Re: [time-nuts] WTS: Efratom PTB-100 Precision Timebase
Don, I've noticed that in general IEEE retains copyright on most stuff they publish. I've been a member for more than 20 years, and this galls me. For an organization that purports to be for the good of mankind, they seem awfully stingy with the information they gather. But if you do acquire papers from IEEE, you are generally *not *authorized to publish or distribute it further without getting explicit permission (and probably paying for it). Sometimes I wonder why I hang onto the organizaiton- perhaps it's because, as a retiree, I'm unable to subscribe to all the usual "freebie" rags. I still very much want to keep up with developments in my field. Dana On Sun, Jul 8, 2018 at 2:09 PM, djl wrote: > Greg et.al. IEEE stuff is just too expensive for single purchase. I have > found, to my sorrow over 40 odd years, that they also do not contain > information, that is, info of actual use, because some other company or > person might actually benefit. In other words, the papers are markers in > the sand. > Now, this is my own opinion, a bit harsh, admittedly. Of course the > citations do need to be mentioned. > BTW, any published material generated with government funds that is not > classified belongs to the people, and is not copyrighted. I wonder if that > includes IEEE papers? that is, if anyone buys one, it can be copied or > distributed without restriction? > Not being in the lawyer class, I can't say for sure... > Thanks > Don > > > On 2018-07-08 10:39, Gregory Beat via time-nuts wrote: > >> Magnus - >> When I scan/read the 1984 IEEE document, “Lifetime and Reliability of >> Rubidium Discharge Lamps for Use in Atomic Frequency Standards” >> by Aerospace Corp., Efraton-Ball, and EG >> https://ieeexplore.ieee.org/document/1537723/ >> The failure of the rubidium lamps used on early NAVSTAR satellites, >> was the reason for in-depth studies of the Rb lamp, its lifetime and >> failure mechanism. >> >> greg >> >> Hi - >>> I later tried that method on my R XSRM rubidium, with good progress. I >>> have reported on that on the list way back. It took two attempts, one >>> just to realize that I needed to keep the pinch at the top, because that >>> is where the hot atoms go. >>> >>> Essentially, the thin film of rubidium will consume too much of the >>> radiation to emit any useful amount of pumping light. Heating it has the >>> rubidium go into gas and then collect somewhere cold, so it's just about >>> making sure that somewhere cold isn't the glass where it is to emit >>> light. >>> >>> My XSRM have however other issues that I need to attend to. >>> >>> Cheers, >>> Magnus >>> >> >> ___ >> 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 > 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] WTS: Efratom PTB-100 Precision Timebase
Thanks Attila, Yes, that is a procedure I know about. The lamp glow is purple and my lamp monitor voltage is 6.36, not great but should be in the working range. The issue I'm trouble shooting right now is the PS transition from supply voltage, 28V in my case, to 17V after lamp ignition is not stateful. It starts pulsing to 17V after ignition and the duty cycle slowly transitions from mostly at 28V to mostly at 17V over time - never stays at 17V. The PS is working correctly though because the photocell preamplifier output is causing the pulsing. I have the oscillator trimmer cap set for symmetrical frequency change 4Hz above and below 10MHz following the integrator EFC but the EFC sweep is 6.5V to 13.5V and I would expect the low end should start closer to <1V. Still reading the manual and studying the circuits. Regards, Don -Original Message- From: time-nuts On Behalf Of Attila Kinali Sent: Saturday, July 07, 2018 2:32 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] WTS: Efratom PTB-100 Precision Timebase On Fri, 6 Jul 2018 20:56:56 -0500 "Don@True-Cal" wrote: > For someone interested in working on the Rb package which I believe is > the FRK series. Worked great in my lab for years and recently started > being real slow to lock during power cycles and now won't lock at all. > Not sure what the fair asking price would be in this condition. Maybe > someone has repair/refurb experience with the Efratom FRK. It is likely that the lamp degraded to the point it doesnt produce enough light anymore. People have reported that they could revive old lamps by heating it up with a heat gun and let the rubidium condense again at the nook where it is supposed to 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. ___ 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] WTS: Efratom PTB-100 Precision Timebase
On 7/8/18 12:09 PM, djl wrote: Greg et.al. IEEE stuff is just too expensive for single purchase. I have found, to my sorrow over 40 odd years, that they also do not contain information, that is, info of actual use, because some other company or person might actually benefit. In other words, the papers are markers in the sand. Depends a lot on what you're looking at. I make pretty heavy use of such papers on a day to day basis. It is true that of late, there's an awful lot of "we built this specialized circuit as part of a multiproject wafer using tool sets that you can only afford if you're a billionaire or get them as part of a university" stuff out there, which makes it probably non-duplicateable, but there's also a lot of useful things. But the older papers I use a lot (like the one on making coupled line filters) were probably viewed as just as exotic back in the late 50s when making accurate microwave measurements was quite timeconsuming and tedious. Now, this is my own opinion, a bit harsh, admittedly. Of course the citations do need to be mentioned. BTW, any published material generated with government funds that is not classified belongs to the people, and is not copyrighted. I wonder if that includes IEEE papers? that is, if anyone buys one, it can be copied or distributed without restriction? Not precisely - But in general, much government sponsored research has no copyright, and the notice will say as much in the journal. That said, there's no obligation for IEEE to make it available for free. And IEEE has no problem with authors providing a "pre-print" edition of their current papers online on their own server. It is easy to find the whole proceedings for that conference at a government site: http://www.dtic.mil/dtic/tr/fulltext/u2/a217381.pdf Another way to get a free copy (but tedious) is to file a Freedom of Information Act request - JPL gets lots of these every year asking for "Document JPL D-12345" or similar.. and someone prints it out and sends it (or, these days, they may even just send you a .pdf, if that meets the requirements of the FOIA). I would say that for "recent" (last 20 years) papers, most government places have some sort of online repository (yes, it comes and goes, NASA's repo disappeared for a while then came back). It's the older material that's harder to come by (70s and 80s), mostly because the keeper of the docs hasn't got back that far when scanning. You can find "popular" docs that are requested a lot(e.g. the "Los Alamos Primer"), but more obscure ones take a while. The indexing is also sometimes a bit wonky - I find I need to try different searches using parts of the title, or sometimes the report number, or the author's name. But this particular one was easy - it was in the first page of hits from Google. Also, not all government funded research is "public". IN particular, Small Business Innovative Research (SBIR) grants give the grantee exclusive rights for a significant period (5 years??), and the reports can contain proprietary information, and so are not subject to unlimited distribution. Similarly, University research that is funded by the government is subject to the Bayh-Dole Act - the university retains title and rights to the research. It depends on the specific grant/contract whether reports of that research are subject to copyright or not. Philosophically, the government does this to get something of value without having to spend as much money on it, since the producer can then sell it to others as well. More research done, less taxpayer dollars, etc. Another reason taxpayer funded research might not be published is that it uses a third party's proprietary information. If I do a bunch of rocket engine tests (I wish!) on Acme Corp's special proprietary rocket fuel mixture, I might be able to publish the test results, but not be able to publish the analysis that provided the expected values, based on the rocket fuel formulation. Not being in the lawyer class, I can't say for sure... Thanks Don On 2018-07-08 10:39, Gregory Beat via time-nuts wrote: Magnus - When I scan/read the 1984 IEEE document, “Lifetime and Reliability of Rubidium Discharge Lamps for Use in Atomic Frequency Standards” by Aerospace Corp., Efraton-Ball, and EG https://ieeexplore.ieee.org/document/1537723/ The failure of the rubidium lamps used on early NAVSTAR satellites, was the reason for in-depth studies of the Rb lamp, its lifetime and failure mechanism. greg Hi - I later tried that method on my R XSRM rubidium, with good progress. I have reported on that on the list way back. It took two attempts, one just to realize that I needed to keep the pinch at the top, because that is where the hot atoms go. Essentially, the thin film of rubidium will consume too much of the radiation to emit any useful amount of pumping light. Heating it has the rubidium go into gas and then collect
Re: [time-nuts] WTS: Efratom PTB-100 Precision Timebase
Greg et.al. IEEE stuff is just too expensive for single purchase. I have found, to my sorrow over 40 odd years, that they also do not contain information, that is, info of actual use, because some other company or person might actually benefit. In other words, the papers are markers in the sand. Now, this is my own opinion, a bit harsh, admittedly. Of course the citations do need to be mentioned. BTW, any published material generated with government funds that is not classified belongs to the people, and is not copyrighted. I wonder if that includes IEEE papers? that is, if anyone buys one, it can be copied or distributed without restriction? Not being in the lawyer class, I can't say for sure... Thanks Don On 2018-07-08 10:39, Gregory Beat via time-nuts wrote: Magnus - When I scan/read the 1984 IEEE document, “Lifetime and Reliability of Rubidium Discharge Lamps for Use in Atomic Frequency Standards” by Aerospace Corp., Efraton-Ball, and EG https://ieeexplore.ieee.org/document/1537723/ The failure of the rubidium lamps used on early NAVSTAR satellites, was the reason for in-depth studies of the Rb lamp, its lifetime and failure mechanism. greg Hi - I later tried that method on my R XSRM rubidium, with good progress. I have reported on that on the list way back. It took two attempts, one just to realize that I needed to keep the pinch at the top, because that is where the hot atoms go. Essentially, the thin film of rubidium will consume too much of the radiation to emit any useful amount of pumping light. Heating it has the rubidium go into gas and then collect somewhere cold, so it's just about making sure that somewhere cold isn't the glass where it is to emit light. My XSRM have however other issues that I need to attend to. Cheers, Magnus ___ 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 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] WTS: Efratom PTB-100 Precision Timebase
Magnus - When I scan/read the 1984 IEEE document, “Lifetime and Reliability of Rubidium Discharge Lamps for Use in Atomic Frequency Standards” by Aerospace Corp., Efraton-Ball, and EG https://ieeexplore.ieee.org/document/1537723/ The failure of the rubidium lamps used on early NAVSTAR satellites, was the reason for in-depth studies of the Rb lamp, its lifetime and failure mechanism. greg >Hi - >I later tried that method on my R XSRM rubidium, with good progress. I >have reported on that on the list way back. It took two attempts, one >just to realize that I needed to keep the pinch at the top, because that >is where the hot atoms go. > >Essentially, the thin film of rubidium will consume too much of the >radiation to emit any useful amount of pumping light. Heating it has the >rubidium go into gas and then collect somewhere cold, so it's just about >making sure that somewhere cold isn't the glass where it is to emit light. > >My XSRM have however other issues that I need to attend to. > >Cheers, >Magnus ___ 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.
