Dvae, have you looked at the reference in my post #8? This might help to set the offset length properly, for improved calibration accuracy.
Hi,
I did see it, but have not acted on it. I only wanted something to give me the ability to check the analyzer was working properly.
I have an HP cal kit on order - just waiting for Fedex to deliver it. It is not the one I wanted (HP/Agilent 85052B, rated to 26.5 GHz)
http://www.home.agilent.com/agilent/product.jspx?cc=US&lc=eng&nid=-536902693.536880729&pageMode=OV
but a lower cost 85033E
http://www.home.agilent.com/agilent/product.jspx?nid=-536902695.536879921.00&lc=eng&cc=US
which is for DC-9 GHz.
But the 85033E is supported by the instrument. (I see this as one of the choices in the firmware when I select a cal kit).
But in the next few days I will have a supported kit, which is OK to 9 GHz, which is all I need just now.
I'll buy the higher frequency kit at some point when I see one at a sensible price. There's a dealer in the UK with the 26.5 GHz cal kit, but it is over half the price of what I paid for the VNA, which was $16000.
I also got a cheap APC-7 cal kit (HP 11866A) which is only for DC-2 GHz, but I suspect could be pushed quite a bit higher if the HP 909C 2 Ghz load was replaced with a better one such as the HP 909A (18 GHz) load. Unfortunately, 11866A is not supported by the instrument, but it was quite cheap and the 18 GHz load was not that expensive on eBay either. But APC-7 is not something I need much, but the cal kit was quite cheap.
Maybe I am wrong, but in APC-7, I can't see there's going to be much difference between cal kits if they only have the open, load and short.
I've not read much about this, but it would seem the HP VNAs considers the open as having some offset delay in ps, and expresses the fringing capacitance as a 3rd order polynomial. The same is done for the short, but its inductors rather than capacitors in the polynomial. I suspect given one cal kit, it is quite easy to work out the parameters of another cal kit of the same sex, by a simple polymomial curve fit. They don't appear to have done that iwth the economy kit you provided the link to, but I suspect it is possible to improve on that. I would have been more tempted to buy that if it had both sexes, but it did not.
I note some of the coefficients of the HP VNA calibration kits are available in the program "VNA Cal kit manager"
http://na.tm.agilent.com/vnahelp/products.html
but it does not have many of the kits in its database.