[volt-nuts] HP 3458A

[WB6BNQ]

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:

> Your argument would be valid where Type A Uncertainty and/or drift are the
> dominant contributors to a specification. However that's not the case for
> the HP/Agilent 3458A, where Type B Uncertainty is the dominant contributor.
> Over the past 21 years metrology labs and National Metrology Institutes have
> successfully used this fact to their advantage by using 'Golden' 3458As in
> order to reduce the propagation of Type B Uncertainty in their state-of-art
> applications.
>
> This is the same technique used by the same labs to reduce propagation of
> Type B Uncertainty in their state-of-art processes for other devices like
> attenuators, thermal converters and power sensors, etc.
>
> That this opportunity exists with the 3458A speaks very highly of it.
>
> Keep in mind that, for all such 'golden' processes, it's necessary to use
> the standards labs' measurement data (of your 'golden' instrument) as
> correction factors in your processes.
>
> If you're not actively involved (with state-of-art processes requiring such
> reduction of the propagation of Type B Uncertainty) - and if you're not
> actively using a 3458A in a state-of-art application like this - then don't
> worry about it.
>
> http://lvldstdslabagilent.blogspot.com/2005/01/faq-what-3458a-calibrations-are.html
>
> http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1989-04.pdf
>
> -Greg
>
> ----- Original Message -----
> From: "WB6BNQ" <wb6bnq at cox.net>
> To: "Discussion of precise voltage measurement" <volt-nuts at febo.com>
> Sent: Saturday, August 06, 2011 6:13 PM
> Subject: Re: [volt-nuts] HP 3458A
>
> This response illustrates the absurdity in the whole process.  The so-called
> "Golden Calibration" is only of value in shifting from a fixed standard to
> an
> instrument that can measure "in-between" values to a high degree if done
> within
> minutes of the set up.  It is called the transfer ratio and is the 24 hour
> specification.
>
> The absurdity to think your going spend additional money for the "Golden"
> part
> and get something is total BS.  Even the STE/9000 is the value at the time
> of
> calibration.  Bouncing around in shipping could certainly invalidate that
> value.
>
> Such antics could best be described as the cat chasing his tail.
>
> Bill....WB6BNQ
>
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