Calibration, is only testing and noting the deviation from the standard used. To adjust the meter to this standard is an extra service. And indeed shipping, other air humidity, other temperature ect and time will change this. I have a guildline cabinet. The papers it was calibrated every year in the 79's and 80's. I have the reports ( and some copy of the bills) because it came with all documentation . I got it as a gift from an internal calibration lab of a very big company. I was lookimg on the net to search info and I wrote some firms like guildline to find out more about these wonderfull cabinets. Then I heard that calibrating such a cabinet ( that was, if I lived in the USA, but over here it must be allso posdible I guess) was still possible and  transportation alone was 750 dollar)

Fred PA4TIM

Op 7 aug. 2011 om 02:13 heeft WB6BNQ wb6bnq@cox.net het volgende geschreven:

In message 4E3DD8AF.FF938E47@cox.net, WB6BNQ writes:

Bill, think about it for a moment, isn't that exactly what you would want
your secondary calibration lab to do ?

If you use the 3458A as bench-instrument, you want it to be stable for
multiple years so you save on calibration cost/cycles.

If you use the 3458A to compare your josephson standard to the customers
Fluke 73x, you want rock steady short term stability, but the absolute
precision doesn't really matter, as long as it is stable.

Just because you don't need it, or see the point, doesn't make it "BS".

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@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.

I agree, i have my calibration stuff, just for hobby. I tried to get everything as good as possible. I'm rather sure I can get accurate to 10 uV. Probably a bit better. That is not perfect but more then decent to get my collection of old multimeters and scopes accurate again. I bought a Calibrated new 6,5 Keithley, measured my weston cells immeiate after receiving it and a few hours wrming up. That was in line with the known specs and history from the company I got it from. I checked that with more meters and agains some calibrators and I use the 10 uV limit as worst case.  That is my golden standard. I use a solartron 7061as reference. Before calibration I calibrate my solartron using the weston cells and after that the solartron to check the calibrators and dividers. I have to try to do the best as I can but it is a hobby, I do sometimes a calibration for a friend but free of charge, so no garantees ;-)

Fred PA4TIM

Op 7 aug. 2011 om 07:41 heeft "Poul-Henning Kamp" phk@phk.freebsd.dk het volgende geschreven:

Greg, Marv, Bill, et al,

This has been a very enlightening thread and I appreciate everyone's input. From a hobbyist perspective the STE9000 cal is all I'll need unless a contract should come along that would demand MU better than that.

It's too bad the Agilent cal services description isn't as clear as what's available on this list! Of course once the explanations supplied here are applied to the Agilent descriptions they become much clearer.

Best regards,

Steve

On Aug 6, 2011, at 5:14 AM, "gbusg" gbusg@comcast.net wrote:

Hi Poul,

I guess you missed my point.

Unless you are a business that relies on a traceable process, such as a real Second
Level Lab, it makes no sense for the hobbyist to spend the money to go beyond the
basic calibration service.  To the hobbyist, for all intent and purpose, the basic
calibration would exceed any reasonable measurement requirement the hobbyist could
come up with.

Unless a hobbyist has a lot of money, the average hobbyist person is not going to be
able to provide a Lab area that would be controllable to within one degree
centigrade.  That is the level needed to make real use of the 24 hour specification
and that specification is using the 3458A as a transfer standard.

The only thing a real Primary Lab, with the capability, could do that would be worth
the value would be to use the JJ array to verify the actual linearity of the A/D of
that specific meter.  That would also evaluate the meter’s internal reference to an
absolute standard.  In all truth, I doubt that is what is being classed as a
so-called “Golden” calibration because the money is not high enough to cover the
time and cost required for a full verification of the meter’s A/D linearity and the
meter’s absolute stability.  HP has already done such work in the verification of
their production line of the 3458A to prove its worth.  That effort, assuming you
accept it, has shown the validity of the circuit design, repeatability and stability
in production units.

The real problem is the average person getting caught up the numbers game where they
have no way in hell proving it one way or another.  They also have no reason for
such so-called extreme accuracy and resolution.  Sure it is a damn good meter and if
you can afford one it is a very nice meter to have.  A hobbyist who owns one should
consider himself as being lucky and that it only cost around $500 to get it
calibrated if you have the means.  They should be especially thankful that they can
have the calibration from a, hopefully, trustworthy source, such as the very maker
of the instrument, at such a reasonable price.

For the hobbyist, making smart use of the instrument with basic calibration and
understanding how to use it properly would be way more profitable then getting
caught up in the numbers game to an insane level.

My two cents.

Bill....WB6BNQ

Poul-Henning Kamp wrote:

Greg,

While I can appreciate your enthusiasm, I think you are caught up in the numbers game.
Unless I am mistaken, most people on this list are dealing with their personal
hobbies.  As such their efforts are done on a limited budget and playing with the big
boys gets expensive.

So my comments are coming from that perspective.  Also, my comments are coming from
what is reasonable in the real world as it relates to the hobbyist or amateur
experimenter.

And NO Greg, I have no idea what you mean by type A or B.  How about explaining that ?

Your first link goes to someone’s blog whose data amounts to heresy.  Where is the
information from a valid HP site ?  If you actually go to a HP site on the 3458A, you
will see that the additional Calibration costs are referring to additional verification
paperwork.  If there is such a thing as a “Golden” anything, then it needs to properly
explained; not spoke of as though you got to have the secret password and decoder ring
to get any information.  Those type of comments are generally born out of
misunderstandings and little substance.

Your second link references a HP Journal about the meter from over 20 years ago.  How
does that support or address your comments ?  If your trying to point to the
complexity, then see my response to Poul.

Bill....WB6BNQ

gbusg wrote:

Bill wrote:

Yes, Bill, your last few posts have persuaded me that volt-nuts is likely
not the right forum for this kind of esoteric information. (I'll remember to
qualify that the next time being tempted to jump-in with information.) :)

Again, apparently we're beyond the scope of volt-nuts interest, but since
you asked (and to close-out this topic), see:

Guide to the Expression of Uncertainty in Measurement
http://www.bipm.org/utils/common/documents/jcgm/JCGM_100_2008_E.pdf

NIST Reference
http://physics.nist.gov/cuu/Uncertainty/basic.html

UKAS Lab-12
http://www.ukas.com/library/Technical-Information/Pubs-Technical-Articles/Pubs-List/LAB12.PDF

-Greg

Volt-nuts is to voltage measurement and standards as time-nuts is to
time measurement and standards.  It should include everyone with an
interest in maintaining voltage (current/resistance) standards.

I, for one, would like to learn about making JJ voltage standards in
a volt-nut setting.

-Chuck Harris

gbusg wrote:

Chuck,

Would that be possible for an amateur to make. Count me in ;-) but I read a paper about them, if i remember well,  Fluke in germany and the USA must have one. It sounded rather big and very expensive.

Fred PA4TIM

Op 9 aug. 2011 om 01:06 heeft Chuck Harris cfharris@erols.com het volgende geschreven: