Re: [time-nuts] Ultra Stable Rb
In message , Skip Withrow writes: >I did not want to drive the EFC (to remove a many variables as >possible). The C-field was set to get the unit about on frequency at >around 20Torr, then the supply voltage was tweaked to put it exactly >on frequency. >For the 238 day period ending 3Nov19 the aging was -3.76x10E-14 /day. >Not bad as far as Rb goes, but I can certainly do better. Keep in mind here is that you are not only dealing with the Rb's aging, you are also dealing with outgassing from the "normal" components and with a different mix of thermal transport mechanisms. There is no reason to think that multi-variable equation has only one flat spot. -- 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@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
On 4/9/20 8:36 AM, Skip Withrow wrote: Hello Time-Nuts, This is a subject that I have been interested in for quite some time. If you do some searching on Rb oscillator aging, there is a paper from FEI that showed GPS units aging in vacuum (and space) differently (as in opposite sign) than at sea level. My thought was that there should be a pressure where the aging should go to zero. I have been told by several people (that should know) that this has been studied in the industry and has never come to anything. But I'm a sucker for punishment. In April of 2018 I acquired a very nice vacuum chamber surplus from the aerospace industry. I I did not want to drive the EFC (to remove a many variables as possible). The C-field was set to get the unit about on frequency at around 20Torr, then the supply voltage was tweaked to put it exactly on frequency. If I had to guess (and that's what it is) I would say you're seeing an effect of the internal temperature distribution being dominated by gas conduction/convection to radiation. The mean free path of air at 10 hPa (10 mBar, 7.6 Torr) is about 6.7 microns. That's probably pretty small compared to the assembly dimensions, but it's starting to get bigger. At 1 micron (0.001 Torr) MFP is around 7cm I have found that, indeed, the aging direction can be changed with pressure. And there is a pressure that you can get the drift to zero. However, another fly in the ointment is that changing the supply voltage to put the unit on frequency also changes the aging. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
Very nice experiment. What do you think might be affected by pressure? At least in the physics pkg? Don On 2020-04-09 09:36, Skip Withrow wrote: Hello Time-Nuts, This is a subject that I have been interested in for quite some time. If you do some searching on Rb oscillator aging, there is a paper from FEI that showed GPS units aging in vacuum (and space) differently (as in opposite sign) than at sea level. My thought was that there should be a pressure where the aging should go to zero. I have been told by several people (that should know) that this has been studied in the industry and has never come to anything. But I'm a sucker for punishment. In April of 2018 I acquired a very nice vacuum chamber surplus from the aerospace industry. I contemplated which Rb oscillator to use and finally decided on the LPRO-101 since it had no DDS (and thus no discrete steps) and a wide supply voltage range (and I had several of them). The unit was mounted to the heavy aluminum lid of the chamber (which had five 61-pin electrical feedthru connectors, so no problem there). Kapton heaters were applied to the outside of the chamber and connected to a temperature controller, and a low noise power supply that could be varied from 18-32 volts was used to power the LPRO. A modified NTBW50 is used to monitor the output of the LPRO. A UPS and line conditioner were also added to the system. I did not want to drive the EFC (to remove a many variables as possible). The C-field was set to get the unit about on frequency at around 20Torr, then the supply voltage was tweaked to put it exactly on frequency. I have found that, indeed, the aging direction can be changed with pressure. And there is a pressure that you can get the drift to zero. However, another fly in the ointment is that changing the supply voltage to put the unit on frequency also changes the aging. At this point (Jan 2019) I connected the NTBW EFC drive to the LPRO. Now the LPRO could be disciplined, but as we all know GPS degrades the short-term performance. So, I run the unit with discipline disabled and just manually change the DAC voltage to keep the LPRO on frequency. The supply voltage, chamber pressure, and chamber temperature have not been touched since that point. By knowing the EFC gain I can calculate the aging. For the 238 day period ending 3Nov19 the aging was -3.76x10E-14 /day. Not bad as far as Rb goes, but I can certainly do better. The next step I would like to take is to move the C-field adjustment outside the chamber (and increase its resolution) so that I can put the oscillator on frequency without any changes in supply voltage. And again disconnect the EFC (since there is a temperature dependence on the DAC value). Then I should be able to get back to finding the exact pressure the chamber should be set at. The whole system is contained in a very short rack with the chamber on top of it and an insulation shield over it. I call it RUFUS (RUbidium Frequency Ultra Stable). It lives underneath the stairs going to the basement. I have also considered just building a box to drive the EFC and increment the voltage at the proper rate for whatever the drift might be for the temperature, pressure, and supply voltage that the oscillator might be at. Too much fun! Sorry for the long post. I'm hoping to have a detailed paper with all the details at some point, but getting all the data of course goes very slow. Regards, Skip Withrow ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. -- Dr. Don Latham AJ7LL PO Box 404, Frenchtown, MT, 59834 VOX: 406-626-4304 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
Hello Time-Nuts, This is a subject that I have been interested in for quite some time. If you do some searching on Rb oscillator aging, there is a paper from FEI that showed GPS units aging in vacuum (and space) differently (as in opposite sign) than at sea level. My thought was that there should be a pressure where the aging should go to zero. I have been told by several people (that should know) that this has been studied in the industry and has never come to anything. But I'm a sucker for punishment. In April of 2018 I acquired a very nice vacuum chamber surplus from the aerospace industry. I contemplated which Rb oscillator to use and finally decided on the LPRO-101 since it had no DDS (and thus no discrete steps) and a wide supply voltage range (and I had several of them). The unit was mounted to the heavy aluminum lid of the chamber (which had five 61-pin electrical feedthru connectors, so no problem there). Kapton heaters were applied to the outside of the chamber and connected to a temperature controller, and a low noise power supply that could be varied from 18-32 volts was used to power the LPRO. A modified NTBW50 is used to monitor the output of the LPRO. A UPS and line conditioner were also added to the system. I did not want to drive the EFC (to remove a many variables as possible). The C-field was set to get the unit about on frequency at around 20Torr, then the supply voltage was tweaked to put it exactly on frequency. I have found that, indeed, the aging direction can be changed with pressure. And there is a pressure that you can get the drift to zero. However, another fly in the ointment is that changing the supply voltage to put the unit on frequency also changes the aging. At this point (Jan 2019) I connected the NTBW EFC drive to the LPRO. Now the LPRO could be disciplined, but as we all know GPS degrades the short-term performance. So, I run the unit with discipline disabled and just manually change the DAC voltage to keep the LPRO on frequency. The supply voltage, chamber pressure, and chamber temperature have not been touched since that point. By knowing the EFC gain I can calculate the aging. For the 238 day period ending 3Nov19 the aging was -3.76x10E-14 /day. Not bad as far as Rb goes, but I can certainly do better. The next step I would like to take is to move the C-field adjustment outside the chamber (and increase its resolution) so that I can put the oscillator on frequency without any changes in supply voltage. And again disconnect the EFC (since there is a temperature dependence on the DAC value). Then I should be able to get back to finding the exact pressure the chamber should be set at. The whole system is contained in a very short rack with the chamber on top of it and an insulation shield over it. I call it RUFUS (RUbidium Frequency Ultra Stable). It lives underneath the stairs going to the basement. I have also considered just building a box to drive the EFC and increment the voltage at the proper rate for whatever the drift might be for the temperature, pressure, and supply voltage that the oscillator might be at. Too much fun! Sorry for the long post. I'm hoping to have a detailed paper with all the details at some point, but getting all the data of course goes very slow. Regards, Skip Withrow ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
On 4/8/2020 3:33 PM, Dana Whitlow wrote: Bob, what I' was getting at was: what do you do differently to make a stable Rb versus one that drifts a lot? Never mind price issues. My understanding from working on the HP10816 Rb standard is that aging (as opposed to temperature drift) is due to the vagaries of Rb atoms moving around and blocking the light causing light shift. The lamp also has wearout mechanisms having to do with the Rb dissolving into the glass and possibly making it opaque etc. If the cell is not "flooded", then how unflooded it is changes as Rb gets absorbed by the glass. The glass used is the next best thing to Fused Quartz, in order to make it as impervious as possible to Rb. Could one buy, say, a PRS-10, extract the physics package from it, then engineer a stable Rb with that as a core? No, the aging is a function of the physics package, especially the glassware. The electronics would have to be fairly poorly designed to contribute to aging. Note: thermal drift (as opposed to aging) is a different discussion altogether. There are a gazillion temperature effects, both in the physics and the electronics that need to be addressed. I think some designs simply use a TCXO type of technique to address all of these at once. Rick Dana On Wed, Apr 8, 2020 at 4:19 PM Bob kb8tq wrote: Hi The GPS Rb’s are “couple million dollar” sort of devices. Once GPS is up and running, the order volume drops off. The idea was to branch out into the broader military market. The design of the FRK did not change in any way as the price “morphed”. They simply had been making a pretty healthy margin on the product. What happened to the RFS in the years after I left … no idea. Bob On Apr 8, 2020, at 4:32 PM, djl wrote: So it's Chinese engineering? Find something good that works, start removing parts until it doesn't, put in the part last removed, and sell it? My granddad worked for a guy in LA called Madman Muntz who made tv's that way in the late 1940's. They worked. Sorta. For a while. If the signal was strong enough. Voila! $X-$400 On 2020-04-08 13:51, Bob kb8tq wrote: Hi At the time EG had done the GPS Rb’s but not done any other military parts. Some research showed that indeed the FRK went into a variety of systems and the price was $X. (It varied a bit with quantity) Push the numbers around and look at this and that. The decision was made that indeed if you could sell a few hundred to maybe a thousand a year at $X, it was a good thing. A design was done and (as noted earlier) it was a good little device. The fun part came with that $X pricing. Out comes a request for some few hundred pieces to this or that organization. Bid $X, order goes down to the competition for X-$300. Next request for a few hundred, bid X-$400, order goes down to the other guy for X-$500. This step by step process goes on for a year …. same result again and again. At the end of that time period it was far less clear just *why* one does up an FRK like part …. Bob On Apr 8, 2020, at 2:32 PM, djl wrote: What a tease! OK, very well WHY??? Don On 2020-04-08 08:04, Bob kb8tq wrote: Hi A few of the long running FRK’s ( in a very similar package … hmmm ….. wonder why …. yes, I was there way back then and know very well why :) ) have crazy good long term aging. That said, I don’t think that I’ve seen a FRK quite this good. Thanks for sharing !!! Bob On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote: Hi Guys, Just though you'd be interested in my prototype rubidium frequency standard I made in the 1990's. http://www.ptsyst.com/RFS10-FrequencyDrift.pdf I have measured its frequency at random intervals for the past 18 years. Its never been adjusted and is just free running. It was turned off in 2005 and sent to a customer in Japan for a few weeks, then returned and turned back on. For the past 18 years its stayed within plus/minus 3 x 10E-11. The overall linear drift is something like 1.85 x 10E-13 per month. This is not an advert. There's no way any of our production units are as good as this one, well I assume so as I've never measured any for 18 years continuous! Its now over 25 years old, have hardly ever been turned off. Any day I expect it to fail, but it keeps on running!! Regards Martyn ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. -- Dr. Don Latham AJ7LL PO Box 404, Frenchtown, MT, 59834 VOX: 406-626-4304 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to
Re: [time-nuts] Ultra Stable Rb
Hi The “conventional wisdom” is that the “big cell” Rb’s ( like the GPS Rb and the 5065 ) *do* have a fundamental advantage. The 5065 design dates to the 60’s. There are a lot of things that can be addressed there. PHK has a great set of observations on his web site looking into that. The “ultimate” Rb would likely be a large cell version. Various groups are working on tune up’s for things like the FRK. Things like compensation that simply where not considered back in the day, may be rational today. How close this gets you …. only time will tell. Best guess is that Rb’s and OCXO’s share some basic gotchas. Your design only gets you just so far. Some percentage of the parts will be utterly rotten. Some percentage will be pretty amazing. There will be a significant group in the middle. Screening has *always* been a way to deal with this. If you are willing to run through a few hundred samples to get less than 5 “good ones”, you can do pretty crazy things. This is done on OCXO’s, I don’t know of any examples of it being done on Rb’s. Bob > On Apr 8, 2020, at 6:33 PM, Dana Whitlow wrote: > > Bob, what I' was getting at was: what do you do differently to make a > stable Rb versus one > that drifts a lot? Never mind price issues. > > Could one buy, say, a PRS-10, extract the physics package from it, then > engineer a stable > Rb with that as a core? > > Dana > > > On Wed, Apr 8, 2020 at 4:19 PM Bob kb8tq wrote: > >> Hi >> >> The GPS Rb’s are “couple million dollar” sort of devices. Once GPS is up >> and running, >> the order volume drops off. The idea was to branch out into the broader >> military market. >> The design of the FRK did not change in any way as the price “morphed”. >> They simply >> had been making a pretty healthy margin on the product. What happened to >> the RFS >> in the years after I left … no idea. >> >> Bob >> >>> On Apr 8, 2020, at 4:32 PM, djl wrote: >>> >>> So it's Chinese engineering? Find something good that works, start >> removing parts until it doesn't, put in the part last removed, and sell it? >>> >>> My granddad worked for a guy in LA called Madman Muntz who made tv's >> that way in the late 1940's. They worked. Sorta. For a while. If the signal >> was strong enough. >>> Voila! $X-$400 >>> >>> On 2020-04-08 13:51, Bob kb8tq wrote: Hi At the time EG had done the GPS Rb’s but not done any other military parts. Some research showed that indeed the FRK went into a variety of systems and the price was $X. (It varied a bit with >> quantity) Push the numbers around and look at this and that. The decision was made that indeed if you could sell a few hundred to maybe a thousand a year >> at $X, it was a good thing. A design was done and (as noted earlier) it was a good little device. The fun part came with that $X pricing. Out comes a request for some few hundred pieces to this or that organization. Bid $X, order goes down to >> the competition for X-$300. Next request for a few hundred, bid X-$400, >> order goes down to the other guy for X-$500. This step by step process goes on for a year …. same result again and again. At the end of that time period it was far less clear just *why* one >> does up an FRK like part …. Bob > On Apr 8, 2020, at 2:32 PM, djl wrote: > What a tease! OK, very well WHY??? > Don > On 2020-04-08 08:04, Bob kb8tq wrote: >> Hi >> A few of the long running FRK’s ( in a very similar package … >> hmmm ….. wonder why …. yes, I was there way back then >> and know very well why :) ) have crazy good long term aging. >> That said, I don’t think that I’ve seen a FRK quite this good. >> Thanks for sharing !!! >> Bob >>> On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote: >>> Hi Guys, >>> Just though you'd be interested in my prototype rubidium frequency >> standard >>> I made in the 1990's. >>> http://www.ptsyst.com/RFS10-FrequencyDrift.pdf >>> I have measured its frequency at random intervals for the past 18 >> years. >>> Its never been adjusted and is just free running. >>> It was turned off in 2005 and sent to a customer in Japan for a few >> weeks, >>> then returned and turned back on. >>> For the past 18 years its stayed within plus/minus 3 x 10E-11. >>> The overall linear drift is something like 1.85 x 10E-13 per month. >>> This is not an advert. There's no way any of our production units >> are as >>> good as this one, well I assume so as I've never measured any for 18 >> years >>> continuous! >>> Its now over 25 years old, have hardly ever been turned off. Any >> day I >>> expect it to fail, but it keeps on running!! >>> Regards >>> Martyn >>> ___ >>> time-nuts mailing list -- time-nuts@lists.febo.com >>> To unsubscribe, go to >>
Re: [time-nuts] Ultra Stable Rb
Bob, what I' was getting at was: what do you do differently to make a stable Rb versus one that drifts a lot? Never mind price issues. Could one buy, say, a PRS-10, extract the physics package from it, then engineer a stable Rb with that as a core? Dana On Wed, Apr 8, 2020 at 4:19 PM Bob kb8tq wrote: > Hi > > The GPS Rb’s are “couple million dollar” sort of devices. Once GPS is up > and running, > the order volume drops off. The idea was to branch out into the broader > military market. > The design of the FRK did not change in any way as the price “morphed”. > They simply > had been making a pretty healthy margin on the product. What happened to > the RFS > in the years after I left … no idea. > > Bob > > > On Apr 8, 2020, at 4:32 PM, djl wrote: > > > > So it's Chinese engineering? Find something good that works, start > removing parts until it doesn't, put in the part last removed, and sell it? > > > > My granddad worked for a guy in LA called Madman Muntz who made tv's > that way in the late 1940's. They worked. Sorta. For a while. If the signal > was strong enough. > > Voila! $X-$400 > > > > On 2020-04-08 13:51, Bob kb8tq wrote: > >> Hi > >> At the time EG had done the GPS Rb’s but not done any other > >> military parts. Some research showed that indeed the FRK went into > >> a variety of systems and the price was $X. (It varied a bit with > quantity) > >> Push the numbers around and look at this and that. The decision was made > >> that indeed if you could sell a few hundred to maybe a thousand a year > at > >> $X, it was a good thing. A design was done and (as noted earlier) it was > >> a good little device. > >> The fun part came with that $X pricing. Out comes a request for some few > >> hundred pieces to this or that organization. Bid $X, order goes down to > the > >> competition for X-$300. Next request for a few hundred, bid X-$400, > order > >> goes down to the other guy for X-$500. This step by step process goes on > >> for a year …. same result again and again. > >> At the end of that time period it was far less clear just *why* one > does up > >> an FRK like part …. > >> Bob > >>> On Apr 8, 2020, at 2:32 PM, djl wrote: > >>> What a tease! OK, very well WHY??? > >>> Don > >>> On 2020-04-08 08:04, Bob kb8tq wrote: > Hi > A few of the long running FRK’s ( in a very similar package … > hmmm ….. wonder why …. yes, I was there way back then > and know very well why :) ) have crazy good long term aging. > That said, I don’t think that I’ve seen a FRK quite this good. > Thanks for sharing !!! > Bob > > On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote: > > Hi Guys, > > Just though you'd be interested in my prototype rubidium frequency > standard > > I made in the 1990's. > > http://www.ptsyst.com/RFS10-FrequencyDrift.pdf > > I have measured its frequency at random intervals for the past 18 > years. > > Its never been adjusted and is just free running. > > It was turned off in 2005 and sent to a customer in Japan for a few > weeks, > > then returned and turned back on. > > For the past 18 years its stayed within plus/minus 3 x 10E-11. > > The overall linear drift is something like 1.85 x 10E-13 per month. > > This is not an advert. There's no way any of our production units > are as > > good as this one, well I assume so as I've never measured any for 18 > years > > continuous! > > Its now over 25 years old, have hardly ever been turned off. Any > day I > > expect it to fail, but it keeps on running!! > > Regards > > Martyn > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > >>> -- > >>> Dr. Don Latham AJ7LL > >>> PO Box 404, Frenchtown, MT, 59834 > >>> VOX: 406-626-4304 > >>> ___ > >>> time-nuts mailing list -- time-nuts@lists.febo.com > >>> To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >>> and follow the instructions there. > >> ___ > >> time-nuts mailing list -- time-nuts@lists.febo.com > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > > > > -- > > Dr. Don Latham AJ7LL > > PO Box 404, Frenchtown, MT, 59834 > > VOX: 406-626-4304 > > > > > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to >
Re: [time-nuts] Ultra Stable Rb
Hi The GPS Rb’s are “couple million dollar” sort of devices. Once GPS is up and running, the order volume drops off. The idea was to branch out into the broader military market. The design of the FRK did not change in any way as the price “morphed”. They simply had been making a pretty healthy margin on the product. What happened to the RFS in the years after I left … no idea. Bob > On Apr 8, 2020, at 4:32 PM, djl wrote: > > So it's Chinese engineering? Find something good that works, start removing > parts until it doesn't, put in the part last removed, and sell it? > > My granddad worked for a guy in LA called Madman Muntz who made tv's that way > in the late 1940's. They worked. Sorta. For a while. If the signal was strong > enough. > Voila! $X-$400 > > On 2020-04-08 13:51, Bob kb8tq wrote: >> Hi >> At the time EG had done the GPS Rb’s but not done any other >> military parts. Some research showed that indeed the FRK went into >> a variety of systems and the price was $X. (It varied a bit with quantity) >> Push the numbers around and look at this and that. The decision was made >> that indeed if you could sell a few hundred to maybe a thousand a year at >> $X, it was a good thing. A design was done and (as noted earlier) it was >> a good little device. >> The fun part came with that $X pricing. Out comes a request for some few >> hundred pieces to this or that organization. Bid $X, order goes down to the >> competition for X-$300. Next request for a few hundred, bid X-$400, order >> goes down to the other guy for X-$500. This step by step process goes on >> for a year …. same result again and again. >> At the end of that time period it was far less clear just *why* one does up >> an FRK like part …. >> Bob >>> On Apr 8, 2020, at 2:32 PM, djl wrote: >>> What a tease! OK, very well WHY??? >>> Don >>> On 2020-04-08 08:04, Bob kb8tq wrote: Hi A few of the long running FRK’s ( in a very similar package … hmmm ….. wonder why …. yes, I was there way back then and know very well why :) ) have crazy good long term aging. That said, I don’t think that I’ve seen a FRK quite this good. Thanks for sharing !!! Bob > On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote: > Hi Guys, > Just though you'd be interested in my prototype rubidium frequency > standard > I made in the 1990's. > http://www.ptsyst.com/RFS10-FrequencyDrift.pdf > I have measured its frequency at random intervals for the past 18 years. > Its never been adjusted and is just free running. > It was turned off in 2005 and sent to a customer in Japan for a few weeks, > then returned and turned back on. > For the past 18 years its stayed within plus/minus 3 x 10E-11. > The overall linear drift is something like 1.85 x 10E-13 per month. > This is not an advert. There's no way any of our production units are as > good as this one, well I assume so as I've never measured any for 18 years > continuous! > Its now over 25 years old, have hardly ever been turned off. Any day I > expect it to fail, but it keeps on running!! > Regards > Martyn > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. >>> -- >>> Dr. Don Latham AJ7LL >>> PO Box 404, Frenchtown, MT, 59834 >>> VOX: 406-626-4304 >>> ___ >>> time-nuts mailing list -- time-nuts@lists.febo.com >>> To unsubscribe, go to >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > -- > Dr. Don Latham AJ7LL > PO Box 404, Frenchtown, MT, 59834 > VOX: 406-626-4304 > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
So it's Chinese engineering? Find something good that works, start removing parts until it doesn't, put in the part last removed, and sell it? My granddad worked for a guy in LA called Madman Muntz who made tv's that way in the late 1940's. They worked. Sorta. For a while. If the signal was strong enough. Voila! $X-$400 On 2020-04-08 13:51, Bob kb8tq wrote: Hi At the time EG had done the GPS Rb’s but not done any other military parts. Some research showed that indeed the FRK went into a variety of systems and the price was $X. (It varied a bit with quantity) Push the numbers around and look at this and that. The decision was made that indeed if you could sell a few hundred to maybe a thousand a year at $X, it was a good thing. A design was done and (as noted earlier) it was a good little device. The fun part came with that $X pricing. Out comes a request for some few hundred pieces to this or that organization. Bid $X, order goes down to the competition for X-$300. Next request for a few hundred, bid X-$400, order goes down to the other guy for X-$500. This step by step process goes on for a year …. same result again and again. At the end of that time period it was far less clear just *why* one does up an FRK like part …. Bob On Apr 8, 2020, at 2:32 PM, djl wrote: What a tease! OK, very well WHY??? Don On 2020-04-08 08:04, Bob kb8tq wrote: Hi A few of the long running FRK’s ( in a very similar package … hmmm ….. wonder why …. yes, I was there way back then and know very well why :) ) have crazy good long term aging. That said, I don’t think that I’ve seen a FRK quite this good. Thanks for sharing !!! Bob On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote: Hi Guys, Just though you'd be interested in my prototype rubidium frequency standard I made in the 1990's. http://www.ptsyst.com/RFS10-FrequencyDrift.pdf I have measured its frequency at random intervals for the past 18 years. Its never been adjusted and is just free running. It was turned off in 2005 and sent to a customer in Japan for a few weeks, then returned and turned back on. For the past 18 years its stayed within plus/minus 3 x 10E-11. The overall linear drift is something like 1.85 x 10E-13 per month. This is not an advert. There's no way any of our production units are as good as this one, well I assume so as I've never measured any for 18 years continuous! Its now over 25 years old, have hardly ever been turned off. Any day I expect it to fail, but it keeps on running!! Regards Martyn ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. -- Dr. Don Latham AJ7LL PO Box 404, Frenchtown, MT, 59834 VOX: 406-626-4304 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. -- Dr. Don Latham AJ7LL PO Box 404, Frenchtown, MT, 59834 VOX: 406-626-4304 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
Hi At the time EG had done the GPS Rb’s but not done any other military parts. Some research showed that indeed the FRK went into a variety of systems and the price was $X. (It varied a bit with quantity) Push the numbers around and look at this and that. The decision was made that indeed if you could sell a few hundred to maybe a thousand a year at $X, it was a good thing. A design was done and (as noted earlier) it was a good little device. The fun part came with that $X pricing. Out comes a request for some few hundred pieces to this or that organization. Bid $X, order goes down to the competition for X-$300. Next request for a few hundred, bid X-$400, order goes down to the other guy for X-$500. This step by step process goes on for a year …. same result again and again. At the end of that time period it was far less clear just *why* one does up an FRK like part …. Bob > On Apr 8, 2020, at 2:32 PM, djl wrote: > > What a tease! OK, very well WHY??? > Don > > On 2020-04-08 08:04, Bob kb8tq wrote: >> Hi >> A few of the long running FRK’s ( in a very similar package … >> hmmm ….. wonder why …. yes, I was there way back then >> and know very well why :) ) have crazy good long term aging. >> That said, I don’t think that I’ve seen a FRK quite this good. >> Thanks for sharing !!! >> Bob >>> On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote: >>> Hi Guys, >>> Just though you'd be interested in my prototype rubidium frequency standard >>> I made in the 1990's. >>> http://www.ptsyst.com/RFS10-FrequencyDrift.pdf >>> I have measured its frequency at random intervals for the past 18 years. >>> Its never been adjusted and is just free running. >>> It was turned off in 2005 and sent to a customer in Japan for a few weeks, >>> then returned and turned back on. >>> For the past 18 years its stayed within plus/minus 3 x 10E-11. >>> The overall linear drift is something like 1.85 x 10E-13 per month. >>> This is not an advert. There's no way any of our production units are as >>> good as this one, well I assume so as I've never measured any for 18 years >>> continuous! >>> Its now over 25 years old, have hardly ever been turned off. Any day I >>> expect it to fail, but it keeps on running!! >>> Regards >>> Martyn >>> ___ >>> time-nuts mailing list -- time-nuts@lists.febo.com >>> To unsubscribe, go to >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > -- > Dr. Don Latham AJ7LL > PO Box 404, Frenchtown, MT, 59834 > VOX: 406-626-4304 > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
What a tease! OK, very well WHY??? Don On 2020-04-08 08:04, Bob kb8tq wrote: Hi A few of the long running FRK’s ( in a very similar package … hmmm ….. wonder why …. yes, I was there way back then and know very well why :) ) have crazy good long term aging. That said, I don’t think that I’ve seen a FRK quite this good. Thanks for sharing !!! Bob On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote: Hi Guys, Just though you'd be interested in my prototype rubidium frequency standard I made in the 1990's. http://www.ptsyst.com/RFS10-FrequencyDrift.pdf I have measured its frequency at random intervals for the past 18 years. Its never been adjusted and is just free running. It was turned off in 2005 and sent to a customer in Japan for a few weeks, then returned and turned back on. For the past 18 years its stayed within plus/minus 3 x 10E-11. The overall linear drift is something like 1.85 x 10E-13 per month. This is not an advert. There's no way any of our production units are as good as this one, well I assume so as I've never measured any for 18 years continuous! Its now over 25 years old, have hardly ever been turned off. Any day I expect it to fail, but it keeps on running!! Regards Martyn ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. -- Dr. Don Latham AJ7LL PO Box 404, Frenchtown, MT, 59834 VOX: 406-626-4304 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
Martyn, is there anything special about the design to which you might attribute the low drift? Even if your unit's siblings are not "quite as good", they might still be quite a bit better than the usual run-of-the-mill Rbs. Thanks, Dana On Wed, Apr 8, 2020 at 8:46 AM wrote: > Hi Guys, > > Just though you'd be interested in my prototype rubidium frequency standard > I made in the 1990's. > > http://www.ptsyst.com/RFS10-FrequencyDrift.pdf > > I have measured its frequency at random intervals for the past 18 years. > > Its never been adjusted and is just free running. > > It was turned off in 2005 and sent to a customer in Japan for a few weeks, > then returned and turned back on. > > For the past 18 years its stayed within plus/minus 3 x 10E-11. > > The overall linear drift is something like 1.85 x 10E-13 per month. > > This is not an advert. There's no way any of our production units are as > good as this one, well I assume so as I've never measured any for 18 years > continuous! > > Its now over 25 years old, have hardly ever been turned off. Any day I > expect it to fail, but it keeps on running!! > > Regards > > Martyn > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
Hi A few of the long running FRK’s ( in a very similar package … hmmm ….. wonder why …. yes, I was there way back then and know very well why :) ) have crazy good long term aging. That said, I don’t think that I’ve seen a FRK quite this good. Thanks for sharing !!! Bob > On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote: > > Hi Guys, > > Just though you'd be interested in my prototype rubidium frequency standard > I made in the 1990's. > > http://www.ptsyst.com/RFS10-FrequencyDrift.pdf > > I have measured its frequency at random intervals for the past 18 years. > > Its never been adjusted and is just free running. > > It was turned off in 2005 and sent to a customer in Japan for a few weeks, > then returned and turned back on. > > For the past 18 years its stayed within plus/minus 3 x 10E-11. > > The overall linear drift is something like 1.85 x 10E-13 per month. > > This is not an advert. There's no way any of our production units are as > good as this one, well I assume so as I've never measured any for 18 years > continuous! > > Its now over 25 years old, have hardly ever been turned off. Any day I > expect it to fail, but it keeps on running!! > > Regards > > Martyn > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
respect. On Wed, Apr 8, 2020 at 3:46 PM wrote: > Hi Guys, > > Just though you'd be interested in my prototype rubidium frequency standard > I made in the 1990's. > > http://www.ptsyst.com/RFS10-FrequencyDrift.pdf > > I have measured its frequency at random intervals for the past 18 years. > > Its never been adjusted and is just free running. > > It was turned off in 2005 and sent to a customer in Japan for a few weeks, > then returned and turned back on. > > For the past 18 years its stayed within plus/minus 3 x 10E-11. > > The overall linear drift is something like 1.85 x 10E-13 per month. > > This is not an advert. There's no way any of our production units are as > good as this one, well I assume so as I've never measured any for 18 years > continuous! > > Its now over 25 years old, have hardly ever been turned off. Any day I > expect it to fail, but it keeps on running!! > > Regards > > Martyn > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Ultra Stable Rb
Hi Guys, Just though you'd be interested in my prototype rubidium frequency standard I made in the 1990's. http://www.ptsyst.com/RFS10-FrequencyDrift.pdf I have measured its frequency at random intervals for the past 18 years. Its never been adjusted and is just free running. It was turned off in 2005 and sent to a customer in Japan for a few weeks, then returned and turned back on. For the past 18 years its stayed within plus/minus 3 x 10E-11. The overall linear drift is something like 1.85 x 10E-13 per month. This is not an advert. There's no way any of our production units are as good as this one, well I assume so as I've never measured any for 18 years continuous! Its now over 25 years old, have hardly ever been turned off. Any day I expect it to fail, but it keeps on running!! Regards Martyn ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
