Products > Test Equipment
Kirkby calibration kit alternatives?
hendorog:
See if you can manually scale the normalised phase charts - the glitch is killing all of the detail due to the auto scaling.
From what I am seeing it is hard to get a good match 0-6GHz. Much better dividing into 0-3GHz and 3-6GHz.
suj:
I think I need to change the way the phase is displayed. Error during changing the phase from -180 to +180 obscures the situation.
G0HZU:
Hi suj, thanks for putting the data into METAS.
I noticed that the loss response of that SMA F-F (OPEN) on S11 looks a bit poor up to 3GHz and I tried another SMA F-F bullet and this one looks better. Both are clean and look similar but one has lower loss. I assume there must a difference in materials used and/or subtle differences in Zo along the connector.
--- Quote ---Also, if the cal is done offline in software, then changing coefficients (i.e. recalibrating using a different set of coefficents) is purely software and doesn't require another sweep. So it would be technically possible to do a full sweep and change cal definitions on the fly.
--- End quote ---
That would be neat, I'd definitely be interested in being able to do this. My original DIY SMA kit must be about 12 years old now and it would be nice to retweak the corrections for any wear. I spent ages optimising the cal kit for it when I first got my HP8714B VNA and this involved lots of repetitive tests and calibrations. I don't really want to do this the hard way again.
I've dug out the HP8714B from under the stairs and powered it up for a bit of nostalgia. I do like the big old CRT display on it even though it is just mono.
in3otd:
--- Quote from: hendorog on February 25, 2018, 07:23:09 pm ---Then I found a bug in the model calculation for the Lx params. Fixed that and tada, now it lines up :)
--- End quote ---
:-[ uh, oh, you mean the indices of the Lx coefficients were off by 1in the std_model_s_params() function, right? I'll upload a corrected version shortly, thanks!
suj:
Hi,
I changed the files on my server. After refreshing, the normalized data should look OK.
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