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Kirkby calibration kit alternatives?

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G0HZU:
I can have a play at making a quick and dirty cal kit using commercial SMA F-F bullets and a shorting end cap and a commercial SMA load and show you what happens if you just try and guess the delays based on caliper measurements and/or the typical delay in an SMA F-F barrel? This would represent about the crudest cal kit you could make for maybe <$20. The performance won't be very good but it might be fun to try this. My current SMA DIY kit uses precision end launcher connectors and this needed some adjusting with a rotary tool to get good results. But the quick and dirty cal kit described above would be made in the time it takes to screw the SMA connections together... :)

It might not be tonight though. Any interest in this?

Mechatrommer:

--- Quote from: G0HZU on February 22, 2018, 02:42:21 pm ---Can you post up your Kirkby cal kit correction file or list its corrections for Cx and delay etc?

--- End quote ---
maybe the attached file is what you looking for. its for agilent VNA if using my cal kit with them. its not relevant to my VNA though.. fwiw...


--- Quote from: G0HZU on February 22, 2018, 03:41:27 pm ---Note also that I'm just doing this in my workroom at home and using an RF simulator to create the comparison model.

--- End quote ---
what rf simulator? is this simulator accessible to mortal? ;D can i learn? ... for the rest of your post, i need time understanding that...


--- Quote from: G0HZU on February 22, 2018, 03:41:27 pm ---I think your problems may be due to the type of VNA you are using. I've not seen one of those models before and it may have quite poor performance.

--- End quote ---
now isnt that golden? (from your link above http://www.kirkbymicrowave.co.uk/support/Kits/85033/)



its been announced in public :palm:

G0HZU:
I'm using an old version of Eagleware SW for the simulator. It's old and obsolete but it supports some features that aren't in the later Keysight version of this SW and I'm using one of these (script/equation based) features to model the Cx and Lx coefficients. So it won't run on the latest version below.

https://www.keysight.com/en/pc-1297125/genesys-rf-and-microwave-design-software?cc=US

I checked your custom correction data for your specific Kirkby cal kit and the results for the OPEN are very good when tested for the simulator mode against the measured/supplied S1p data for the actual OPEN in your kit. I get a flat line as below :)

The results for the short aren't as good because there aren't any Lx corrections in the data. But it is still good considering it is using SMA based connectors in the SHORT. It would be easy to correct this for VNAs that support Lx coefficients and if a VNA supports this feature then I guess these would be included in the data?

Note that my attempts to model this stuff are fairly quick and basic. But because the results for the OPEN are spot on for both the Keysight 85033 and the Kirkby kits I suspect I've got this nailed OK :)

technogeeky:

--- Quote from: G0HZU on February 22, 2018, 07:45:30 pm ---...

--- End quote ---

Just to make sure you've seen it, have you ever looked at this
 guy's this DIY SMA female and this SMA male open/short/load kits? I notice that he never publishes the phase charts that you are showing.

G0HZU:
Thanks. It's interesting to see how people approach this in different ways. I had a look at the links you gave and the IN30TD cal kit corrections have some very odd values in them. I guess there are no rules here but the numbers do seem very strange.

Back when I made/optimised my DIY kit I wanted flat phase to 3GHz and low loss in both open and short. I went to fairly nerdy lengths to achieve this so I could measure/model SMD parts accurately in a test fixture with my old HP8714B VNA. I kept on refining it until it gave the performance I wanted.

My cal kit cost nothing in parts because I salvaged the SMA parts but it cost a lot in time spent optimising it both electronically and with a rotary tool.

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