[time-nuts] time-nuts Digest, Vol 47, Issue 72
Rich and Marcia Putz
rputz at bnin.net
Mon Jun 30 01:32:51 UTC 2008
----- Original Message -----
From: <time-nuts-request at febo.com>
To: <time-nuts at febo.com>
Sent: Sunday, June 29, 2008 2:59 PM
Subject: time-nuts Digest, Vol 47, Issue 72
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> Today's Topics:
>
> 1. Re: Home built Ammonia cell std !! / Home built
> cesiumclocks??? (John Franke)
> 2. Datum 9390 (jack)
> 3. Re: Home built Ammonia cell std !! / Home built
> cesiumclocks??? (Magnus Danielson)
> 4. Re: Datum 9390 (GandalfG8 at aol.com)
> 5. Re: Home built Ammonia cell std !! / Home built
> cesiumclocks??? (John Franke)
> 6. Re: Home built Ammonia cell std !! / Home built
> cesiumclocks??? (Magnus Danielson)
> 7. Re: Datum 9390 (jack)
> 8. Re: Datum 9390 (John Miles)
> 9. Re: Home built cesium clocks??? (Predrag Dukic)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 29 Jun 2008 12:20:28 -0400
> From: "John Franke" <jmfranke at cox.net>
> Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built
> cesiumclocks???
> To: "Discussion of precise time and frequency measurement"
> <time-nuts at febo.com>
> Message-ID: <001e01c8da04$0b83a3c0$1e89a662 at youre7075dc078>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> Now that is something I am interested in doing. I finally secured use of
> a
> diffusion pump at a local university and expect to be making my first
> sealed
> all-glass absorption cells this fall. The ammonia pressure needs to be
> around 8-10 microns. I will be trying for a double pass cell giving a
> pass
> length between 10 and 12 feet. The first ammonia atomic clock used a path
> length of 33 feet. The cell was made from waveguide and did not hold a
> charge due to leaks or the ammonia reacting with the gold plated
> waveguide.
> I believe the best ammonia based standard was only good to 10 ^ -8 in
> frequency stability.
>
> John WA4WDL
>
> ----- Original Message -----
> From: "Luis Cupido" <cupido at mail.ua.pt>
> To: "Discussion of precise time and frequency measurement"
> <time-nuts at febo.com>
> Sent: Sunday, June 29, 2008 11:40 AM
> Subject: [time-nuts] Home built Ammonia cell std !! / Home built
> cesiumclocks???
>
>
>> We dont get much info/comments about this
>> But what would an ammonia cell standard be able to do.
>> I mean frequency/time wise.
>>
>> Maybe easier and simpler ?
>> comments ?
>>
>> Luis Cupido.
>> ct1dmk.
>>
>> (I understand the frequencies are much higher
>> but that is not a problem, at least for me).
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Sun, 29 Jun 2008 19:16:12 +0200
> From: "jack" <jack at sandumshaugen.no>
> Subject: [time-nuts] Datum 9390
> To: <time-nuts at febo.com>
> Message-ID: <000b01c8da0b$d6be24a0$843a6de0$@no>
> Content-Type: text/plain; charset="us-ascii"
>
> Do anybody have a manual for the Datum GPS synchronized Generator.
> 9390-53111. ??
>
> Or a manual for a model "close" to this?
>
> Or know where I can find one?
>
>
>
> Jack Sandum
>
> Norway
>
> Jack at sandumshaugen.no
>
>
>
> ------------------------------
>
> Message: 3
> Date: Sun, 29 Jun 2008 19:26:58 +0200 (CEST)
> From: Magnus Danielson <magnus at rubidium.dyndns.org>
> Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built
> cesiumclocks???
> To: time-nuts at febo.com
> Message-ID: <20080629.192658.114191476474940587.cfmd at bredband.net>
> Content-Type: Text/Plain; charset=us-ascii
>
> From: "John Franke" <jmfranke at cox.net>
> Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built
> cesiumclocks???
> Date: Sun, 29 Jun 2008 12:20:28 -0400
> Message-ID: <001e01c8da04$0b83a3c0$1e89a662 at youre7075dc078>
>
>> Now that is something I am interested in doing. I finally secured use of
>> a
>> diffusion pump at a local university and expect to be making my first
>> sealed
>> all-glass absorption cells this fall. The ammonia pressure needs to be
>> around 8-10 microns. I will be trying for a double pass cell giving a
>> pass
>> length between 10 and 12 feet. The first ammonia atomic clock used a
>> path
>> length of 33 feet. The cell was made from waveguide and did not hold a
>> charge due to leaks or the ammonia reacting with the gold plated
>> waveguide.
>> I believe the best ammonia based standard was only good to 10 ^ -8 in
>> frequency stability.
>
> More like 5E-11 both in cavity pulling and collision effects. Cavity
> pulling was reduced in 1961 by means of automatic cavity tuning.
>
> Recall that you do state-selection on the ammonia beam. An electrostatic
> quadrapole configuration was used. Just like a Hydrogen maser.
>
> Cheers,
> Magnus
>
>
>
> ------------------------------
>
> Message: 4
> Date: Sun, 29 Jun 2008 13:39:53 EDT
> From: GandalfG8 at aol.com
> Subject: Re: [time-nuts] Datum 9390
> To: time-nuts at febo.com
> Message-ID: <d33.336dc555.359922e9 at aol.com>
> Content-Type: text/plain; charset="US-ASCII"
>
>
> In a message dated 29/06/2008 18:18:17 GMT Daylight Time,
> jack at sandumshaugen.no writes:
>
> Do anybody have a manual for the Datum GPS synchronized Generator.
> 9390-53111. ??
>
> Or a manual for a model "close" to this?
>
> Or know where I can find one?
>
>
>
> -------------
> Hi Jack
>
> I've got the manual for the 9390-52054, don't know how similar it is but
> presumably quite close.
> I thought I downloaded it from Symmetricom but don't see it there now.
> It's just over 3MB, if you'd like a copy please send me an email address
> known to accept this size attachment and I'll send it direct.
>
> regards
>
> Nigel
> GM8PZR
>
>
>
>
>
>
> ------------------------------
>
> Message: 5
> Date: Sun, 29 Jun 2008 14:02:06 -0400
> From: "John Franke" <jmfranke at cox.net>
> Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built
> cesiumclocks???
> To: "Discussion of precise time and frequency measurement"
> <time-nuts at febo.com>
> Message-ID: <004301c8da12$3e04fd40$1e89a662 at youre7075dc078>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> No, I am talking about the 1948 gas absorption design by Lyons, not the
> ammonia MASER. There is no state-selection. There is no flowing gas
> molecules. There is no quadrapole device. It is a simple oscillator
> locked
> to the attenuation dip in an absorption cell. Once built, there is no gas
> replenishment or need for additional pumping. But, the accuracy is
> limited.
> By the way, Lyons cell path was 25 feet not 33 feet as I had thought.
>
> John WA4WDL
>
> ----- Original Message -----
> From: "Magnus Danielson" <magnus at rubidium.dyndns.org>
> To: <time-nuts at febo.com>
> Sent: Sunday, June 29, 2008 1:26 PM
> Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built
> cesiumclocks???
>
>
>> From: "John Franke" <jmfranke at cox.net>
>> Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built
>> cesiumclocks???
>> Date: Sun, 29 Jun 2008 12:20:28 -0400
>> Message-ID: <001e01c8da04$0b83a3c0$1e89a662 at youre7075dc078>
>>
>>> Now that is something I am interested in doing. I finally secured use
>>> of
>>> a
>>> diffusion pump at a local university and expect to be making my first
>>> sealed
>>> all-glass absorption cells this fall. The ammonia pressure needs to be
>>> around 8-10 microns. I will be trying for a double pass cell giving a
>>> pass
>>> length between 10 and 12 feet. The first ammonia atomic clock used a
>>> path
>>> length of 33 feet. The cell was made from waveguide and did not hold a
>>> charge due to leaks or the ammonia reacting with the gold plated
>>> waveguide.
>>> I believe the best ammonia based standard was only good to 10 ^ -8 in
>>> frequency stability.
>>
>> More like 5E-11 both in cavity pulling and collision effects. Cavity
>> pulling was reduced in 1961 by means of automatic cavity tuning.
>>
>> Recall that you do state-selection on the ammonia beam. An electrostatic
>> quadrapole configuration was used. Just like a Hydrogen maser.
>>
>> Cheers,
>> Magnus
>>
>> _______________________________________________
>> 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.
>>
>
>
>
>
> ------------------------------
>
> Message: 6
> Date: Sun, 29 Jun 2008 20:10:16 +0200 (CEST)
> From: Magnus Danielson <magnus at rubidium.dyndns.org>
> Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built
> cesiumclocks???
> To: time-nuts at febo.com
> Message-ID: <20080629.201016.236772213938164352.cfmd at bredband.net>
> Content-Type: Text/Plain; charset=us-ascii
>
> From: "John Franke" <jmfranke at cox.net>
> Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built
> cesiumclocks???
> Date: Sun, 29 Jun 2008 14:02:06 -0400
> Message-ID: <004301c8da12$3e04fd40$1e89a662 at youre7075dc078>
>
>> No, I am talking about the 1948 gas absorption design by Lyons, not the
>> ammonia MASER. There is no state-selection. There is no flowing gas
>> molecules. There is no quadrapole device. It is a simple oscillator
>> locked
>> to the attenuation dip in an absorption cell. Once built, there is no
>> gas
>> replenishment or need for additional pumping. But, the accuracy is
>> limited.
>> By the way, Lyons cell path was 25 feet not 33 feet as I had thought.
>
> Sorry, my bad. I suspect wall-pulling is significant.
>
> Cheers,
> Magnus
>
>
>
> ------------------------------
>
> Message: 7
> Date: Sun, 29 Jun 2008 20:10:15 +0200
> From: "jack" <jack at sandumshaugen.no>
> Subject: Re: [time-nuts] Datum 9390
> To: "'Discussion of precise time and frequency measurement'"
> <time-nuts at febo.com>
> Message-ID: <001001c8da13$63274190$2975c4b0$@no>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hallo Nigel
> If you could send the file. 3M is ok by me.
> Look forward to the manual, hope it is close to my HW.
> Jack
> jack at sandumshaugen.no
>
> -----Opprinnelig melding-----
> Fra: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] P?
> vegne
> av GandalfG8 at aol.com
> Sendt: 29. juni 2008 19:40
> Til: time-nuts at febo.com
> Emne: Re: [time-nuts] Datum 9390
>
>
> In a message dated 29/06/2008 18:18:17 GMT Daylight Time,
> jack at sandumshaugen.no writes:
>
> Do anybody have a manual for the Datum GPS synchronized Generator.
> 9390-53111. ??
>
> Or a manual for a model "close" to this?
>
> Or know where I can find one?
>
>
>
> -------------
> Hi Jack
>
> I've got the manual for the 9390-52054, don't know how similar it is but
> presumably quite close.
> I thought I downloaded it from Symmetricom but don't see it there now.
> It's just over 3MB, if you'd like a copy please send me an email address
> known to accept this size attachment and I'll send it direct.
>
> regards
>
> Nigel
> GM8PZR
>
>
>
>
> _______________________________________________
> 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.
>
>
>
>
>
> ------------------------------
>
> Message: 8
> Date: Sun, 29 Jun 2008 11:31:51 -0700
> From: "John Miles" <jmiles at pop.net>
> Subject: Re: [time-nuts] Datum 9390
> To: "Discussion of precise time and frequency measurement"
> <time-nuts at febo.com>
> Message-ID: <PKEGJHPHLLBACEOICCBJIECFJAAB.jmiles at pop.net>
> Content-Type: text/plain; charset="us-ascii"
>
> Nigel --
>
> Can you send it to the upload page at
> http://www.ko4bb.com/cgi-bin/upload.pl
> (user 'manuals', password 'manuals', without the quotes)? I could use
> that
> one myself...
>
> -- john, KE5FX
>
>
>> -------------
>> Hi Jack
>>
>> I've got the manual for the 9390-52054, don't know how similar it is but
>> presumably quite close.
>> I thought I downloaded it from Symmetricom but don't see it there now.
>> It's just over 3MB, if you'd like a copy please send me an email address
>> known to accept this size attachment and I'll send it direct.
>>
>> regards
>>
>> Nigel
>> GM8PZR
>>
>>
>>
>
>
>
>
> ------------------------------
>
> Message: 9
> Date: Sun, 29 Jun 2008 21:01:51 +0200
> From: Predrag Dukic <stijena at tapko.de>
> Subject: Re: [time-nuts] Home built cesium clocks???
> To: Discussion of precise time and frequency measurement
> <time-nuts at febo.com>
> Message-ID: <7.0.1.0.1.20080629210110.01f0ae78 at tapko.de>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
>
>
>>Date: Sun, 29 Jun 2008 14:49:13 +0200
>>To: Magnus Danielson <magnus at rubidium.dyndns.org>
>>From: Predrag Dukic <stijena at tapko.de>
>>Subject: Re: [time-nuts] Home built cesium clocks???
>>
>>
>>
>>Magnus, Bruce,
>>
>>One of the requirements for applying for a reference laboratory in
>>Croatia is also to show "scientific excellence" in the area of work
>>(of the lab).
>>
>>So I'd have to make a some original contribution to the subject and
>>of course to publish it.
>>
>>It is true that at the moment I need only 250+ optical shift. That
>>with 9+ GHz achieved through "optical frequency shift
>>multiplication" (apart from "optical frequency multiplication" which
>>is more difficult)
>>
>>is one of the ideas that I didn't find reference to in existing
>>published articles. Something to be explored in the future (see
>>above), but very interesting, because I could avoid phase noise from
>>SRD multiplication.
>>
>>Another idea to be tried is to use PREDICTABLE jitter from FPGA DDS
>>as phase modulation normally used to find the center of the central
>>Ramsey fringe.
>>
>>DDS achieve desired frequency by slipping reference frequency cycles
>>from time to time and that way shifting the phase of the output
>>signal. It is a jitter, but it is not random. Well thought
>>
>>phase shift/modulation plan can exploit this as phase modulation.
>>
>>Predrag
>>
>>
>>
>>
>>
>>
>>
>>
>>At 14:17 29.6.2008, you wrote:
>>>From: Predrag Dukic <stijena at tapko.de>
>>>Subject: Re: [time-nuts] Home built cesium clocks???
>>>Date: Sun, 29 Jun 2008 12:10:46 +0200
>>>Message-ID: <7.0.1.0.1.20080629120421.01ebecc8 at tapko.de>
>>>
>>> >
>>> >
>>> > Bruce,
>>> >
>>> > I did my homework and collected everything from the internet I could
>>> > get. I have this one too.
>>> >
>>> > If I go optical way, I still need 9+GHz electrical source, so I will
>>> > first recreate electronics. Using off the shelf DDS chips, or using
>>> > FPGA.
>>>
>>>A YIG oscillator or similar should be considered. The FPGA would be great
>>>for the state handling, but be sure to externally reclock the signal
>>>before use to remove the FPGA jitter.
>>>
>>> > Also I need 9 GHz AOM, so that I can split the same optical beam and
>>> > have two wavelengths 9ghz apart. That is a problem because I have
>>> > only 350 MHz AOM.
>>>
>>>In the article he referenced, the AOM only needs to handle 250,1 MHz.
>>>Only if you intend to achieve 100% pumping and detection ratios you need
>>>a full set of frequencies. Notice the important note on relation between
>>>laser linewidth and S/N relationship. Luckilly those are limitations
>>>outside of the cavity.
>>>
>>>The interesting aspect with an optically pumped cesium is that one of the
>>>common failuremodes, the contamination of the masspectrometer is removed.
>>>The detection is off-axis from the beam. Wonder if an open oven could not
>>>be installed there. That would allow for a ping-pong mode of operation,
>>>which the optical pumping itself fits very nicely too. It would cancel
>>>some of the systematic shifts due to assymetries in the microwave
>>>assembly which to the best of my knowledge is hard to compensate
>>>normally.
>>>Maybe state of art designs have found a way to handle it properly.
>>>
>>> > Multiple pass is difficult, it would take cca 27 passes to get 9
>>> > GHz. On the other side, I wouldn't need the last stages of SRD
>>> > multiplication to get 9 GHz microwave.
>>> >
>>> > No doubt, I will have a lot of fun with the project.
>>>
>>>Surely. It could be hairpulling too.
>>>
>>>Cheers,
>>>Magnus
>
>
>
>
> ------------------------------
>
> _______________________________________________
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> time-nuts at febo.com
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> End of time-nuts Digest, Vol 47, Issue 72
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