Re: [time-nuts] Thinking outside the box a super reference

[Attila Kinali]

Hoi Rick,


Thanks for the detailed explanation!


On Sat, 5 Nov 2016 08:32:58 -0700
"Richard (Rick) Karlquist"  wrote:

> In the 5071, the only place 9192 shows up is in the
> microwave module that is directly attached to the
> coax to waveguide transition into the cavity.

Ah.. neat! That's a nice way to avoid any stray field!

> There are no frequencies anywhere that are sub
> harmonics of 9192.  Incidentally, there are no
> frequencies anywhere that are coherent with
> 50 Hz, 60 Hz, etc line frequencies.  Nothing
> is by accident when Len Cutler is involved.

Interesting. I guess the choice not to sync to line frequency
was to avoid any kind of offset that would cause and instead
let the system "average" the line noise?


Attila Kinali

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Re: [time-nuts] Thinking outside the box a super reference

[Bruce Griffiths]

Neither Rb cells nor isolators are difficult to source.They are both catalog 
items. However if using a cavity it may need to be tailored to the available 
cells.Walk-off isolators using double refraction are somewhat more convenient 
than those requiring a strong magnetic field.
Bruce 

On Sunday, 6 November 2016 10:10 PM, Anders Wallin 
 wrote:
 

 >
> > Just for the heck of it, I'd go laser instead of the old UHF lamp.
> >
> > With respect to precision machining, that space has changed a lot
> > over the last five years, with precision CNC machines, factory
> > or home-built, dropping dramatically in price.
> Yes, the laser technique is doable even if one has to build an ECDL.
> What would be nice would be a scheme that allows the same Rb filled bulb
> to be used to both lock the laser to the right wavelength and to detect
> that the microwave signal is also locked to the Rb microwave transition.
>

FWIW we have the remains of this experiment somewhere in the basement - but
no time or resources to really play with it...
http://lib.tkk.fi/Diss/2010/isbn9789526035024/article4.pdf
Fig 3 is a fairly clear overview of the two cells and loops, one for
stabilizing the laser wavelength, and one for the 3 GHz
sidebands/clock-transition.
For hobby tinkering I would expect the Rb-cells and the optical isolator to
be hard/expensive to source. Otherwise the electronics needed looks
DIY-able.

Anders
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Re: [time-nuts] Thinking outside the box a super reference

[Anders Wallin]

>
> > Just for the heck of it, I'd go laser instead of the old UHF lamp.
> >
> > With respect to precision machining, that space has changed a lot
> > over the last five years, with precision CNC machines, factory
> > or home-built, dropping dramatically in price.
> Yes, the laser technique is doable even if one has to build an ECDL.
> What would be nice would be a scheme that allows the same Rb filled bulb
> to be used to both lock the laser to the right wavelength and to detect
> that the microwave signal is also locked to the Rb microwave transition.
>

FWIW we have the remains of this experiment somewhere in the basement - but
no time or resources to really play with it...
http://lib.tkk.fi/Diss/2010/isbn9789526035024/article4.pdf
Fig 3 is a fairly clear overview of the two cells and loops, one for
stabilizing the laser wavelength, and one for the 3 GHz
sidebands/clock-transition.
For hobby tinkering I would expect the Rb-cells and the optical isolator to
be hard/expensive to source. Otherwise the electronics needed looks
DIY-able.

Anders
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Re: [time-nuts] Thinking outside the box a super reference

[Poul-Henning Kamp]

In message , "Tom Van Baak" writes:
>Attila, PHK, et al --
>
>Rb maser proposal, including some photos. 3 PDF's, 175 pages of weekend 
>reading:
>
>https://archive.org/details/NASA_NTRS_Archive_19720025867
>
>https://archive.org/details/NASA_NTRS_Archive_19730017775
>
>https://archive.org/details/NASA_NTRS_Archive_19750006044


Interesting!

As is this:

https://arxiv.org/abs/physics/0508227

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
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Re: [time-nuts] Thinking outside the box a super reference

[Ruslan Nabioullin]

On 11/03/2016 06:10 PM, Attila Kinali wrote:

On Thu, 3 Nov 2016 16:37:06 -0400
Ruslan Nabioullin  wrote:


What about instead establishing an open-source hardware project for a
frequency standard fusor?  I was researching COTS solutions for this for
my rubidium ensemble and could only find this one product, which
obviously should be exorbitant in cost:


You don't need a hardware project for this, as long as a paper clock
is enough for you. Just buy a couple of kiwi-sdr (or anything similar),
provide all of them with a common clock source and you get a comparison
of all your atomic clocks with minimum effort and can build from that
a paper clock easily. The paper clock can than be used for the measurement
you do, using one of the atomic clocks (preferably the one with the lowest
phase noise) as reference.


If it's so relatively straightforward, then why not establish such a 
project instead of reinventing the wheel by attempting to perform atomic 
standard R and fabrication on a shoestring?  It should be much more 
practical, even considering the fact that one will obtain diminishing 
returns on the ensemble's n, and furthermore should be extremely 
successful---apparently only a single Russian company holds a global 
monopoly on this product, apart from custom-fabricated setups in 
national metrology labs, and numerous people would benefit (why purchase 
an exorbitantly-expensive and short-lifespan cesium standard when one 
can fuse a redundant ensemble of rubidium standards?  Or for 
lower-budget and/or higher-MTBF setups, the same for a rubidium standard 
and OCXO standards, resp.)


Another project, much simpler in comparison but even more useful, would 
be a rack-mount standard for an OCXO or rubidium physics package, which 
should consist of just a chassis, power supply, thermal structure, and a 
monitoring subsystem with interfaces (LEDs, an LCD display, and 
RS-232/USB/GPIB/Ethernet).  The used market is flooded with cheap 
physics packages, yet actual standards are uncommon and expensive.


-Ruslan
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Re: [time-nuts] Thinking outside the box a super reference

[Magnus Danielson]

On 11/05/2016 03:16 PM, Attila Kinali wrote:

On Sat, 05 Nov 2016 12:25:35 +
"Poul-Henning Kamp"  wrote:



Active maser like the hydrogen would be possible naturally, but would
require the resonator.


I don't think they are.


They are. It took a while, but they have been a thing since '64.
Though all of them have been using vapor cells.


As I understand it not all excited modes of all atoms and molecules
have the not-quite-pinned-down quantum-thaumagic property to do that.

And I remember reading somewhere that the alkali atoms have been
poked and prodded to no end about this, in the hope of creating
active Cs, Rb or Sr frequency standards, but the very reluctant
(and expensive) conclusion was that hydrogen is the only one in the
family which knows the trick.


Nope, the problem, as far as I understand it, is not that you cannot
get the atoms to emit, but to keep them in one place without perturbing
them. For hydrogen, a teflon coating does a very good job and the atom
can go for many wall collisions without losing its state/phase. Even the
early hydrogen maser got to >10^4 collisions and modern coatings offer
something like 10^6 IIRC, ie the life time is measured in seconds
to minutes.


Hydrogren maser is really a development out of the beam device, through 
the intermediary step of a beam device who's beam is extended with a 
"bounce box" to increase the time between the two Ramsey interegation 
zones. The quick decorrelation due to the wall-bounces for many atoms 
made this impractical except for the hydrogen, and the hydrogen maser is 
a refined variant of it.


In the end of the day, many of the classicial atomic clocks and the 
choice of elements for them is really dependent on what is "practical".


Cheers,
Magnus
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Re: [time-nuts] Thinking outside the box a super reference

[Tom Van Baak]

Attila, PHK, et al --

Rb maser proposal, including some photos. 3 PDF's, 175 pages of weekend reading:

https://archive.org/details/NASA_NTRS_Archive_19720025867

https://archive.org/details/NASA_NTRS_Archive_19730017775

https://archive.org/details/NASA_NTRS_Archive_19750006044

/tvb

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Re: [time-nuts] Thinking outside the box a super reference

[Richard (Rick) Karlquist]

One of the main limiting factors in the 5061 was
microwave leakage.  An excellent Italian engineer
named DiMarchi mastered the so called "top cover
effect", where removing the top cover changed the
frequency.  He had a small business going refurbishing
5061's by cleaning up the waveguide gasketing, etc.
If any 9192.63177 reaches the beam at one end or
the other, it will upset the phase balance.  In
the 5071, phase balance is the main limiting factor
in accuracy.  They go to extreme measures to make
the cavity absolutely symmetrical using fabrication
techniques analogous to "self aligning" IC masking.
In the 5071, the only place 9192 shows up is in the
microwave module that is directly attached to the
coax to waveguide transition into the cavity.
There are no frequencies anywhere that are sub
harmonics of 9192.  Incidentally, there are no
frequencies anywhere that are coherent with
50 Hz, 60 Hz, etc line frequencies.  Nothing
is by accident when Len Cutler is involved.

In terms of basic synthesizer architecture, the
mix from 9280 to 9192 using 87 is described by
the technical term "free lunch" :-)  We pick
up two decades of resolution.  Furthermore, we
don't have to filter out 9280 or 9367 because
they are ignored by the CBT.  One of the reasons
for going up from 12 to 87 was to get these
spurs safely removed from anything that would
interact quantum mechanically with the cesium
line tail.  With the increased accuracy, 12
was no longer high enough.

Rick

On 11/5/2016 7:39 AM, Attila Kinali wrote:

Hoi Rick,

On Sat, 5 Nov 2016 07:17:21 -0700
"Richard (Rick) Karlquist"  wrote:


I think this is all described in the 1992 FCS papers,
but the executive summary is that a direct synthesizer
on 9192.63177 is to be avoided at all costs because
of the danger of it leaking into the CBT cavity.
This is also the reason why you don't multiply up
a subharmonic of this frequency.



I don't get what you mean with "danger of leaking into the CBT cavity"?
When signal leakage into the cavity is a problem, shouldn't that also
exist for the signal after the mixer? And what does this leaking actually
mean? The 9192.63177 is supposed to end up in the cavity anyways.

Attila Kinali


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Re: [time-nuts] Thinking outside the box a super reference

[Richard (Rick) Karlquist]

On 11/5/2016 12:18 AM, Poul-Henning Kamp wrote:


In message <768ee5a7-1c53-06cf-cf36-ec75e2901...@karlquist.com>, "Richard (Rick) 
Karlquist" w
rites:


Reminds me of an interesting Jack Kusters story.
There was some customer who was having problems with
his atomic clocks being noisy (I don't remember exactly
the story) but the bottom line was that they determined
it was because of helium contamination.


How would helium make his clocks noisy ?

Isn't it more likely that it was the alphas from the
radon decay that did it by their charge ?


I probably am not remembering the story exactly, but
I do definitely remember it had to do with unexplained
helium, which they tried to blame Kusters company for.
He said there was a simple explanation, namely radon
gas emitting alpha particles that turn into helium
and helium can diffuse into "sealed" containers.
He basically told them that if they dropped the issue,
it wouldn't be necessary for him to publicize the fact
that their plant was full of radon.  It was really
funny when Jack himself told it.

Rick

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Re: [time-nuts] Thinking outside the box a super reference

[Attila Kinali]

Hoi Rick,

On Sat, 5 Nov 2016 07:17:21 -0700
"Richard (Rick) Karlquist"  wrote:

> I think this is all described in the 1992 FCS papers,
> but the executive summary is that a direct synthesizer
> on 9192.63177 is to be avoided at all costs because
> of the danger of it leaking into the CBT cavity.
> This is also the reason why you don't multiply up
> a subharmonic of this frequency.


I don't get what you mean with "danger of leaking into the CBT cavity"?
When signal leakage into the cavity is a problem, shouldn't that also
exist for the signal after the mixer? And what does this leaking actually
mean? The 9192.63177 is supposed to end up in the cavity anyways.

Attila Kinali

-- 
Malek's Law:
Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] Thinking outside the box a super reference

[Attila Kinali]

On Sat, 5 Nov 2016 06:53:45 -0700
jimlux  wrote:

> On 11/5/16 2:59 AM, Attila Kinali wrote:
>   But we still need to ensure that the field is properly
> > oriented and homogenous over the whole vapor cell. For this you need
> > a cavity that is properly designed and most likely will be resonant at 
> > 6.9GHz.
> > (I don't know whether it is possible to design a non-resonant cavity with
> > the above properties)
> 
> isn't a TEM cell, as used in EMI/EMC testing, something like this?  It's 
> a tapered transmission line and produces a uniform field within an area 
> inside the line.

Yes, they fullfill the "constant field" condition, but not the "properly
oriented" condition. The field in these cells has still a quite considerable
curl. One can of course minimize that by building a larger one, but
then there are smaller structures with similar properties, when one does
not need the the wideband property of those TEM cells.

Attila Kinali

-- 
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Re: [time-nuts] Thinking outside the box a super reference

[Richard (Rick) Karlquist]

I think this is all described in the 1992 FCS papers,
but the executive summary is that a direct synthesizer
on 9192.63177 is to be avoided at all costs because
of the danger of it leaking into the CBT cavity.
This is also the reason why you don't multiply up
a subharmonic of this frequency.
It would also have made the synthesizer a lot more
complicated.  We multiplied 10 to 320 and then used
an SRD to get to 9280 and applied a sideband at 87.36
MHz to it.  The 87.36 MHz synthesizer was a phase
locked VCXO using a 5th OT crystal.

It took me a long time for me to sell this to Len Cutler.
It was pretty advanced for 1989.

Rick

On 11/4/2016 7:12 PM, paul swed wrote:

Rick on the pll DRO I agree with you for today.
So is it built for 9180 and then the 12.63 is mixed with it? Or is it
actually a direct PLL precisely at the frequency so not even the
synthesizer is used?
Regards
Paul
WB8TSL

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Re: [time-nuts] Thinking outside the box a super reference

[Attila Kinali]

On Sat, 05 Nov 2016 12:25:35 +
"Poul-Henning Kamp"  wrote:


> >Active maser like the hydrogen would be possible naturally, but would 
> >require the resonator.
> 
> I don't think they are.

They are. It took a while, but they have been a thing since '64.
Though all of them have been using vapor cells.

> As I understand it not all excited modes of all atoms and molecules
> have the not-quite-pinned-down quantum-thaumagic property to do that.
> 
> And I remember reading somewhere that the alkali atoms have been
> poked and prodded to no end about this, in the hope of creating
> active Cs, Rb or Sr frequency standards, but the very reluctant
> (and expensive) conclusion was that hydrogen is the only one in the
> family which knows the trick.

Nope, the problem, as far as I understand it, is not that you cannot
get the atoms to emit, but to keep them in one place without perturbing
them. For hydrogen, a teflon coating does a very good job and the atom
can go for many wall collisions without losing its state/phase. Even the
early hydrogen maser got to >10^4 collisions and modern coatings offer
something like 10^6 IIRC, ie the life time is measured in seconds
to minutes.

Until recently, there didn't exist such a coating for Rb or Cs [1] and
relaxation time was measured in milliseconds. For comparison, have a look at
page 37 of Bandi's dissertation[2], the broadening due to wall collisions
is stated as 300Hz for the wall coated, evacuated cell, while the buffer
gas collision broadening is a mere 10Hz (yes, I am cheating here, the
correct comparison would be the total broadening which is 350Hz vs 600Hz).
Yes, the wall shift is smaller than the buffer gas shift (4000Hz vs 300Hz)
but this is in first order approximation a constant. 

Additionally, all the coatings have rather low temperature limits
(the hydrocarbon coatings are very similar to parafin wax) and the
high temperatures that were needed for the Rb lamps didn't work togheter.
And even for modern laser pumped systems, you still need a rather high
temperature (40-90°C are usual) to get a high enough amount or Rb in the cell.

I guess you can understand that people have not been using vapor cell
active masers because they do not offer the long term stability one
seeks (due to buffer gas changes) and their short term stability is
not any better than the passive masers (limited by buffer gas relaxation).

Probably, with the new coatings and laser pumping one could build a usable
Rb active maser with evacuated cells instead of buffer gas. But sofar
nobody has tried that yet (as far as I am aware of). I guess it's more
sexy to investigate optical standards than something as old as Rb.
Especially as there are already Rb fountains[3] which offer quite a
high stability already.


Attila Kinali


[1] "Polarized Alkali-Metal Vapor with Minute-Long Transverse
Spin-Relaxation Time", by Balabas, Kraulanov, Ledbetter, Budker, 2010
http://dx.doi.org/10.1103/PhysRevLett.105.070801

[2] "Double-Resonance Studies on Compact, High-performance Rubidium Cell
Frequency Standards", by Thejesh Bandi, 2013
https://doc.rero.ch/record/32317/files/2318.pdf

[3] "The USNO rubidium fountains", by Peil et al. 2015
http://dx.doi.org/10.1088/1742-6596/723/1/012004
-- 
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Re: [time-nuts] Thinking outside the box a super reference

[jimlux]

On 11/5/16 2:59 AM, Attila Kinali wrote:
 But we still need to ensure that the field is properly

oriented and homogenous over the whole vapor cell. For this you need
a cavity that is properly designed and most likely will be resonant at 6.9GHz.
(I don't know whether it is possible to design a non-resonant cavity with
the above properties)


isn't a TEM cell, as used in EMI/EMC testing, something like this?  It's 
a tapered transmission line and produces a uniform field within an area 
inside the line.




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Re: [time-nuts] Thinking outside the box a super reference

[Poul-Henning Kamp]

In message <0e976194-3cc1-2bc7-1289-0d9433132...@rubidium.dyndns.org>, Magnus D
anielson writes:

>> They won't be coherent photons, like in a Hydrogen maser, but we
>> don't need them to be, in fact that just causes the same exact
>> problems as the tuned cavity anyway, as long as we can measure
>> the frequency well enough.
>
>Active maser like the hydrogen would be possible naturally, but would 
>require the resonator.

I don't think they are.

With hydrogen, hitting the excited electron with the right frequency
increases the probability of coherent emission of the photon enough
that you get to the "SE" we know from LASER and MASER.

As I understand it not all excited modes of all atoms and molecules
have the not-quite-pinned-down quantum-thaumagic property to do that.

And I remember reading somewhere that the alkali atoms have been
poked and prodded to no end about this, in the hope of creating
active Cs, Rb or Sr frequency standards, but the very reluctant
(and expensive) conclusion was that hydrogen is the only one in the
family which knows the trick.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@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.
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Re: [time-nuts] Thinking outside the box a super reference

[Gerhard Hoffmann]

Am 05.11.2016 um 00:45 schrieb David:

On Fri, 04 Nov 2016 14:39:54 -0700, you wrote:

87-Rb has a half life of something like 4.9e10 years — you'll be waiting
a while for that strontium. /gp

Various online sources say that natural rubidium is radioactive enough
to fog photographic film in 1 to 2 months but that is also the case
with unprocessed uranium ore so I would not worry about it at all.

That's next to nothing. A friend of mine with interest in minerals found a
piece of Pechblende (Uranit) simply laying on the street near 
St.Joachimsthal
where they used to dig for silver over the centuries and after 1945 for 
uranium.


We put it on a sheet of Polaroid film for the Tektronix scope cameras and
sure enough, next morning we could see the silhouette of the stone,
completely white, probably way overexposed.

regards, Gerhard
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Re: [time-nuts] Thinking outside the box a super reference

[Attila Kinali]

On Fri, 04 Nov 2016 23:04:22 +
"Poul-Henning Kamp"  wrote:

> First:  Yes, but if you pick a sensible vibration mode for your
> microwave resonance, that can be done with an screw-in endcap.
> 
> Second:  No, I would actually not need to tune it.
> 
> Historically resonance cavities were used so that step/avalance
> diode multipliers had enough power to excite them.  Today we have
> semiconductors which work at those frequencies.

Yes, it is easier to create the required frequencies with high power
(getting 7GHz with 10dBm is trivial and 30dBm can be readily achieved
with single chip amplifiers) and the signal will be cleaner than what
an SRD setup can achieve (no spurs, comparable close-in phase noise
characteristic). Thus we can use cavities with lower Q which are easier
to build and tune. But we still need to ensure that the field is properly
oriented and homogenous over the whole vapor cell. For this you need
a cavity that is properly designed and most likely will be resonant at 6.9GHz.
(I don't know whether it is possible to design a non-resonant cavity with
the above properties)
 
> But the resonanance leads to all sorts of trouble, including frequency
> pulling, temperature sensitivities etc.

Frequency pulling is not so much of an issue for a vapor cell standard
as it is for hydrogen masers or the primary standards. The shifts due
to buffer gas and wall collisions are so large that a calibration is
needed anyways. Frequency pulling just adds another term. Temperature
sensitivity is IIRC lower for frequency pulling than for buffer gas shift,
but I could be mistaken. For high stability applications, temperature
stabilization of the cavity and the cell are advised anyways.

> Third:  A lot of the "everybody knows" about which atoms can be
> used for active vs. passive atomic standards comes from the
> state of the art electronics about 30 years ago.

A lot of the "everybody knows" has been challenged and rewritten
in the past 10-20 years. Although, it looks like the vapor cell
standards have not changed in 50 years, there has been a lot of
research going on and people optimized old ideas and came up with
new ones. Yes, a lot of the electronics design is rather crude,
but most of the people working in the field a physicists or electrical
engineers that just graduated, one cannot expect the level of skill
and expertise of someone who has been doing RF designs for 30 years.
Beside, these people are there to do research, not to design electronics.
The circuits are just a tool for the research, not their main topic.
Hence they rather spend 100k€ on a synthesiser from keysight instead
of spending 6 months for designing their own to save money.

 
> Using laser-pumping and modern semiconductors, it might actually
> be possible to detect the 6.8GHz photons from the Rb.

You mean an optically pumped active maser? (our vapor cell standards
are passive masers allready) This has been already done in the 60's[1]
and studied later again (eg [2]). I guess this isn't popular because
the short term stability of Rb vapor cell standards is already quite
good and the long term stability does not get improved. So it does not
justify the additional complexity.


> They won't be coherent photons, like in a Hydrogen maser, but we
> don't need them to be, in fact that just causes the same exact
> problems as the tuned cavity anyway, as long as we can measure
> the frequency well enough.

If you mean to detect the decay from the 5S hyperfine splitting,
then i have to disapoint you. There will not be much radiation to detect.
On one hand, the lifetime of the hyperfine splitting is quite long, thus
the electrons will just get stuck on the upper level after they fell
down from the 5P state (it's a forbidden transition after all).
A photon to stimulate the fall to the lower state is required, either
provided by spontaneous emission from other Rb atoms or from an external
source. On the other hand, if the photons are not coherent, they will
not build up a signal that one could detect. They will just be spikes
that get burried in noise. Yes, one could build a spectrometer which would
average over a lot of these photons, but that would require a stable
frequency source to be able to avearge for a long time. And I don't think
a simple OCXO is up to this task. 


Attila Kinali

[1] "The Optically Pumped Rubidium Maser", by Davidovits and Novik, 1966
http://dx.doi.org/10.1109/PROC.1966.4628

[2] "Experimental Study of the Laser Diode Pumped Rubidium Maser",
by Michaud Tremblay and Tetu, 1991
http://dx.doi.org/10.1109/TIM.1990.1032908
https://arxiv.org/abs/physics/0508227

-- 
Malek's Law:
Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] Thinking outside the box a super reference

[Poul-Henning Kamp]

In message <768ee5a7-1c53-06cf-cf36-ec75e2901...@karlquist.com>, "Richard 
(Rick) Karlquist" w
rites:

>Reminds me of an interesting Jack Kusters story.
>There was some customer who was having problems with
>his atomic clocks being noisy (I don't remember exactly
>the story) but the bottom line was that they determined
>it was because of helium contamination.

How would helium make his clocks noisy ?

Isn't it more likely that it was the alphas from the
radon decay that did it by their charge ?


-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
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Re: [time-nuts] Thinking outside the box a super reference

[jimlux]

On 11/4/16 5:27 PM, Richard (Rick) Karlquist wrote:

On 11/4/2016 4:04 PM, Poul-Henning Kamp wrote:


Historically resonance cavities were used so that step/avalance
diode multipliers had enough power to excite them.  Today we have
semiconductors which work at those frequencies.



A great deal of complexity in the 5061 went into
exciting an SRD at 90 MHz and getting a sufficient
line at 9180 MHz to put on a sideband at 9192.
I spent a lot of time trying to do this during the
5071 project and was never able to get anywhere
near the efficiency that the 5061 waveguide structure
was able to do.  It was designed by a visiting Korean
professor, so he wasn't around to mentor me.
The 10816 also used an SRD, and it was also a
struggle, although I was able to make it work.

Fortunately, we were able to replace all this with a
DRO and PLL, and that was 25 years ago.  At this time,
it is even more of a no brainer that you don't want
to knock yourself out trying to make an SRD multiplier
work.  Also, these days, it is harder than ever to
purchase good SRD's.

You can get a nice GaAs VCO that will tune 9GHz with no sweat, and the 
PLL parts to go around it. I'm not sure what the DRO market is these 
days - You can probably build a synthesizer with lower DC power with a 
DRO than using GaAs (although CMOS is getting ever better and getting up 
to that kind of range).  There are probably low cost low precision 
(unlocked) designs like LNBs that use a DRO.


But things like 10 GHz microwave motion detectors these days use VCOs, 
not DROs.


DROs are subject to microphonics and such - yes, the dominant resonance 
is the puck, but the cavity it's in affects it too, so vibration and 
temperature have effects.



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Re: [time-nuts] Thinking outside the box a super reference

[paul swed]

Rick on the pll DRO I agree with you for today.
So is it built for 9180 and then the 12.63 is mixed with it? Or is it
actually a direct PLL precisely at the frequency so not even the
synthesizer is used?
Regards
Paul
WB8TSL

On Fri, Nov 4, 2016 at 9:40 PM, bownes  wrote:

> Not to mention there is not so sensitive film, sensitive film and really
> sensitive film.
>
> Good old orthographic film took minutes in bright light.
>
>
>
> > On Nov 4, 2016, at 20:24, Poul-Henning Kamp  wrote:
> >
> > 
> > In message , David writes:
> >
> >> Various online sources say that natural rubidium is radioactive enough
> >> to fog photographic film in 1 to 2 months but that is also the case
> >> with unprocessed uranium ore so I would not worry about it at all.
> >
> > Yes, that sounds about right for an isotope with a 40 billion years
> > half-life.
> >
> > 1 to 2 months is a LNG time for photographic film.
> >
> > --
> > Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> > p...@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.
> > ___
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> mailman/listinfo/time-nuts
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[time-nuts] Thinking outside the box a super reference

[Mark Sims]

I have a scintillator that will pick up a small piece of uranium ore from 
several feet away.  I just checked some Rb lamps and cells and got no response.

Every single fireplace that I have checked sends the scintillator off into 
clicking heaven.  Apparently firebrick is rather hot stuff in more ways than 
one.  I have some uranium glazed pottery that is less active.

The guy that lived behind us when I was a kid was a geologist.  His living room 
coffee table was a chunk of yellow uranium ore about 36x36x18 inches with a 
piece of glass on top...  he had discovered a very large uranium deposit and 
kept a "souvenir" for his living room.


-

> fog photographic film in 1 to 2 months but that is also the case
>with unprocessed uranium ore so I would not worry about it at all
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Re: [time-nuts] Thinking outside the box a super reference

[bownes]

Not to mention there is not so sensitive film, sensitive film and really 
sensitive film. 

Good old orthographic film took minutes in bright light. 



> On Nov 4, 2016, at 20:24, Poul-Henning Kamp  wrote:
> 
> 
> In message , David writes:
> 
>> Various online sources say that natural rubidium is radioactive enough
>> to fog photographic film in 1 to 2 months but that is also the case
>> with unprocessed uranium ore so I would not worry about it at all.
> 
> Yes, that sounds about right for an isotope with a 40 billion years
> half-life.
> 
> 1 to 2 months is a LNG time for photographic film.
> 
> -- 
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> p...@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.
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Re: [time-nuts] Thinking outside the box a super reference

[Richard (Rick) Karlquist]

On 11/4/2016 5:24 PM, Poul-Henning Kamp wrote:

Yes, that sounds about right for an isotope with a 40 billion years
half-life.



The problem with the half life number is that the cylinder
still was marked "radioactive" complex with the radiation
symbol.  Radioactivity (for legal purposes) is a binary
property.  We used to mark CBT's "cesium device, non radioactive"
because the work "cesium" means "cesium 137 nuclear fallout"
to many people.

Reminds me of an interesting Jack Kusters story.
There was some customer who was having problems with
his atomic clocks being noisy (I don't remember exactly
the story) but the bottom line was that they determined
it was because of helium contamination.  Kusters was
called in to answer to the customer about this contamination
and how they were going to fix it.  Kusters measured the
air in the customer's plant and found that in contained
helium.  But the customer did not use helium at all in the
plant.  Kusters pointed out that that could mean only one
thing:  the plant had a radon problem, and radon breaks down
into helium.  Kusters told the customer that if they
dropped the complaint, he wouldn't have to say anything
about radon to anyone.  That was the last heard about the
helium problem.

Rick

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Re: [time-nuts] Thinking outside the box a super reference

[Richard (Rick) Karlquist]

On 11/4/2016 4:04 PM, Poul-Henning Kamp wrote:


Historically resonance cavities were used so that step/avalance
diode multipliers had enough power to excite them.  Today we have
semiconductors which work at those frequencies.



A great deal of complexity in the 5061 went into
exciting an SRD at 90 MHz and getting a sufficient
line at 9180 MHz to put on a sideband at 9192.
I spent a lot of time trying to do this during the
5071 project and was never able to get anywhere
near the efficiency that the 5061 waveguide structure
was able to do.  It was designed by a visiting Korean
professor, so he wasn't around to mentor me.
The 10816 also used an SRD, and it was also a
struggle, although I was able to make it work.

Fortunately, we were able to replace all this with a
DRO and PLL, and that was 25 years ago.  At this time,
it is even more of a no brainer that you don't want
to knock yourself out trying to make an SRD multiplier
work.  Also, these days, it is harder than ever to
purchase good SRD's.

Rick
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Re: [time-nuts] Thinking outside the box a super reference

[Poul-Henning Kamp]

In message , David writes:

>Various online sources say that natural rubidium is radioactive enough
>to fog photographic film in 1 to 2 months but that is also the case
>with unprocessed uranium ore so I would not worry about it at all.

Yes, that sounds about right for an isotope with a 40 billion years
half-life.

1 to 2 months is a LNG time for photographic film.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@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.
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Re: [time-nuts] Thinking outside the box a super reference

[David]

On Fri, 04 Nov 2016 14:39:54 -0700, you wrote:

>On Fri, Nov 4, 2016, at 02:27 PM, Poul-Henning Kamp wrote:
>> 
>> In message <2af27ebe-9200-c348-c89b-b98f9c973...@karlquist.com>, "Richard
>> (Rick) Karlquist" w
>> rites:
>> >Also, one of the Rb isotopes is slightly radioactive.
>> >35 years ago, the guy in the next cubicle got away with
>> >storing it under his desk.  He also happily smoked
>> >cigarettes all day at his desk.  Another ERA.
>
>> Rb87 has a halflife north of the age of the planet as far
>> as I recall, and the result is a beta which goes nowhere
>> far and Sr87 which is stable.
>
>87-Rb has a half life of something like 4.9e10 years — you'll be waiting
>a while for that strontium. /gp

Various online sources say that natural rubidium is radioactive enough
to fog photographic film in 1 to 2 months but that is also the case
with unprocessed uranium ore so I would not worry about it at all.
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Re: [time-nuts] Thinking outside the box a super reference

[Bruce Griffiths]

The N resonance discussedd 
in:http://walsworth.physics.harvard.edu/publications/2005_Smallwood_HUBAThesis.pdf

May be a better bet than traditional CPT.
Bruce 

On Saturday, 5 November 2016 12:17 PM, Magnus Danielson 
 wrote:
 

 Poul-Henning,

On 11/05/2016 12:04 AM, Poul-Henning Kamp wrote:
> 
> In message <59dc074a-3a09-6315-29d4-6877c3bf7...@rubidium.dyndns.org>, Magnus 
> Danielson write
> s:
>
>>> With respect to precision machining, that space has changed a lot
>>> over the last five years, with precision CNC machines, factory
>>> or home-built, dropping dramatically in price.
>>
>> You need to tune it regardless.
>
> First:  Yes, but if you pick a sensible vibration mode for your
> microwave resonance, that can be done with an screw-in endcap.

Indeed.

> Second:  No, I would actually not need to tune it.
>
> Historically resonance cavities were used so that step/avalance
> diode multipliers had enough power to excite them.  Today we have
> semiconductors which work at those frequencies.
>
> Later people kept the resonance, because it works well with low
> power budgets in telecoms/milspec applications.
>
> But the resonanance leads to all sorts of trouble, including frequency
> pulling, temperature sensitivities etc.
>
> We're neither space nor power constrained, we'd probably be
> perfectly happy if the end result is 4U and 100W, so resonance
> is not mandatory.

Sure, but if you do have a cavity, as you was hinting at, tuning it is 
still needed for the cavity pull effect.

> Third:  A lot of the "everybody knows" about which atoms can be
> used for active vs. passive atomic standards comes from the
> state of the art electronics about 30 years ago.

Sure, but some behaviors just remains there when still using such setups.

> Using laser-pumping and modern semiconductors, it might actually
> be possible to detect the 6.8GHz photons from the Rb.
>
> They won't be coherent photons, like in a Hydrogen maser, but we
> don't need them to be, in fact that just causes the same exact
> problems as the tuned cavity anyway, as long as we can measure
> the frequency well enough.

You can avoid the cavity using sidebands of the pumping laser and all 
that, yes I know.

Active maser like the hydrogen would be possible naturally, but would 
require the resonator.

A passive direct observation would also possible, but detection will be 
harder and then you would run into S/N issues.

> (No, I havn't done the math on this, my wife has banned me from
> starting any new projects until our house is finished.)

Probably a wise thing.

Cheers,
Magnus
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Re: [time-nuts] Thinking outside the box a super reference

[Magnus Danielson]

Poul-Henning,

On 11/05/2016 12:04 AM, Poul-Henning Kamp wrote:


In message <59dc074a-3a09-6315-29d4-6877c3bf7...@rubidium.dyndns.org>, Magnus 
Danielson write
s:


With respect to precision machining, that space has changed a lot
over the last five years, with precision CNC machines, factory
or home-built, dropping dramatically in price.


You need to tune it regardless.


First:  Yes, but if you pick a sensible vibration mode for your
microwave resonance, that can be done with an screw-in endcap.


Indeed.


Second:  No, I would actually not need to tune it.

Historically resonance cavities were used so that step/avalance
diode multipliers had enough power to excite them.  Today we have
semiconductors which work at those frequencies.

Later people kept the resonance, because it works well with low
power budgets in telecoms/milspec applications.

But the resonanance leads to all sorts of trouble, including frequency
pulling, temperature sensitivities etc.

We're neither space nor power constrained, we'd probably be
perfectly happy if the end result is 4U and 100W, so resonance
is not mandatory.


Sure, but if you do have a cavity, as you was hinting at, tuning it is 
still needed for the cavity pull effect.



Third:  A lot of the "everybody knows" about which atoms can be
used for active vs. passive atomic standards comes from the
state of the art electronics about 30 years ago.


Sure, but some behaviors just remains there when still using such setups.


Using laser-pumping and modern semiconductors, it might actually
be possible to detect the 6.8GHz photons from the Rb.

They won't be coherent photons, like in a Hydrogen maser, but we
don't need them to be, in fact that just causes the same exact
problems as the tuned cavity anyway, as long as we can measure
the frequency well enough.


You can avoid the cavity using sidebands of the pumping laser and all 
that, yes I know.


Active maser like the hydrogen would be possible naturally, but would 
require the resonator.


A passive direct observation would also possible, but detection will be 
harder and then you would run into S/N issues.



(No, I havn't done the math on this, my wife has banned me from
starting any new projects until our house is finished.)


Probably a wise thing.

Cheers,
Magnus
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Re: [time-nuts] Thinking outside the box a super reference

[Magnus Danielson]

Hej Bruce,

Ah yes, that's it. Sorry for the bad wording.

Cheers,
Magnus

On 11/04/2016 11:41 PM, Bruce Griffiths wrote:

Hej Magnus
A quarter waveplate doesn't depolarise, it can however convert a linearly 
polarised beam to a circularly polarised one.If you really need to depolarise a 
laser beam, scattering from a colloidal suspension of Titanium dioxide is very 
effective.There are no macroscopic moving parts.Brownian motion of the 
colloidal partticels suffices.
Bruce

On Saturday, 5 November 2016 11:28 AM, Magnus Danielson 
 wrote:


 Hi,

On 11/04/2016 10:27 PM, Poul-Henning Kamp wrote:


In message <2af27ebe-9200-c348-c89b-b98f9c973...@karlquist.com>, "Richard (Rick) 
Karlquist" w
rites:


Also, one of the Rb isotopes is slightly radioactive.
35 years ago, the guy in the next cubicle got away with
storing it under his desk.  He also happily smoked
cigarettes all day at his desk.  Another ERA.


Rb87 has a halflife north of the age of the planet as far
as I recall, and the result is a beta which goes nowhere
far and Sr87 which is stable.


With a half-life of 49.2 Gigayears compared to universe life around 13.8
Gigayears and the beta-decay within both glas and metal enclosure, I'm
not overly concerned. For all practical purposes it is essentially stable.


He got a lot more ionizing radiation from his cigaretess than he
ever got from the Rb87.

Just for the heck of it, I'd go laser instead of the old UHF lamp.


The 780 nm laserdiodes isn't all that hard to get, in fact I've got some
lying around. Depolarizing needed with a quarter-wave needed not to get
a Stark-pull.


With respect to precision machining, that space has changed a lot
over the last five years, with precision CNC machines, factory
or home-built, dropping dramatically in price.


You need to tune it regardless.

Cheers,
Magnus
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Re: [time-nuts] Thinking outside the box a super reference

[Poul-Henning Kamp]

In message <59dc074a-3a09-6315-29d4-6877c3bf7...@rubidium.dyndns.org>, Magnus 
Danielson write
s:

>> With respect to precision machining, that space has changed a lot
>> over the last five years, with precision CNC machines, factory
>> or home-built, dropping dramatically in price.
>
>You need to tune it regardless.

First:  Yes, but if you pick a sensible vibration mode for your
microwave resonance, that can be done with an screw-in endcap.

Second:  No, I would actually not need to tune it.

Historically resonance cavities were used so that step/avalance
diode multipliers had enough power to excite them.  Today we have
semiconductors which work at those frequencies.

Later people kept the resonance, because it works well with low
power budgets in telecoms/milspec applications.

But the resonanance leads to all sorts of trouble, including frequency
pulling, temperature sensitivities etc.

We're neither space nor power constrained, we'd probably be
perfectly happy if the end result is 4U and 100W, so resonance
is not mandatory.

Third:  A lot of the "everybody knows" about which atoms can be
used for active vs. passive atomic standards comes from the
state of the art electronics about 30 years ago.

Using laser-pumping and modern semiconductors, it might actually
be possible to detect the 6.8GHz photons from the Rb.

They won't be coherent photons, like in a Hydrogen maser, but we
don't need them to be, in fact that just causes the same exact
problems as the tuned cavity anyway, as long as we can measure
the frequency well enough.

(No, I havn't done the math on this, my wife has banned me from
starting any new projects until our house is finished.)

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@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.
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Re: [time-nuts] Thinking outside the box a super reference

[Bruce Griffiths]

Hej Magnus
A quarter waveplate doesn't depolarise, it can however convert a linearly 
polarised beam to a circularly polarised one.If you really need to depolarise a 
laser beam, scattering from a colloidal suspension of Titanium dioxide is very 
effective.There are no macroscopic moving parts.Brownian motion of the 
colloidal partticels suffices.
Bruce 

On Saturday, 5 November 2016 11:28 AM, Magnus Danielson 
 wrote:
 

 Hi,

On 11/04/2016 10:27 PM, Poul-Henning Kamp wrote:
> 
> In message <2af27ebe-9200-c348-c89b-b98f9c973...@karlquist.com>, "Richard 
> (Rick) Karlquist" w
> rites:
>
>> Also, one of the Rb isotopes is slightly radioactive.
>> 35 years ago, the guy in the next cubicle got away with
>> storing it under his desk.  He also happily smoked
>> cigarettes all day at his desk.  Another ERA.
>
> Rb87 has a halflife north of the age of the planet as far
> as I recall, and the result is a beta which goes nowhere
> far and Sr87 which is stable.

With a half-life of 49.2 Gigayears compared to universe life around 13.8 
Gigayears and the beta-decay within both glas and metal enclosure, I'm 
not overly concerned. For all practical purposes it is essentially stable.

> He got a lot more ionizing radiation from his cigaretess than he
> ever got from the Rb87.
>
> Just for the heck of it, I'd go laser instead of the old UHF lamp.

The 780 nm laserdiodes isn't all that hard to get, in fact I've got some 
lying around. Depolarizing needed with a quarter-wave needed not to get 
a Stark-pull.

> With respect to precision machining, that space has changed a lot
> over the last five years, with precision CNC machines, factory
> or home-built, dropping dramatically in price.

You need to tune it regardless.

Cheers,
Magnus
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Re: [time-nuts] Thinking outside the box a super reference

[Magnus Danielson]

Hi,

On 11/04/2016 10:27 PM, Poul-Henning Kamp wrote:


In message <2af27ebe-9200-c348-c89b-b98f9c973...@karlquist.com>, "Richard (Rick) 
Karlquist" w
rites:


Also, one of the Rb isotopes is slightly radioactive.
35 years ago, the guy in the next cubicle got away with
storing it under his desk.  He also happily smoked
cigarettes all day at his desk.  Another ERA.


Rb87 has a halflife north of the age of the planet as far
as I recall, and the result is a beta which goes nowhere
far and Sr87 which is stable.


With a half-life of 49.2 Gigayears compared to universe life around 13.8 
Gigayears and the beta-decay within both glas and metal enclosure, I'm 
not overly concerned. For all practical purposes it is essentially stable.



He got a lot more ionizing radiation from his cigaretess than he
ever got from the Rb87.

Just for the heck of it, I'd go laser instead of the old UHF lamp.


The 780 nm laserdiodes isn't all that hard to get, in fact I've got some 
lying around. Depolarizing needed with a quarter-wave needed not to get 
a Stark-pull.



With respect to precision machining, that space has changed a lot
over the last five years, with precision CNC machines, factory
or home-built, dropping dramatically in price.


You need to tune it regardless.

Cheers,
Magnus
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Re: [time-nuts] Thinking outside the box a super reference

[Gian-Paolo Musumeci]

On Fri, Nov 4, 2016, at 02:27 PM, Poul-Henning Kamp wrote:
> 
> In message <2af27ebe-9200-c348-c89b-b98f9c973...@karlquist.com>, "Richard
> (Rick) Karlquist" w
> rites:
> >Also, one of the Rb isotopes is slightly radioactive.
> >35 years ago, the guy in the next cubicle got away with
> >storing it under his desk.  He also happily smoked
> >cigarettes all day at his desk.  Another ERA.
> Rb87 has a halflife north of the age of the planet as far
> as I recall, and the result is a beta which goes nowhere
> far and Sr87 which is stable.

87-Rb has a half life of something like 4.9e10 years — you'll be waiting
a while for that strontium. /gp
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Re: [time-nuts] Thinking outside the box a super reference

[Bruce Griffiths]

On Friday, November 04, 2016 09:27:59 PM Poul-Henning Kamp wrote:
> 
> In message <2af27ebe-9200-c348-c89b-b98f9c973...@karlquist.com>, 
"Richard
> (Rick) Karlquist" w
> rites:
> >Also, one of the Rb isotopes is slightly radioactive.
> >35 years ago, the guy in the next cubicle got away with
> >storing it under his desk.  He also happily smoked
> >cigarettes all day at his desk.  Another ERA.
> 
> Rb87 has a halflife north of the age of the planet as far
> as I recall, and the result is a beta which goes nowhere
> far and Sr87 which is stable.
> 
> He got a lot more ionizing radiation from his cigaretess than he
> ever got from the Rb87.
> 
> Just for the heck of it, I'd go laser instead of the old UHF lamp.
> 
> With respect to precision machining, that space has changed a lot
> over the last five years, with precision CNC machines, factory
> or home-built, dropping dramatically in price.
Yes, the laser technique is doable even if one has to build an ECDL.
What would be nice would be a scheme that allows the same Rb filled bulb 
to be used to both lock the laser to the right wavelength and to detect 
that the microwave signal is also locked to the Rb microwave transition.

Bruce
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Re: [time-nuts] Thinking outside the box a super reference

[Poul-Henning Kamp]

In message <2af27ebe-9200-c348-c89b-b98f9c973...@karlquist.com>, "Richard 
(Rick) Karlquist" w
rites:

>Also, one of the Rb isotopes is slightly radioactive.
>35 years ago, the guy in the next cubicle got away with
>storing it under his desk.  He also happily smoked
>cigarettes all day at his desk.  Another ERA.

Rb87 has a halflife north of the age of the planet as far
as I recall, and the result is a beta which goes nowhere
far and Sr87 which is stable.

He got a lot more ionizing radiation from his cigaretess than he
ever got from the Rb87.

Just for the heck of it, I'd go laser instead of the old UHF lamp.

With respect to precision machining, that space has changed a lot
over the last five years, with precision CNC machines, factory
or home-built, dropping dramatically in price.


-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@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.
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Re: [time-nuts] Thinking outside the box a super reference

[Bob Camp]

Hi

You are indeed effectively either doing a startup or contracting with somebody
already in the business. In a lot of ways, contracting this out might be the 
easier
approach. The trick there will be having enough business to make it attractive 
to them. 

Bob

> On Nov 4, 2016, at 11:21 AM, Scott Stobbe  wrote:
> 
> You will also share the same challenges as Touchstone semi did, no one
> wanted to stick their neck out to design in a little startup.
> 
> On Thu, Nov 3, 2016 at 7:49 PM, Bob Camp  wrote:
> 
>> Hi
>> 
>> Not many people have had exposure to Rb’s or Cs standards actually being
>> built. That leaves a major gap in who you can call when you run into a
>> problem.
>> 
>> Until you have tried to build one it’s not at all clear just how much
>> “missing information” there
>> is in all those papers. It’s very much like the semiconductor business.
>> Lots of
>> information is published. There are indeed lots of gaps. At some point you
>> must
>> build tooling and get it all working.
>> 
>> Again, we are talking about a device that is at least as good as a 5065
>> and not
>> something that just barely works. If you *could* build something better
>> than a 5065
>> for a thousand or two dollars, it would be on the market today.
>> 
>> Bob
>> 
>>> On Nov 3, 2016, at 6:34 PM, Attila Kinali  wrote:
>>> 
>>> On Thu, 3 Nov 2016 16:54:24 -0400
>>> Bob Camp  wrote:
>>> 
 If you look at a modern CPU as “just a handful of sand and some stuff”,
>> it seems
 pretty easy to build one in the kitchen after an hour or two of setup.
>> When you dig
 into the nasty details the line costs rapidly spiral off into the
>> stratosphere. Atomic
 standards are not quite as complex, but there still is more than just a
>> little custom
 equipment involved. $1M sounds a bit on the low side of what it might
>> take.
>>> 
>>> 
>>> Not necessarily. There is a large corpus of knowledge available on
>>> how to build vapor cells standards and what is a good idea and what
>>> isn't. Most of it is documented in papers of the PTTI, EFTF and IFCS.
>>> The former two are freely available (for PTTI until 2010, but that
>>> should be good enough). Getting access to those papers behind a
>>> paywall, you only need to know someone with access to a university.
>>> (not for PTTI post 2010 though, ION has quite anal access rules)
>>> 
>>> Additionally, the people in the time and frequeny community are very
>>> open to discussion and exchange of knowledge. You can almost always
>>> just walk up to someone and ask questions with a high chance of getting
>>> not only answers but help in how to proceede.
>>> 
>>> Tapping into this knowhow would avoid the need to try out the whole
>>> solution space and concentrate on the few parts that are unkown or
>>> not well enough understood and optimize those. And by doing so safe
>>> a lot of money.
>>> 
>>>  Attila Kinali
>>> 
>>> --
>>> Malek's Law:
>>>   Any simple idea will be worded in the most complicated way.
>>> ___
>>> time-nuts mailing list -- time-nuts@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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Re: [time-nuts] Thinking outside the box a super reference

[Scott Stobbe]

You will also share the same challenges as Touchstone semi did, no one
wanted to stick their neck out to design in a little startup.

On Thu, Nov 3, 2016 at 7:49 PM, Bob Camp  wrote:

> Hi
>
> Not many people have had exposure to Rb’s or Cs standards actually being
> built. That leaves a major gap in who you can call when you run into a
> problem.
>
> Until you have tried to build one it’s not at all clear just how much
> “missing information” there
> is in all those papers. It’s very much like the semiconductor business.
> Lots of
> information is published. There are indeed lots of gaps. At some point you
> must
> build tooling and get it all working.
>
> Again, we are talking about a device that is at least as good as a 5065
> and not
> something that just barely works. If you *could* build something better
> than a 5065
> for a thousand or two dollars, it would be on the market today.
>
> Bob
>
> > On Nov 3, 2016, at 6:34 PM, Attila Kinali  wrote:
> >
> > On Thu, 3 Nov 2016 16:54:24 -0400
> > Bob Camp  wrote:
> >
> >> If you look at a modern CPU as “just a handful of sand and some stuff”,
> it seems
> >> pretty easy to build one in the kitchen after an hour or two of setup.
> When you dig
> >> into the nasty details the line costs rapidly spiral off into the
> stratosphere. Atomic
> >> standards are not quite as complex, but there still is more than just a
> little custom
> >> equipment involved. $1M sounds a bit on the low side of what it might
> take.
> >
> >
> > Not necessarily. There is a large corpus of knowledge available on
> > how to build vapor cells standards and what is a good idea and what
> > isn't. Most of it is documented in papers of the PTTI, EFTF and IFCS.
> > The former two are freely available (for PTTI until 2010, but that
> > should be good enough). Getting access to those papers behind a
> > paywall, you only need to know someone with access to a university.
> > (not for PTTI post 2010 though, ION has quite anal access rules)
> >
> > Additionally, the people in the time and frequeny community are very
> > open to discussion and exchange of knowledge. You can almost always
> > just walk up to someone and ask questions with a high chance of getting
> > not only answers but help in how to proceede.
> >
> > Tapping into this knowhow would avoid the need to try out the whole
> > solution space and concentrate on the few parts that are unkown or
> > not well enough understood and optimize those. And by doing so safe
> > a lot of money.
> >
> >   Attila Kinali
> >
> > --
> > Malek's Law:
> >Any simple idea will be worded in the most complicated way.
> > ___
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> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> > and follow the instructions there.
>
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Re: [time-nuts] Thinking outside the box a super reference

[Attila Kinali]

On Thu, 3 Nov 2016 23:52:00 + (UTC)
Bruce Griffiths  wrote:

> Attached graph indicates ADEV achieved with a 25mm double resonance Rb vapour 
> cell 
> Performance appears somewhat better than HP5065A (even Corby's souped up 
> version).
> The thesis (by  Thejesh N. Bandi) on this double resonance Rubidium vapour 
> cell in a Magnetron style cavity was completed at the University of Neuchatel.

The dissertation in question is:
"Double-Resonance Studies on Compact, High-performance Rubidium Cell
Frequency Standards, bay Thejesh Bandi, 2013
https://doc.rero.ch/record/32317/files/2318.pdf


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
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Re: [time-nuts] Thinking outside the box a super reference

[Brooke Clarke]

Hi Bert:

Have you looked into the Stanford Research PRS-10?  It a current production Rb standard with internal provision to sync 
to 1 PPS.

http://prc68.com/I/PRS10.shtml
You can choose to run it like a GPSDO but it needs an external 1 PPS for that (there is no GPS receiver in the PRS-10).  
Or, you can time stamp an external 1 PPS.


The company was founded by a physicist and they hire mostly physicists rather 
than engineers.  I like their stuff.
The crystal oscillator in the PRS-10 is the SC-10, also made by SR and comes in many flavors that among other things 
trade off aging for stability.  I assume you could order a custom PRS-10 with the desired crystal oscillator specs.


Before spending a lot of money you might want to experiment with the PRS-10 and the best currently available GNS timing 
receiver.


I experimented with both hardware and software sawtooth correction and they both have pluses and minuses.  I seem to 
remember that CNS Systems had a sawtooth corrected GPS timing receiver that ran TAC32 software, but haven't kept up on it.


--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.

 Original Message 
  
Over the past there has been talk about building from  scratch high

performance references. I think consensus was that it is out of  reach. In the 
mean
time Corby is reworking an active maser which takes a lot of  know how. But
let us look at his work on the super HP5065. It is able to  outperform a
passive maser in the below 100 second range! Long term a proper  GPSDO should
be possible to step in. We are working on it including pressure and
temperature control. To make full use of it you also need to have the capability
to monitor, record and analyze on a continuous basis preferably with out
tying  up expensive equipment. We have the pieces in place and looking forward
of  combining all the pieces and compare with Corby’s active Maser. We are
back to  the GPSDO after being distracted by Tbolt performance. A third party
is working  combining the GPSDO data stream with the data from the unit that
generates  frequency, pressure and temperature data along with time to a
USB stick, while  also be able to monitor with a PC.
I know it is considered by some heresy but our lack of a  Maser and in Juerg
’s case no access to one, we try to overcome it with a GPSDO  tailored for
Rb and Cs and control our Cs’s C field .
There was a time that I did have a HP5065A but got rid of  it when I got
some Cs’s. My best counter was A HP5345 and even with a Tracor 527  1 second
performance was not an issue. That changed when Corby introduced me to  time
nuts and frankly it was the first  time I learned about ADEV. But the
HP5065A was gone. Now I have a cell  that Corby has plotted and time permitting
may become a project.
Let me get to the real issue. There are not enough  HP5065A’s out there and
not affordable for all time nuts. Most are being kept  and are not for
sale. But if a combined effort by many time nuts it MAY be  possible to recreate
the guts of the HP5065A. The key word is MAY. 200 time nuts  be willing to
invest $ 5000 each may get us there. The market does not justify  such an
effort but time nuts keep bringing up discussions. All the other ideas  kicked
around in the past will cost more. There are some among us that know what
it cost and who can make the key elements like lamps, cells, filters etc.
Just a  thought outside the box and hopefully may turn in to a limited
constructive  dialog. We will continue on our path, which include FRK/M100, 
HP5065
and  Cs.
We would not be capable to contribute technically on the  physics package
but I would be willing to contribute financially and with  monitoring
equipment even if I would not be around when finished.
Bert Kehren
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Re: [time-nuts] Thinking outside the box a super reference

[Bruce Griffiths]

Suitable ECDL laser for Rb 
clock:https://www.sacher-laser.com/home/industrial-lasers/point_and_line_laser_module.html
the 784.8 nm version has 0.2nm of tuning range,
Bruce 

On Friday, 4 November 2016 2:43 PM, Tim Shoppa  wrote:
 

 Zero. But the answer is also zero for a Rb or Cs cell!


On Thu, Nov 3, 2016 at 8:59 PM, Bob Camp  wrote:

> Hi
>
> Ok, how many full performance Hydrogen Masers can you build (size is not
> an issue) and
> deliver for < $10,000 (2X Bert’s number) ?
>
> Bob
>
> > On Nov 3, 2016, at 8:55 PM, Tim Shoppa  wrote:
> >
> > It would obviously be larger than a homebrew Cs, but why not a homebrew
> > Hydrogen Maser Frequency standard?
> >
> > The commercial Cs units always seemed objects of pure miniaturized
> hi-tech
> > materials science magic, while the Hydrogen Masers I've seen seem much
> > larger-scale\ and more a matter of vacuum plumbing. Obviously the
> materials
> > cost for the copper microwave cavity will be very large, and I'm sure
> > Teflon-coating a quartz chamber is an art, but the pumps and magnets are
> > very familiar from my years in grad school working with plasma kettles
> and
> > mass spectrometers.
> >
> > Tim N3QE
> >
> >
> >
> >
> >
> > On Thu, Nov 3, 2016 at 4:07 PM, Bert Kehren via time-nuts <
> > time-nuts@febo.com> wrote:
> >
> >>
> >> Over the past there has been talk about building from  scratch high
> >> performance references. I think consensus was that it is out of  reach.
> In
> >> the mean
> >> time Corby is reworking an active maser which takes a lot of  know how.
> But
> >> let us look at his work on the super HP5065. It is able to  outperform a
> >> passive maser in the below 100 second range! Long term a proper  GPSDO
> >> should
> >> be possible to step in. We are working on it including pressure and
> >> temperature control. To make full use of it you also need to have the
> >> capability
> >> to monitor, record and analyze on a continuous basis preferably with out
> >> tying  up expensive equipment. We have the pieces in place and looking
> >> forward
> >> of  combining all the pieces and compare with Corby’s active Maser. We
> are
> >> back to  the GPSDO after being distracted by Tbolt performance. A third
> >> party
> >> is working  combining the GPSDO data stream with the data from the unit
> >> that
> >> generates  frequency, pressure and temperature data along with time to a
> >> USB stick, while  also be able to monitor with a PC.
> >> I know it is considered by some heresy but our lack of a  Maser and in
> >> Juerg
> >> ’s case no access to one, we try to overcome it with a GPSDO  tailored
> for
> >> Rb and Cs and control our Cs’s C field .
> >> There was a time that I did have a HP5065A but got rid of  it when I got
> >> some Cs’s. My best counter was A HP5345 and even with a Tracor 527  1
> >> second
> >> performance was not an issue. That changed when Corby introduced me to
> >> time
> >> nuts and frankly it was the first  time I learned about ADEV. But the
> >> HP5065A was gone. Now I have a cell  that Corby has plotted and time
> >> permitting
> >> may become a project.
> >> Let me get to the real issue. There are not enough  HP5065A’s out there
> and
> >> not affordable for all time nuts. Most are being kept  and are not for
> >> sale. But if a combined effort by many time nuts it MAY be  possible to
> >> recreate
> >> the guts of the HP5065A. The key word is MAY. 200 time nuts  be willing
> to
> >> invest $ 5000 each may get us there. The market does not justify  such
> an
> >> effort but time nuts keep bringing up discussions. All the other ideas
> >> kicked
> >> around in the past will cost more. There are some among us that know
> what
> >> it cost and who can make the key elements like lamps, cells, filters
> etc.
> >> Just a  thought outside the box and hopefully may turn in to a limited
> >> constructive  dialog. We will continue on our path, which include
> >> FRK/M100, HP5065
> >> and  Cs.
> >> We would not be capable to contribute technically on the  physics
> package
> >> but I would be willing to contribute financially and with  monitoring
> >> equipment even if I would not be around when finished.
> >> Bert Kehren
> >> ___
> >> time-nuts mailing list -- time-nuts@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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Re: [time-nuts] Thinking outside the box a super reference

[Tim Shoppa]

Zero. But the answer is also zero for a Rb or Cs cell!


On Thu, Nov 3, 2016 at 8:59 PM, Bob Camp  wrote:

> Hi
>
> Ok, how many full performance Hydrogen Masers can you build (size is not
> an issue) and
> deliver for < $10,000 (2X Bert’s number) ?
>
> Bob
>
> > On Nov 3, 2016, at 8:55 PM, Tim Shoppa  wrote:
> >
> > It would obviously be larger than a homebrew Cs, but why not a homebrew
> > Hydrogen Maser Frequency standard?
> >
> > The commercial Cs units always seemed objects of pure miniaturized
> hi-tech
> > materials science magic, while the Hydrogen Masers I've seen seem much
> > larger-scale\ and more a matter of vacuum plumbing. Obviously the
> materials
> > cost for the copper microwave cavity will be very large, and I'm sure
> > Teflon-coating a quartz chamber is an art, but the pumps and magnets are
> > very familiar from my years in grad school working with plasma kettles
> and
> > mass spectrometers.
> >
> > Tim N3QE
> >
> >
> >
> >
> >
> > On Thu, Nov 3, 2016 at 4:07 PM, Bert Kehren via time-nuts <
> > time-nuts@febo.com> wrote:
> >
> >>
> >> Over the past there has been talk about building from  scratch high
> >> performance references. I think consensus was that it is out of  reach.
> In
> >> the mean
> >> time Corby is reworking an active maser which takes a lot of  know how.
> But
> >> let us look at his work on the super HP5065. It is able to  outperform a
> >> passive maser in the below 100 second range! Long term a proper  GPSDO
> >> should
> >> be possible to step in. We are working on it including pressure and
> >> temperature control. To make full use of it you also need to have the
> >> capability
> >> to monitor, record and analyze on a continuous basis preferably with out
> >> tying  up expensive equipment. We have the pieces in place and looking
> >> forward
> >> of  combining all the pieces and compare with Corby’s active Maser. We
> are
> >> back to  the GPSDO after being distracted by Tbolt performance. A third
> >> party
> >> is working  combining the GPSDO data stream with the data from the unit
> >> that
> >> generates  frequency, pressure and temperature data along with time to a
> >> USB stick, while  also be able to monitor with a PC.
> >> I know it is considered by some heresy but our lack of a  Maser and in
> >> Juerg
> >> ’s case no access to one, we try to overcome it with a GPSDO  tailored
> for
> >> Rb and Cs and control our Cs’s C field .
> >> There was a time that I did have a HP5065A but got rid of  it when I got
> >> some Cs’s. My best counter was A HP5345 and even with a Tracor 527  1
> >> second
> >> performance was not an issue. That changed when Corby introduced me to
> >> time
> >> nuts and frankly it was the first  time I learned about ADEV. But the
> >> HP5065A was gone. Now I have a cell  that Corby has plotted and time
> >> permitting
> >> may become a project.
> >> Let me get to the real issue. There are not enough  HP5065A’s out there
> and
> >> not affordable for all time nuts. Most are being kept  and are not for
> >> sale. But if a combined effort by many time nuts it MAY be  possible to
> >> recreate
> >> the guts of the HP5065A. The key word is MAY. 200 time nuts  be willing
> to
> >> invest $ 5000 each may get us there. The market does not justify  such
> an
> >> effort but time nuts keep bringing up discussions. All the other ideas
> >> kicked
> >> around in the past will cost more. There are some among us that know
> what
> >> it cost and who can make the key elements like lamps, cells, filters
> etc.
> >> Just a  thought outside the box and hopefully may turn in to a limited
> >> constructive  dialog. We will continue on our path, which include
> >> FRK/M100, HP5065
> >> and  Cs.
> >> We would not be capable to contribute technically on the  physics
> package
> >> but I would be willing to contribute financially and with  monitoring
> >> equipment even if I would not be around when finished.
> >> Bert Kehren
> >> ___
> >> time-nuts mailing list -- time-nuts@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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> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> > and follow the instructions there.
>
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Re: [time-nuts] Thinking outside the box a super reference

[Bob Camp]

Hi

Ok, how many full performance Hydrogen Masers can you build (size is not an 
issue) and 
deliver for < $10,000 (2X Bert’s number) ?  

Bob

> On Nov 3, 2016, at 8:55 PM, Tim Shoppa  wrote:
> 
> It would obviously be larger than a homebrew Cs, but why not a homebrew
> Hydrogen Maser Frequency standard?
> 
> The commercial Cs units always seemed objects of pure miniaturized hi-tech
> materials science magic, while the Hydrogen Masers I've seen seem much
> larger-scale\ and more a matter of vacuum plumbing. Obviously the materials
> cost for the copper microwave cavity will be very large, and I'm sure
> Teflon-coating a quartz chamber is an art, but the pumps and magnets are
> very familiar from my years in grad school working with plasma kettles and
> mass spectrometers.
> 
> Tim N3QE
> 
> 
> 
> 
> 
> On Thu, Nov 3, 2016 at 4:07 PM, Bert Kehren via time-nuts <
> time-nuts@febo.com> wrote:
> 
>> 
>> Over the past there has been talk about building from  scratch high
>> performance references. I think consensus was that it is out of  reach. In
>> the mean
>> time Corby is reworking an active maser which takes a lot of  know how. But
>> let us look at his work on the super HP5065. It is able to  outperform a
>> passive maser in the below 100 second range! Long term a proper  GPSDO
>> should
>> be possible to step in. We are working on it including pressure and
>> temperature control. To make full use of it you also need to have the
>> capability
>> to monitor, record and analyze on a continuous basis preferably with out
>> tying  up expensive equipment. We have the pieces in place and looking
>> forward
>> of  combining all the pieces and compare with Corby’s active Maser. We are
>> back to  the GPSDO after being distracted by Tbolt performance. A third
>> party
>> is working  combining the GPSDO data stream with the data from the unit
>> that
>> generates  frequency, pressure and temperature data along with time to a
>> USB stick, while  also be able to monitor with a PC.
>> I know it is considered by some heresy but our lack of a  Maser and in
>> Juerg
>> ’s case no access to one, we try to overcome it with a GPSDO  tailored for
>> Rb and Cs and control our Cs’s C field .
>> There was a time that I did have a HP5065A but got rid of  it when I got
>> some Cs’s. My best counter was A HP5345 and even with a Tracor 527  1
>> second
>> performance was not an issue. That changed when Corby introduced me to
>> time
>> nuts and frankly it was the first  time I learned about ADEV. But the
>> HP5065A was gone. Now I have a cell  that Corby has plotted and time
>> permitting
>> may become a project.
>> Let me get to the real issue. There are not enough  HP5065A’s out there and
>> not affordable for all time nuts. Most are being kept  and are not for
>> sale. But if a combined effort by many time nuts it MAY be  possible to
>> recreate
>> the guts of the HP5065A. The key word is MAY. 200 time nuts  be willing to
>> invest $ 5000 each may get us there. The market does not justify  such an
>> effort but time nuts keep bringing up discussions. All the other ideas
>> kicked
>> around in the past will cost more. There are some among us that know what
>> it cost and who can make the key elements like lamps, cells, filters etc.
>> Just a  thought outside the box and hopefully may turn in to a limited
>> constructive  dialog. We will continue on our path, which include
>> FRK/M100, HP5065
>> and  Cs.
>> We would not be capable to contribute technically on the  physics package
>> but I would be willing to contribute financially and with  monitoring
>> equipment even if I would not be around when finished.
>> Bert Kehren
>> ___
>> time-nuts mailing list -- time-nuts@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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Re: [time-nuts] Thinking outside the box a super reference

[Tim Shoppa]

It would obviously be larger than a homebrew Cs, but why not a homebrew
Hydrogen Maser Frequency standard?

The commercial Cs units always seemed objects of pure miniaturized hi-tech
materials science magic, while the Hydrogen Masers I've seen seem much
larger-scale\ and more a matter of vacuum plumbing. Obviously the materials
cost for the copper microwave cavity will be very large, and I'm sure
Teflon-coating a quartz chamber is an art, but the pumps and magnets are
very familiar from my years in grad school working with plasma kettles and
mass spectrometers.

Tim N3QE





On Thu, Nov 3, 2016 at 4:07 PM, Bert Kehren via time-nuts <
time-nuts@febo.com> wrote:

>
> Over the past there has been talk about building from  scratch high
> performance references. I think consensus was that it is out of  reach. In
> the mean
> time Corby is reworking an active maser which takes a lot of  know how. But
> let us look at his work on the super HP5065. It is able to  outperform a
> passive maser in the below 100 second range! Long term a proper  GPSDO
> should
> be possible to step in. We are working on it including pressure and
> temperature control. To make full use of it you also need to have the
> capability
> to monitor, record and analyze on a continuous basis preferably with out
> tying  up expensive equipment. We have the pieces in place and looking
> forward
> of  combining all the pieces and compare with Corby’s active Maser. We are
> back to  the GPSDO after being distracted by Tbolt performance. A third
> party
> is working  combining the GPSDO data stream with the data from the unit
> that
> generates  frequency, pressure and temperature data along with time to a
> USB stick, while  also be able to monitor with a PC.
> I know it is considered by some heresy but our lack of a  Maser and in
> Juerg
> ’s case no access to one, we try to overcome it with a GPSDO  tailored for
> Rb and Cs and control our Cs’s C field .
> There was a time that I did have a HP5065A but got rid of  it when I got
> some Cs’s. My best counter was A HP5345 and even with a Tracor 527  1
> second
> performance was not an issue. That changed when Corby introduced me to
> time
> nuts and frankly it was the first  time I learned about ADEV. But the
> HP5065A was gone. Now I have a cell  that Corby has plotted and time
> permitting
> may become a project.
> Let me get to the real issue. There are not enough  HP5065A’s out there and
> not affordable for all time nuts. Most are being kept  and are not for
> sale. But if a combined effort by many time nuts it MAY be  possible to
> recreate
> the guts of the HP5065A. The key word is MAY. 200 time nuts  be willing to
> invest $ 5000 each may get us there. The market does not justify  such an
> effort but time nuts keep bringing up discussions. All the other ideas
> kicked
> around in the past will cost more. There are some among us that know what
> it cost and who can make the key elements like lamps, cells, filters etc.
> Just a  thought outside the box and hopefully may turn in to a limited
> constructive  dialog. We will continue on our path, which include
> FRK/M100, HP5065
> and  Cs.
> We would not be capable to contribute technically on the  physics package
> but I would be willing to contribute financially and with  monitoring
> equipment even if I would not be around when finished.
> Bert Kehren
> ___
> time-nuts mailing list -- time-nuts@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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Re: [time-nuts] Thinking outside the box a super reference

[Bob Camp]

Hi

Not many people have had exposure to Rb’s or Cs standards actually being 
built. That leaves a major gap in who you can call when you run into a problem. 

Until you have tried to build one it’s not at all clear just how much “missing 
information” there
is in all those papers. It’s very much like the semiconductor business. Lots of 
information is published. There are indeed lots of gaps. At some point you must
build tooling and get it all working. 

Again, we are talking about a device that is at least as good as a 5065 and not
something that just barely works. If you *could* build something better than a 
5065
for a thousand or two dollars, it would be on the market today. 

Bob

> On Nov 3, 2016, at 6:34 PM, Attila Kinali  wrote:
> 
> On Thu, 3 Nov 2016 16:54:24 -0400
> Bob Camp  wrote:
> 
>> If you look at a modern CPU as “just a handful of sand and some stuff”, it 
>> seems
>> pretty easy to build one in the kitchen after an hour or two of setup. When 
>> you dig
>> into the nasty details the line costs rapidly spiral off into the 
>> stratosphere. Atomic 
>> standards are not quite as complex, but there still is more than just a 
>> little custom 
>> equipment involved. $1M sounds a bit on the low side of what it might take. 
> 
> 
> Not necessarily. There is a large corpus of knowledge available on
> how to build vapor cells standards and what is a good idea and what
> isn't. Most of it is documented in papers of the PTTI, EFTF and IFCS.
> The former two are freely available (for PTTI until 2010, but that
> should be good enough). Getting access to those papers behind a
> paywall, you only need to know someone with access to a university.
> (not for PTTI post 2010 though, ION has quite anal access rules)
> 
> Additionally, the people in the time and frequeny community are very
> open to discussion and exchange of knowledge. You can almost always
> just walk up to someone and ask questions with a high chance of getting
> not only answers but help in how to proceede. 
> 
> Tapping into this knowhow would avoid the need to try out the whole
> solution space and concentrate on the few parts that are unkown or
> not well enough understood and optimize those. And by doing so safe
> a lot of money.
> 
>   Attila Kinali
> 
> -- 
> Malek's Law:
>Any simple idea will be worded in the most complicated way.
> ___
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Re: [time-nuts] Thinking outside the box a super reference

[Bob Camp]

Hi

Do you believe that they could produced in volume for < $1,000 each without 
any significant setup investment?

Bob


> On Nov 3, 2016, at 7:52 PM, Bruce Griffiths  
> wrote:
> 
> Attached graph indicates ADEV achieved with a 25mm double resonance Rb vapour 
> cell 
> Performance appears somewhat better than HP5065A (even Corby's souped up 
> version).
> The thesis (by  Thejesh N. Bandi) on this double resonance Rubidium vapour 
> cell in a Magnetron style cavity was completed at the University of Neuchatel.
> Bruce 
> 
>On Friday, 4 November 2016 11:58 AM, Bruce Griffiths 
>  wrote:
> 
> 
> There is at least one recent thesis where a dual resonance rubidium vapor 
> cell was built and used to lock a low noise OCXO,The machining of the cavity 
> didnt appear particularly challenging nor did the locking of the laser to the 
> relevant wavelength using an auxiliary rubidium vapour cell.IIRC thee 
> performance was better than the telecom market rubidium standards.
> Bruce 
> 
> On Friday, 4 November 2016 11:34 AM, Attila Kinali  
> wrote:
> 
> 
> On Thu, 3 Nov 2016 16:54:24 -0400
> Bob Camp  wrote:
> 
>> If you look at a modern CPU as “just a handful of sand and some stuff”, it 
>> seems
>> pretty easy to build one in the kitchen after an hour or two of setup. When 
>> you dig
>> into the nasty details the line costs rapidly spiral off into the 
>> stratosphere. Atomic 
>> standards are not quite as complex, but there still is more than just a 
>> little custom 
>> equipment involved. $1M sounds a bit on the low side of what it might take. 
> 
> 
> Not necessarily. There is a large corpus of knowledge available on
> how to build vapor cells standards and what is a good idea and what
> isn't. Most of it is documented in papers of the PTTI, EFTF and IFCS.
> The former two are freely available (for PTTI until 2010, but that
> should be good enough). Getting access to those papers behind a
> paywall, you only need to know someone with access to a university.
> (not for PTTI post 2010 though, ION has quite anal access rules)
> 
> Additionally, the people in the time and frequeny community are very
> open to discussion and exchange of knowledge. You can almost always
> just walk up to someone and ask questions with a high chance of getting
> not only answers but help in how to proceede. 
> 
> Tapping into this knowhow would avoid the need to try out the whole
> solution space and concentrate on the few parts that are unkown or
> not well enough understood and optimize those. And by doing so safe
> a lot of money.
> 
> Attila Kinali
> 
> -- 
> Malek's Law:
> Any simple idea will be worded in the most complicated way.
> ___
> time-nuts mailing list -- time-nuts@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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> and follow the instructions there.
> 
> 
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Re: [time-nuts] Thinking outside the box a super reference

[Bruce Griffiths]

Attached graph indicates ADEV achieved with a 25mm double resonance Rb vapour 
cell 
Performance appears somewhat better than HP5065A (even Corby's souped up 
version).
The thesis (by  Thejesh N. Bandi) on this double resonance Rubidium vapour cell 
in a Magnetron style cavity was completed at the University of Neuchatel.
Bruce 

On Friday, 4 November 2016 11:58 AM, Bruce Griffiths 
 wrote:
 

 There is at least one recent thesis where a dual resonance rubidium vapor cell 
was built and used to lock a low noise OCXO,The machining of the cavity didnt 
appear particularly challenging nor did the locking of the laser to the 
relevant wavelength using an auxiliary rubidium vapour cell.IIRC thee 
performance was better than the telecom market rubidium standards.
Bruce 

    On Friday, 4 November 2016 11:34 AM, Attila Kinali  wrote:
 

 On Thu, 3 Nov 2016 16:54:24 -0400
Bob Camp  wrote:

> If you look at a modern CPU as “just a handful of sand and some stuff”, it 
> seems
> pretty easy to build one in the kitchen after an hour or two of setup. When 
> you dig
> into the nasty details the line costs rapidly spiral off into the 
> stratosphere. Atomic 
> standards are not quite as complex, but there still is more than just a 
> little custom 
> equipment involved. $1M sounds a bit on the low side of what it might take. 


Not necessarily. There is a large corpus of knowledge available on
how to build vapor cells standards and what is a good idea and what
isn't. Most of it is documented in papers of the PTTI, EFTF and IFCS.
The former two are freely available (for PTTI until 2010, but that
should be good enough). Getting access to those papers behind a
paywall, you only need to know someone with access to a university.
(not for PTTI post 2010 though, ION has quite anal access rules)

Additionally, the people in the time and frequeny community are very
open to discussion and exchange of knowledge. You can almost always
just walk up to someone and ask questions with a high chance of getting
not only answers but help in how to proceede. 

Tapping into this knowhow would avoid the need to try out the whole
solution space and concentrate on the few parts that are unkown or
not well enough understood and optimize those. And by doing so safe
a lot of money.

            Attila Kinali

-- 
Malek's Law:
        Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] Thinking outside the box a super reference

[Bruce Griffiths]

There is at least one recent thesis where a dual resonance rubidium vapor cell 
was built and used to lock a low noise OCXO,The machining of the cavity didnt 
appear particularly challenging nor did the locking of the laser to the 
relevant wavelength using an auxiliary rubidium vapour cell.IIRC thee 
performance was better than the telecom market rubidium standards.
Bruce 

On Friday, 4 November 2016 11:34 AM, Attila Kinali  wrote:
 

 On Thu, 3 Nov 2016 16:54:24 -0400
Bob Camp  wrote:

> If you look at a modern CPU as “just a handful of sand and some stuff”, it 
> seems
> pretty easy to build one in the kitchen after an hour or two of setup. When 
> you dig
> into the nasty details the line costs rapidly spiral off into the 
> stratosphere. Atomic 
> standards are not quite as complex, but there still is more than just a 
> little custom 
> equipment involved. $1M sounds a bit on the low side of what it might take. 


Not necessarily. There is a large corpus of knowledge available on
how to build vapor cells standards and what is a good idea and what
isn't. Most of it is documented in papers of the PTTI, EFTF and IFCS.
The former two are freely available (for PTTI until 2010, but that
should be good enough). Getting access to those papers behind a
paywall, you only need to know someone with access to a university.
(not for PTTI post 2010 though, ION has quite anal access rules)

Additionally, the people in the time and frequeny community are very
open to discussion and exchange of knowledge. You can almost always
just walk up to someone and ask questions with a high chance of getting
not only answers but help in how to proceede. 

Tapping into this knowhow would avoid the need to try out the whole
solution space and concentrate on the few parts that are unkown or
not well enough understood and optimize those. And by doing so safe
a lot of money.

            Attila Kinali

-- 
Malek's Law:
        Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] Thinking outside the box a super reference

[Attila Kinali]

On Thu, 3 Nov 2016 16:54:24 -0400
Bob Camp  wrote:

> If you look at a modern CPU as “just a handful of sand and some stuff”, it 
> seems
> pretty easy to build one in the kitchen after an hour or two of setup. When 
> you dig
> into the nasty details the line costs rapidly spiral off into the 
> stratosphere. Atomic 
> standards are not quite as complex, but there still is more than just a 
> little custom 
> equipment involved. $1M sounds a bit on the low side of what it might take. 


Not necessarily. There is a large corpus of knowledge available on
how to build vapor cells standards and what is a good idea and what
isn't. Most of it is documented in papers of the PTTI, EFTF and IFCS.
The former two are freely available (for PTTI until 2010, but that
should be good enough). Getting access to those papers behind a
paywall, you only need to know someone with access to a university.
(not for PTTI post 2010 though, ION has quite anal access rules)

Additionally, the people in the time and frequeny community are very
open to discussion and exchange of knowledge. You can almost always
just walk up to someone and ask questions with a high chance of getting
not only answers but help in how to proceede. 

Tapping into this knowhow would avoid the need to try out the whole
solution space and concentrate on the few parts that are unkown or
not well enough understood and optimize those. And by doing so safe
a lot of money.

Attila Kinali

-- 
Malek's Law:
Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] Thinking outside the box a super reference

[jimlux]

On 11/3/16 1:54 PM, Bob Camp wrote:

Hi

Since you can *buy* a working Rb that runs to a given level. My assumption is 
that
the objective is to do something that is significantly better than you can get 
for $100
or less.  I see no point in setting up to build a device that it 10X worse and 
costs 10X
more money.

Making the physics package of a good Rb takes a lot of custom tooling. It also 
takes
a bunch of engineering experiments to get the process running on that tooling, 
You
also need to train the operators on how to do this or that with the setup.  If 
good performance
is the goal, you probably need some sort of quality process backing it all up.

If you look at a modern CPU as “just a handful of sand and some stuff”, it seems
pretty easy to build one in the kitchen after an hour or two of setup. When you 
dig
into the nasty details the line costs rapidly spiral off into the stratosphere. 
Atomic
standards are not quite as complex, but there still is more than just a little 
custom
equipment involved. $1M sounds a bit on the low side of what it might take.




Two books everyone contemplating this should have:

Procedures in Experimental Physics, John Strong
Roll your own, in the 30s and 40s.


Building Scientific Apparatus, Moore, Davis, Coplan, and Greer
Vacuum systems, Ion optics, Temperature control, etc. etc.


https://www.amazon.com/Procedures-Experimental-Physics-John-Strong/dp/0917914562


https://www.amazon.com/Building-Scientific-Apparatus-John-Moore/dp/0521878586


I figure everyone on this list is already sufficiently knowledgeable 
about oscillators, amplifiers, etc.



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Re: [time-nuts] Thinking outside the box a super reference

[Attila Kinali]

On Thu, 3 Nov 2016 16:37:06 -0400
Ruslan Nabioullin  wrote:

> What about instead establishing an open-source hardware project for a 
> frequency standard fusor?  I was researching COTS solutions for this for 
> my rubidium ensemble and could only find this one product, which 
> obviously should be exorbitant in cost: 

You don't need a hardware project for this, as long as a paper clock
is enough for you. Just buy a couple of kiwi-sdr (or anything similar),
provide all of them with a common clock source and you get a comparison
of all your atomic clocks with minimum effort and can build from that
a paper clock easily. The paper clock can than be used for the measurement
you do, using one of the atomic clocks (preferably the one with the lowest
phase noise) as reference.

If you really want to have a physical realization, things become quite
interesting and not easy to handle. There are two parts of the problem,
one is to steer an frequency source accurately, and the other is to
generate the steering value in realtime. Neither of those is trivial.
Especially for the latter one, there is still a lot of research going on.

Attila Kinali

-- 
Malek's Law:
Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] Thinking outside the box a super reference

[Eric Scace]

Kickstarter?

> On 2016 Nov 03, at 16:07 , Bert Kehren via time-nuts  
> wrote:
> 
> 
> Over the past there has been talk about building from  scratch high 
> performance references. I think consensus was that it is out of  reach. In 
> the mean 
> time Corby is reworking an active maser which takes a lot of  know how. But 
> let us look at his work on the super HP5065. It is able to  outperform a 
> passive maser in the below 100 second range! Long term a proper  GPSDO should 
> be possible to step in. We are working on it including pressure and  
> temperature control. To make full use of it you also need to have the 
> capability  
> to monitor, record and analyze on a continuous basis preferably with out 
> tying  up expensive equipment. We have the pieces in place and looking 
> forward 
> of  combining all the pieces and compare with Corby’s active Maser. We are 
> back to  the GPSDO after being distracted by Tbolt performance. A third party 
> is working  combining the GPSDO data stream with the data from the unit that 
> generates  frequency, pressure and temperature data along with time to a 
> USB stick, while  also be able to monitor with a PC.  
> I know it is considered by some heresy but our lack of a  Maser and in Juerg
> ’s case no access to one, we try to overcome it with a GPSDO  tailored for 
> Rb and Cs and control our Cs’s C field .   
> There was a time that I did have a HP5065A but got rid of  it when I got 
> some Cs’s. My best counter was A HP5345 and even with a Tracor 527  1 second 
> performance was not an issue. That changed when Corby introduced me to  time 
> nuts and frankly it was the first  time I learned about ADEV. But the 
> HP5065A was gone. Now I have a cell  that Corby has plotted and time 
> permitting 
> may become a project. 
> Let me get to the real issue. There are not enough  HP5065A’s out there and 
> not affordable for all time nuts. Most are being kept  and are not for 
> sale. But if a combined effort by many time nuts it MAY be  possible to 
> recreate 
> the guts of the HP5065A. The key word is MAY. 200 time nuts  be willing to 
> invest $ 5000 each may get us there. The market does not justify  such an 
> effort but time nuts keep bringing up discussions. All the other ideas  
> kicked 
> around in the past will cost more. There are some among us that know what  
> it cost and who can make the key elements like lamps, cells, filters etc. 
> Just a  thought outside the box and hopefully may turn in to a limited 
> constructive  dialog. We will continue on our path, which include FRK/M100, 
> HP5065 
> and  Cs. 
> We would not be capable to contribute technically on the  physics package 
> but I would be willing to contribute financially and with  monitoring 
> equipment even if I would not be around when finished. 
> Bert Kehren
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Re: [time-nuts] Thinking outside the box a super reference

[Mark Spencer]

On a somewhat related note

Several years ago I pondering getting a Cs standard.   After considering the 
performance of my references and my stack of time interval counters I concluded 
that in practice I could more or less get the level of measurement accuracy I 
wanted by comparing the "device under test" to a reference and at the same time 
comparing the reference to several other references.   I wouldn't want to use 
this technique in a professional setting but for my hobby use I believe it met 
my needs.

In hindsight though I expect I could have bought a fairly nice Cs unit for the 
money I sunk into the time interval counters and the various references but 
that wouldn't have been as much fun.  The wear out aspects of used Cs standards 
are also a bit of a concern for me.   That being said a few of my time interval 
counters have also stopped working properly so I seem to have just traded one 
set of issues for another but I'm considerably more optimistic of being able to 
repair / re align a couple of my HP5370's than trying to revive a dead Cs 
standard.

All the best 
Mark S



> On Nov 3, 2016, at 1:37 PM, Ruslan Nabioullin  wrote:
> 
>> On 11/03/2016 04:07 PM, Bert Kehren via time-nuts wrote:
>> 
>> Over the past there has been talk about building from  scratch high
>> performance references. I think consensus was that it is out of  reach.
> 
> What about instead establishing an open-source hardware project for a 
> frequency standard fusor?  I was researching COTS solutions for this for my 
> rubidium ensemble and could only find this one product, which obviously 
> should be exorbitant in cost: 
> http://vremya-ch.com/english/product/indexe817.html?Razdel=11=54
> 
> -Ruslan
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> 
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Re: [time-nuts] Thinking outside the box a super reference

[Attila Kinali]

On Thu, 3 Nov 2016 16:07:59 -0400
Bert Kehren via time-nuts  wrote:

> Let me get to the real issue. There are not enough  HP5065A’s out there and 
> not affordable for all time nuts. Most are being kept  and are not for 
> sale. But if a combined effort by many time nuts it MAY be  possible to 
> recreate 
> the guts of the HP5065A. The key word is MAY. 200 time nuts  be willing to 
> invest $ 5000 each may get us there. The market does not justify  such an 
> effort but time nuts keep bringing up discussions. All the other ideas  
> kicked 
> around in the past will cost more. There are some among us that know what  
> it cost and who can make the key elements like lamps, cells, filters etc. 
> Just a  thought outside the box and hopefully may turn in to a limited 
> constructive  dialog. We will continue on our path, which include FRK/M100, 
> HP5065 
> and  Cs. 
> We would not be capable to contribute technically on the  physics package 
> but I would be willing to contribute financially and with  monitoring 
> equipment even if I would not be around when finished.


I challenge your cost estimate! :-)

My guestimate on the cost for a Rb vapor cell standard would be somwhere
in the region of 2000€ to 5000€, per unit. If you add some experimentation
it might become something like 10k€ for the first unit. How do I come to
this number? A vapor cell is quite cheap, 300-500€ can buy you an off
the shelf cell. They will not have the best buffer gas filling, but they
will be good enough for at least to get a reasonable stability.

>From here on, the analyis splits into two: dual resonance and coherent
population trapping standards.

For the dual resonance standard, a cavity is required. As the vapor cell
has a predetermined form, that cannot be changed (unless one goes for
full custom cells from the beginning), the cavity has to be adapted to the
cell. This means a cavity that is resonant at the 6.9GHz, yet fits the
cell has to be designed. My guess is, that this can be done by someone
with enough experience in microwave resonant cavities/filters and simulated
using tools like OpenEMS for verification. Producing them using aluminium
should be in the order of 200-1000€ plus cost of aluminium which I guess
to be less than 100€. Excitation of the cell can be done using either
the way the super-5065 with its filter, or tuning the laser diode. Both
way work and as far as i can tell are mostly a matter of taste with a
slightly increased complexity in the control loop for the tuned laser diode.
The detection electronics for the signal can be build for probably less
than 300€/board in batches of 10, definitely less than 1000€. Complexity
should be relatively easy to handle, as we have today access to the nice
UHF devices from Hittite, which handle all the 6.9GHz and bring it down
to easy to handle frequencies. Add a uC, some ADC and DAC and you are
basically done. For advanced features a small to medium sized FPGA (~20-50€)
can be added. If you want to be fancy, add an OCXO (like Abracon AOCJY4 or
Axtal AXIOM10HP/AXIM15) to the equation. What is missing is the magnetic
shielding, which is probably cheapest by using multiple layers of soft-iron.
Maybe using a composite of soft-iron and ferrite pads could improve things
at moderate costs. I don't think that mu-metal would be a good choice,
as it will in almost all cases need to be anealed which is not something
you can easily do (needs a furnace that goes to IIRC 800°C and can be
flooded with hydrogen)


For coherent population trapping, the cavity goes away. The excitation
is either done using a single laser that is modulated with 3.5GHz and
tuned like above, or by using two lasers that are locked to eachother
using an opto-electronic PLL (basically direct both beams at an avalance
photodiode, then use an ordinary PLL to control one of the laser).
For enhanced perfromance the two laser variant can use extenernal cavities
to narrow the laser linewidth from 10-100MHz of an "raw" laser diode
to 10-100kHz. Descriptions how to build such ECDL are available on the
net, including mechanical drawings. The price for the single diode
version is the same as the dual resonance approach, minus the cavity.
The double laser diodes add a slight cost for the OPLL (probably <100€).
An external cavity would probably be in the order of 200-500€ each.


All that said, if someone would want to tackle this project, I would
be willing to help with knowhow and electronic design. Unfortunately
due to limited finances I would not be able to invest much money.


Attila Kinali
-- 
Malek's Law:
Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] Thinking outside the box a super reference

[Richard (Rick) Karlquist]

On 11/3/2016 1:07 PM, Bert Kehren via time-nuts wrote:


Over the past there has been talk about building from  scratch high
performance references. I think consensus was that it is out of  reach. In the 
mean


I was on the design team for the HP 10816 mini rubidium
which leveraged the production capabilities of the
HP 5065 such as glass blowing, etc., although what we
called "glassware" was much smaller in the 10811
than the 5065.  IMHO, the glassware
is the critical item.  Of the glassware, the lamp is
probably the most finicky.  The glassware used some
glass type (forgot the number) that was only slightly
removed from fused quartz.  Very difficult to work
with.  Also, one of the Rb isotopes is slightly radioactive.
35 years ago, the guy in the next cubicle got away with
storing it under his desk.  He also happily smoked
cigarettes all day at his desk.  Another ERA.

HP IIRC supplied "RVFR" assemblies to customers who wanted
to roll their own electronics to use in military applications
where the 5065 wasn't suitable.  I would consider approaching
current manufacturers of Rb standards to see if they would
make glassware to order.

Another thing to consider is optically pumped Rb.  This is
now possible with available lasers.  There are some DARPA
projects in this area that I know of.  I can put you in
contact with the right person.  Optical pumping gets rid of
the lamp hassle and the radioactive isotope for the filter
cell.

The rest of the standard can be built in a garage using various
contract manufacturers available online.   If I can give any advice 
about this project, feel free to throw me some questions.


Rick Karlquist N6RK

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Re: [time-nuts] Thinking outside the box a super reference

[Bob Camp]

Hi

Since you can *buy* a working Rb that runs to a given level. My assumption is 
that
the objective is to do something that is significantly better than you can get 
for $100
or less.  I see no point in setting up to build a device that it 10X worse and 
costs 10X
more money. 

Making the physics package of a good Rb takes a lot of custom tooling. It also 
takes
a bunch of engineering experiments to get the process running on that tooling, 
You 
also need to train the operators on how to do this or that with the setup.  If 
good performance
is the goal, you probably need some sort of quality process backing it all up. 

If you look at a modern CPU as “just a handful of sand and some stuff”, it seems
pretty easy to build one in the kitchen after an hour or two of setup. When you 
dig
into the nasty details the line costs rapidly spiral off into the stratosphere. 
Atomic 
standards are not quite as complex, but there still is more than just a little 
custom 
equipment involved. $1M sounds a bit on the low side of what it might take. 

Bob

> On Nov 3, 2016, at 4:37 PM, Ruslan Nabioullin  wrote:
> 
> On 11/03/2016 04:07 PM, Bert Kehren via time-nuts wrote:
>> 
>> Over the past there has been talk about building from  scratch high
>> performance references. I think consensus was that it is out of  reach.
> 
> What about instead establishing an open-source hardware project for a 
> frequency standard fusor?  I was researching COTS solutions for this for my 
> rubidium ensemble and could only find this one product, which obviously 
> should be exorbitant in cost: 
> http://vremya-ch.com/english/product/indexe817.html?Razdel=11=54
> 
> -Ruslan
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Re: [time-nuts] Thinking outside the box a super reference

[Ruslan Nabioullin]

On 11/03/2016 04:07 PM, Bert Kehren via time-nuts wrote:


Over the past there has been talk about building from  scratch high
performance references. I think consensus was that it is out of  reach.


What about instead establishing an open-source hardware project for a 
frequency standard fusor?  I was researching COTS solutions for this for 
my rubidium ensemble and could only find this one product, which 
obviously should be exorbitant in cost: 
http://vremya-ch.com/english/product/indexe817.html?Razdel=11=54


-Ruslan
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[time-nuts] Thinking outside the box a super reference

[Bert Kehren via time-nuts]

 
Over the past there has been talk about building from  scratch high 
performance references. I think consensus was that it is out of  reach. In the 
mean 
time Corby is reworking an active maser which takes a lot of  know how. But 
let us look at his work on the super HP5065. It is able to  outperform a 
passive maser in the below 100 second range! Long term a proper  GPSDO should 
be possible to step in. We are working on it including pressure and  
temperature control. To make full use of it you also need to have the 
capability  
to monitor, record and analyze on a continuous basis preferably with out 
tying  up expensive equipment. We have the pieces in place and looking forward 
of  combining all the pieces and compare with Corby’s active Maser. We are 
back to  the GPSDO after being distracted by Tbolt performance. A third party 
is working  combining the GPSDO data stream with the data from the unit that 
generates  frequency, pressure and temperature data along with time to a 
USB stick, while  also be able to monitor with a PC.  
I know it is considered by some heresy but our lack of a  Maser and in Juerg
’s case no access to one, we try to overcome it with a GPSDO  tailored for 
Rb and Cs and control our Cs’s C field .   
There was a time that I did have a HP5065A but got rid of  it when I got 
some Cs’s. My best counter was A HP5345 and even with a Tracor 527  1 second 
performance was not an issue. That changed when Corby introduced me to  time 
nuts and frankly it was the first  time I learned about ADEV. But the 
HP5065A was gone. Now I have a cell  that Corby has plotted and time permitting 
may become a project. 
Let me get to the real issue. There are not enough  HP5065A’s out there and 
not affordable for all time nuts. Most are being kept  and are not for 
sale. But if a combined effort by many time nuts it MAY be  possible to 
recreate 
the guts of the HP5065A. The key word is MAY. 200 time nuts  be willing to 
invest $ 5000 each may get us there. The market does not justify  such an 
effort but time nuts keep bringing up discussions. All the other ideas  kicked 
around in the past will cost more. There are some among us that know what  
it cost and who can make the key elements like lamps, cells, filters etc. 
Just a  thought outside the box and hopefully may turn in to a limited 
constructive  dialog. We will continue on our path, which include FRK/M100, 
HP5065 
and  Cs. 
We would not be capable to contribute technically on the  physics package 
but I would be willing to contribute financially and with  monitoring 
equipment even if I would not be around when finished. 
Bert Kehren
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