Re: [time-nuts] Am I the only Time Nut who doesn't wear a watch?
On 7/10/2011 4:10 PM, Hal Murray wrote: omni...@gmail.com said: Then there is this little number... http://forums.watchnet.com/index.php?t=treegoto=415170rid=0 From their web page: The power reserve is 52 hours, and the watch is actually very accurate at about plus or minus 4 seconds a day. 4 seconds per day? I'd expected better from a very expensive watch. Are belts nasty when it comes to keeping good time? I wear a $50 watch that is a radio controlled atomic watch. Less than 1/2 a second off at any time, it's plenty good enough for normal human affairs. It's the only watch (so far) that I found to be satisfyingly accurate. I use it as my ship's chronometer when I drive and potentially have to use one of Chicago's parking pay boxes or to deliberately time my arrival into a free parking spot that depends on timing to get. (i.e. the school zone parking tactic) 4 seconds off a day? If it's a Rolex, I'd (understandably) be PISSED!!! I'd expect a watch that damn expensive to be off less than the 5 milliseconds to grab the WWVB signal! After all, isn't the whole purpose of a watch is to keep time? Unless, I suppose, you really want the bling factor... (and I'm not into bling) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] The future of UTC
Daylight savings seems to be a bit archaic especially with modern flexible working practices. Why not fit the working day around the clock seasons, rather than try to correct things twice a year? Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Spencer Sent: 15 July 2011 5:51 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The future of UTC Sorry for the prior email with no text. If the world could agree on the dates when DST adjustments are applied (if individual countries, states etc elect to make DST adjustments) and make any needed leap second adjustments at the same time that would be a positive step IMHO. - Original Message From: Jose Camara camar...@quantacorp.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, July 15, 2011 9:18:03 AM Subject: Re: [time-nuts] The future of UTC I think before adding to the fire of UTC1, UTC7 etc. why not just abolish this silliness called Daylight Savings Time? If there is any benefit to it, just change business operating hours instead. In summer you work 10 to 6 instead of 9 to 5 and we don't have to go around the house, car, etc. changing clocks. And Congress doesn't have to change the dates the VCRs were programmed to do automatically, leaving time for them to take care of something more important... I used to have pet tortoises that would always ignore DST, looking for their food one hour earlier... -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Steve Rooke Sent: Friday, July 15, 2011 8:24 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The future of UTC On 16 July 2011 03:14, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message CACTjVNynr5Vhrj=e+gfungebpa_u8__26bhjamk2nv6uxgi...@mail.gmail.com , Steve Rooke writes: Nope, once they have scheduled a leap-second, it happens. And if it's not needed? It is needed, otherwise they would not have scheduled it. So, your saying they will predict all the wobbling, drift, internal earth changes, etc and do this with any accuracy 20 years in advance, when we have already seen significant variations in this. If they predict wrong all that happens is that DUT1 wanders a bit more around and they will have to catch up with it over the next couple of decades. Given that straight-jacket, I suggest they schedule one every year then they can add and subtract them willy nilly. Yes, New Years Day, worldwide let's change the clock regardless. It would make it much more fun for all of us to watch what happens. Yes, I'm game for that, great idea. Cheers, Steve -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Am I the only Time Nut who doesn't wear a watch?
On 7/10/2011 6:33 AM, Raj wrote: To me when someone tells me a time of day the first thing I visualize is the clock hands and not numbers. I suspect the present gen visualize numbers. They must have trouble with 60 minutes in the hour.. a quarter past six and such.. I'm 48 years old and prefer digital. Why? Analog clocks are such that a little play is found with the minute hand. That means that if you calibrate it to be accurate (within the limitation of the movement) on one side of the hour it will lose or gain a minute on the other side due to the play in that needle on the gauge. Digital completely eliminates the play found with the minute needle. Note that the play comes into, well, play, if the clock is mounted vertically on a wall and is a decent large size. An analog watch will not have the problem nor will a clock with 3 separate stepper engines for each of the 3 needed gauge needles. (or at least 2 steppers and gears for the hour needle with direct drive for the second and minute needles) The typical wall clock will have one stepper engine and and gears for the minute and hour needles on the gauge with direct drive for the seconds needle. Therein lies a source of the play with the minutes needle. What's a measly minute off? Well, we all know! :) If you want a watch with some bling to it, try a Citizen Skyhawk series analog watch. These gems are radio controlled so it'll be less than half a second off at any time and are a little blingy (and a little expensive like $300). ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] The future of UTC
Far out. This discussion is so not time-nuts. I'm going to vent here. I'll do my best to be polite. Daylight savings is more beneficial the further from the equator you go. I love it and would never want it to go. As pointed out, this is a local issue. Go lobby your local representative. Metric time? FFS. The US can't even talk SI with rest of the world yet - even though their stupid measures are defined in terms of SI - as they have been for decades. So don't even think about it. Change the definition of the second?? Just stop right now. Go and learn what the effects of changing the most accurately measured thing we have before making silly comments like that!!! Ok, that's all sorted, let's get to the point on leap seconds. I can see both sides I really can. Making big changes years in the future is bad. Remember Y2K? I don't like the idea of letting DUT1 getting big. But it could be bigger than it is now without huge issues. I must admit Poul-Henning's idea of a 20 year advance notice is the best idea I've heard so far. But I'd recommend 10 years. A good metric number. Don't get hung up on noon occurring at 12:00 - the equation of time blows that right out. I think stopping leap seconds is bad, and having them regularly is good for practice - no Y2K problems. So again, 10 years advance notice is a really nice solution. /rant On Saturday, 16 July 2011, Rob Kimberley r...@timing-consultants.com wrote: Daylight savings seems to be a bit archaic especially with modern flexible working practices. Why not fit the working day around the clock seasons, rather than try to correct things twice a year? Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Spencer Sent: 15 July 2011 5:51 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The future of UTC Sorry for the prior email with no text. If the world could agree on the dates when DST adjustments are applied (if individual countries, states etc elect to make DST adjustments) and make any needed leap second adjustments at the same time that would be a positive step IMHO. - Original Message From: Jose Camara camar...@quantacorp.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, July 15, 2011 9:18:03 AM Subject: Re: [time-nuts] The future of UTC I think before adding to the fire of UTC1, UTC7 etc. why not just abolish this silliness called Daylight Savings Time? If there is any benefit to it, just change business operating hours instead. In summer you work 10 to 6 instead of 9 to 5 and we don't have to go around the house, car, etc. changing clocks. And Congress doesn't have to change the dates the VCRs were programmed to do automatically, leaving time for them to take care of something more important... I used to have pet tortoises that would always ignore DST, looking for their food one hour earlier... -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Steve Rooke Sent: Friday, July 15, 2011 8:24 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The future of UTC On 16 July 2011 03:14, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message CACTjVNynr5Vhrj=e+gfungebpa_u8__26bhjamk2nv6uxgi...@mail.gmail.com , Steve Rooke writes: Nope, once they have scheduled a leap-second, it happens. And if it's not needed? It is needed, otherwise they would not have scheduled it. So, your saying they will predict all the wobbling, drift, internal earth changes, etc and do this with any accuracy 20 years in advance, when we have already seen significant variations in this. If they predict wrong all that happens is that DUT1 wanders a bit more around and they will have to catch up with it over the next couple of decades. Given that straight-jacket, I suggest they schedule one every year then they can add and subtract them willy nilly. Yes, New Years Day, worldwide let's change the clock regardless. It would make it much more fun for all of us to watch what happens. Yes, I'm game for that, great idea. Cheers, Steve -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow
Re: [time-nuts] Am I the only Time Nut who doesn't wear a watch?
On 7/10/2011 5:04 AM, Javier Herrero wrote: My car has an interior look similar to this: http://upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Jaguar_XKR_Convertible_interior.jpg/800px-Jaguar_XKR_Convertible_interior.jpg Time ago, I pick a young engineer (quite digitally oriented, may I say) to go somewhere. He saw the three gauges in the central console (oil pressure, analog clock, and battery), pointed to the center one (the clock) and asked me: and what does this one measures? I was quite surprised by the question... :) Put that bloke in the engineroom of a ship and he'd be COMPLETELY lost looking at the dash. :) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Am I the only Time Nut who doesn't wear a watch?
I'd love to find a Smiths analogue clock to match the gauges in the dash of my old British car! On Jul 16, 2011, at 10:56, Michael Poulos poulo...@gmail.com wrote: On 7/10/2011 5:04 AM, Javier Herrero wrote: My car has an interior look similar to this: http://upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Jaguar_XKR_Convertible_interior.jpg/800px-Jaguar_XKR_Convertible_interior.jpg Time ago, I pick a young engineer (quite digitally oriented, may I say) to go somewhere. He saw the three gauges in the central console (oil pressure, analog clock, and battery), pointed to the center one (the clock) and asked me: and what does this one measures? I was quite surprised by the question... :) Put that bloke in the engineroom of a ship and he'd be COMPLETELY lost looking at the dash. :) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Am I the only Time Nut who doesn't wear a watch?
On 7/9/2011 10:18 PM, Raj wrote: I dont wear a watch since 25 years or more. Plenty of clocks around and now will cell phone and other personal devices all have clocks. Watch it. Those clocks on the cell phones are consistently slow compared to a WWVB watch. The time clocks where I work which have a phone connection to an (real deal) atomic clock are one second slow compared to my WWVB watch. At the end of the day I supply a countdown taking into account the one second off. The second off is due to digital delay in the system. It's about like having my own time clock except I can't punch in or out with the watch. Can't have EVERYTHING! But you are right about the plentiful number of clocks around, most being less than a minute off, usually slow. For years I didn't wear a watch until I got a WWVB watch. I was never happy with watches until I got that one due to inaccuracy. I want my watch to be exact. (OK, less than half a second off) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Am I the only Time Nut who doesn't wear a watch?
Javier shouldn't have been surprised! This level of understanding from the so-called smartest people who have ever lived, is quite common. Not too long ago I was checking the references of a young man who had just earned a master's degree in mechanical engineering. I was assured by one of his professors that you can ask him to do just about anything. And when asked to analyze deflection of a beam he presented me with an 18 page mathematical analysis. A few weeks later I found him in the tool room with a puzzled expression on his face. Do you have a question? Lee, how do they put threads on the inside of a hole? Lee (the person who does have an HP3801 but who uses the average presented by three Big Ben Alarm clocks for working time) - Original Message - From: bownes bow...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Cc: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, July 16, 2011 9:00 AM Subject: Re: [time-nuts] Am I the only Time Nut who doesn't wear a watch? I'd love to find a Smiths analogue clock to match the gauges in the dash of my old British car! On Jul 16, 2011, at 10:56, Michael Poulos poulo...@gmail.com wrote: On 7/10/2011 5:04 AM, Javier Herrero wrote: My car has an interior look similar to this: http://upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Jaguar_XKR_Convertible_interior.jpg/800px-Jaguar_XKR_Convertible_interior.jpg Time ago, I pick a young engineer (quite digitally oriented, may I say) to go somewhere. He saw the three gauges in the central console (oil pressure, analog clock, and battery), pointed to the center one (the clock) and asked me: and what does this one measures? I was quite surprised by the question... :) Put that bloke in the engineroom of a ship and he'd be COMPLETELY lost looking at the dash. :) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] The future of UTC
In message 002001cc43c0$8dab3010$a9019030$@timing-consultants.com, Rob Kimbe rley writes: Daylight savings seems to be a bit archaic especially with modern flexible working practices. Why not fit the working day around the clock seasons, rather than try to correct things twice a year? Call your local politician ? DST is a national matter, so all you have to do is convince your politicians[1]. [1] ... That daylight savings time is an terrorist socialist muslim plan to disrupt the precisous bodily fluids of real americans and they will be gone before you know it. :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] The future of UTC
Wouldn't trust any politician! :-) -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: 16 July 2011 6:04 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The future of UTC In message 002001cc43c0$8dab3010$a9019030$@timing-consultants.com, Rob Kimbe rley writes: Daylight savings seems to be a bit archaic especially with modern flexible working practices. Why not fit the working day around the clock seasons, rather than try to correct things twice a year? Call your local politician ? DST is a national matter, so all you have to do is convince your politicians[1]. [1] ... That daylight savings time is an terrorist socialist muslim plan to disrupt the precisous bodily fluids of real americans and they will be gone before you know it. :-) -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Follow-up on Z3801A high EFC reading
John: If it was turned off for more than a year, in my experience, the HP10811 (or similar) oscillators at the heart of the Z3801A will take about three weeks to settle down, and rejoin the previous mature aging curve. I have built a few GPSDOs using HP10811 oscillators, that I bought off of eBay, and they all took three weeks to settle down. You can ask the experts on the list why. Something about temperature related stress relief and gas sublimation on the surface of the crystal. --- Graham == On 7/16/2011 3:39 PM, John Ackermann N8UR wrote: Last week I posted about one of my Z3801As having a very high EFC reading and an EFC ERR message in the health status when powered up again after about 18 months of sleep and a 500 mile location change. Over the last week, the error message has continued, but the EFC has consistently trended downward. It started out at about 1015000 and is now down to 1012070. During the first day or so, the EFC count was going down more than one unit per minute; in the last day or so, it's more like 4 or 5 units per hour. But since it's moving in the right direction, I'm not going to try to rip open the outer oven at this point. This sort of aging effect is a bit odd given that this unit had been running continuously for about 7 years before it was shut down for the move; I might expect to see this is in a brand new unit but not in one with so much running time. I've been comparing the 10 MHz output against a cesium during this time, and an ADEV plot is attached. It seems to indicate that the performance is just fine -- the short term floor is probably limited by the 5061B's noise, and we can see the 5061A long-term noise floor starting to show up at 200K seconds, but there's certainly nothing here to question the performance of the GPSDO. Now that I've captured this baseline data, I'm going to power cycle the Z3801A to see if it lands in the same general vicinity. John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Follow-up on Z3801A high EFC reading
One crystal expert, who's name escapes me, sorry, told me that if you power up an oscillator that has been off for an extended period, you should expect a very rapid ageing process to occur with a lot of the accumulated changes that would have happened had it been powered on then to occur when it was restarted. But I can't quote chapter and verse, obviously. Dan ac6ao ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] The future of UTC
Jim: time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics Until there is a more specific charter listing what one can post about or not, or elected people with horned hats to judge what is noise and what is signal, DST discussion should be perfectly acceptable. It is a related topic. Even the jokes about people jumping on chairs, farting always west, and it's effects on UTC are a small contribution, as others actually show calculations that dismiss it before it becomes the next twitter mob project... Don't forget the -nuts part of the list! :-) -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Jim Palfreyman Sent: Saturday, July 16, 2011 7:53 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The future of UTC Far out. This discussion is so not time-nuts. I'm going to vent here. I'll do my best to be polite. Daylight savings is more beneficial the further from the equator you go. I love it and would never want it to go. As pointed out, this is a local issue. Go lobby your local representative. Metric time? FFS. The US can't even talk SI with rest of the world yet - even though their stupid measures are defined in terms of SI - as they have been for decades. So don't even think about it. Change the definition of the second?? Just stop right now. Go and learn what the effects of changing the most accurately measured thing we have before making silly comments like that!!! Ok, that's all sorted, let's get to the point on leap seconds. I can see both sides I really can. Making big changes years in the future is bad. Remember Y2K? I don't like the idea of letting DUT1 getting big. But it could be bigger than it is now without huge issues. I must admit Poul-Henning's idea of a 20 year advance notice is the best idea I've heard so far. But I'd recommend 10 years. A good metric number. Don't get hung up on noon occurring at 12:00 - the equation of time blows that right out. I think stopping leap seconds is bad, and having them regularly is good for practice - no Y2K problems. So again, 10 years advance notice is a really nice solution. /rant On Saturday, 16 July 2011, Rob Kimberley r...@timing-consultants.com wrote: Daylight savings seems to be a bit archaic especially with modern flexible working practices. Why not fit the working day around the clock seasons, rather than try to correct things twice a year? Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Spencer Sent: 15 July 2011 5:51 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The future of UTC Sorry for the prior email with no text. If the world could agree on the dates when DST adjustments are applied (if individual countries, states etc elect to make DST adjustments) and make any needed leap second adjustments at the same time that would be a positive step IMHO. - Original Message From: Jose Camara camar...@quantacorp.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Fri, July 15, 2011 9:18:03 AM Subject: Re: [time-nuts] The future of UTC I think before adding to the fire of UTC1, UTC7 etc. why not just abolish this silliness called Daylight Savings Time? If there is any benefit to it, just change business operating hours instead. In summer you work 10 to 6 instead of 9 to 5 and we don't have to go around the house, car, etc. changing clocks. And Congress doesn't have to change the dates the VCRs were programmed to do automatically, leaving time for them to take care of something more important... I used to have pet tortoises that would always ignore DST, looking for their food one hour earlier... -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Steve Rooke Sent: Friday, July 15, 2011 8:24 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] The future of UTC On 16 July 2011 03:14, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message CACTjVNynr5Vhrj=e+gfungebpa_u8__26bhjamk2nv6uxgi...@mail.gmail.com , Steve Rooke writes: Nope, once they have scheduled a leap-second, it happens. And if it's not needed? It is needed, otherwise they would not have scheduled it. So, your saying they will predict all the wobbling, drift, internal earth changes, etc and do this with any accuracy 20 years in advance, when we have already seen significant variations in this. If they predict wrong all that happens is that DUT1 wanders a bit more around and they will have to catch up with it over the next couple of decades. Given that straight-jacket, I suggest they schedule one every year then they can add and subtract them willy
Re: [time-nuts] Follow-up on Z3801A high EFC reading
Hi John and Graham, On 16/07/11 22:50, Graham / KE9H wrote: John: If it was turned off for more than a year, in my experience, the HP10811 (or similar) oscillators at the heart of the Z3801A will take about three weeks to settle down, and rejoin the previous mature aging curve. I have built a few GPSDOs using HP10811 oscillators, that I bought off of eBay, and they all took three weeks to settle down. You can ask the experts on the list why. Something about temperature related stress relief and gas sublimation on the surface of the crystal. I was just about to make this point. While I am not an expert in crystal oscillators (I think I can name at least 4-5 people here with their hands dirty from it) from what I have read up and from what I have seen the type of re-trace properties you describe is typical. It is to avoid this re-trace that instruments keep their oscillators oven heated in stand-by mode. If you look for it, you will find the effect well covered in literature. There are several mechanisms in play, but polution depositing on the crystal surface is one of them that I've heard of. Mechanical stress as the temperature change causes re-shaping of all mechanical aspects and the forces it puts on the crystal blank until realigned again is another. So, that was in the back of my mind when I said that you should wait. For a crystal of 10811 class weeks is to be expected before saying it is bad or badly out of tune. Anyway, good to hear about the progress. The EFC track-in cruve looks like expected from this type of event. Notice that you might need to use a curve-fit cancellation matching the drift curve. ADEV is sensitive to drift and isn't particularly gifted in illustrating the drift either. I could dig up a few references for you if you badly need it. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Follow-up on Z3801A high EFC reading
I think it is in Matthys, Crystal oscillator circuits. Can't quote page number now, as my verson is somwhere I cant remember. It's an excellent book if you do some experimentation. I did write an letter to R.J. Matthys a couple of years ago, and reveiced an answer. 73 de Thomas LA3PNA/AE5YS. 2011/7/16 Dan Rae dan...@verizon.net: One crystal expert, who's name escapes me, sorry, told me that if you power up an oscillator that has been off for an extended period, you should expect a very rapid ageing process to occur with a lot of the accumulated changes that would have happened had it been powered on then to occur when it was restarted. But I can't quote chapter and verse, obviously. Dan ac6ao ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Please avoid sending me Word or PowerPoint attachments. See http://www.gnu.org/philosophy/no-word-attachments.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Follow-up on Z3801A high EFC reading
Thomas, Dan, Magnus, Graham -- Thanks for the replies! This is an interesting example of no two oscillators are the same. I certainly expected that there would be aging and retrace on a cold oscillator, but I started both Z3801As almost simultaneously and within about 12 hours unit #1 had stabilized and the EFC was showing normal noise over a fairly small range with no real trend apparent. But unit #2 (the one shown in the plots) continued to have the very pronounced aging trend of after 12 hours, with one click per minute more than a day after power-on, as well as having a much higher absolute EFC value than it did before, or than unit #1 has now. So, based on unit #1, I was suspicious of what was going on in the second unit. It may just be that #2 doesn't have as good an oscillator as #1. John Thomas S. Knutsen said the following on 07/16/2011 05:32 PM: I think it is in Matthys, Crystal oscillator circuits. Can't quote page number now, as my verson is somwhere I cant remember. It's an excellent book if you do some experimentation. I did write an letter to R.J. Matthys a couple of years ago, and reveiced an answer. 73 de Thomas LA3PNA/AE5YS. 2011/7/16 Dan Raedan...@verizon.net: One crystal expert, who's name escapes me, sorry, told me that if you power up an oscillator that has been off for an extended period, you should expect a very rapid ageing process to occur with a lot of the accumulated changes that would have happened had it been powered on then to occur when it was restarted. But I can't quote chapter and verse, obviously. Dan ac6ao ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
