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Take out the "Regards,Jim" and you won't get a "404"

To me, the sq

Firstly, of course a NanoVNA can be used directly to measure some tube characteristics, such as interelectrode capacitances, without powering up the tube. And then, I don't see why it should be

A vacuum tube is a multi port device. it is no different than any other device that would be characterized by matrix methods, like Z, Y, ABCD and S. In fact if you search the IEEE data base, you will

Plenty of L-band TWTs around (big honkin' things) and some Nanos go up to 1.5 GHz. But mostly in space applications, and if you're playing in that ballpark, you can probably afford suitable test

I learned that S Parameters came into use when devices designed for higher frequencies (UHF and Microwave) had to be characterized. Also, test equipment have to be developed which could measure S

Hard to find a TWT that a Nano could test. He's thinking more 12AX7! (Been using TWT's for over 40 years, don't think I have ever seen one for under 1 GHz.) Kent

Its working now white my laptop.

Its working now, only with the laptop!

Zack Published S-parameters for a W-band TWT, Figure 5. See:?https://aip.scitation.org/doi/10.1063/5.0075447 Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.?

Yes, that's true. But what is the probability that the OP wants to test a TWT? Zack W9SZ

Pretty much every manufacturer of Traveling Wave Tubes publishes S-parameters - In particular one tends to be interested in the S12 (reverse gain) at the second harmonic of the intended frequency

Most likely. In the really early days, there weren't any transistors that worked above HF. Then some VHF transistors came along. There were no high-frequency FET's in the early days. Now we have some

"The frequency ranges used for most commonly-available tubes do not require s-parameters. There are very few tube amps around that operate above 1296 MHz." I remember back in the day, using the giant

I have never seen any manufacturer publish s-parameters for tubes. And the design techniques are different. The parts and methods used in biasing and matching tubes are completely different than those

Yes, I did this kind of testing for HF to UHF range bias-T's. As others said, just connect 2 RF ports to to VNA ports, no DC of course. Look at S21 and S11. I settled on 30 turns on FT37-43 for the

You would do it the same way you would measure a high voltage MOSFET but since you are asking the question, I would not do it considering the voltages involved.

That's the kind of capability you get when you step up to the multi-thousand dollar level. Yes. and there's all kinds of interesting measurements and analyses possible. If you look at the

DonIt seems that this thread is headed in the direction of Load Pull measurements.? Those interested can get a heads up here:https://www.maurymw.com/pdf/datasheets/5A-062.pdfRegards,Jim Logic: Method

You don't seem to understand the NanoVNA is in NO Way a tube tester. Clyde Lambert KC7BJE