Hi Over here NIST is very much part of the government. In many cases, if I want a certain gizmo calibrated, I would not / could not send it there. It either would be fairly expensive or simply something they don’t do. In the case of 50 ohm terminations, ours go back to Agilent / HP / Keysight (what ever their name is this week …). The resulting calibration is traceable to NIST standards over the stated range of frequencies and accuracies.
Yes that begs the question of “how do they do it”. Last time I (briefly) dug into it, the answer was not at all simple. It appeared that you were more “traceable to HP” than “traceable to NIST”. What ever the approach, I’ve never seen a problem when I’ve checked the returned standards against each other and against our internal reference standards. Bob On Jun 29, 2014, at 6:33 AM, Dr. David Kirkby <drkir...@gmail.com> wrote: > I know of NPL in the UK, and NIST in the USA, but is anyone aware of > other "standard labs". In particular I am looking for the Australian > equivalent. A Google search came across "Standards Australia" > > http://www.standards.org.au/ > > but I don't know how "authoritative" this is. There is basically > nothing stopping any body here setting up a web site claiming to be > the countries leading non-government standards labs. I have a very > healthy skepticism of calibration laboratories in general > > NIST for example does have a ".gov" domain, which gives it a bit more > credibility than a typical .com. > NPL does not have a .gov, despite we use it in the UK. > > I found the The National Measurement Institute (NMI) > http://www.measurement.gov.au/ > > which is probably the one I am looking for. > > There are people on this list who I would trust to produce a list of > national standards labs more than I would from a Google search or > Wikipedia. > > There are a couple of things I am looking to find out - neither of > which are very time-nut related, but both are to some extent as they > they involve measuring the phase difference between two signals. > > 1) There was some work done somewhere (I believe an Australian lab), > which showed that calibrating a VNA with 1/8 and 3/8 offset shorts is > superior to a flush short and 1/4 spacer. Both give the desired 180 > degree difference in reflected signal, so at first thought they are > equivalent. I do know the reason the 1/8 and 3/8 are superior, but I'd > like to find a reference. > > 2) Who in Australia would be best at measuring the reflection > coefficient of a 50 Ohm termination? > > -- > Dr. David Kirkby G8WRB > http://www.vnacalibration.co.uk/ > Economical & accurate VNA calibration kits. > Coefficients available for HP, Agilent, Anritsu, Rohde & Schwarz and > VNWA network analyzers. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
