Re: [time-nuts] Shortt Clock Recent Measurements
Hi Tom: The way I read the comment about detecting the influence of the Moon was that it was discovered in 1984, but I was under the impression that Loomis found it long before. I looked on other Wiki pages and did not see on any of the them information about Loomis and the effect of the Moon on pendulum clocks. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Tom Van Baak (lab) wrote: Brooke, Not sure what you find in error; please explain. I have all the Shortt info you need. Not all of it is for Wikipedia; contact me off-line. Just got back from the CalTech Time Symposium: http://leapsecond.com/nawcc2013/ The conjecture about tides is explained in great detail here: http://leapsecond.com/hsn2006/ Meanwhile, see: http://leapsecond.com/pend/shortt/ http://leapsecond.com/pend/shortt/1931-RAS-Analysis-Loomis-Chronograph-Brown-Brouwer.pdf http://leapsecond.com/pend/shortt/1931-RAS-Precise-Measurement-Time-Loomis.pdf /tvb (i5s) On Dec 9, 2013, at 5:02 PM, Brooke Clarke wrote: Hi: The Wiki page for the Shortt pendulum clock has a "Recent Measurements" (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Is there a link to his paper at the Royal Society on that topic that could be added to the Wiki page? Also see: http://www.amazon.com/Tuxedo-Park-Street-Science-Changed/dp/0684872889/ref=sr_1_1 http://www.leapsecond.com/hsn2006/ch1.htm -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.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. ___ 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] MS3106R10SL-4S connector question
the ones I have seen take the place of a crimp pin to be inserted into the connector to maintain moisture integrity. With the length, it looks like it would take the place of a wire in the water seal / strain relief, if only one wire were to be used. 73 Glenn Never seen one like that before, At 09:52 PM 12/9/2013, you wrote: Take a look at ebay auction 261315795465. It's a mil-spec connector and I don't see any way for the connector pins to come out. It looks like it's probably pressure tight. You can see the blue plastic pin in the third picture. It's almost like it has something to do with the rubber strain relief/enviro shield, but I dunno what. Bob > > From: J. Forster >To: Bob Stewart ; Discussion of precise time and frequency measurement >Sent: Monday, December 9, 2013 8:33 PM >Subject: Re: [time-nuts] MS3106R10SL-4S connector question > > >If the contacts are loose and individually extractable/insertable, the pin >is probably a dummy pin to substitute for the more expensive brass/gold >pins. This is so the rubber does not distorted over time. > >-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] MS3106R10SL-4S connector question
OK, now it makes sense! thanks! Bob > > From: J. Forster >To: Bob Stewart ; Discussion of precise time and frequency >measurement >Sent: Monday, December 9, 2013 8:58 PM >Subject: Re: [time-nuts] MS3106R10SL-4S connector question > > >It's what I said. A blanking pin for the hole in the rubber seal, except >that it's only for the seal, not the whole connector. > >-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.
Re: [time-nuts] MS3106R10SL-4S connector question
That is a dummy pin to seal a position in the connector that does not have a pin. If all of the pins are installed it is not used. 73 Glenn WB4UIV At 07:13 PM 12/9/2013, you wrote: I got a GPS Source splitter recently and since my little Adafruit doesn't have enough power to run it I got an MS3016R connector to hook up external power. What I can't figure out is what is that blue plastic pin for that comes in the package? Bob - AE6RV ___ 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] MS3106R10SL-4S connector question
It's what I said. A blanking pin for the hole in the rubber seal, except that it's only for the seal, not the whole connector. -John > Take a look at ebay auction 261315795465. It's a mil-spec connector and I > don't see any way for the connector pins to come out. It looks like it's > probably pressure tight. You can see the blue plastic pin in the third > picture. It's almost like it has something to do with the rubber strain > relief/enviro shield, but I dunno what. > > Bob > > > > >> >> From: J. Forster >>To: Bob Stewart ; Discussion of precise time and >> frequency measurement >>Sent: Monday, December 9, 2013 8:33 PM >>Subject: Re: [time-nuts] MS3106R10SL-4S connector question >> >> >>If the contacts are loose and individually extractable/insertable, the >> pin >>is probably a dummy pin to substitute for the more expensive brass/gold >>pins. This is so the rubber does not distorted over time. >> >>-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] MS3106R10SL-4S connector question
Take a look at ebay auction 261315795465. It's a mil-spec connector and I don't see any way for the connector pins to come out. It looks like it's probably pressure tight. You can see the blue plastic pin in the third picture. It's almost like it has something to do with the rubber strain relief/enviro shield, but I dunno what. Bob > > From: J. Forster >To: Bob Stewart ; Discussion of precise time and frequency >measurement >Sent: Monday, December 9, 2013 8:33 PM >Subject: Re: [time-nuts] MS3106R10SL-4S connector question > > >If the contacts are loose and individually extractable/insertable, the pin >is probably a dummy pin to substitute for the more expensive brass/gold >pins. This is so the rubber does not distorted over time. > >-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.
Re: [time-nuts] Shortt Clock Recent Measurements
Brooke, Not sure what you find in error; please explain. I have all the Shortt info you need. Not all of it is for Wikipedia; contact me off-line. Just got back from the CalTech Time Symposium: http://leapsecond.com/nawcc2013/ The conjecture about tides is explained in great detail here: http://leapsecond.com/hsn2006/ Meanwhile, see: http://leapsecond.com/pend/shortt/ http://leapsecond.com/pend/shortt/1931-RAS-Analysis-Loomis-Chronograph-Brown-Brouwer.pdf http://leapsecond.com/pend/shortt/1931-RAS-Precise-Measurement-Time-Loomis.pdf /tvb (i5s) > On Dec 9, 2013, at 5:02 PM, Brooke Clarke wrote: > > Hi: > > The Wiki page for the Shortt pendulum clock has a "Recent Measurements" > (1984) paragraph that's in error. > http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_measurement > > While it's probably true that the clock is stable to 200 uS per day (i.e. > 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock > a long time ago. > Is there a link to his paper at the Royal Society on that topic that could be > added to the Wiki page? > > Also see: > http://www.amazon.com/Tuxedo-Park-Street-Science-Changed/dp/0684872889/ref=sr_1_1 > http://www.leapsecond.com/hsn2006/ch1.htm > > -- > Have Fun, > > Brooke Clarke > http://www.PRC68.com > http://www.end2partygovernment.com/2012Issues.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. ___ 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] MS3106R10SL-4S connector question
If the contacts are loose and individually extractable/insertable, the pin is probably a dummy pin to substitute for the more expensive brass/gold pins. This is so the rubber does not distorted over time. -John = > I got a GPS Source splitter recently and since my little Adafruit doesn't > have enough power to run it I got an MS3016R connector to hook up external > power. What I can't figure out is what is that blue plastic pin for that > comes in the package? > > Bob - AE6RV > ___ > 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] Shortt Clock Recent Measurements
I thought I needed to throw this in the mix. http://www.allanstime.com/Research/Pendulum/index.html Enjoy. Thomas Knox > Date: Mon, 9 Dec 2013 17:02:22 -0800 > From: bro...@pacific.net > To: time-nuts@febo.com > Subject: [time-nuts] Shortt Clock Recent Measurements > > Hi: > > The Wiki page for the Shortt pendulum clock has a "Recent Measurements" > (1984) paragraph that's in error. > http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_measurement > > While it's probably true that the clock is stable to 200 uS per day (i.e. > 2E-9) I believe Alfred Loomis discovered the > effect of the moon on this clock a long time ago. > Is there a link to his paper at the Royal Society on that topic that could be > added to the Wiki page? > > Also see: > http://www.amazon.com/Tuxedo-Park-Street-Science-Changed/dp/0684872889/ref=sr_1_1 > http://www.leapsecond.com/hsn2006/ch1.htm > > -- > Have Fun, > > Brooke Clarke > http://www.PRC68.com > http://www.end2partygovernment.com/2012Issues.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. ___ 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] Shortt Clock Recent Measurements
Hi: The Wiki page for the Shortt pendulum clock has a "Recent Measurements" (1984) paragraph that's in error. http://en.wikipedia.org/wiki/Shortt-Synchronome_clock#Recent_accuracy_measurement While it's probably true that the clock is stable to 200 uS per day (i.e. 2E-9) I believe Alfred Loomis discovered the effect of the moon on this clock a long time ago. Is there a link to his paper at the Royal Society on that topic that could be added to the Wiki page? Also see: http://www.amazon.com/Tuxedo-Park-Street-Science-Changed/dp/0684872889/ref=sr_1_1 http://www.leapsecond.com/hsn2006/ch1.htm -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.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.
[time-nuts] MS3106R10SL-4S connector question
I got a GPS Source splitter recently and since my little Adafruit doesn't have enough power to run it I got an MS3016R connector to hook up external power. What I can't figure out is what is that blue plastic pin for that comes in the package? Bob - AE6RV ___ 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] Hp5061A K15 distribution amp
Sort of, John. The amplifier modules are not the same, but the chassis is very similar. Don J. Forster > Is this a rebadged 5087A? > > -John > > > > >> 10 MHz 6 output amps, 1 input amp. Matches 5061A Cs standard. >> fs, contact me off list please. >> Don >> -- >> "The power of accurate observation is commonly called cynicism by >> those >> who have not got it." >> -George Bernard Shaw >> -- >> Dr. Don Latham AJ7LL >> Six Mile Systems LLC >> 17850 Six Mile Road >> POB 134 >> Huson, MT, 59846 >> VOX 406-626-4304 >> Skype: buffler2 >> www.lightningforensics.com >> www.sixmilesystems.com >> >> >> ___ >> 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. > > -- "The power of accurate observation is commonly called cynicism by those who have not got it." -George Bernard Shaw Dr. Don Latham AJ7LL Six Mile Systems LLC 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 Skype: buffler2 www.lightningforensics.com www.sixmilesystems.com ___ 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] temperature
Hi The way it was spec’d by HP, there was no allowance for hysteresis. They also had some issues with probe drift / calibration costs. They apparently decided to drop the product rather than update it. Bob On Dec 9, 2013, at 9:41 AM, Azelio Boriani wrote: > Is the hysteresis related to the retrace effect? If so, then I think > that the quartz thermometer may be succesfully used where the > tenperature has only small variations. > > On Mon, Dec 9, 2013 at 3:12 PM, Daniel Mendes wrote: >> >> It´s still used in the oil industry as "the standard" for temp and pressure >> monitoring... >> >> Daniel >> >> Em 09/12/2013 10:28, Bob Camp escreveu: >> >>> Hi >>> >>> The Quartz Thermometer died when somebody proved that hysteresis was a big >>> deal on the probes. >>> >>> Bob >>> >>> On Dec 8, 2013, at 11:22 PM, Tim Shoppa wrote: >>> Interestingly, HP for a long time sold"quartz thermometers" based around a probe with a quartz crystal with a well characterized linear temperature coefficient. They called the crystal cut "LC" (Linear Coefficient): http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1965-03.pdf http://en.wikipedia.org/wiki/Quartz_thermometer On Sun, Dec 8, 2013 at 10:55 PM, Neville Michie wrote: > Hi, > I use a HP3468A multimeter to measure a PT100 platinum resistance > thermometer. It gives me resolution of one mK, but calibration is > another > matter. > It is best to use a 4 terminal device, but 2 terminal into the 4 > terminal > input works well. Thermoelectric effects and the requirement for 1 > microvolt stability > makes wiring them into your own circuit difficult. One of the great > technical difficulties is to get a resistor to compare them against, it > must be very stable, > have no thermoelectric effects and have a temperature coefficient in the > order of one PPM. I always admire the way HP designed their ohm meters. > There are other issues, however. Whereas a volt meter can connect > perfectly to a reference, a PRT can only report its own temperature. > That is no problem when you are working in a well stirred water bath, > that > will have the PRT at the same temperature as the object in the same > bath. > When you get to measure air temperature you are into serious sampling > errors, the PRT has some self heating and so is air velocity sensitive, > and > the air > you are measuring may not be the same air as is over your OCXO or item > of > interest. There is a personal plume of warm air rising from an observer, > so > you must be careful with your measurement technique. > The same problems occur with quartz crystal thermometers, which is why > they are not more commonly found in surplus. > A PT100 sensor is quite cheap, and their calibration is little short of > brilliant. However a they would cost much more if their calibration is > traceable. > For my use, I use an ice-point cell as a calibration check, with care > you > get 10mK accuracy. You only need the knowledge how to set it up, a > blender > to make ice slush, > and a picnic vacuum flask, to make your own calibration reference. > I use thermistors for air measurement, and calibrate them against the > PT100 in a thermostatic water bath. Thermistors can be run with a very > low > level of self heating and they are very sensitive, their resistance > changes 4% per Centigrade degree, and they come in high values like 100K > ohm. You read > them in a bridge circuit with a voltmeter, so they are many orders of > magnitude easier to use than a 100 ohm PRT. > They are made small enough to get them in close contact > with the object to be measured. > If you want to know about humidity measurement I can tell you much about > that, > cheers, > Neville Michie > > On 08/12/2013, at 12:40 PM, Mark Spencer wrote: > >> Sorry if this is somewhat off topic, but I'd be interested in more > > details re precision temperature measurement devices. Have been using > an > inexpensive USB temperature sensor for the last year or so to monitor > the > temperature in my lab and have been looking at the correlation between > frequency shifts in some ocxo's vs temperature changes. I should also > start taking humidity measurements as well at some point. >> >> >> Any pointers re suitable instruments to accomplish this that can be > > sourced via the usual surplus sources would be welcome. >> >> Thanks in advance >> Mark Spencer >> >> Sent from my iPad >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>
Re: [time-nuts] temperature
HI The one currently in use is a *very* different animal than the HP version. Bob On Dec 9, 2013, at 9:12 AM, Daniel Mendes wrote: > > It´s still used in the oil industry as "the standard" for temp and pressure > monitoring... > > Daniel > > Em 09/12/2013 10:28, Bob Camp escreveu: >> Hi >> >> The Quartz Thermometer died when somebody proved that hysteresis was a big >> deal on the probes. >> >> Bob >> >> On Dec 8, 2013, at 11:22 PM, Tim Shoppa wrote: >> >>> Interestingly, HP for a long time sold"quartz thermometers" based around a >>> probe with a quartz crystal with a well characterized linear temperature >>> coefficient. They called the crystal cut "LC" (Linear Coefficient): >>> >>> http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1965-03.pdf >>> >>> http://en.wikipedia.org/wiki/Quartz_thermometer >>> >>> >>> On Sun, Dec 8, 2013 at 10:55 PM, Neville Michie wrote: >>> Hi, I use a HP3468A multimeter to measure a PT100 platinum resistance thermometer. It gives me resolution of one mK, but calibration is another matter. It is best to use a 4 terminal device, but 2 terminal into the 4 terminal input works well. Thermoelectric effects and the requirement for 1 microvolt stability makes wiring them into your own circuit difficult. One of the great technical difficulties is to get a resistor to compare them against, it must be very stable, have no thermoelectric effects and have a temperature coefficient in the order of one PPM. I always admire the way HP designed their ohm meters. There are other issues, however. Whereas a volt meter can connect perfectly to a reference, a PRT can only report its own temperature. That is no problem when you are working in a well stirred water bath, that will have the PRT at the same temperature as the object in the same bath. When you get to measure air temperature you are into serious sampling errors, the PRT has some self heating and so is air velocity sensitive, and the air you are measuring may not be the same air as is over your OCXO or item of interest. There is a personal plume of warm air rising from an observer, so you must be careful with your measurement technique. The same problems occur with quartz crystal thermometers, which is why they are not more commonly found in surplus. A PT100 sensor is quite cheap, and their calibration is little short of brilliant. However a they would cost much more if their calibration is traceable. For my use, I use an ice-point cell as a calibration check, with care you get 10mK accuracy. You only need the knowledge how to set it up, a blender to make ice slush, and a picnic vacuum flask, to make your own calibration reference. I use thermistors for air measurement, and calibrate them against the PT100 in a thermostatic water bath. Thermistors can be run with a very low level of self heating and they are very sensitive, their resistance changes 4% per Centigrade degree, and they come in high values like 100K ohm. You read them in a bridge circuit with a voltmeter, so they are many orders of magnitude easier to use than a 100 ohm PRT. They are made small enough to get them in close contact with the object to be measured. If you want to know about humidity measurement I can tell you much about that, cheers, Neville Michie On 08/12/2013, at 12:40 PM, Mark Spencer wrote: > Sorry if this is somewhat off topic, but I'd be interested in more details re precision temperature measurement devices. Have been using an inexpensive USB temperature sensor for the last year or so to monitor the temperature in my lab and have been looking at the correlation between frequency shifts in some ocxo's vs temperature changes. I should also start taking humidity measurements as well at some point. > > Any pointers re suitable instruments to accomplish this that can be sourced via the usual surplus sources would be welcome. > Thanks in advance > Mark Spencer > > Sent from my iPad > ___ > 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 --
Re: [time-nuts] Hp5061A K15 distribution amp
Is this a rebadged 5087A? -John > 10 MHz 6 output amps, 1 input amp. Matches 5061A Cs standard. > fs, contact me off list please. > Don > -- > "The power of accurate observation is commonly called cynicism by those > who have not got it." > -George Bernard Shaw > -- > Dr. Don Latham AJ7LL > Six Mile Systems LLC > 17850 Six Mile Road > POB 134 > Huson, MT, 59846 > VOX 406-626-4304 > Skype: buffler2 > www.lightningforensics.com > www.sixmilesystems.com > > > ___ > 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] Hp5061A K15 distribution amp
10 MHz 6 output amps, 1 input amp. Matches 5061A Cs standard. fs, contact me off list please. Don -- "The power of accurate observation is commonly called cynicism by those who have not got it." -George Bernard Shaw -- Dr. Don Latham AJ7LL Six Mile Systems LLC 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 Skype: buffler2 www.lightningforensics.com www.sixmilesystems.com ___ 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] temperature
Is the hysteresis related to the retrace effect? If so, then I think that the quartz thermometer may be succesfully used where the tenperature has only small variations. On Mon, Dec 9, 2013 at 3:12 PM, Daniel Mendes wrote: > > It´s still used in the oil industry as "the standard" for temp and pressure > monitoring... > > Daniel > > Em 09/12/2013 10:28, Bob Camp escreveu: > >> Hi >> >> The Quartz Thermometer died when somebody proved that hysteresis was a big >> deal on the probes. >> >> Bob >> >> On Dec 8, 2013, at 11:22 PM, Tim Shoppa wrote: >> >>> Interestingly, HP for a long time sold"quartz thermometers" based around >>> a >>> probe with a quartz crystal with a well characterized linear temperature >>> coefficient. They called the crystal cut "LC" (Linear Coefficient): >>> >>> http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1965-03.pdf >>> >>> http://en.wikipedia.org/wiki/Quartz_thermometer >>> >>> >>> On Sun, Dec 8, 2013 at 10:55 PM, Neville Michie >>> wrote: >>> Hi, I use a HP3468A multimeter to measure a PT100 platinum resistance thermometer. It gives me resolution of one mK, but calibration is another matter. It is best to use a 4 terminal device, but 2 terminal into the 4 terminal input works well. Thermoelectric effects and the requirement for 1 microvolt stability makes wiring them into your own circuit difficult. One of the great technical difficulties is to get a resistor to compare them against, it must be very stable, have no thermoelectric effects and have a temperature coefficient in the order of one PPM. I always admire the way HP designed their ohm meters. There are other issues, however. Whereas a volt meter can connect perfectly to a reference, a PRT can only report its own temperature. That is no problem when you are working in a well stirred water bath, that will have the PRT at the same temperature as the object in the same bath. When you get to measure air temperature you are into serious sampling errors, the PRT has some self heating and so is air velocity sensitive, and the air you are measuring may not be the same air as is over your OCXO or item of interest. There is a personal plume of warm air rising from an observer, so you must be careful with your measurement technique. The same problems occur with quartz crystal thermometers, which is why they are not more commonly found in surplus. A PT100 sensor is quite cheap, and their calibration is little short of brilliant. However a they would cost much more if their calibration is traceable. For my use, I use an ice-point cell as a calibration check, with care you get 10mK accuracy. You only need the knowledge how to set it up, a blender to make ice slush, and a picnic vacuum flask, to make your own calibration reference. I use thermistors for air measurement, and calibrate them against the PT100 in a thermostatic water bath. Thermistors can be run with a very low level of self heating and they are very sensitive, their resistance changes 4% per Centigrade degree, and they come in high values like 100K ohm. You read them in a bridge circuit with a voltmeter, so they are many orders of magnitude easier to use than a 100 ohm PRT. They are made small enough to get them in close contact with the object to be measured. If you want to know about humidity measurement I can tell you much about that, cheers, Neville Michie On 08/12/2013, at 12:40 PM, Mark Spencer wrote: > Sorry if this is somewhat off topic, but I'd be interested in more details re precision temperature measurement devices. Have been using an inexpensive USB temperature sensor for the last year or so to monitor the temperature in my lab and have been looking at the correlation between frequency shifts in some ocxo's vs temperature changes. I should also start taking humidity measurements as well at some point. > > > Any pointers re suitable instruments to accomplish this that can be sourced via the usual surplus sources would be welcome. > > Thanks in advance > Mark Spencer > > Sent from my iPad > ___ > 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 >>>
Re: [time-nuts] temperature
> Any pointers re suitable instruments to accomplish this that can be sourced > via the usual surplus sources would be welcome. > > Thanks in advance > Mark Spencer Hi Mark, Here's a list of the thermometers I use: - Vintage hp 2804. Still my favorite, high-resolution thermometer. I use it in GPIB talk-only mode with a NI GPIB-serial converter. Absolute calibration is probably off, but I'm more interested in temperature stability. - HMP 230 (www.vaisala.com). Expensive new but occasionally very cheap on eBay. Superb, high-resolution temperature and hygrometer. Very nice command set. - TempTrax model F (www.sensatronics.com). Cheap and easy to use. You send it a 'T' and it replies with temperature(s). Now obsolete; replaced by professional, expensive model E. - Sparkfun USB weather board (https://www.sparkfun.com/products/10586). The design changes now and then. Gives temperature, humidity, and pressure every second over USB (virtual com port). - 4-chan DS1820 temperature (http://www.ebay.com/itm/220920837443). A simple design that's very convenient to use. Older models were serial, newer ones USB. Plug it in and it talks. No software required. - Stanford Research Systems SR630 16-channel Thermocouple Monitor (www.thinksrs.com). Nice if you have lots of points to measure, and collect data over time. In general, regardless of the device, I log all raw data from native serial (or USB virtual serial) ports, prefixing every line with a MJD timestamp. That way I can correlate environmental measurements with clock measurements. /tvb ___ 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] temperature
On 12/9/13 6:12 AM, Daniel Mendes wrote: It´s still used in the oil industry as "the standard" for temp and pressure monitoring... Probably because they're an inherently rugged sensor ___ 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] temperature
It´s still used in the oil industry as "the standard" for temp and pressure monitoring... Daniel Em 09/12/2013 10:28, Bob Camp escreveu: Hi The Quartz Thermometer died when somebody proved that hysteresis was a big deal on the probes. Bob On Dec 8, 2013, at 11:22 PM, Tim Shoppa wrote: Interestingly, HP for a long time sold"quartz thermometers" based around a probe with a quartz crystal with a well characterized linear temperature coefficient. They called the crystal cut "LC" (Linear Coefficient): http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1965-03.pdf http://en.wikipedia.org/wiki/Quartz_thermometer On Sun, Dec 8, 2013 at 10:55 PM, Neville Michie wrote: Hi, I use a HP3468A multimeter to measure a PT100 platinum resistance thermometer. It gives me resolution of one mK, but calibration is another matter. It is best to use a 4 terminal device, but 2 terminal into the 4 terminal input works well. Thermoelectric effects and the requirement for 1 microvolt stability makes wiring them into your own circuit difficult. One of the great technical difficulties is to get a resistor to compare them against, it must be very stable, have no thermoelectric effects and have a temperature coefficient in the order of one PPM. I always admire the way HP designed their ohm meters. There are other issues, however. Whereas a volt meter can connect perfectly to a reference, a PRT can only report its own temperature. That is no problem when you are working in a well stirred water bath, that will have the PRT at the same temperature as the object in the same bath. When you get to measure air temperature you are into serious sampling errors, the PRT has some self heating and so is air velocity sensitive, and the air you are measuring may not be the same air as is over your OCXO or item of interest. There is a personal plume of warm air rising from an observer, so you must be careful with your measurement technique. The same problems occur with quartz crystal thermometers, which is why they are not more commonly found in surplus. A PT100 sensor is quite cheap, and their calibration is little short of brilliant. However a they would cost much more if their calibration is traceable. For my use, I use an ice-point cell as a calibration check, with care you get 10mK accuracy. You only need the knowledge how to set it up, a blender to make ice slush, and a picnic vacuum flask, to make your own calibration reference. I use thermistors for air measurement, and calibrate them against the PT100 in a thermostatic water bath. Thermistors can be run with a very low level of self heating and they are very sensitive, their resistance changes 4% per Centigrade degree, and they come in high values like 100K ohm. You read them in a bridge circuit with a voltmeter, so they are many orders of magnitude easier to use than a 100 ohm PRT. They are made small enough to get them in close contact with the object to be measured. If you want to know about humidity measurement I can tell you much about that, cheers, Neville Michie On 08/12/2013, at 12:40 PM, Mark Spencer wrote: Sorry if this is somewhat off topic, but I'd be interested in more details re precision temperature measurement devices. Have been using an inexpensive USB temperature sensor for the last year or so to monitor the temperature in my lab and have been looking at the correlation between frequency shifts in some ocxo's vs temperature changes. I should also start taking humidity measurements as well at some point. Any pointers re suitable instruments to accomplish this that can be sourced via the usual surplus sources would be welcome. Thanks in advance Mark Spencer Sent from my iPad ___ 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. ___ 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] active vs passive hydrogen maser long term stability
Attila, That diagram looks outdated to me, by 20 to 40 years. See modern plots in: http://tycho.usno.navy.mil/ptti/2004papers/paper38.pdf The Long-Term Stability of the U.S. Naval Observatory's Masers http://www.ptfinc.com/dsheets/CH1_75A.pdf CH1-75 Active Hydrogen Maser http://www.ptfinc.com/dsheets/CH1_76A.pdf CH1-76 Passive Hydrogen Maser http://www.oscilloquartz.com/files/1383126805-da_3700.pdf OSA 3700 Passive Hydrogen Maser http://www.symmetricom.com/resources/download-library/documents/datasheets/mhm-2010/ Symmetricom (Sigma Tau) MHM 2010, Active Hydrogen Maser See also: http://www.spectratime.com/documents/EPTF2010_Paper_SHM.pdf 2010, Development of the space active hydrogen maser for the ACES mission http://hal.archives-ouvertes.fr/docs/00/22/17/13/PDF/ajp-jphyscol198142C818.pdf 1981, Hydrogen Maser: Active or Passive? Note also these days most active masers have cavity auto-tuning. /tvb ___ 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] temperature
Hi The Quartz Thermometer died when somebody proved that hysteresis was a big deal on the probes. Bob On Dec 8, 2013, at 11:22 PM, Tim Shoppa wrote: > Interestingly, HP for a long time sold"quartz thermometers" based around a > probe with a quartz crystal with a well characterized linear temperature > coefficient. They called the crystal cut "LC" (Linear Coefficient): > > http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1965-03.pdf > > http://en.wikipedia.org/wiki/Quartz_thermometer > > > On Sun, Dec 8, 2013 at 10:55 PM, Neville Michie wrote: > >> Hi, >> I use a HP3468A multimeter to measure a PT100 platinum resistance >> thermometer. It gives me resolution of one mK, but calibration is another >> matter. >> It is best to use a 4 terminal device, but 2 terminal into the 4 terminal >> input works well. Thermoelectric effects and the requirement for 1 >> microvolt stability >> makes wiring them into your own circuit difficult. One of the great >> technical difficulties is to get a resistor to compare them against, it >> must be very stable, >> have no thermoelectric effects and have a temperature coefficient in the >> order of one PPM. I always admire the way HP designed their ohm meters. >> There are other issues, however. Whereas a volt meter can connect >> perfectly to a reference, a PRT can only report its own temperature. >> That is no problem when you are working in a well stirred water bath, that >> will have the PRT at the same temperature as the object in the same bath. >> When you get to measure air temperature you are into serious sampling >> errors, the PRT has some self heating and so is air velocity sensitive, and >> the air >> you are measuring may not be the same air as is over your OCXO or item of >> interest. There is a personal plume of warm air rising from an observer, so >> you must be careful with your measurement technique. >> The same problems occur with quartz crystal thermometers, which is why >> they are not more commonly found in surplus. >> A PT100 sensor is quite cheap, and their calibration is little short of >> brilliant. However a they would cost much more if their calibration is >> traceable. >> For my use, I use an ice-point cell as a calibration check, with care you >> get 10mK accuracy. You only need the knowledge how to set it up, a blender >> to make ice slush, >> and a picnic vacuum flask, to make your own calibration reference. >> I use thermistors for air measurement, and calibrate them against the >> PT100 in a thermostatic water bath. Thermistors can be run with a very low >> level of self heating and they are very sensitive, their resistance >> changes 4% per Centigrade degree, and they come in high values like 100K >> ohm. You read >> them in a bridge circuit with a voltmeter, so they are many orders of >> magnitude easier to use than a 100 ohm PRT. >> They are made small enough to get them in close contact >> with the object to be measured. >> If you want to know about humidity measurement I can tell you much about >> that, >> cheers, >> Neville Michie >> >> On 08/12/2013, at 12:40 PM, Mark Spencer wrote: >> >>> Sorry if this is somewhat off topic, but I'd be interested in more >> details re precision temperature measurement devices. Have been using an >> inexpensive USB temperature sensor for the last year or so to monitor the >> temperature in my lab and have been looking at the correlation between >> frequency shifts in some ocxo's vs temperature changes. I should also >> start taking humidity measurements as well at some point. >>> >>> >>> Any pointers re suitable instruments to accomplish this that can be >> sourced via the usual surplus sources would be welcome. >>> >>> Thanks in advance >>> Mark Spencer >>> >>> Sent from my iPad >>> ___ >>> 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.
[time-nuts] Attila & Active vs Passive H Masers
If I may direct you to www.quartzlock.com and the online catalog, you will see specifications of the small H Masers. We have both in use. Nicholai Demidov's paper at EFTF 2012 showed real results of a number of active H maser's with drifts down to E-17 levels One might ask when some benefit will be seen from all the trapped ion and optical clock work over the last 20 years ? cw a €160k AHM. We used a NIST system here for months to look at our AHM drift / offset, but our maser was below the noise level of the NIST system, so we just had https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] active vs passive hydrogen maser long term stability
Hi, I just read [1] and stumbled over a small detail in figure 1, which compares the stabilities of various frequency standards: The stability of active hydrogen masers is higher than the passive ones for short and medium term taus. But for long term, the active maser has a higher variation than the passive. I thought that the long term drift of the hydrogen maser was mostly due to changes in the wall coating (thus changing the wall shift) and temperature dependent variations of the cavity. These two variations should be the same for both passive and active masers. Yet, their long term stability shows a dramatically different behaviour. Can someone explain where this difference comes from or can point me to documents/papers/books that might explain it? Thanks in advance Attila Kinali [1] "An Introduction to Frequency Standards", by Lewis, 1991 http://www.nist.gov/calibrations/upload/ie79-7.pdf http://ieeexplore.ieee.org/iel1/5/2781/00084969.pdf (better quality, but paywall) -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ 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.
