Turning off the Rb is a good idea. That is one of the best features of the Rb is that it will come back on from a zero power and be pretty much spot on the frequency but the phase will be random. So the question is that if you want to re-calibrate the OCXO how long to you need to compare it to the Rb. You can't look at the phase difference, that has been randomized by the power cycle.
I think one could get at least 10 and maybe 100 times better than the OP's requirement and still be under the $500 limit. On Thu, May 2, 2013 at 12:59 PM, Bob Camp <[email protected]> wrote: > Hi > > A clock based on an eBay Rb can be set up to pull less than 10 watts. Based > on 8 hours of light a day that would get you to 30 watts of solar needed to > power it. That's a pretty small fraction of your 480W setup. You will get > CSAC level timing and still fit your budget. > > For a lower power solution, wake up the Rb once a day around mid day. Only > do it if the solar has surplus power. Re-sync your OCXO to the Rb. That > should cut the power by a factor of about 10:1. A Google search for "RBXO" > will turn up details on the process. Not quite CSAC performance, but far > better than the OCXO alone. > > Bob > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Timothy Bastian > Sent: Thursday, May 02, 2013 12:36 PM > To: [email protected] > Subject: Re: [time-nuts] time-nuts newbie > > Wow I didn't know how much I was going to stir up here. As for the accuracy > of the DS32khz you are correct in what the literature says. They call for an > accuracy of one minute per year. The 10 seconds / year is what the gentleman > who designed the clock thought would be possible. The testing he has done is > giving better results than 10 seconds / year. My clock has not been running > long enough to give you any meaningful results. > > > As far as the requirements for my chronometer... there is what I would like > to have and what I can afford. A clock driven by a csac (SA.45s) would be > the ultimate. I am however shooting for something in the $500.00 or > less price range. I have ships power available to power the clock but would > like to have the ability to run on an internal battery for an extended > period if needed. Say for two months. I have 4, 120 watt solar panels with > 500 amp hours of 12 volt battery power. I'm shooting for a size of not more > than one cubic foot. You are correct about the 100 ppb aging, which I > believe will put me at +/- 3 seconds / year. A GPS time reference to set the > clock would be acceptable however the whole point of having said clock is to > still be able to navigate in the event of GPS failure. > > Thanks for all of the replies, > > Tim KK4FQB > > ________________________________ > From: "[email protected]" <[email protected]> > To: [email protected] > Sent: Wednesday, May 1, 2013 11:08 AM > Subject: time-nuts Digest, Vol 106, Issue 1 > > > Send time-nuts mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of time-nuts digest..." > > > Today's Topics: > > 1. Re: Time nut newbie (Rex) > 2. Re: 10811 (John Miles) > 3. Re: HP5065B !!! (Jim Palfreyman) > 4. Re: Time nut newbie (Jim Palfreyman) > 5. Re: Time nut newbie (Hal Murray) > 6. Re: Time nut newbie (Chris Albertson) > 7. Re: Time nut newbie (Attila Kinali) > 8. Re: Time nut newbie (Bob Camp) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 30 Apr 2013 18:57:20 -0700 > From: Rex <[email protected]> > To: Discussion of precise time and frequency measurement > <[email protected]> > Subject: Re: [time-nuts] Time nut newbie > Message-ID: <[email protected]> > Content-Type: text/plain; charset=windows-1252; format=flowed > > It doesn't affect the general magnitude conclusions by Bruce, but as > long as we are making corrections, my calculator seems to think > 60 * 60 * 24 * 12 = 1036800 seconds in 12 days, not 1024800. That does > come out to 115.7 days for 1 sec error. Maybe the 12-day number was a typo? > > -Rex > > > On 4/30/2013 12:57 PM, Bruce Griffiths wrote: >> 12 days is 1024800 s ie just over 1 million seconds so a frequency >> offset of 0.1ppm results in a time error of ~ 0.1s not 1s. >> 1sec error would occur in just under 116 days, >> >> Bruce >> >> Bob Camp wrote: >>> Hi >>> >>> If you take a look down in the fine print on the OCXO spec, the aging >>> rate >>> is 100 ppb / year in the first year. If you are off by 0.1 ppm (100 ppb) >>> your clock will gain a second in less than 12 days. >>> >>> Bob >>> > > > > ------------------------------ > > Message: 2 > Date: Tue, 30 Apr 2013 19:53:49 -0700 > From: "John Miles" <[email protected]> > To: "'Discussion of precise time and frequency measurement'" > <[email protected]> > Subject: Re: [time-nuts] 10811 > Message-ID: <[email protected]> > Content-Type: text/plain; charset="UTF-8" > >> Close, but it's for the 105, not the 5061, and the boards are physically > very >> different. > > The 5061A upgrade used those 105-series boards. With the 5061B, they > changed the part number of A1A3 (the OCXO interface board) from 00105-6044 > to 05061-6198, but I don't see any major differences in the schematic, > looking at the Artek .PDF manual for the 5061B. > >> The part number on the connector for the board is the same as the > connector >> for the 10811. Does anyone know where to get boards that fit the > connector? >> Mouser carries the connector, but I can't find any boards. > > You don't really need a board -- I didn't use one (see > http://www.ke5fx.com/tbolt.htm ). It uses a pretty common edge connector > that can be pulled off of any number of random surplus HP PCBs, if you don't > want to order one. > >> how often do people need to retune the 10811? I have a pair of the 10811- >> 60109's, another 10811, and a 10544 and all are within 1 Hz of 10 MHz. > That's close >> enough > > Some anecdata: my GPS-disciplined 10811-60109 has been running for about 5 > years without any retuning. The DAC voltage is currently about 0.52V, and > I'm sure I would have started it out near 0.0, so about 10% of its EFC > control range has been needed after 5 years. (Of course it could have > wandered around arbitrarily in the meantime, but I doubt it.) > > At -0.324 Hz/volt, this would be about 0.03 Hz per year of positive drift on > average, or 3E-9 per year. That's in line with what I've seen other > well-settled 10811s achieve. > >> Is there any advantage in using the 723 voltage regulator? The 10811 and >> 10544 manuals both show the use of the 723 for the regulator for the > oscillator supply, >> but on the HP schematic for the 6198 board they use a pair of three > terminal >> regulators. > > HP's use of an LM317T-style regulator to drive the 18V oven supply, a 78L12 > to drive the oscillator, and a Zener+emitter follower to drive the 7474 > divider was a bit funky. Regulator noise on the oven supply isn't critical, > but for driving the oscillator circuit itself, the difference between a 7812 > and an LM317T can be seen in some cases. Not sure offhand how sensitive the > 10811 is to supply noise, but you can certainly see the difference in > regulators with a Wenzel ULN. > > In any event an LM317T would be fine for driving the +12 rail. > > -- john, KE5FX > Miles Design LLC > > > > > ------------------------------ > > Message: 3 > Date: Wed, 1 May 2013 13:36:43 +1000 > From: Jim Palfreyman <[email protected]> > To: Discussion of precise time and frequency measurement > <[email protected]> > Subject: Re: [time-nuts] HP5065B !!! > Message-ID: > <calh-g5ynyi2o4wgjmzpdcict8+hpgjfx0qpnjg1ew+h0kgx...@mail.gmail.com> > Content-Type: text/plain; charset=windows-1252 > > Am I missing something? What actual modifications were done and how? > > Jim > > > > On 1 May 2013 07:30, <[email protected]> wrote: > >> Attilla >> No one should or will discourage you from developing a laser pumped Rb. >> Bruce posted the following link. It addresses some of the issues and for > me >> looking at lamp Rb's is most helpful. >> >> http://tf.boulder.nist.gov/general/pdf/1219.pdf >> >> Bert Kehren >> >> >> >> In a message dated 4/30/2013 4:51:57 P.M. Eastern Daylight Time, >> [email protected] writes: >> >> On Mon, 29 Apr 2013 17:19:05 -0400 (EDT) >> [email protected] wrote: >> >> > I am still sitting here trying to figure out the purpose of posting > the >> >> > article on laser diode pumping of the Rb. One look at the data and it >> is >> > clear that Corby?s work far surpasses the data shown in the paper. All >> it does >> > is distract from Corb?s accomplishments. >> >> Sorry i didnt mean to do that. I am very gratefull at the work Corby >> has done and the new insights on what error sources a Rb gas cell >> has. >> >> But as someone living in europe, i have certain problems getting my >> hands on a HP5065. There is virtually no surplus market here. And >> if there is anything sold in europe, the price is nearly that of >> a new device, sometimes even more (no, i'm neither joking nor >> exagerating). >> I cannot buy any of the fancy devices you have access to in the US. >> Buying a Cs beam, as a few of you have, is a dream that will not come >> true for me, unless i win in the lottery. >> But building my own Rb standard using laser diodes is feasible. >> I still lack a lot of knowledge and understanding how to do that, >> but this group has been very helpfull in filling my gaps, when asking >> the right questions. And if you don't mind, i would like to keep >> asking those questions. >> >> >> Attila Kinali >> -- >> The people on 4chan are like brilliant psychologists >> who also happen to be insane and gross. >> -- unknown >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > ------------------------------ > > Message: 4 > Date: Wed, 1 May 2013 12:40:02 +1000 > From: Jim Palfreyman <[email protected]> > To: Discussion of precise time and frequency measurement > <[email protected]> > Subject: Re: [time-nuts] Time nut newbie > Message-ID: > <CALH-g5ZoeGsGnfXj2SX=dl2cmhs+f+_vnig5p3kc4xxtop9...@mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > Buy a cheap rubidium off ebay and use it to drive a micro-controller and > write some clock software. > > > On 1 May 2013 11:57, Rex <[email protected]> wrote: > >> It doesn't affect the general magnitude conclusions by Bruce, but as long >> as we are making corrections, my calculator seems to think >> 60 * 60 * 24 * 12 = 1036800 seconds in 12 days, not 1024800. That does >> come out to 115.7 days for 1 sec error. Maybe the 12-day number was a > typo? >> >> -Rex >> >> >> >> On 4/30/2013 12:57 PM, Bruce Griffiths wrote: >> >>> 12 days is 1024800 s ie just over 1 million seconds so a frequency offset >>> of 0.1ppm results in a time error of ~ 0.1s not 1s. >>> 1sec error would occur in just under 116 days, >>> >>> Bruce >>> >>> Bob Camp wrote: >>> >>>> Hi >>>> >>>> If you take a look down in the fine print on the OCXO spec, the aging >>>> rate >>>> is 100 ppb / year in the first year. If you are off by 0.1 ppm (100 ppb) >>>> your clock will gain a second in less than 12 days. >>>> >>>> Bob >>>> >>>> >> ______________________________**_________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/** >> > mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/tim > e-nuts> >> and follow the instructions there. >> > > > ------------------------------ > > Message: 5 > Date: Tue, 30 Apr 2013 23:13:44 -0700 > From: Hal Murray <[email protected]> > To: [email protected], Discussion of precise time and frequency > measurement <[email protected]> > Subject: Re: [time-nuts] Time nut newbie > Message-ID: > <[email protected]> > Content-Type: text/plain; charset=us-ascii > > > [email protected] said: >> A bit OT, but back in the day there was what amounted to an X-prize for a >> real accurate chronometer for navigation. > >> Make that way back in the day. > http://en.m.wikipedia.org/wiki/John_Harrison > > There is a good book out on that topic: > Longitude by Dava Sobel > There is also a fancy version with lots of very good pictures. > I'll have to go find my copy so I can look at them again. > > > > -- > These are my opinions. I hate spam. > > > > > > ------------------------------ > > Message: 6 > Date: Tue, 30 Apr 2013 23:36:57 -0700 > From: Chris Albertson <[email protected]> > To: Discussion of precise time and frequency measurement > <[email protected]> > Subject: Re: [time-nuts] Time nut newbie > Message-ID: > <cabbxvhuujp3af0tpkrg6e26brsqgqvimcri3wzgsyt9+ofz...@mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > On Tue, Apr 30, 2013 at 7:40 PM, Jim Palfreyman <[email protected]> wrote: >> Buy a cheap rubidium off ebay and use it to drive a micro-controller and >> write some clock software. > > That was exactly my solution but I'm waiting ti hear about his size, > power and cost budget. If this has to run on Battery power for the > entire year the Rb unit is not going to work > > The OP's 1 second per year goal is only asking for 3.2E-7 level > performance if I did the math correctly. Even the $100 Rb is at > least 100 times better than required. > -- > > Chris Albertson > Redondo Beach, California > > > ------------------------------ > > Message: 7 > Date: Wed, 1 May 2013 09:45:06 +0200 > From: Attila Kinali <[email protected]> > To: Discussion of precise time and frequency measurement > <[email protected]> > Subject: Re: [time-nuts] Time nut newbie > Message-ID: <[email protected]> > Content-Type: text/plain; charset=UTF-8 > > On Tue, 30 Apr 2013 13:49:43 -0400 > "Tim Bastian"<[email protected]> wrote: > > >> I'm a time nut newbie. My obsession started with the search for an > accurate chronometer to carry on my boat for celestial navigation. Yes there > still are a few of us left that practice the art. >> >> My current project is a quartz chronometer using a DS32Khz tcxo oscillator > and two 74HC4060s (+ or- 10 seconds / year).? >> >> For my next project I'm looking at an Abricon Part Number > AOCJY2-10.000MHZ? ocxo 5 ppb running through a pic and using the algorithm > posted on http://www.romanblack.com/one_sec.htm. I'm shooting for + or - 1 > seconds / year.? >> >> Is there an archive of old posts that might be helpful in answering some > of my questions and for getting ideas. > > You want to read Vig's Quartz Crystal Tutorial. That explains a lot about > where the instabilities of a crystal oscillator come from. You can find > them (and a lot more) on http://www.ko4bb.com/ in the Manuals section. > Have a look at different versions, as some interesting things were left > out in the newer versions. > > An idea how to get to the stability you want without wasting too much > power might be an MCXO. [1] gives a pretty decent overview of the way how > they work including a schematic for an oscillator. [2] has some ideas how > to simplify the circuit and get lower power. > > In your case, i guess it would be an idea to leave out the second stage > frequency generation (the VCO or DDS) and generate a PPS directly from > the microcontroller. > > Attila Kinali > > > [1] "A microcomputer compensated crystal oscillator using a > dual-mode resonator", by Benjaminson and Stallings, 1989 > > [2] "An Improved Method of MCXO", by Zhou, Liu, Wang, 2000 > -- > The people on 4chan are like brilliant psychologists > who also happen to be insane and gross. > -- unknown > > > ------------------------------ > > Message: 8 > Date: Wed, 1 May 2013 07:00:33 -0400 > From: Bob Camp <[email protected]> > To: Discussion of precise time and frequency measurement > <[email protected]> > Subject: Re: [time-nuts] Time nut newbie > Message-ID: <[email protected]> > Content-Type: text/plain; charset=windows-1252 > > Hi > > It was tired old eyes and tiny numbers on the calculator ?.That plus to much > distraction to double check things. > > Bob > > On Apr 30, 2013, at 9:57 PM, Rex <[email protected]> wrote: > >> It doesn't affect the general magnitude conclusions by Bruce, but as long > as we are making corrections, my calculator seems to think >> 60 * 60 * 24 * 12 = 1036800 seconds in 12 days, not 1024800. That does > come out to 115.7 days for 1 sec error. Maybe the 12-day number was a typo? >> >> -Rex >> >> >> On 4/30/2013 12:57 PM, Bruce Griffiths wrote: >>> 12 days is 1024800 s ie just over 1 million seconds so a frequency offset > of 0.1ppm results in a time error of ~ 0.1s not 1s. >>> 1sec error would occur in just under 116 days, >>> >>> Bruce >>> >>> Bob Camp wrote: >>>> Hi >>>> >>>> If you take a look down in the fine print on the OCXO spec, the aging > rate >>>> is 100 ppb / year in the first year. If you are off by 0.1 ppm (100 ppb) >>>> your clock will gain a second in less than 12 days. >>>> >>>> Bob >>>> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > > > ------------------------------ > > _______________________________________________ > time-nuts mailing list > [email protected] > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > End of time-nuts Digest, Vol 106, Issue 1 > ***************************************** > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. -- Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
