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What is needed is some kind of NTE/ECG/SK catalog for most of the makers/seller of core material. Found this a long time ago and not sure if this will be useful to anybody. See attached. Also, is

You can stack them for higher voltages. The DC isolation lets you do that. Yeah, filtering for a specific application would be application specific.

Jim, yes, ready-made DC-DC converters are inexpensive these days, and are a good option in many applications. But for RF switching, I don't see the one you linked as very usable. 15V is definitely not

I found this data a year ago - "The easiest way to identify most ferrite materials is to wind about four turns of wire through the core and then measure the lowest frequency at which the value of

I'd buy an isolated DC/DC integrated converter something like Cui PQME1-S12-S15-M -- 12V in 15V out. $5 each You can also get the 5V in. So you can

Don, I have seen that RF rectification technique used to bias switching diodes. But personally I don't like it much, at least not generally. Maybe in a specific application. Bias development by that

Gary, that was an interesting read! But if I understand integrated SOI FETs correctly, then they have no body diodes, and very low capacitances! So the main two problems of common MOSFETs for RF

Try it with some known cores first. -- John AE5X https://ae5x.blogspot.com/

Often a voltage doubler or tripler is used to "steal" some of the incoming RF, rectify it, and derive a high bias voltage that way, which will always be high enough to avoid conduction, since it will

Again, Fair-Rite has a wonderful YouTube presentation that outlines how to determine the mix of a ferrite. There's also a lot of additional information which may be quite useful. Visit the Fair-Rite

I didn't see this topic after a brief search, so here goes. My NanoVNA H3 (ver. 3.3) randomly reboots for no apparent reason, and it won't save configs. It's even happened when in DFU mode,

The subject of measuring toroid characteristics (ferrite and powdered iron) has been discussed in this group before. When Rune added the graphing capability of S11 R/ω & X/ω to NanoVNA Saver there

Yeah, that's cheaper than some relays. Of course, a relay won't vanish in a puff of smoke if you accidentally hook up line voltage or the B+ anode supply shorts to the output.

On Wed, Nov 9, 2022 at 10:17 AM, Manfred Mornhinweg wrote: Good points! Worth rereading again!

Yes, with 1kW PIN that affordable I question my attempt to use MOSFET with all the inherit problems it comes with

MOSFETs as RF switches are ubiquitous in cellular phones. You can never use just one FET as a switch because the gate-source/drain voltage is limited and will cause breakdown which is easy to realize

Miro, I would imagine that a MOSFET, with 10V or so on the gate, will behave like a low value resistor in series with a small inductance. Given the small size of the MOSFET chip, at HF the resistance

I come back to de Graph S11 R/ω & X/ω (?Ω/Hz) Already, numerically, it's not /ω but /F (frequency). Do not forget to reset the graph I still haven't understood what it can be for torus. How can

But the FET idea is interesting, and the NanoVNA makes it possible to easily test it. Not so expensive $10 each for the UM9415 direct from Microchip.

Since this is an antenna switch, one really doesn't have to worry about timing issues. It would be a very simple straight forward design.