[volt-nuts] HP 3458A

[WB6BNQ]

Hi Poul,

I completely understand your points of observation, especially the last
paragraph.

I was trying to stay within a standard explanation without deviating to much
off-point.  I was probably to verbose as it was.  If so, my apologies.

What drove me to write was the fact that people respond to all the digits
displayed, even if they are not factual.  Thus their efforts may be in the wrong
direction.

Bill....WB6BNQ


Poul-Henning Kamp wrote:

> In message <4E3CE362.D9B12F73 at cox.net>, WB6BNQ writes:
>
> >First, a 'Primary Lab' is one that has attained a very high degree of
> >accuracy and stability in their in-house standards [...]
>
> I think that while your explanation is pretty spot on, it suffers one
> bit of terminology confusion.
>
> At the top of the hierarchy you have the "national metrology labs"
> which are the ones your government points at, for all matters
> pertaining to the Metre Convention.
>
> These may or may not be primary labs in your terminology.
>
> And they may or may not implement all the units of the Metre Convetion,
> most only implement a subset and typically focuses on just a few, which
> for one reason or other are important for them.  In Denmark the national
> lab specializes is conductivity of water, because this is crucially
> important for production of insulin.
>
> The important distinction is that they _decide_ what the meter, kg,
> second etc. they don't merely try to _reproduce_ it.
>
> If some weird quantum-murphylogical event suddenly changed the speed
> of light or the fine structure constant, the national metrology labs
> are the ones who decides how that affects the price of butter, so to
> speak.
>
> And here's the trick:   Most of them have a josephson voltage
> standard and a lot of them are pretty academic, which means that
> if you find the right person and bring home baked apple-pie, you
> can get a pretty damn good cal of your 3458a for free...
>
> --
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
>
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