Re: [time-nuts] Modern Rb atomic reference vs classic Cs
Hi, It defines the expected target environment. VLBI stations and similar tends to have two Hydrogren masers, so that service can be done in house or even ship it for service, while maintaining operations. This seems to be the type of operations that these would fit into until they figured out how to do longer operational runs. For more expensive equipment, field serviceability becomes more important, such as replacing ion pumps etc. I only recall some passive masers that might have long operational life, but it seem it always comes with a performance hit. Cheers, Magnus On 2020-03-19 13:06, Bob kb8tq wrote: > Hi > > As the price of these gizmos goes up, the likelihood of them only going into > something *necessary* also goes up. You simply can’t get the purchase > approved otherwise. If you have to do a ship and return, you take that > necessary chunk of the operation offline for (weeks / months?) while that > process works its self out. > > So - I wonder how well the device can project when it’s going to run out of > Rb? A scheduled shutdown is always preferable to an unscheduled one. > > Bob > >> On Mar 19, 2020, at 5:52 AM, Paul Boven wrote: >> >> Hi Attila, list, >> >> On 3/17/20 9:51 PM, Attila Kinali wrote: >>> At those prices, I'd rather go for a µQuans or SDS Rb clock. >>> Those don't lose atoms like the Cs beam does and thus don't need >>> a refill. Their lifetime is more likely in the decades than just >>> a few years. Weakest link, as far as I know, are the lasers. >>> And yes, after the second, at latest after the third Cs tube, >>> these Rb devices are cheaper. And they are as much a primary >>> standard as the 5071 is. >> We've actually looked into purchasing the muQuans Rb. We learned from the >> vendor that they need to be serviced and refilled every four years, which >> could possibly be stretched to five years. This entails sending your clock >> back to the manufacturer. Otherwise, it simply runs out of Rb. >> >> Given that we were going to deploy these in rather remote locations, we >> decided that the repeated shipping and down-time was just going to be too >> difficult to deal with. >> >> Regards, Paul Boven. >> >> ___ >> 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 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] Modern Rb atomic reference vs classic Cs
Hi As the price of these gizmos goes up, the likelihood of them only going into something *necessary* also goes up. You simply can’t get the purchase approved otherwise. If you have to do a ship and return, you take that necessary chunk of the operation offline for (weeks / months?) while that process works its self out. So - I wonder how well the device can project when it’s going to run out of Rb? A scheduled shutdown is always preferable to an unscheduled one. Bob > On Mar 19, 2020, at 5:52 AM, Paul Boven wrote: > > Hi Attila, list, > > On 3/17/20 9:51 PM, Attila Kinali wrote: >> At those prices, I'd rather go for a µQuans or SDS Rb clock. >> Those don't lose atoms like the Cs beam does and thus don't need >> a refill. Their lifetime is more likely in the decades than just >> a few years. Weakest link, as far as I know, are the lasers. >> And yes, after the second, at latest after the third Cs tube, >> these Rb devices are cheaper. And they are as much a primary >> standard as the 5071 is. > > We've actually looked into purchasing the muQuans Rb. We learned from the > vendor that they need to be serviced and refilled every four years, which > could possibly be stretched to five years. This entails sending your clock > back to the manufacturer. Otherwise, it simply runs out of Rb. > > Given that we were going to deploy these in rather remote locations, we > decided that the repeated shipping and down-time was just going to be too > difficult to deal with. > > Regards, Paul Boven. > > ___ > 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] Modern Rb atomic reference vs classic Cs
On Thu, 19 Mar 2020 10:52:49 +0100 Paul Boven wrote: > We've actually looked into purchasing the muQuans Rb. We learned from > the vendor that they need to be serviced and refilled every four years, > which could possibly be stretched to five years. This entails sending > your clock back to the manufacturer. Otherwise, it simply runs out of Rb. Damn! I didn't know that. Sorry for the wrong information. Now I wonder where the Rb goes to. It's a closed system after all. I'll have to ask them at the next conference (whenever that will be) Attila Kinali -- The bad part of Zurich is where the degenerates throw DARK chocolate at you. ___ 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] Modern Rb atomic reference vs classic Cs
Clearly the muQuans clock is a horse of another color from our usual Rb standards. Considering its size and weight, shipping it back to the mfr every few years would be a royal pain, too. I looked over the datasheet and could find no mention of the active atomic species in use. Is it Rb for sure? Dana On Thu, Mar 19, 2020 at 4:53 AM Paul Boven wrote: > Hi Attila, list, > > On 3/17/20 9:51 PM, Attila Kinali wrote: > > At those prices, I'd rather go for a µQuans or SDS Rb clock. > > Those don't lose atoms like the Cs beam does and thus don't need > > a refill. Their lifetime is more likely in the decades than just > > a few years. Weakest link, as far as I know, are the lasers. > > And yes, after the second, at latest after the third Cs tube, > > these Rb devices are cheaper. And they are as much a primary > > standard as the 5071 is. > > We've actually looked into purchasing the muQuans Rb. We learned from > the vendor that they need to be serviced and refilled every four years, > which could possibly be stretched to five years. This entails sending > your clock back to the manufacturer. Otherwise, it simply runs out of Rb. > > Given that we were going to deploy these in rather remote locations, we > decided that the repeated shipping and down-time was just going to be > too difficult to deal with. > > Regards, Paul Boven. > > ___ > 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] Modern Rb atomic reference vs classic Cs
Hi Attila, list, On 3/17/20 9:51 PM, Attila Kinali wrote: At those prices, I'd rather go for a µQuans or SDS Rb clock. Those don't lose atoms like the Cs beam does and thus don't need a refill. Their lifetime is more likely in the decades than just a few years. Weakest link, as far as I know, are the lasers. And yes, after the second, at latest after the third Cs tube, these Rb devices are cheaper. And they are as much a primary standard as the 5071 is. We've actually looked into purchasing the muQuans Rb. We learned from the vendor that they need to be serviced and refilled every four years, which could possibly be stretched to five years. This entails sending your clock back to the manufacturer. Otherwise, it simply runs out of Rb. Given that we were going to deploy these in rather remote locations, we decided that the repeated shipping and down-time was just going to be too difficult to deal with. Regards, Paul Boven. ___ 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] Modern Rb atomic reference vs classic Cs
On Tue, 17 Mar 2020 22:16:38 + Greg Maxwell wrote: > Given that it's possible measure frequency differences very precisely > (and without a multi billion dollar particle accelerator), it might be > interesting to search for some of these. However, the frequency > ratios might not be the most natural ratios to search for. E.g. it > might be useful to first back out various effects which we know how to > account for precisely and see if there is a simple expression for the > residual. No, it would not. If there would have been a simple solution, then the formulas would be simple which means we would be able to calculate them. At the same time, if you try to find a pattern you will find one if you just look hard enough. Same as when you turn your TV set (yeah, an old CRT one) to an empty channel and look at the noise.. at some point it will start moving around and patterns will arise, where no pattern resides. Let me quickly explain what makes this so hard: We are looking at a set of differential equations that describe the movement, or rather the energetic states of the electrons around the atoms. Now, if you have a simple equation, you can find a solution ... maybe. Differential equations have the nasty behavior, that even the smallest complication, like adding a constant, can make the equation unsolvable. If you add multiple simple differential equations together you might also get something solvable...until it isn't anymore. The famous three body problem ( https://en.wikipedia.org/wiki/Three-body_problem ) is the most famous example where just adding "more of the same" makes the differential equations unsolvable even at a level where it is still almost trivial. Now, for a Rubidium atom, you have 38 bodies: 37 electroncs and the nucleus. This is so far beyond the 3 body problem that there is no hope that this will ever lead to a closed formula. Keep in mind that all 38 elements interact with each other and cannot be really seperated. And looking at it as an many body problem is still just a classical description and ignores all the quantum mechanic dynamics, that have to be described with more differential equations. This makes the problem so hard, that even numerical solutions are very very time consuming, to the point that it is not feasible for anything but very simple atoms. Hence, the most common way is to simplify the inner electrons and the nucleus as a single object, with only a single electron orbiting. This way, the atom can be treated as a Hydrogen atom, for which we can find solutions. Of course, how accurate these solutions are depends on how well we can approximate the effect of the nucleus and the inner electrons. For a more thorough explanation of the problem with differential equations, see 3blue1brown's videos on this: https://www.youtube.com/playlist?list=PLZHQObOWTQDNPOjrT6KVlfJuKtYTftqH6 Unfortunately, I don't know an easily accessable resource for calulating the energy levels of an atom. Attila Kinali -- The bad part of Zurich is where the degenerates throw DARK chocolate at you. ___ 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] Modern Rb atomic reference vs classic Cs
On Tue, Mar 17, 2020 at 8:52 PM Attila Kinali wrote: > On Sat, 14 Mar 2020 13:57:21 -0700 > Hal Murray wrote: > > > Can the physics-nuts calculate the Rb frequency relative to Cs? > > Theoretically yes, practically no. While we "know" exactly what > each electron in the atom is doing and how it interacts with each > other electron and the nucleus, there are so many of them that there > is no closed form solution (c.f. three/many body problem). As far > as I am aware of, nobody has even done a complete numerical model. > So all the calculations we have today are approximations that > bunch most if not all inner electrons together and approximate them > by an average field. There have been some intriguing results in using computational methods to find simple expressions for physical ratios: E.g. https://vixra.org/pdf/1410.0054v6.pdf (oh man, an I actually sharing a vixra link? I promise that Plouffe is not a kook, even if these results are a bit kooky as far as physics go.) Given that it's possible measure frequency differences very precisely (and without a multi billion dollar particle accelerator), it might be interesting to search for some of these. However, the frequency ratios might not be the most natural ratios to search for. E.g. it might be useful to first back out various effects which we know how to account for precisely and see if there is a simple expression for the residual. If one were found it might suggest some avenues to search for physical explanations justifying the match as a closed form solution. Unfortunately, the Plouffe Inverter grew pretty big and as a result no one has an instance of it online anymore AFAICT. So anyone interested in exploring this would probably need to contact plouffe. ___ 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] Modern Rb atomic reference vs classic Cs
A couple of years ago Time Tech was selling a OSA 8607 GPSDO with an AV of 8 E-14. AXTAL has one. Takes a lot of characterization, fully understand and constantly compensate the OCXO and continous GPS monitoring for more than 24 hours. W. Schaefer has the smarts. Does not have the aging of a Maser.Not having their smarts I am trying to do something close using aging compensation along with pressure and temperature on a FRK/M100 Rb and use a 8607 for clean up. Will use multi day GPS averaging for fine control. Presently running 4 Rb to pick the best. Use HP5065A for AV and Datum RS 2000 for frequency ,does 24 hour GPS averaging. Have 5061B with new small tube. Bert Kehren In a message dated 3/17/2020 4:52:23 PM Eastern Standard Time, att...@kinali.ch writes: On Sat, 14 Mar 2020 14:50:45 -0400 Bob kb8tq wrote: > A brand new 5071 with that tube appears to be over $90,000 these days. Based > on > running one for a lot of years, After about 6 years of operation, you will be > sending > it back for a new tube. By the time the unit is back in your lab, the refit > will cost > roughly half the price the whole unit cost new …. gulp ….. At those prices, I'd rather go for a µQuans or SDS Rb clock. Those don't lose atoms like the Cs beam does and thus don't need a refill. Their lifetime is more likely in the decades than just a few years. Weakest link, as far as I know, are the lasers. And yes, after the second, at latest after the third Cs tube, these Rb devices are cheaper. And they are as much a primary standard as the 5071 is. On Sat, 14 Mar 2020 13:57:21 -0700 Hal Murray wrote: > Can the physics-nuts calculate the Rb frequency relative to Cs? Theoretically yes, practically no. While we "know" exactly what each electron in the atom is doing and how it interacts with each other electron and the nucleus, there are so many of them that there is no closed form solution (c.f. three/many body problem). As far as I am aware of, nobody has even done a complete numerical model. So all the calculations we have today are approximations that bunch most if not all inner electrons together and approximate them by an average field. > What's missing on a gas cell? Is the problem theory or implementation? Both. For one, you cannot control all parameters during production well enough that a calulated shift would be any more accurate. For another, there are quite a few shifts in the system, from buffer gas shift (dependent on exact composition) to light shift to RF power shift to RF field gradient shift to temperature gradient shift to . Some of them nobody thought of until a PhD student tried to figure out what the next limiting factor was. If you would try to make the system as well characterizable as a Cs beam standard, then you would end up with a product that is at least as expensive, if not more. If you want to know more, have a look at the publications, especially the dissertations, by the time/frequency lab at UniNE: https://www.unine.ch/ltf/home/publications.html They go into quite detailed analysis of what the different shifts are that are affecting the long term stability of Rb vapor cells. Attila Kinali -- The bad part of Zurich is where the degenerates throw DARK chocolate at you. ___ 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] Modern Rb atomic reference vs classic Cs
On Sat, 14 Mar 2020 14:50:45 -0400 Bob kb8tq wrote: > A brand new 5071 with that tube appears to be over $90,000 these days. Based > on > running one for a lot of years, After about 6 years of operation, you will be > sending > it back for a new tube. By the time the unit is back in your lab, the refit > will cost > roughly half the price the whole unit cost new …. gulp ….. At those prices, I'd rather go for a µQuans or SDS Rb clock. Those don't lose atoms like the Cs beam does and thus don't need a refill. Their lifetime is more likely in the decades than just a few years. Weakest link, as far as I know, are the lasers. And yes, after the second, at latest after the third Cs tube, these Rb devices are cheaper. And they are as much a primary standard as the 5071 is. On Sat, 14 Mar 2020 13:57:21 -0700 Hal Murray wrote: > Can the physics-nuts calculate the Rb frequency relative to Cs? Theoretically yes, practically no. While we "know" exactly what each electron in the atom is doing and how it interacts with each other electron and the nucleus, there are so many of them that there is no closed form solution (c.f. three/many body problem). As far as I am aware of, nobody has even done a complete numerical model. So all the calculations we have today are approximations that bunch most if not all inner electrons together and approximate them by an average field. > What's missing on a gas cell? Is the problem theory or implementation? Both. For one, you cannot control all parameters during production well enough that a calulated shift would be any more accurate. For another, there are quite a few shifts in the system, from buffer gas shift (dependent on exact composition) to light shift to RF power shift to RF field gradient shift to temperature gradient shift to . Some of them nobody thought of until a PhD student tried to figure out what the next limiting factor was. If you would try to make the system as well characterizable as a Cs beam standard, then you would end up with a product that is at least as expensive, if not more. If you want to know more, have a look at the publications, especially the dissertations, by the time/frequency lab at UniNE: https://www.unine.ch/ltf/home/publications.html They go into quite detailed analysis of what the different shifts are that are affecting the long term stability of Rb vapor cells. Attila Kinali -- The bad part of Zurich is where the degenerates throw DARK chocolate at you. ___ 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] Modern Rb atomic reference vs classic Cs
Hi Used Cs standards show up for a wide range of prices. Sometimes that $50 hamfest acquisition *does* turn out to be a working device. For most of us, most of the time eBay is the source and you pay the “market price” there. Even there, figuring out what that price *is* can be a chore. Best guess is that you are unlikely to get a working unit for less than $1,500 delivered. There are a lot of listings at 2X to 5X that price level. Most of those listings do not provide a lot of “hope” for the device being in working condition. There are also a lot of listings below that price point for what appear to be gutted chassis.( = no hope at all). You could easily go through more than one purchase before you get a unit that is still reasonably close to working a year or two later. There are brand new instruments like the FS 740 or FS 752 that are “in the same ballpark” as far as cost. (assuming you don’t get lucky first time). They come with nice things like warranties. Power, size, and feature wise they are pretty competitive compared to the eBay 506. Is any GPSDO “as good as” a 5071 with a high performance tube in it in all respects? No, of course not. There will *always* be things the GPSDO falls behind on. There are also standards running around places like NIST that do some things better than a 5071 with the fancy tube. A brand new 5071 with that tube appears to be over $90,000 these days. Based on running one for a lot of years, After about 6 years of operation, you will be sending it back for a new tube. By the time the unit is back in your lab, the refit will cost roughly half the price the whole unit cost new …. gulp ….. Lots to think about …… Bob > On Mar 14, 2020, at 2:23 PM, Taka Kamiya via-nuts > wrote: > > Paul and Bob are my valuable mentors, and I trust their opinion. > I do have an old working Cs but my go-to are GPSDO. For most part, it's more > than sufficient. I also have ex-telecom Rb. There aren't too many things > one of them can't do, except for measuring themselves. In my lab, the "lab > standard" is GPSDO and backup is Rb. > At a hobby level, one of the big issue (at least to me) is power consumption, > and the heat they generate. My lab gets significantly warm. Plus, instant > availability of GPSDO and Rb (because they are always on) is hard to beat. > To save Cs, I only turn on mine when needed, then wait for 2 days. > To be honest, I'd love to have an HP5071A with warranty. But it's far beyond > affordable range for me. Also, a "standard" I can't trust isn't a standard. > I am not good enough to properly care for Cs and I don't have good enough > measuring system. It takes a lot to keep Cs happy and usable in many ways. > Signed, on laziest ham. > > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > >On Saturday, March 14, 2020, 12:14:43 PM EDT, paul swed > wrote: > > I will chime in here also. It is indeed great to say you have a cesium. HP > 5061s are just good fun to play with. It teaches you that as much as you > think you know you actually don't. But they do honestly take care and > feeding especially in the tail-end market that i can afford. > So to Bobs comment if you want a good reference for time-nuttery the GPSDO > is a really effortless way to go. Hard to say if RB or Xtal is better it > depends on what you might get at a flea market. But there is a lot to be > said for turn it on and be happy. I actually run a GPSD-TCXO as a instant > on sort of right there for my ham stuff. Power consumption sub 10 Watts. > Then flip to a HP3801 or any number of alternates including Cesium for > serious stuff like D-PSK-R development. > Signed one lazy ham. > Regards > Paul > WB8TSL > > On Sat, Mar 14, 2020 at 8:31 AM Bob kb8tq wrote: > >> Hi >> >> Backing off a bit, as long as GPS is doing it’s part ( or your GNSS system >> of >> choice …) an OCXO based setup may do as well as / better than your typical >> “almost dead” used Cs standard. >> >> It is very easy to find a used Cs with a dead tube. It is quite hard to >> find one >> with a tube that is fully up to original specs / runs for years. Finding >> replacement >> tubes is ( and always has been) a very involved process. There are way >> more >> used / dead tubes out there than used / working. >> >> Buying a new tube is in the “forget about it” price range. There also is >> no practical >> way to rebuild one. You can do this or that trick to maybe get a bit more >> time out >> of this or that tube … but maybe not. >> >> Thus the pair of dead 5061’s sitting in the basement. >> >> Bob >> >>> On Mar 14, 2020, at 12:06 AM, Peter Membrey wrote: >>> >>> Hi guys, >>> >>> Potentially a bit of a loaded topic, but I'm really curious as to what >> the consensus is on this. For the research I've been doing over the past >> few years, I've been predominantly using an SRS FS-725 (which uses the >> PRS-10) disciplined by a Microsemi S650
Re: [time-nuts] Modern Rb atomic reference vs classic Cs
Paul and Bob are my valuable mentors, and I trust their opinion. I do have an old working Cs but my go-to are GPSDO. For most part, it's more than sufficient. I also have ex-telecom Rb. There aren't too many things one of them can't do, except for measuring themselves. In my lab, the "lab standard" is GPSDO and backup is Rb. At a hobby level, one of the big issue (at least to me) is power consumption, and the heat they generate. My lab gets significantly warm. Plus, instant availability of GPSDO and Rb (because they are always on) is hard to beat. To save Cs, I only turn on mine when needed, then wait for 2 days. To be honest, I'd love to have an HP5071A with warranty. But it's far beyond affordable range for me. Also, a "standard" I can't trust isn't a standard. I am not good enough to properly care for Cs and I don't have good enough measuring system. It takes a lot to keep Cs happy and usable in many ways. Signed, on laziest ham. --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Saturday, March 14, 2020, 12:14:43 PM EDT, paul swed wrote: I will chime in here also. It is indeed great to say you have a cesium. HP 5061s are just good fun to play with. It teaches you that as much as you think you know you actually don't. But they do honestly take care and feeding especially in the tail-end market that i can afford. So to Bobs comment if you want a good reference for time-nuttery the GPSDO is a really effortless way to go. Hard to say if RB or Xtal is better it depends on what you might get at a flea market. But there is a lot to be said for turn it on and be happy. I actually run a GPSD-TCXO as a instant on sort of right there for my ham stuff. Power consumption sub 10 Watts. Then flip to a HP3801 or any number of alternates including Cesium for serious stuff like D-PSK-R development. Signed one lazy ham. Regards Paul WB8TSL On Sat, Mar 14, 2020 at 8:31 AM Bob kb8tq wrote: > Hi > > Backing off a bit, as long as GPS is doing it’s part ( or your GNSS system > of > choice …) an OCXO based setup may do as well as / better than your typical > “almost dead” used Cs standard. > > It is very easy to find a used Cs with a dead tube. It is quite hard to > find one > with a tube that is fully up to original specs / runs for years. Finding > replacement > tubes is ( and always has been) a very involved process. There are way > more > used / dead tubes out there than used / working. > > Buying a new tube is in the “forget about it” price range. There also is > no practical > way to rebuild one. You can do this or that trick to maybe get a bit more > time out > of this or that tube … but maybe not. > > Thus the pair of dead 5061’s sitting in the basement. > > Bob > > > On Mar 14, 2020, at 12:06 AM, Peter Membrey wrote: > > > > Hi guys, > > > > Potentially a bit of a loaded topic, but I'm really curious as to what > the consensus is on this. For the research I've been doing over the past > few years, I've been predominantly using an SRS FS-725 (which uses the > PRS-10) disciplined by a Microsemi S650 (with the Rb option, though it > never went into holdover). > > > > Modern Caesium references are expensive compared to the FS-725, but now > and then more classic Caesium references become available such as the HP > 5061A. These still aren't cheap (actually, not far off a brand new PRS-10) > so I was wondering how do they generally compare with a modern Rb? > > > > If I have a PRS-10 that's being disciplined by a good GPS source, would > I see any benefit if I replaced the PRS-10 with an HP5061A (particularly in > terms of stability)? > > > > Thanks in advance! > > > > Kind Regards, > > > > > > Peter Membrey > > > > ___ > > 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 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] Modern Rb atomic reference vs classic Cs
I will chime in here also. It is indeed great to say you have a cesium. HP 5061s are just good fun to play with. It teaches you that as much as you think you know you actually don't. But they do honestly take care and feeding especially in the tail-end market that i can afford. So to Bobs comment if you want a good reference for time-nuttery the GPSDO is a really effortless way to go. Hard to say if RB or Xtal is better it depends on what you might get at a flea market. But there is a lot to be said for turn it on and be happy. I actually run a GPSD-TCXO as a instant on sort of right there for my ham stuff. Power consumption sub 10 Watts. Then flip to a HP3801 or any number of alternates including Cesium for serious stuff like D-PSK-R development. Signed one lazy ham. Regards Paul WB8TSL On Sat, Mar 14, 2020 at 8:31 AM Bob kb8tq wrote: > Hi > > Backing off a bit, as long as GPS is doing it’s part ( or your GNSS system > of > choice …) an OCXO based setup may do as well as / better than your typical > “almost dead” used Cs standard. > > It is very easy to find a used Cs with a dead tube. It is quite hard to > find one > with a tube that is fully up to original specs / runs for years. Finding > replacement > tubes is ( and always has been) a very involved process. There are way > more > used / dead tubes out there than used / working. > > Buying a new tube is in the “forget about it” price range. There also is > no practical > way to rebuild one. You can do this or that trick to maybe get a bit more > time out > of this or that tube … but maybe not. > > Thus the pair of dead 5061’s sitting in the basement. > > Bob > > > On Mar 14, 2020, at 12:06 AM, Peter Membrey wrote: > > > > Hi guys, > > > > Potentially a bit of a loaded topic, but I'm really curious as to what > the consensus is on this. For the research I've been doing over the past > few years, I've been predominantly using an SRS FS-725 (which uses the > PRS-10) disciplined by a Microsemi S650 (with the Rb option, though it > never went into holdover). > > > > Modern Caesium references are expensive compared to the FS-725, but now > and then more classic Caesium references become available such as the HP > 5061A. These still aren't cheap (actually, not far off a brand new PRS-10) > so I was wondering how do they generally compare with a modern Rb? > > > > If I have a PRS-10 that's being disciplined by a good GPS source, would > I see any benefit if I replaced the PRS-10 with an HP5061A (particularly in > terms of stability)? > > > > Thanks in advance! > > > > Kind Regards, > > > > > > Peter Membrey > > > > ___ > > 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 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] Modern Rb atomic reference vs classic Cs
Hi Backing off a bit, as long as GPS is doing it’s part ( or your GNSS system of choice …) an OCXO based setup may do as well as / better than your typical “almost dead” used Cs standard. It is very easy to find a used Cs with a dead tube. It is quite hard to find one with a tube that is fully up to original specs / runs for years. Finding replacement tubes is ( and always has been) a very involved process. There are way more used / dead tubes out there than used / working. Buying a new tube is in the “forget about it” price range. There also is no practical way to rebuild one. You can do this or that trick to maybe get a bit more time out of this or that tube … but maybe not. Thus the pair of dead 5061’s sitting in the basement. Bob > On Mar 14, 2020, at 12:06 AM, Peter Membrey wrote: > > Hi guys, > > Potentially a bit of a loaded topic, but I'm really curious as to what the > consensus is on this. For the research I've been doing over the past few > years, I've been predominantly using an SRS FS-725 (which uses the PRS-10) > disciplined by a Microsemi S650 (with the Rb option, though it never went > into holdover). > > Modern Caesium references are expensive compared to the FS-725, but now and > then more classic Caesium references become available such as the HP 5061A. > These still aren't cheap (actually, not far off a brand new PRS-10) so I was > wondering how do they generally compare with a modern Rb? > > If I have a PRS-10 that's being disciplined by a good GPS source, would I see > any benefit if I replaced the PRS-10 with an HP5061A (particularly in terms > of stability)? > > Thanks in advance! > > Kind Regards, > > > Peter Membrey > > ___ > 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] Modern Rb atomic reference vs classic Cs
Well, I fixed two typing mistakes. Blame it on the corona, too many that is. Bill WB6BNQ On 3/13/2020 10:35 PM, WB6BNQ wrote: *Hello,* * * *By definition a Cesium frequency standard is just that, an absolute primary reference ! The only difference between the 5061A and another Cesium reference is a matter of degree of closeness to the absolute value. For example the 5061A has a spec of +/- 1 in 10 to the -11th for accuracy, whereas, 30 years later, the hp5071 has a spec of +/- 1 in 10 to the -12th.* *The Rubidium standard is similar but has a known drift, slight as it is, but does not allow it to be primary standard. If you have a good working hp-5061A, the best you can say is your standard is good to +/- 1 in ten to the -11th in accuracy. However, your FS725, while a very nice instrument has to be cross referenced to a primary standard in order to make any kind of absolute statement as to accuracy.* * * *BillWB6BNQ* On 3/13/2020 9:06 PM, Peter Membrey wrote: Hi guys, Potentially a bit of a loaded topic, but I'm really curious as to what the consensus is on this. For the research I've been doing over the past few years, I've been predominantly using an SRS FS-725 (which uses the PRS-10) disciplined by a Microsemi S650 (with the Rb option, though it never went into holdover). Modern Caesium references are expensive compared to the FS-725, but now and then more classic Caesium references become available such as the HP 5061A. These still aren't cheap (actually, not far off a brand new PRS-10) so I was wondering how do they generally compare with a modern Rb? If I have a PRS-10 that's being disciplined by a good GPS source, would I see any benefit if I replaced the PRS-10 with an HP5061A (particularly in terms of stability)? Thanks in advance! Kind Regards, Peter Membrey ___ time-nuts mailing list --time-nuts@lists.febo.com To unsubscribe, go tohttp://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] Modern Rb atomic reference vs classic Cs
Correction on the last sentence on accuracy of the hp-5061A was meant to say +/- 1 in 10 to the -11th. On 3/13/2020 10:35 PM, WB6BNQ wrote: *Hello,* * * *By definition a Cesium frequency standard is just that, an absolute primary reference ! The only difference between the 5061A and another Cesium reference is a matter of degree of closeness to the absolute value. For example the 5061A has a spec of +/- 1 in 10 to the -11th for accuracy, whereas, 30 later, the hp5071 has a spec of +/- 1 in 10 to the -12th.* *The Rubidium standard is similar but has a known drift, slight as it is, but does not allow it to be primary standard. If you have a good working hp-5061A, the best you can say is your standard is good to +/- 1 in ten to the -12th in accuracy. However, your FS725, while a very nice instrument has to be cross referenced to a primary standard in order to make any kind of absolute statement as to accuracy.* * * *BillWB6BNQ* On 3/13/2020 9:06 PM, Peter Membrey wrote: Hi guys, Potentially a bit of a loaded topic, but I'm really curious as to what the consensus is on this. For the research I've been doing over the past few years, I've been predominantly using an SRS FS-725 (which uses the PRS-10) disciplined by a Microsemi S650 (with the Rb option, though it never went into holdover). Modern Caesium references are expensive compared to the FS-725, but now and then more classic Caesium references become available such as the HP 5061A. These still aren't cheap (actually, not far off a brand new PRS-10) so I was wondering how do they generally compare with a modern Rb? If I have a PRS-10 that's being disciplined by a good GPS source, would I see any benefit if I replaced the PRS-10 with an HP5061A (particularly in terms of stability)? Thanks in advance! Kind Regards, Peter Membrey ___ time-nuts mailing list --time-nuts@lists.febo.com To unsubscribe, go tohttp://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] Modern Rb atomic reference vs classic Cs
*Hello,* * * *By definition a Cesium frequency standard is just that, an absolute primary reference ! The only difference between the 5061A and another Cesium reference is a matter of degree of closeness to the absolute value. For example the 5061A has a spec of +/- 1 in 10 to the -11th for accuracy, whereas, 30 later, the hp5071 has a spec of +/- 1 in 10 to the -12th.* *The Rubidium standard is similar but has a known drift, slight as it is, but does not allow it to be primary standard. If you have a good working hp-5061A, the best you can say is your standard is good to +/- 1 in ten to the -12th in accuracy. However, your FS725, while a very nice instrument has to be cross referenced to a primary standard in order to make any kind of absolute statement as to accuracy.* * * *BillWB6BNQ* On 3/13/2020 9:06 PM, Peter Membrey wrote: Hi guys, Potentially a bit of a loaded topic, but I'm really curious as to what the consensus is on this. For the research I've been doing over the past few years, I've been predominantly using an SRS FS-725 (which uses the PRS-10) disciplined by a Microsemi S650 (with the Rb option, though it never went into holdover). Modern Caesium references are expensive compared to the FS-725, but now and then more classic Caesium references become available such as the HP 5061A. These still aren't cheap (actually, not far off a brand new PRS-10) so I was wondering how do they generally compare with a modern Rb? If I have a PRS-10 that's being disciplined by a good GPS source, would I see any benefit if I replaced the PRS-10 with an HP5061A (particularly in terms of stability)? Thanks in advance! Kind Regards, Peter Membrey ___ 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.
