[volt-nuts] Agilent calibration - certificate for a vector network analyzer (VNA)

[Joseph Gray]

David,

That is quite a difference between the two certificates. The Techmaster one
doesn't tell you anything about what they actualy measured, or the
uncertainties. You have to trust that they know what they are doing and
that they actually did it. With the Agilent certificate, there is data to
give you confidence that things were done properly.

Thanks for posting those. It was educational.

Joe Gray
W5JG



On Sat, Aug 24, 2013 at 6:20 AM, Dr. David Kirkby <drkirkby at gmail.com>wrote:

> Since there has been a few discussions about calibration, and in
> particular Agilent calibration, I thought I'd share my calibration
> certificate for my VNA which came back from Agilent (UK) last week.
>
>
> http://sage.math.washington.edu/home/kirkby/Agilent-standard-calibration-with-uncertainties-for-8720D-vector-network-analyzer.pdf
>
> It is *much* more informative than the certificate issued from a US
> calibration laboratory
>
>
> http://www.home.agilent.com/owc_discussions/servlet/JiveServlet/download/74-35894-109799-6353/Calibration%20certificate%20of%20HP%208720D%20VNA.png
>
> a year earlier for the same instrument.
>
> Note the instrument was not adjusted. The instrument has an intermal
> oscillator and also a high precision version which is an option. Both
> were sligltly off, but neither was adjusted as they met the spec.
>
> There some comments on this thread
>
> http://www.home.agilent.com/owc_discussions/message.jspa?messageID=109805
>
> from an Agilent VNA expert that
>
> "I will be very sceptical when a VNA calibration service does not
> include a cal kit and verification kit. "
>
> The other lab did not use a verification kit and the calibration kit
> they used was an Agilent "economy" model 85052D, which uses fixed
> loads, not the more accurate sliding loads of the much more expensive
> 85052B calibration kit.
>
> I personally don't grudge paying Agilent £500 (~$750) for the
> calibration. In contrast, unless I just needed the cal certificate to
> satisfy somebody else, I would not spend a penny getting it calibrated
> by the other lab.
>
> I think on something as complex as a VNA, one really is better letting
> the manufacturer calibrate it. On a 6.5 digit or less multi-meter,
> there are probably a lot of labs able to do a decent job. Personally
> though, if I get my 3457A calibrated I will send  it to Agilent, since
> I don't personally know of any lab that is competent to do it. It is
> less justifiable to me to spend a lot of money getting an inexpensive
> instrument calibrated.
>
>
> Dave
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