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Kirkby calibration kit alternatives?
orin:
--- Quote from: rfspezi on March 19, 2018, 08:06:25 pm ---
Next, i start a "S11 1-Port" calibration.
When selecting "OPENS", a new menue appears and asks me for "OPEN (M)" or "OPEN (F)".
Since i am using the female-open, i guess selecting "OPEN (F)" is correct here?
--- End quote ---
Not usually for HP VNAs.
The (M) means a male test port and (F) a female test port. So if you are using a female open, you should select OPEN (M) and if using a male open, select OPEN (F).
(Later Agilent changed the convention to indicate the sex of the standard and replaced the parentheses with hyphens so OPEN -F- would indicate a female open and so on.)
This information is on Dr Kirkby's web site, but I could only find it under the old NCV032B kit information here:
http://www.kirkbymicrowave.co.uk/support/Kits/NCV032B/HP/
G0HZU:
--- Quote ---Ok, so after i finalize the calibration by pressing "DONE 1-PORT CAL", i set the VAN to Smith-chart to verify if calibration is correct.
I do this by attaching the SHORT again and check if the Smith-chart gives me a point at the short-position.
However, i don't get a dot at the short position but a line reaching from short to almost infinit on the upper, outer pure inductor circle.
Similar, just mirrored is displayed when the OPEN reference is connected.
For compensation, i applied a port extension of 58.14 ps and get the expected results (dots) with all 3 calibration standards.
--- End quote ---
Don't forget that your cal kit SHORT and OPEN is at the far end of either a male-male SMA adaptor or a female SMA adaptor. The typical delay in the F-F adaptor is about 42ps and the M-M is probably about 58ps.
So the moment you put your cal kit OPEN back on the VNA after a calibration the open end of your OPEN will be either 42ps or 58ps away from your reference plane. So the smith chart on the VNA will show a 0-6GHz line going maybe halfway around the smith chart. It's effectively measuring the SMA F-F barrel.
My guess is that you have tried to do a 1 port calibration and told the VNA the wrong gender for the cal kit. So the 42ps and 58ps are muddled. Try again for the 42ps female OPEN (and don't forget the VNA refers to this as OPEN (M) ) and it might look like this:
G0HZU:
If you put the female SHORT back on the VNA after a successful calibration it will probably look like the image below. These smith chart images for the female SHORT and OPEN are based on s1p data from another Kirkby cal kit. i.e. the SHORT will look like a short that is shifted about 42ps from your reference plane once you fit it back on the VNA after a calibration.
Bud:
--- Quote from: rfspezi on March 19, 2018, 08:06:25 pm ---
Ok, so after i finalize the calibration by pressing "DONE 1-PORT CAL", i set the VAN to Smith-chart to verify if calibration is correct.
I do this by attaching the SHORT again and check if the Smith-chart gives me a point at the short-position.
However, i don't get a dot at the short position but a line reaching from short to almost infinit on the upper, outer pure inductor circle.
Similar, just mirrored is displayed when the OPEN reference is connected.
For compensation, i applied a port extension of 58.14 ps and get the expected results (dots) with all 3 calibration standards.
I thought that with the complete calibration data on the floppy disk, there would be no need for manual port extension entry?
--- End quote ---
You should not do this. Why? Think about what your VNA will show if you connect an ideal Short or ideal Open. They will Not be at zero and infinity dot position as they should, because you offset the chart by 58ps. Therfore any measurements you take with such port extension applied will be invalid.
TheSteve:
--- Quote from: rfspezi on March 19, 2018, 08:06:25 pm ---Another thing that irritates me is that the 50 Ohm references are 49,5 and 51,1 Ohm instead of "50,0".
I would expect to get better quality references for that price?
--- End quote ---
On my "out of spec" SMA kit my female load is 51.05 ohms and my male load is 49.25 ohms.
And I do get the expected smith chart results G0HZU suggested you would.
The kit cal info does have a max frequency entered into it that was supplied for my N9912A, I'm not familiar with the 8753ES but is it possible Dr Kirkby entered 3 GHz into your data for a max frequency instead of the spec'd 7 GHz or your 8753ES's 6 GHz.
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