Hello I am back from exile. Thanks to all who want to help us out! I agree that in the future we want to make this content more "open source". Also, since ad revenue is nearly non-existent, we want to reduce the volume of ads on the pages. On the other hand, maybe there is a way to drop the price of ads and get some suppliers back. The first problem I want to figure out is how to reduce the monthly costs, we are working on this. We don't want to solicit contributions from our readers, we just want to reduce the monthly hole-in-the-pocket. We have some stuff we need to do to simplify tax time, those changes won't be noticeable.

Like any project that seems overwhelming, the easiest thing to do is procrastinate. Let's keep up the chatter, it helps us focus on this end!

Steve

I had to actually look ho this connector style. Here it is on YouTube.

https://youtu.be/eplckCGbRPc?si=A1AG6APIZZSqB0d_

Wikipedia says it is not a well controlled impedance, and there are no standards for this type of connector

https://en.wikipedia.org/wiki/UHF_connector

Maybe a TDR measurement could shed some light on performance?

Steve

Sorry I fell down on the job here. I am expecting to start a gig that will come with the usual EDA software. I did look at dot terminations in the past, whether they work in your band or not depends on the substrate ER and thickness. I was looking at 100um GaAs I recall, so not really cheap or high power handling...

Assuming the resistor substrate can dissipate a good amount of heat, the effects of mounting the resistor on the substrate is another issue to address. Then of course there is the cost...

Update... we have a couple of offers to buy the content for the price of a used car... Maybe that's the way to go. But maybe there could be a way to get some sponsors to do the needful and cough up enough cash to keep the lights on and offset the cost of visiting the IMS conference (or European Microwave?) once in a while. Email us if you have any ideas or if you want to know what it actually costs to keep this thing running... Patreon, anyone?

To be fair we could keep on keeping on until we die, without eating dog food. But we'd like some other skin in the game.

Steve and Brenda

Was going to use 2.5D analysis to predict the response of a circuit. Anyone know of freeware that will do that?

Steve

Here is George, at long last. Thanks for the tip! Let me know if you wish to edit or expand on what we wrote.

Steve

https://www.microwaves101.com/encyclopedias/microwave-hall-of-fame-part-iii#szentirmai

We can put him there next month! Remind me if I forget...

Thanks
Steve

Good question, I will ask around at the BCICTS conference.

Sorry for the late response Steve. I will take a look and get back to you. Please email me at Steveatmicrowaves101dotcom.

I bought some replacements, SK3304, on Ebay. Supposed to be a drop-in replacement. We will see about that...

Circling back to the original intent of this thread, I was looking for a way to tune a cheap thick-film resistor, grounded with an inductive via hole. Adding some tuning stubs and changing the resistor value are all fair game, or any other tricks you might have. I don't want to worry about radiated power, but I was thinking the resistor would be mounted to exposed traces (microstrip, not stripline). DC to 40 GHz with 20 dB return loss would be nice... and performance to 60 GHz would be appreciated. I'll post what I come up with at some point.

This thread is pretty old. I had seen a pile of maybe 100 bent probes going to the dumpster before I posted it. No one responded, and all those probes went out with the trash. Then a month or so ago, someone asked if they were still available. Any RF lab consumes probes over time, I went and checked out what was newly trashed. After looking at about twenty ruined probes, I can say that most of them are beyond repair. I grabbed a half dozen that might have some hope and intend to ship them shortly, to see if they can be restored. I'll post the result later. Meanwhile, every day, somewhere, an RF probe crashes.... be careful with them!

Steve

I'd post some images of it but I can't figure out how to do that here...

Wow, great minds think alike. I also built a tapered resistive open-circuit stub. You can tune it with some conductive stripes, i.e. the load is like five resistors in series. I will have to dig that up and take a photo. Of course it was on alumina, lately everything is on circuit boards.

You can buy an HP-67 on Ebay to try it out...

https://www.ebay.com/itm/286361753781

- Steve

Wow, I need to post a photo of my library as well! I gave away some of the lesser titles. I have boxes and boxes of old app notes and technical memos, I have fooled myself into thinking I will someday do something with them... Some of the old memos are comedy gold. Imagine someone writing a memo about how impressed he was with his own work, then further imagine he became a VP...

Steve

I found him (thanks, Chris!), then jumped down the another rabbit hole. Thanks to a certain patent troll, we even have a photo of Mr. Bagley.

https://www.microwaves101.com/encyclopedias/bagley-power-divider

That's a good article. Next time I get stuck measuring NF I will be better prepared. Thanks for all your help!

This could be a problem with the input match that the detector provides. Looking at a tunnel diode detector data sheet is spec'ed at 2:1 VSWR

https://www.pasternack.com/images/ProductPDF/PE80T6000.pdf

looing at a Schottky detector, the input match is not even specified

https://www.pasternack.com/images/ProductPDF/PE8004-P.pdf

I am not saying this is the smoking gun, but maybe the combined LNAs are conditionally stable. It would be worth looking at broadband input match on both detectors.

Steve

We will attempt to get another venue for next year at IMS 2025. Hopefully a livestream! This year was a bit of a broken play because it was not planned early.

If there are any full-sized microwave engineers out there, we still have a lot of XXL and XXXL Microwaves101 tee shirts. Contact us if you want one. It's like five bucks to mail a shirt in the US, we don't mind paying. But if you are out of the country, we might want you to kick in part of the postage using Venmo or whatever....

Steve