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Matlab upload s2p file without rf toolbox12/21/2023 Why did doubling the Open/Short Offset Delay delta of -14.491 ps to be the Thru's Offset Delay give the results it did?Ģ. The results now look pretty good.īut why does doubling the Thru delay give these results? And so my questions are:ġ. That is, rather than making it -14.491 ps, make it -30 ps. So I tried doubling the Thru's Offset Delay. Maybe, I thought, the Thru's delay change needed to be positive, not negative, so I changed its Offset Delay from -14.491ps to +14.491ps. The results weren't quite as good as I expected (see attached T-check PNG). O The Thru Offset Delay changed from 0 ps to -14.491 ps O The Short Offset Delay changed from 16.695 ps to 2.204 ps O The Open Offset Delay changed from 14.491 ps to 0 ps. So, as an experiment, I decided to subtract 14.491 ps from HP's "stored" 3.5mm definitions. at the location of the actual open and short). Much to my surprise, the results were very good, as you can see in the attached T-check plot.īut, I wondered, do the "stock" HP delays bear any resemblance to the actual delays of my SOLT standards?Īssuming HP's Offset Delays were not the same as my SOLT Offset Delays, why not change HP's "stock" Offset Delays (as defined above) to move the reference plane to the end of my standards (i.e. The key parameters of the "stock" 3.5mm definitions (to match HP's 85033C kit) are: Of course, I had not characterized my standards, and so I thought, as a first attempt at checking them, I would use the "stock" 3.5mm cal-kit definitions that are stored in the 8753C. And so I thought I'd check their accuracy, using my 8753C and the Rohde & Schwarz T-check method. With my purchase of a NanoVNA I thought I could put them to use in lieu of the male standards the NanoVNA comes with. I never used the open and short above about 30 MHz, so I didn't worry too much about their accuracy. Til: Homebrew Female SMA standards and T-CheckĪ few years ago I made an open and a short female SMA standard for calibrating my HP 8753C VNA (for the load I used a very nice 85052 female 3.5mm load). The load being 50 ohm it is not sensitive to a small displacement of the calibration plane. I do not accept private email due to forum scraping groups.io I have them to calibrate the HP4191A I have and work well for the nanovna. The HP load is definately air (minimal dielectric) to the resistance. One last, many of the HP loads are air, the most often home made open and short are PTFE loaded, there is a VF difference. Til: Re: Homebrew Female SMA standards and T-Check However the Display/Scale/Electrical delay in the NanoVNA can fix it if you enter the offset delay of the male versus female short. But you are not calibrating to the calibration plane of the Female adaptor of the NanoVNA or the Male adaptor at the end of the test cable if using a such. Sure they will work fien with thee NanoVNA as the difference in offset delay is very small as the NanoVNA is designed for ideal calibration kit except the open is compensated by 50fF.
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