I managed to get to the Agilent forums in the end.
What I have found is there are huge discrepancies in the list of kits supported by my VNA and those which the firmware has support for. There are kits list as "unsupported" yet are in my firmware, and there are kits listed as "in F/W" but they are not in my firmware.
I need to work out the best way to get the data on some kits. If you look at some kits, the definitions in the files are different for different VNAs.
Take for example the 85032F 9 GHz N kit:
http://na.tm.agilent.com/pna/caldefs/stddefs.html
This is supposed to be unsupported in my VNA, yet it is in the firmware. But there are two files one can download for other VNAs. Those two files have different values for the same cal kit.
For the PNA series of VNAs using the 85032F 9 GHz N kit:
**broken link removed**
and for the 8753D (3 GHz VNA) using the same 85032F 9 GHz N kit:
http://na.tm.agilent.com/pna/caldefs/87xx/D53N5F.htm
so that is the same kit, having different values on different VNAs. For the 8753D, both opens, have the same C0 term of 89.939 fF. But for the PNA series, the value of C0 is 94.9227 fF for the male open, and 101.3493 fF for the female open.
From what I can gather a polynomial is fitted to data to give the best values of the capacitance parameters. But if the VNA has a more restricted frequency range (such as a 3 GHz VNA) on a cal kit that's usable to 9 GHz, then the optimal coefficients are different, since you can obviously fit a curve more closely using a polynomial if you restrict the range of the fit to 3 GHz rather than worry about 9 GHz.
I've asked Agient to clarify exactly what the status is with the 85033E 3.5 mm kit is in my VNA. But me and the Agilent guy think it should be ok since its in the firmware. But he is going to get it clarified for me.
I've bought 85032B 6 GHz N cal kit, which is supposed to be supported in firmware, but it is not. I'd like Agilent to clarify what the values I should be using are. I suspect I should take them from the modern PNA series data rather than from the older 3 GHz VNA.
I don't know if the only difference between the B (6 GHz) and F (9 GHz) suffixes of the 85032 are the loads. If so, I suspect using the 85032F data which is in my firmware will be ok. It might not be optimal, since the data for the 85032F in the firmware is fitted over 9 GHz, when the loads in the 85032B kit are only 6 GHz.
Perhaps, changing a couple of loads in the 6 GHz 85032B kit to 9 GHz loads might allow it to work to 9 GHz and me use the data in firmware for the 85032F 9 GHz kit. I'm hoping to get the differences between the 85032B and 85032F kits clarified, since if is only the loads, there's a cheap and easy method to get it to work to 9 GHz using firmware already in my VNA.
I believe I can only have one user calibration set in my VNA, which is annoying. So if you use a mixture of connectors, it would become rather tedious to load a different set of cal data every time one wants to use another connector.
To me at least, this is a rather confusing topic, though I think I am slowly getting my head around it!
Dave
- - - Updated - - -
You might find the comments on
www.microwaves101.com about How to (not) trash a cal kit interesting. Hopefully they will not apply to the one you purchased.
Regards,
Azulykit
Yes, I had seen that. As far as I can see, they are ok. But I am going to take some photos later today with real Nikon macro lens (not a normal lens with a macro mode) and investigate more carefully. But as far as I can tell, they are ok.
The cal kit has a recent calibration certificate, but I'm a bit weary of what values these cal certificates actually have.
I managed to pick up an 18 GHz N verification kit fairly cheaply (about 10% of the new price) and will send that to Agilent for calibration, as it is 20 years old, though it look unused.
I should be in a position very soon to have both N (6 GHz) and 3.5 mm (9 GHz) cal kits. Once I have those, I'll look around more for better (18 and 26.5 Ghz) cal kits, and sell off the ones I have. For now at least, 6 Ghz is all I need, so there is no hurry to go to the higher frequencies, but I will need them later, so I will try to acquire kits which go to the higher frequencies.
Dave