----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[email protected]> Sent: Sunday, June 29, 2008 2:59 PM Subject: time-nuts Digest, Vol 47, Issue 72
> 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: 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 ([EMAIL PROTECTED]) > 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" <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built > cesiumclocks??? > To: "Discussion of precise time and frequency measurement" > <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > 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" <[EMAIL PROTECTED]> > To: "Discussion of precise time and frequency measurement" > <[email protected]> > 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 -- [email protected] >> 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" <[EMAIL PROTECTED]> > Subject: [time-nuts] Datum 9390 > To: <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > 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 > > [EMAIL PROTECTED] > > > > ------------------------------ > > Message: 3 > Date: Sun, 29 Jun 2008 19:26:58 +0200 (CEST) > From: Magnus Danielson <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built > cesiumclocks??? > To: [email protected] > Message-ID: <[EMAIL PROTECTED]> > Content-Type: Text/Plain; charset=us-ascii > > From: "John Franke" <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built > cesiumclocks??? > Date: Sun, 29 Jun 2008 12:20:28 -0400 > Message-ID: <[EMAIL PROTECTED]> > >> 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: [EMAIL PROTECTED] > Subject: Re: [time-nuts] Datum 9390 > To: [email protected] > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="US-ASCII" > > > In a message dated 29/06/2008 18:18:17 GMT Daylight Time, > [EMAIL PROTECTED] 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" <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built > cesiumclocks??? > To: "Discussion of precise time and frequency measurement" > <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > 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" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Sunday, June 29, 2008 1:26 PM > Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built > cesiumclocks??? > > >> From: "John Franke" <[EMAIL PROTECTED]> >> Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built >> cesiumclocks??? >> Date: Sun, 29 Jun 2008 12:20:28 -0400 >> Message-ID: <[EMAIL PROTECTED]> >> >>> 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 -- [email protected] >> 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 <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built > cesiumclocks??? > To: [email protected] > Message-ID: <[EMAIL PROTECTED]> > Content-Type: Text/Plain; charset=us-ascii > > From: "John Franke" <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built > cesiumclocks??? > Date: Sun, 29 Jun 2008 14:02:06 -0400 > Message-ID: <[EMAIL PROTECTED]> > >> 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" <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Datum 9390 > To: "'Discussion of precise time and frequency measurement'" > <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > 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 > [EMAIL PROTECTED] > > -----Opprinnelig melding----- > Fra: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] P? > vegne > av [EMAIL PROTECTED] > Sendt: 29. juni 2008 19:40 > Til: [email protected] > Emne: Re: [time-nuts] Datum 9390 > > > In a message dated 29/06/2008 18:18:17 GMT Daylight Time, > [EMAIL PROTECTED] 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 -- [email protected] > 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" <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Datum 9390 > To: "Discussion of precise time and frequency measurement" > <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > 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 <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] Home built cesium clocks??? > To: Discussion of precise time and frequency measurement > <[email protected]> > Message-ID: <[EMAIL PROTECTED]> > Content-Type: text/plain; charset="us-ascii"; format=flowed > > >>Date: Sun, 29 Jun 2008 14:49:13 +0200 >>To: Magnus Danielson <[EMAIL PROTECTED]> >>From: Predrag Dukic <[EMAIL PROTECTED]> >>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 <[EMAIL PROTECTED]> >>>Subject: Re: [time-nuts] Home built cesium clocks??? >>>Date: Sun, 29 Jun 2008 12:10:46 +0200 >>>Message-ID: <[EMAIL PROTECTED]> >>> >>> > >>> > >>> > 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 > > > > > ------------------------------ > > _______________________________________________ > time-nuts mailing list > [email protected] > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > End of time-nuts Digest, Vol 47, Issue 72 > ***************************************** > _______________________________________________ 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.
