[time-nuts] Bls: time-nuts Digest, Vol 148, Issue 2
Anton Moehammad
moehanton at yahoo.com
Wed Nov 2 17:51:13 EDT 2016
Hi all,a few day ago I read "super HP5065A" from Mr Corby and I wondering if any one has done same thing with "telecom" Rubidium pack ? I found an optical bandpass filter cost is cheap enough to a third country people like me but if any one has tried before and know a lot more than what I know I really appreciate if You can share it
Pada Rabu, 2 November 2016 23:00, "time-nuts-request at febo.com" <time-nuts-request at febo.com> menulis:
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Today's Topics:
1. Re: Cs tube pics (Tom Van Baak)
2. So what’s inside that Cs Beam Tube anyway? (Mark Sims)
3. Re: Cs tube pics (Poul-Henning Kamp)
4. Technical Paper: GPS Receiver Impact from the UTC Offset
(UTCO) Anomaly of 25-26 January 2016 (Martin Burnicki)
5. Re: Cs tube pics (Attila Kinali)
6. Re: Cs tube pics (Poul-Henning Kamp)
7. Re: Cs tube pics (Attila Kinali)
8. OCXO's (EWKehren at aol.com)
9. Re: So what’s inside that Cs Beam Tube anyway? (paul swed)
10. HP 105 and Piezo gone (EWKehren at aol.com)
11. Re: So what’s inside that Cs Beam Tube anyway?
(Richard (Rick) Karlquist)
12. Re: Cs tube pics (paul swed)
13. Re: So what’s inside that Cs Beam Tube anyway? (paul swed)
14. Re: So what’s inside that Cs Beam Tube anyway?
(EWKehren at aol.com)
15. Re: So what’s inside that Cs Beam Tube anyway? (Peter Reilley)
----------------------------------------------------------------------
Message: 1
Date: Tue, 1 Nov 2016 09:10:25 -0700
From: "Tom Van Baak" <tvb at LeapSecond.com>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Subject: Re: [time-nuts] Cs tube pics
Message-ID: <6393D7A80E184F169329467E49E7F97E at pc52>
Content-Type: text/plain; charset="utf-8"
Clint:
> While I've no need for such accuracy in my little home workshop, I
> *really* would like a Cs standard, just because.
>
> The Rb and GPSDO are more than adequate for my needs but I can understand
> (and, for now, manage to resist) the addiction to accuracy and find it
> fascinating that such results can be achieved.
Attila:
> I really would like to do that. But they are a tad bit expensive.
> Especially on this side of the big pond. If anyone is willing
> to part with a Cs standard and want to have it a good home, feel
> free to contact me :-)
It's true that a cheap GPS receiver is more accurate long-term than a surplus cesium standard, but you're right about the "just because" part. To me at least, this time nut hobby is not so much about the pursuit of accuracy as it is an appreciation for the variety, ingenuity and complexity of timekeeping. In some cases "how it works" is far more interesting that "does it work".
A used but known working cesium standard can be expensive, but like most of you almost all my gear comes from eBay via automated daily keyword searches. Many of my mil- or telecom-surplus FTS 4050 and HP 5061 were obtained for just a couple hundred dollars. You may search for months or even years, but amazing bargains show up. Not all of them work, of course, but the op/svc manuals are superb, the design / construction is very repair-friendly, and there's a weird group called time nuts with helpful advice.
Plus once you get more than one unit you can mix parts and create your own Frankenstein. It turns out that many surplus cesium standards are not dead due to tube failures so its a very happy day when a beat up 5061 turns out to have only a failed power supply or a bad OCXO yet the tube is in perfect condition. I remember one person picked up a "dead" FTS cesium standard only to find the reason it didn't work is that the switch on the back was in standby mode! Only one time nut I know ever bought a replacement Cs tube new from the factory. All the rest of us sift through the graveyard looking for the one that cries "I'm not dead yet".
/tvb
------------------------------
Message: 2
Date: Wed, 2 Nov 2016 03:38:04 +0000
From: Mark Sims <holrum at hotmail.com>
To: "time-nuts at febo.com" <time-nuts at febo.com>
Subject: [time-nuts] So what’s inside that Cs Beam Tube anyway?
Message-ID:
<CY1PR17MB0297AD89FE7719DE68578163CEA00 at CY1PR17MB0297.namprd17.prod.outlook.com>
Content-Type: text/plain; charset="Windows-1252"
You mean I can't just drill a hole in, wash out the old cesium with some tap water ;-), toss in some new cesium, suck out the air, bung a cork in the hole, and call it a day? Drat! foiled again...
---------------
> Because it's not that easy. We are talking about a high vacuum system here.
------------------------------
Message: 3
Date: Wed, 02 Nov 2016 08:14:51 +0000
From: "Poul-Henning Kamp" <phk at phk.freebsd.dk>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>, Clint Jay <cjaysharp at gmail.com>
Subject: Re: [time-nuts] Cs tube pics
Message-ID: <13566.1478074491 at critter.freebsd.dk>
Content-Type: text/plain; charset="us-ascii"
--------
In message <CAN7ULzQS4bVwTPsp0kPrd8mNyash4pn7Qgf3zODA9puqnHV++Q at mail.gmail.com>, Clint Jay wr
ites:
>While I've no need for such accuracy in my little home workshop, I
>*really* would like a Cs standard, just because.
>
>The Rb and GPSDO are more than adequate for my needs but I can understand
>(and, for now, manage to resist) the addiction to accuracy and find it
>fascinating that such results can be achieved.
Many years a go, we installed ethernet over the entire campus of Denmarks
largest engineering company (FLS). At the center of it all, we had the
first Cisco AGS+ sold, fitted with all ethernet ports.
Of course at some point the CEO comes round and wants to see "that new
expensive network box" which had cost so much money.
I will never forget the look on his face when the CIO opened the rackdoor
and showed him a 6U box with a huge Cisco logo and nothing else.
(https://cdn-images-1.medium.com/max/800/1*A1Qt9uU3lRmzfx_5O_QkgA.png)
Cesiums are a lot like that.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
------------------------------
Message: 4
Date: Wed, 2 Nov 2016 09:11:13 +0100
From: Martin Burnicki <martin.burnicki at burnicki.net>
To: time-nuts at febo.com
Subject: [time-nuts] Technical Paper: GPS Receiver Impact from the UTC
Offset (UTCO) Anomaly of 25-26 January 2016
Message-ID: <58199FA1.6000002 at burnicki.net>
Content-Type: text/plain; charset=UTF-8
There's now a paper with an analysis of the problem available:
http://www.gps.gov/systems/gps/performance/2016-UTC-offset-anomaly-impact.pdf
Martin
------------------------------
Message: 5
Date: Wed, 2 Nov 2016 10:41:03 +0100
From: Attila Kinali <attila at kinali.ch>
To: Tom Van Baak <tvb at leapsecond.com>, Discussion of precise time and
frequency measurement <time-nuts at febo.com>
Subject: Re: [time-nuts] Cs tube pics
Message-ID: <20161102104103.0c58d35a72b7b36253b3d6b2 at kinali.ch>
Content-Type: text/plain; charset=UTF-8
On Tue, 1 Nov 2016 09:10:25 -0700
"Tom Van Baak" <tvb at LeapSecond.com> wrote:
> > I really would like to do that. But they are a tad bit expensive.
> > Especially on this side of the big pond. If anyone is willing
> > to part with a Cs standard and want to have it a good home, feel
> > free to contact me :-)
>
> It's true that a cheap GPS receiver is more accurate long-term than
> a surplus cesium standard, but you're right about the "just because" part.
> To me at least, this time nut hobby is not so much about the pursuit of
> accuracy as it is an appreciation for the variety, ingenuity and complexity
> of timekeeping. In some cases "how it works" is far more interesting that
> "does it work".
I think, most of us are in it for the "how it works" and
"how far can I push it". :-)
> A used but known working cesium standard can be expensive, but like most of
> you almost all my gear comes from eBay via automated daily keyword searches.
> Many of my mil- or telecom-surplus FTS 4050 and HP 5061 were obtained for
> just a couple hundred dollars. You may search for months or even years, but
> amazing bargains show up. Not all of them work, of course, but the op/svc
> manuals are superb, the design / construction is very repair-friendly, and
> there's a weird group called time nuts with helpful advice.
It still is prohibitevly expensive in Europe. There are much fewer
Cs standards going around than in the US in the first place, and there
is also less a tinkering mentality. Ie a lot of companies just say
"it's broken, it's no use for anyone anymore, let's just scrap it" and
thus a lot of stuff ends up in recycling instead of on ebay. Heck, a couple
of years ago i got an 3458 because the company wanted to throw it away.
Mind you, it was in full working condition, only the NVRAM batteries were low.
I still would like to try to build my own atomic clock at some point,
even if it would be a quite costly, and a many years project.
IMHO the easiest to build would be an Rb or Cs vapor cell using either
dual resonance or coherent population trapping. Cells can be bought
for 300-500€. For a bit more you can get them made to spec. Machining
a resonant cavity from aluminium is pretty easy and cheap these days,
if one wants to go for the dual resonance. The biggest issue for both
types would be the laser system. Either getting the laser diodes selected
(makes them expensive) or build an external cavity for them (creates
the need of a complex control system and not so simple mechanically).
Putting all toghether would probably cost something in the order of
1000€ to 5000€.
One up in difficulty would be a passive hydrogen maser. This requires a
vacuum system and things like platinum leaks to generate atomar hydrogen
and state selection magnets. If one knows glass blowing, part of it can
be made using pyrex tubes, which simplifies some stuff (like keeping the
state selection magnets outside the vacuum system). Also, the cavity
needed would be quite big. A normaly used TE011 cavity is huge. One can
load it with aluminia and get it down to 15-20cm diameter, but this requires
crystaline aluminia to maintain low loss. Maybe one could use other resonating
structures that are smaller, TE111 or loop-gap resonators have been proposed.
The biggest cost here is definitely the needed vacuum system. Although
the rough pumps are rather cheap (around 500-1000€ if one does not need
fast pumping) and some of these actually end up on ebay without being
destryoed by "testing", the high vacuum pumps (ion pumps, turbo pumps etc)
are not cheap and need to bought new (the stuff you see on ebay are either
systems that were removed from labs because they don't work anymore, or
were destroyed by "testing" them in free air).
An active hydrogen maser should not be that much more difficult. It mostly
involves a low loss, correctly tuned cavity and low noise detection electronics.
The input stream of hydrogen atoms needs to be more precisely controlled as
well...
Another step up in difficulty would be a system using a magneto optical trap.
Glass cavities with flanges for vacuum system are readily available and
also cheap. Again, the vacuum system is one difficulty, though probably
simpler than for the hydrogen maser (less parts that need to be custom made).
But the requirements for the vacuum are a bit higher. The laser system poses
a similar difficult as with the CPT system above, but now there are more
lasers and all need to be locked to eachother. The traping laser also need
to be directed at the cavity from 6 sides, all meeting in the center of the
cavity, which makes alignment problematic. This is also the first system
that offers to be a primary standard, although it probably does not get to
the stability of a 5071, as the trapping lasers will induce a light shift
that is not so easy to control unless one goes for the expensive laboratory
grade lasers.
Next on the list would be an Hg ion trap. But there are so many parts
in such a system that are not easily bought and require a very good
understanding of the physics involved to design custom parts, that
it becomes almost unrealistic that an amateur could be build one at home.
Same goes for ion and neutral atom optical clocks. Yes, they can be build,
yes the principle is simple, but getting it actually to work needs a lot
of understanding and tinkering.
Ah... I'm dreaming again :-)
Attila Kinali
--
It is upon moral qualities that a society is ultimately founded. All
the prosperity and technological sophistication in the world is of no
use without that foundation.
-- Miss Matheson, The Diamond Age, Neil Stephenson
------------------------------
Message: 6
Date: Wed, 02 Nov 2016 10:02:53 +0000
From: "Poul-Henning Kamp" <phk at phk.freebsd.dk>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>, Attila Kinali <attila at kinali.ch>
Subject: Re: [time-nuts] Cs tube pics
Message-ID: <26586.1478080973 at critter.freebsd.dk>
Content-Type: text/plain; charset="us-ascii"
--------
In message <20161102104103.0c58d35a72b7b36253b3d6b2 at kinali.ch>, Attila Kinali writes:
>I still would like to try to build my own atomic clock at some point,
>even if it would be a quite costly, and a many years project.
If you like lasers, build an ion trap.
If you only like lasers a little bit, build an optically pumped standard.
If you *really* like lasers, build a fountain.
If you are more chemically inclined, there are a ton of gasses you
can work with, methane, amonia, CO2 etc.
The one thing nobody has done or even tried yet, (as far as I know),
is optically excite a solid crystal.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
------------------------------
Message: 7
Date: Wed, 2 Nov 2016 11:51:17 +0100
From: Attila Kinali <attila at kinali.ch>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] Cs tube pics
Message-ID: <20161102115117.faa7e8b99f1892d78893a520 at kinali.ch>
Content-Type: text/plain; charset=US-ASCII
On Wed, 02 Nov 2016 10:02:53 +0000
"Poul-Henning Kamp" <phk at phk.freebsd.dk> wrote:
> In message <20161102104103.0c58d35a72b7b36253b3d6b2 at kinali.ch>, Attila Kinali writes:
>
> >I still would like to try to build my own atomic clock at some point,
> >even if it would be a quite costly, and a many years project.
>
> If you like lasers, build an ion trap.
>
> If you only like lasers a little bit, build an optically pumped standard.
>
> If you *really* like lasers, build a fountain.
If you *really*really* like lasers build an neutral atom optical clock :-)
A fountain is a quite intricate design. Beside doing the MOT one needs
to launch the atoms in a precisely determined direction with precisely
controlled speed, such that they pass trough the cavity with a constant
timing. If multiple cavities are used, the alignment is sligtly more
difficult (not just launching straigth up, but in a parabola and mistakes
make the atoms get lost completely, and not just arrive early/late).
It might be easier to just let the atoms fall freely within the cavity
and do the Ramsey probing using lasers instead of a microwave cavity.
Of course this reduces the time avaible and induces a Doppler shift which
needs to be calculated and compensated.
> The one thing nobody has done or even tried yet, (as far as I know),
> is optically excite a solid crystal.
This has been done. Ok, not the whole crystal, but single atoms within
the crystall. The most popular is probably diamond nitrogen vacancy defects:
"Timekeeping with electron spin states in diamond", by Hodges, Yao,
Maclaurin, Rasogi, Lukin, Englund, 2013
http://link.aps.org/doi/10.1103/PhysRevA.87.032118
https://arxiv.org/abs/1109.3241
"Solid-state electronic spin coherence time approaching one second",
by Bar-Gill, Pham, Jarmola, Budker, Walsworth, 2013
http://dx.doi.org/10.1038/ncomms2771
"High-resolution correlation spectroscopy of 13C spins near a
nitrogen-vacancy centre in diamond", by Laraoui, Dolde, Burk, Reinhard,
Wrachtrup, Meriles, 2013,
http://dx.doi.org/10.1038/ncomms2685
But these all suffer from one problem: mounting and temperature effects.
Because the nitrogen atom is not in free space, but bond trough its
valence electrons to the surrounding carbon atoms, it is directly influenced
by them. Any change in distance or strain directly affects the energy levels.
Attila Kinali
--
It is upon moral qualities that a society is ultimately founded. All
the prosperity and technological sophistication in the world is of no
use without that foundation.
-- Miss Matheson, The Diamond Age, Neil Stephenson
------------------------------
Message: 8
Date: Wed, 2 Nov 2016 09:41:38 -0400
From: EWKehren at aol.com
To: time-nuts at febo.com
Subject: [time-nuts] OCXO's
Message-ID: <435946.645a992f.454b4711 at aol.com>
Content-Type: text/plain; charset="US-ASCII"
Still downsizing down to 20 Costco Premium Apple boxes found a box with
OCXO's. One HP 105, a Piezo 10 Mhz looks like a HP 10811/544 knock off an
Ovenaire CSC 85-50 and a CTC 15 MHz WP-93744L1 all available for the cost of
shipping. All at one time tested, working as far back as 2009.Responses
off list please.
Also found five HP 10544 do not know if there is still interest may put
them on ebay.
Bert Kehren
------------------------------
Message: 9
Date: Wed, 2 Nov 2016 09:59:01 -0400
From: paul swed <paulswedb at gmail.com>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] So what’s inside that Cs Beam Tube anyway?
Message-ID:
<CAD2JfAhxXVsrYrJwsvyT5yK3_Yqkm1Ph9ww19o9VdN10esfxEw at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Welllll you know we all love to talk of details. But crazy stuff happens
when you try.
As mentioned you would dirty everything up. But waiting a year to de-gas
etc well what the heck.
I was looking at the pix of the ampule nothing is clear to me at least as
to how you even would insert some new C's. Just curiosity.
Other thing you can actually buy the cesium stuff online and it wasn't that
expensive. Granted quality?????????????????????????????
Regards
Paul
WB8TSL
On Tue, Nov 1, 2016 at 11:38 PM, Mark Sims <holrum at hotmail.com> wrote:
> You mean I can't just drill a hole in, wash out the old cesium with some
> tap water ;-), toss in some new cesium, suck out the air, bung a cork in
> the hole, and call it a day? Drat! foiled again...
>
> ---------------
>
> > Because it's not that easy. We are talking about a high vacuum system
> here.
> _______________________________________________
> 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: 10
Date: Wed, 2 Nov 2016 10:42:00 -0400
From: EWKehren at aol.com
To: time-nuts at febo.com
Subject: [time-nuts] HP 105 and Piezo gone
Message-ID: <43d393.6478f282.454b5538 at aol.com>
Content-Type: text/plain; charset="US-ASCII"
------------------------------
Message: 11
Date: Wed, 2 Nov 2016 07:53:34 -0700
From: "Richard (Rick) Karlquist" <richard at karlquist.com>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] So what’s inside that Cs Beam Tube anyway?
Message-ID: <81696459-fbc8-37b4-e0ea-88579ea5f291 at karlquist.com>
Content-Type: text/plain; charset=utf-8; format=flowed
This has probably been covered here before, but, at least going
to the 5071A, now 25 years ago!, all CBT's, whether high
performance or not, have the same amount of cesium inside.
This means that the standard performance (never call it
"low" performance) CBT has enough cesium to last 30 years!
Thus for those tubes, we can rule out cesium replenishment
even if it were possible.
Rick
On 11/1/2016 8:38 PM, Mark Sims wrote:
> You mean I can't just drill a hole in, wash out the old cesium with some tap water ;-), toss in some new cesium, suck out the air, bung a cork in the hole, and call it a day? Drat! foiled again...
>
> ---------------
>
>> Because it's not that easy. We are talking about a high vacuum system here.
> _______________________________________________
> 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: 12
Date: Wed, 2 Nov 2016 11:34:42 -0400
From: paul swed <paulswedb at gmail.com>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] Cs tube pics
Message-ID:
<CAD2JfAge17bE4yEFWc+i6gpD=yjdgZYSnQDYdnfPSoA5V+S5NQ at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
A comment to the thread.
Desired a C, obtained a C. Discovered they take care, feeding and power.
Mine is after all a rag-tag C.
So thats why they run them on UPS systems....
Anyhow happy that I have one and learned so much.
But for a large group of time-nuts GPSDO may simply be good enough.
No concerns for the C's running out....
So desire is good education is great, but a consideration in reality.
Regards
Paul
WB8TSL
On Wed, Nov 2, 2016 at 6:51 AM, Attila Kinali <attila at kinali.ch> wrote:
> On Wed, 02 Nov 2016 10:02:53 +0000
> "Poul-Henning Kamp" <phk at phk.freebsd.dk> wrote:
>
> > In message <20161102104103.0c58d35a72b7b36253b3d6b2 at kinali.ch>, Attila
> Kinali writes:
> >
> > >I still would like to try to build my own atomic clock at some point,
> > >even if it would be a quite costly, and a many years project.
> >
> > If you like lasers, build an ion trap.
> >
> > If you only like lasers a little bit, build an optically pumped standard.
> >
> > If you *really* like lasers, build a fountain.
>
> If you *really*really* like lasers build an neutral atom optical clock :-)
>
> A fountain is a quite intricate design. Beside doing the MOT one needs
> to launch the atoms in a precisely determined direction with precisely
> controlled speed, such that they pass trough the cavity with a constant
> timing. If multiple cavities are used, the alignment is sligtly more
> difficult (not just launching straigth up, but in a parabola and mistakes
> make the atoms get lost completely, and not just arrive early/late).
>
> It might be easier to just let the atoms fall freely within the cavity
> and do the Ramsey probing using lasers instead of a microwave cavity.
> Of course this reduces the time avaible and induces a Doppler shift which
> needs to be calculated and compensated.
>
> > The one thing nobody has done or even tried yet, (as far as I know),
> > is optically excite a solid crystal.
>
> This has been done. Ok, not the whole crystal, but single atoms within
> the crystall. The most popular is probably diamond nitrogen vacancy
> defects:
>
> "Timekeeping with electron spin states in diamond", by Hodges, Yao,
> Maclaurin, Rasogi, Lukin, Englund, 2013
> http://link.aps.org/doi/10.1103/PhysRevA.87.032118
> https://arxiv.org/abs/1109.3241
>
> "Solid-state electronic spin coherence time approaching one second",
> by Bar-Gill, Pham, Jarmola, Budker, Walsworth, 2013
> http://dx.doi.org/10.1038/ncomms2771
>
> "High-resolution correlation spectroscopy of 13C spins near a
> nitrogen-vacancy centre in diamond", by Laraoui, Dolde, Burk, Reinhard,
> Wrachtrup, Meriles, 2013,
> http://dx.doi.org/10.1038/ncomms2685
>
> But these all suffer from one problem: mounting and temperature effects.
> Because the nitrogen atom is not in free space, but bond trough its
> valence electrons to the surrounding carbon atoms, it is directly
> influenced
> by them. Any change in distance or strain directly affects the energy
> levels.
>
> Attila Kinali
>
> --
> It is upon moral qualities that a society is ultimately founded. All
> the prosperity and technological sophistication in the world is of no
> use without that foundation.
> -- Miss Matheson, The Diamond Age, Neil Stephenson
> _______________________________________________
> 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: 13
Date: Wed, 2 Nov 2016 11:38:47 -0400
From: paul swed <paulswedb at gmail.com>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] So what’s inside that Cs Beam Tube anyway?
Message-ID:
<CAD2JfAhXs-JuCvnxGwNaeYfOZxq_kkWKBoZ0vZDeYPGNGN2bXA at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Oh yes and guess which tubes we find? The 40 year olds at ham prices. :-)
At least thats what I have.
Like your comment as so far what I have learned is that seems like other
things going on.
I sort of believe its C pollution of things like the ionizer and even the
photo tube elements over time. Its a curiosity without much of a way to
prove it.
Regards
Paul
WB8TSL
On Wed, Nov 2, 2016 at 10:53 AM, Richard (Rick) Karlquist <
richard at karlquist.com> wrote:
> This has probably been covered here before, but, at least going
> to the 5071A, now 25 years ago!, all CBT's, whether high
> performance or not, have the same amount of cesium inside.
> This means that the standard performance (never call it
> "low" performance) CBT has enough cesium to last 30 years!
> Thus for those tubes, we can rule out cesium replenishment
> even if it were possible.
>
> Rick
>
>
> On 11/1/2016 8:38 PM, Mark Sims wrote:
>
>> You mean I can't just drill a hole in, wash out the old cesium with some
>> tap water ;-), toss in some new cesium, suck out the air, bung a cork in
>> the hole, and call it a day? Drat! foiled again...
>>
>> ---------------
>>
>> Because it's not that easy. We are talking about a high vacuum system
>>> here.
>>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
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Message: 14
Date: Wed, 2 Nov 2016 11:51:35 -0400
From: EWKehren at aol.com
To: time-nuts at febo.com
Subject: Re: [time-nuts] So what’s inside that Cs Beam Tube anyway?
Message-ID: <5b4b6.6070e749.454b6587 at aol.com>
Content-Type: text/plain; charset="US-ASCII"
30 years that is remarkable glad I have such a tube in my 5061B
In a message dated 11/2/2016 10:53:50 A.M. Eastern Daylight Time,
richard at karlquist.com writes:
This has probably been covered here before, but, at least going
to the 5071A, now 25 years ago!, all CBT's, whether high
performance or not, have the same amount of cesium inside.
This means that the standard performance (never call it
"low" performance) CBT has enough cesium to last 30 years!
Thus for those tubes, we can rule out cesium replenishment
even if it were possible.
Rick
On 11/1/2016 8:38 PM, Mark Sims wrote:
> You mean I can't just drill a hole in, wash out the old cesium with
some tap water ;-), toss in some new cesium, suck out the air, bung a cork
in the hole, and call it a day? Drat! foiled again...
>
> ---------------
>
>> Because it's not that easy. We are talking about a high vacuum system
here.
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Message: 15
Date: Wed, 2 Nov 2016 11:57:00 -0400
From: Peter Reilley <preilley_454 at comcast.net>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] So what’s inside that Cs Beam Tube anyway?
Message-ID: <03a295f5-0809-9765-2ffc-3413e1adff45 at comcast.net>
Content-Type: text/plain; charset=utf-8; format=flowed
Just throwing this out: would it be possible recover the cesium by heating
the tube but cooling it near where the reservior is? This might cause the
cesium to migrate in that direction and some of it end up in the reservior?
Pete.
On 11/2/2016 11:38 AM, paul swed wrote:
> Oh yes and guess which tubes we find? The 40 year olds at ham prices. :-)
> At least thats what I have.
> Like your comment as so far what I have learned is that seems like other
> things going on.
> I sort of believe its C pollution of things like the ionizer and even the
> photo tube elements over time. Its a curiosity without much of a way to
> prove it.
>
> Regards
> Paul
> WB8TSL
>
> On Wed, Nov 2, 2016 at 10:53 AM, Richard (Rick) Karlquist <
> richard at karlquist.com> wrote:
>
>> This has probably been covered here before, but, at least going
>> to the 5071A, now 25 years ago!, all CBT's, whether high
>> performance or not, have the same amount of cesium inside.
>> This means that the standard performance (never call it
>> "low" performance) CBT has enough cesium to last 30 years!
>> Thus for those tubes, we can rule out cesium replenishment
>> even if it were possible.
>>
>> Rick
>>
>>
>> On 11/1/2016 8:38 PM, Mark Sims wrote:
>>
>>> You mean I can't just drill a hole in, wash out the old cesium with some
>>> tap water ;-), toss in some new cesium, suck out the air, bung a cork in
>>> the hole, and call it a day? Drat! foiled again...
>>>
>>> ---------------
>>>
>>> Because it's not that easy. We are talking about a high vacuum system
>>>> here.
>>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/m
>>> ailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>>
>>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
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