TRL Coincidence? - Page 1
Forum section: electronics / rf-microwave

author: jjoonathan
author_rank: Frequent Contributor
timestamp: December 19, 2021, 06:25:43 pm
content: Some time ago I purchased an Anritsu 3654B 1.85mm cal kit from a Canadian gentleman who sold it to me for... less than he could have (thanks). It didn't come with measurement data, but I was able to buy the floppy off another 3654 listing. It had polynomial coefficients that sorta seemed to work. More than a little janky, but hey, still a step up from using my 8510 as a scalar analyzer. In any case, I've been on the hunt for bootstrapping tools. Naturally, a perfectly suited offset short kit was bought and sold on ebay right before I started looking. I haven't seen any since, or any airlines -- you can't win 'em all, I suppose. If you squint hard enough, beaded thrus sort of look like airlines, and that has been the path I've been pursuing. I tried a few cheap 1.85mm-1.85mm adapters without luck, but I recently had a breakthrough.The Anritsu 33VFVF50B and the Agilent 85056-60008 have such a perfectly situated electrical length difference that italmostlooks like the designer for one of them plugged the other into the 20°-160° rule and arranged for 160° to happen at 65GHz. Nice!The resulting calibrations do a fairly decent job of deembedding attenuators. I don't have a Beatty line to check with, I probably won't fabricate one until after I've fabricated proper airlines, and I'm sure the beads come through and corrupt the calibration a bit, but I still thought this little piece of information was worth sharing in case anyone finds themselves in a similar situation with similar constraints. Cheers!

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: December 19, 2021, 06:47:02 pm
content: I would torment my fellow labusers till the end of time for not putting dustcaps on any of those connectors, esp precision ones like calibration standards!But asides from that pretty cool info!

author: jjoonathan
author_rank: Frequent Contributor
timestamp: December 19, 2021, 08:01:53 pm
content: Haha, I would too! The secret is that I don't have to shareso I don't have to trust anyone else to check-before-connect and take preemptive action over the fact that they won'tAlso, new foam, fresh seal. The previous owner had them floating around in one of those plastic component binsFortunately, Aluminum boxes are cheap these days, Kaizen foam makes it easy to whip up some padding, and the good old blowtorch + aluminum rod trick seals up the open cells quite well. I actually took off the covers as a bit of an experiment, but it has been a year and I haven't found a single flake yet! I'm sure they'll show up sooner or later.

author: fourierpwn
author_rank: Regular Contributor
timestamp: December 20, 2021, 06:17:27 am
content: Nice. Thanks for sharing.Are those plots from the Python package - scikit-rf?

author: jjoonathan
author_rank: Frequent Contributor
timestamp: December 20, 2021, 04:01:14 pm
content: Nah, those are mine (holoviews). I plan to contribute them back, along with my 8510 code that knows how to use the binary transfer format, how to stitch together a bunch of 801 point sweeps, etc.Speaking of which, those bits of code have been stable for some time now, so it's probably time to get serious about it.