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

[Dr. David Kirkby]

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