[time-nuts] time-nuts newbie
Timothy Bastian
n714x at yahoo.com
Thu May 2 16:36:12 UTC 2013
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
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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 <rexa at sonic.net>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] Time nut newbie
Message-ID: <51807680.2040705 at sonic.net>
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" <jmiles at pop.net>
To: "'Discussion of precise time and frequency measurement'"
<time-nuts at febo.com>
Subject: Re: [time-nuts] 10811
Message-ID: <004a01ce4617$1ba19710$52e4c530$@pop.net>
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 <jim77742 at gmail.com>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] HP5065B !!!
Message-ID:
<CALH-g5YNYi2o4wGJmzPDciCt8+hPGjfx0QPnjG1Ew+h0KGXXWA at 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, <EWKehren at aol.com> 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,
> attila at kinali.ch writes:
>
> On Mon, 29 Apr 2013 17:19:05 -0400 (EDT)
> EWKehren at aol.com 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
> _______________________________________________
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------------------------------
Message: 4
Date: Wed, 1 May 2013 12:40:02 +1000
From: Jim Palfreyman <jim77742 at gmail.com>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] Time nut newbie
Message-ID:
<CALH-g5ZoeGsGnfXj2SX=dL2cmHs+F+_VniG5p3KC4XXToP9Hxg at mail.gmail.com>
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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 <rexa at sonic.net> 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
>>>
>>>
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------------------------------
Message: 5
Date: Tue, 30 Apr 2013 23:13:44 -0700
From: Hal Murray <hmurray at megapathdsl.net>
To: lists at lazygranch.com, Discussion of precise time and frequency
measurement <time-nuts at febo.com>
Subject: Re: [time-nuts] Time nut newbie
Message-ID:
<20130501061344.DB93980006F at ip-64-139-1-69.sjc.megapath.net>
Content-Type: text/plain; charset=us-ascii
lists at lazygranch.com 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 <albertson.chris at gmail.com>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] Time nut newbie
Message-ID:
<CABbxVHuUjp3Af0tpkRG6E26BrSQGQviMCRi3wzgSYT9+OfzSHw at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
On Tue, Apr 30, 2013 at 7:40 PM, Jim Palfreyman <jim77742 at gmail.com> 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 <attila at kinali.ch>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] Time nut newbie
Message-ID: <20130501094506.966146722efbbaf9c80e5aca at kinali.ch>
Content-Type: text/plain; charset=UTF-8
On Tue, 30 Apr 2013 13:49:43 -0400
"Tim Bastian"<n714x at yahoo.com> 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 <lists at rtty.us>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] Time nut newbie
Message-ID: <7D23F52C-1BC6-449B-A47E-FC9BCC454E3A at rtty.us>
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 <rexa at sonic.net> 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 -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
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