I entered a polynomial for the Lx corrections for my DIY cal kit SHORT and got the result below...
what i concluded from your reply #35 and #36 is, are you suggesting that using less quality cal kit in the same VNA will result in more ripple? if that is the case, there is possibility that kirkby did the attenuator report using agilent cal kit as his calibration standard? i'll need to confirm this back to him.
anyway i'm doing the test with cheap crap china sma connection and 50 ohm coax cable. maybe those also contributes to the rippling effect, i'm not sure. what i'm sure is the cabling still give consistent result even if i move them around a little bit... fwiw...
I just took a closer look at your attachments in the post above this one.
Few comments which hopefully will help:
* The attenuator return loss measurements, with the free port terminated, is probably not too bad given the device. The return loss of that attenuator with attached terminator is probably pushing the limits of your device.
* The Dr Kirkby data and method you have to use (i.e. using the terminator) don't seem to line up with what he has in his FAQ:
http://www.kirkbymicrowave.co.uk/FAQ/How-do-I-verify-the-calibration-kit-is-working-properly/* The S21 measurements are probably poor as the Deepace doesn't seem to support a 'full 2 port' calibration. Do you know if it supports a full 2 port calibration, or is it just a 'response' calibration? In The Signal Path youtube review it shows a simple response cal only with a through.
* A full 2 port cal can correct for many more errors than a simple response cal can. Since you are using a lower cost, compact device which doesn't have great directivity and port return loss, then you will really need this error correction to get decent results on the S21 test.
* If you can pull the raw data out of the device and get it into touchstone format, then you should be able to use scikit-rf or Metas to do the full 2 port cal.
* According the manual it supports using an external bridge/coupler. Sometimes high quality ones come up on eBay which have come from HP gear.