[volt-nuts] HP 3458A

[Fred Schneider]

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 at phk.freebsd.dk> het volgende geschreven:

> In message <4E3DD8AF.FF938E47 at cox.net>, WB6BNQ writes:
> 
>> 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.
> 
> 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 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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