tag:blogger.com,1999:blog-1592992209402300549.post7315519870820736309..comments2024-03-29T09:08:47.702-04:00Comments on The Silicon Graybeard: The Ham Radio Series 36 - What Are S-Parameters and Why Should I Care?SiGraybeardhttp://www.blogger.com/profile/00280583031339062059noreply@blogger.comBlogger15125tag:blogger.com,1999:blog-1592992209402300549.post-22547943635362528182023-03-07T04:08:10.521-05:002023-03-07T04:08:10.521-05:00Looking at p. 2 of HP-AN-95-1, you will see S11 = ...Looking at p. 2 of HP-AN-95-1, you will see S11 = B1/a1 with a2 = 0 = Input reflection coefficient with the output port terminated by a matched load ....Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-20231630797727176762023-03-06T22:22:12.350-05:002023-03-06T22:22:12.350-05:00No, No, No, I was a Satcom tech in the USAF before...No, No, No, I was a Satcom tech in the USAF before I retired and then did it for 10 years as a military contactor. I want nothing to do with RF technology. I drive a CDL Hot Shot truck now as a retirement job.tsquaredhttps://www.blogger.com/profile/02737130316088634658noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-39108881033447983212023-03-06T20:09:30.275-05:002023-03-06T20:09:30.275-05:00Thanks for that. Seems funny that in neither of th...Thanks for that. Seems funny that in neither of the two ham presentations I attended, on the NanoVNA, nobody explained the S11, S21 labeling, with the arrow graphic.jednoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-77462179109217224432023-03-06T20:00:11.576-05:002023-03-06T20:00:11.576-05:00I remember the swivel arms well. I also remember t...I remember the swivel arms well. I also remember that they weren't quite phase stable and match invariant. I had to repeatedly explain to design engineers that you could not measure high Q devices using those arms because the calibration would quickly become invalid.John Fisherhttps://www.blogger.com/profile/00442268389104530659noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-80658036047431925992023-03-06T17:28:38.142-05:002023-03-06T17:28:38.142-05:00The unit in the left rack, just above the desk top...The unit in the left rack, just above the desk top, has the "Mechanical Arms" I mentioned, in case you've never seen them. Amazing things, with swivel joints, airline "coax", and very well made.<br />The young guy sitting there could have been me! Geek glasses, respectably longish hair, and you just know he's carrying a loaded pocket protector.....drjimhttps://www.blogger.com/profile/05647484115197408897noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-27561824260830625052023-03-06T17:03:28.629-05:002023-03-06T17:03:28.629-05:00Thanks for the link, John. Not sure if I've se...Thanks for the link, John. Not sure if I've seen that before, HP is an absolute gold mine of technical documentation. They wanted people to be able to get the most out of their purchase, and had excellent support. HP Manuals are like Heathkit manuals...The Gold Standard of "How To Do It Right".drjimhttps://www.blogger.com/profile/05647484115197408897noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-14343588876232888642023-03-06T10:38:55.499-05:002023-03-06T10:38:55.499-05:00D'oh! I should have remembered that one.
I...D'oh! I should have remembered that one. <br /><br />I would have sworn I had a copy on this machine, but nope. <br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-16008420463083645962023-03-06T10:22:46.332-05:002023-03-06T10:22:46.332-05:00And this is probably still the best tutorial on s-...And this is probably still the best tutorial on s-parameters you can find. There was a myriad of good technical information in the HP app notes from that era. http://hparchive.com/Application_Notes/HP-AN-95-1.pdfJohn Fisherhttps://www.blogger.com/profile/00442268389104530659noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-38572513098502724712023-03-06T10:20:15.078-05:002023-03-06T10:20:15.078-05:00I started my microwave career on one of these. I w...I started my microwave career on one of these. I was the young kid who could spell RF and write code. https://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1970-02.pdfJohn Fisherhttps://www.blogger.com/profile/00442268389104530659noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-57706521635971218412023-03-06T06:19:35.022-05:002023-03-06T06:19:35.022-05:00I would bet that BOTH versions are an accurate des...I would bet that BOTH versions are an accurate description.Mark Matisnoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-3484160183378825862023-03-05T23:00:06.026-05:002023-03-05T23:00:06.026-05:00"It was there when I started working there&qu..."<b>It</b> was there when I started working there", not "I was there..."SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-74751795167541003062023-03-05T22:58:41.066-05:002023-03-05T22:58:41.066-05:00I was going by the equations in that graphic showi...I was going by the equations in that graphic showing them. Top left of the bottom. It says a2=0 as the condition. Notice that a and b are swapped top to bottom as you go left to right. Also notice the box represents the network (Device Under Test), not the VNA. <br />SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-81233034285433459662023-03-05T22:55:16.119-05:002023-03-05T22:55:16.119-05:00ISTRC it had APC-7 connectors on the front panel o...ISTRC it had APC-7 connectors on the front panel of the bottom box, not a mechanical arm. I should try to look up VNAs from that era and see if I can find the model. <br /><br />It was in a 19" rack and several boxes tall. I was there when I started working there. I'd have to try to dig up some details. SiGraybeardhttps://www.blogger.com/profile/00280583031339062059noreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-48684054220477941422023-03-05T22:49:03.460-05:002023-03-05T22:49:03.460-05:00When measuring S11, port 2 is not grounded, it'...When measuring S11, port 2 is not grounded, it's terminated, etc. Just a minor corrections, nothing to see here!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1592992209402300549.post-60915135251875547832023-03-05T21:59:16.271-05:002023-03-05T21:59:16.271-05:00Great primer, SiG! I'm about from "Your E...Great primer, SiG! I'm about from "Your Era", which is why I have a preference for HP equipment. Did the HP VNA you used have the funky "mecahnical arm" with APC-7 connectors on them? IIRC the one at Hughes where I worked had them.<br />I bought a NanoVNA shortly after you published one of your articles on it, and I'm impressed. Been using it to weed out crappy connectors, bad cables, and other things besides just playing with it. Haven't used it yet with a filter or amp, but the amount of power these things pack is astounding, and all for a measly "hunnert bucks".drjimhttps://www.blogger.com/profile/05647484115197408897noreply@blogger.com