *above* the main mode for a normal clock crystal. If that happens, the clock will run to fast, not to slow. Bob -Original Message- From: time-nuts-boun...@febo.com

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2012-11-26 Thread J. Forster
Have you contacted ArtekMedia for any manual information? Also, have you checked/posted a question to the VNA Agilent Forum? -John == I've got an HP 8720D VNA. This has been out of support from Agilent for 8 years, so its getting on a bit. There's a clock in the instrument

Re: [time-nuts] Is a crystal likely to change frequency by 3% ?

2012-11-26 Thread David Kirkby
On 26 November 2012 16:00, J. Forster j...@quikus.com wrote: Have you contacted ArtekMedia for any manual information? No. First I'll try to get a free one! Also, have you checked/posted a question to the VNA Agilent Forum? Yes. Only a few hours ago (just before I posted on time-nuts I