Re: [volt-nuts] Fluke DVMP Care Plan

[Bill Gold]

Ken:

I had my 732B calibrated at FLUKE in Everett WA last year.  I had the
Z540 with before and after data cal done.  The price was $695 which included
FLUKE shipping the 732B back to me, one day service.  FLUKE wanted me to
ship it to them overnight delivery by 10 AM which cost $250 UPS.  But after
that I decided that I would ship it either overnight afternoon delivery
(which is cheaper) or 2 day delivery (which is even more reasonable).
Hindsight is always better, just like Monday morning quarterbacking.

I know that my battery can last 3 days real easy by discharging it for 3
days and monitoring the battery voltage.  I think that FLUKE is just trying
to make sure that some units are not shipped with old, marginal batteries.
Then the battery would go dead and the "before" data could not be supplied
to the customer.  The one surprise was that my unit had the handle missing
and FLUKE installed a new handle and included that in the total cal cost.
The stupid handle retails for $120 and the hardware is another $27.

Bottom line here is that I don't care if the "calibration stickers" are
inplace or not when FLUKE receives the unit, so if the battery wouldn't hold
a 3 day charge I would replace it and test it before I send it in again.  I
would use the 2 day service.

The uncertainty would be how well the bank of 4 732Bs that they compared
my unit with at the Cal Lab.  But since those don't leave FLUKE and are
certified every 90 days (probably to the FLUKE JVS), according to the
certificate, my guess is that the voltage would be within .3 PPM depending
upon how much drift your unit would have during transit.  Since I have 4 ea
732As, collected over the years, and I had checked the stability before I
sent the 732B in, I was pretty sure that my 732B was very stable over 13
days, less than 0.1ppm.  When I got it back I began comparing it again to
the bank of 732As and it remained within 0.1ppm for 90 days.  But after that
it has started to drift steadly upwards around 0.7 ppm per year.  Since I
have a very good history on the bank of 732As I can see that the 732B is
most of the drift against the average of the bank.  Of course all IMHO and
the best data reductions I can make.

The final test of my data keeping would be to send the 732B again and
see if I am close to "The Volt" as defined by FLUKE.  Someday when I am
curious.

The whole turn around time was 10 days portal to portal to me.

Bill

- Original Message - 
From: "Ken Peek" 
To: "volt-nuts" 
Sent: Thursday, October 20, 2016 11:26 AM
Subject: [volt-nuts] Fluke DVMP Care Plan


> I own one 732B that needs calibration.  Fluke wants about $500 for the
> ISO-9001 calibration, but it would be about $250 EACH WAY to ship it
> to/from them with the proper insurance (so, about $1000 total).
>
> Mitch Van Ochten mentioned that the Fluke DVMP program might be a good way
> to do this.  [http://download.flukecal.com/pub/literature/2001531_A_w.pdf]
>
> Does anyone have an idea about how much this costs to calibrate just one
> 732B, and what kind of uncertainty I might expect?
>
> -Ken
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[volt-nuts] Fluke DVMP Care Plan

[Ken Peek]

I own one 732B that needs calibration.  Fluke wants about $500 for the
ISO-9001 calibration, but it would be about $250 EACH WAY to ship it
to/from them with the proper insurance (so, about $1000 total).

Mitch Van Ochten mentioned that the Fluke DVMP program might be a good way
to do this.  [http://download.flukecal.com/pub/literature/2001531_A_w.pdf]

Does anyone have an idea about how much this costs to calibrate just one
732B, and what kind of uncertainty I might expect?

-Ken
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Re: [volt-nuts] Low-cost Josephson Junction Array

[Vince Mulhollon]

I'd agree with, and extend, acbern's remarks

As a pure science experiment and completely inadequate certification
standard you can still have fun with one junction not an array which makes
things enormously cheaper.  Of course this turns it from a calibration lab
experiment to primarily a physics experiment that can also kinda do
comparisons, sort of, poorly.  But running one junction homemade niobium
junction could be an intermediate step on running an array later.  After
the bugs are worked out, swap the single junction for an array and you're
done.

The state of the art in amateur radio microwave work has been rapidly
moving even over just the last decade.  Running a JJ is not really an issue
anymore for advanced ham operators between microwave radio contests.
Serious stuff, but its quite doable now.

I'm not sure what cryonic prices are like in .de but locally liq N2 dewars
are like the cost of a months groceries or a modest fraction of a mortgage
check, liq He dewars are like the cost of a really nice used car, liq N2 is
maybe a tenth the cost of gasoline per volume.  So the cost of filling a
liq N2 dewar is like a night at the bar.  Per liter liq He is maybe the
cost of good wine so filling a 100L dewar is a significant fraction of a
mortgage payment or the cost of a junker used car.  The staggering
difference in price is why you prechill the apparatus with liq N2 and of
course liq N2 freezes well above the temp of liq He so its just SO much fun
to work with (sarcasm).

Cryocoolers are a whole nother problem.  So a contemporary dual pulse tube
crycooler in a research lab on bragging day when cost is no object is like
ten KW of power in, 10001 watts of heat rejected, yeah like one watt of
cooling on the second cryo.  Well, my basement does get cold in the
winter...  So I need insulation that passes less than a watt thermal at a
"basement to liq He" differential in temp... Ouch.  Of course you can do
things like make a bath of cheap liq N2 and pull a vacuum on it so the
differential is only maybe 60K but even so, just getting a watt is an
achievement... And of course even with a decent machine shop the best the
professionals can do in a research lab a couple years ago is not terribly
realistic.  Maybe in 50 years everyone will have a cryocooler in their
basement instead of a deep freeze, but just not today.

Oh and the thermal capacity of liq He is like nothing, so that $1000 of liq
He evaporates when you stare at it harshly.  All cryonic apparatus is
unfortunately ultra high pressure gas apparatus unintentionally because the
vents can freeze over or "stuff" can condense into the insulation, and of
course high pressure gas explosions are highly effective at killing people
so its just an endless pile of headaches, although maybe it can be done?

On Thu, Oct 20, 2016 at 4:53 AM,  wrote:

> About two years ago I started an exercise to determine what it would take
> to build a kind of DIY JJ standard and also looked at certain detail
> technical aspects of designing/building what is reasonable doable. Baseline
> was 10V DC. It was clear that it would not be cheap, and I also looked at
> this as a personal challenge. So here in a nutshell:
> I did talk to a vendor of the JJA, and we finally agreed he would be
> supporting me with supplying a JJA and related waveguide with flange
> attached. Nothing else, to save costs. What would have remained is the
> 75Ghz RF source (including further waveguides with dewar interface and
> helium block, RF source, directional coupler and RF generator. Key is a
> source with low harmonics, so using a trippler and a 26.5GHz generator
> (locked to a gps-calibrated rubidium source) was a potential solution, but
> it was not clear if that would have been sufficienly clean overall, so
> quite some risk here having to go with another solution finally (Gunn...).
> Also the amplifier portion and transmission of the RF signal to the JJA
> without too much loss is not that simple, as the power needed is not that
> low. Lots of discussions with the vendor. Helium would have been obtained
> in a loaner dewar from a gas manufacturer, I did have a quotation at pretty
> reasonable cost, no need to go with a cryocooler (which ca
>  n cause a lot of voltage noise potentialy, killing the DC signal). And
> some driving electronics of course, doable with reasonable effort. While I
> had some equipment such as e.g. the RF generator and reference clock, the
> shopping list was not that short. Also some test gear such as a 75GHz power
> head and so on was also on the shopping list.
> To make a long story short, I ended up with an estimate of 30 to 40 kUSD,
> with about 10k of additional risk, with the majority being the cost of the
> JJA. Quite some expense for an in the end academic exercise, so I finally
> decided to not further pursue this. I need to add that, being an EE, with
> no experience in cryo stuff, I would have got support by a fried who is
> physicist, otherwise I 

Re: [volt-nuts] Low-cost Josephson Junction Array

[acbern]

About two years ago I started an exercise to determine what it would take to 
build a kind of DIY JJ standard and also looked at certain detail technical 
aspects of designing/building what is reasonable doable. Baseline was 10V DC. 
It was clear that it would not be cheap, and I also looked at this as a 
personal challenge. So here in a nutshell: 
I did talk to a vendor of the JJA, and we finally agreed he would be supporting 
me with supplying a JJA and related waveguide with flange attached. Nothing 
else, to save costs. What would have remained is the 75Ghz RF source (including 
further waveguides with dewar interface and helium block, RF source, 
directional coupler and RF generator. Key is a source with low harmonics, so 
using a trippler and a 26.5GHz generator (locked to a gps-calibrated rubidium 
source) was a potential solution, but it was not clear if that would have been 
sufficienly clean overall, so quite some risk here having to go with another 
solution finally (Gunn...). Also the amplifier portion and transmission of the 
RF signal to the JJA without too much loss is not that simple, as the power 
needed is not that low. Lots of discussions with the vendor. Helium would have 
been obtained in a loaner dewar from a gas manufacturer, I did have a quotation 
at pretty reasonable cost, no need to go with a cryocooler (which ca
 n cause a lot of voltage noise potentialy, killing the DC signal). And some 
driving electronics of course, doable with reasonable effort. While I had some 
equipment such as e.g. the RF generator and reference clock, the shopping list 
was not that short. Also some test gear such as a 75GHz power head and so on 
was also on the shopping list. 
To make a long story short, I ended up with an estimate of 30 to 40 kUSD, with 
about 10k of additional risk, with the majority being the cost of the JJA. 
Quite some expense for an in the end academic exercise, so I finally decided to 
not further pursue this. I need to add that, being an EE, with no experience in 
cryo stuff, I would have got support by a fried who is physicist, otherwise I 
would not even have considered it (you cannot just put the JJA into the 
dewar...). There are some potential ways to cut the costs mentioned, e.g. by 
going with 1V instead, or having access to suitable 75GHz gear, but it is still 
a several 10k exercise.
Overall, at least from my perspective, it was just not worth it. Quite some 
risk and lots of time until it works. So I continue to send my references to a 
good lab with well below 1ppm of uncertainty, and I have an independent cal 
document, even though of course, it would certainly have been a lot of (quite 
expensive) fun.




> Gesendet: Donnerstag, 20. Oktober 2016 um 00:35 Uhr
> Von: "Ken Peek" 
> An: volt-nuts 
> Betreff: Re: [volt-nuts] Low-cost Josephson Junction Array
>
> @Vince:
> 
> Thank you for the link!  Very informative!  There is also a nice video
> showing some of the lab techniques, and some cautions working with
> cryogenic liquids.
> 
> I would also like to explore miniature cryocoolers-- as these might be able
> to support a small lower power array (1V) if it doesn't dissipate too much
> power...
> 
> There is already some progress in this area with a QHR made from graphene
> (at the NPL in the UK).  So, maybe the same cryocooler could be used also
> for the low-cost JJA ?
> 
> Having a 10V (fixed output) JJA and a 12K9 QHR would be the basis to
> calibrate all other electrical standards in a lab.  It would be nice to
> have these sitting in their cryocoolers cranking out volts and ohms
> practically indefinitely (or as long as you want)-- and if one has even a
> rubidium atomic clock, then no external signals or standards of any kind
> would be needed.  Well, that and a triple-point of water cell (which I
> have) for temperature calibrations.
> 
> -Ken
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Re: [volt-nuts] Is there a "standard" much better than a LTZ1000, but much cheaper than a Josephson Junction Array?

[Dr. David Kirkby (Kirkby Microwave Ltd)]

On 20 October 2016 at 00:08, Poul-Henning Kamp  wrote:

> 
> In message  g...@mail.gmail.com>
> , "Dr. David Kirkby (Kirkby Microwave Ltd)" writes:
>
> >The question about the Josephson Junction Array got me thinking. I wonder
> >if there are any sort of technologies that can produce a voltage with much
> >better stability than the LTZ1000, but without the cost of a Josephson
> >Junction Array. A sort of half-way house.
>
> As far as I know there are only two steps between the LTZ1000 and JJAs:
>
> 1. Specially cared for LTZ1000's (See: Fluke)
>

Do you have a specific reference?  A google found lots of kits on Fluke and
LTZ1000,  but none of the pages were from Fluke.


> 2. Lots of LTZ1000's to get sqrt(N) reductions.
>


> --
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
>


But that assumes the drifts are completely uncorrelated, which I doubt is
the case - especially if they are all from the same batch. But there are a
limited number of resistors of the quality needed (Vishay is the only one I
can think of), and PCB materials are likely to be the same. It seems to me
that you would not gain sqrt(N) unless N is quite small. How small, is
anyone's guess.

Dave
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