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Thanks!! That should be very helpful. I will try it out very soon - several unknown cores to investigate. -- Doug, K8RFT

Once I get time to put this on my bench I hope that "off isolation" will not be a big deal given that the load on another switch is 50 ohm antenna As power dissipation will be fairly small I will try

I'd expect MOSFET to behave in a similar way, with benefit that I have some high voltage (>400V) and decent current (>6A) handy. Another question that came to mind - how will the the AC (RF is not DC,

On 11/8/22 5:58 PM, Eamon Egan wrote: > Miro: > As far as your "academic" question goes, it's clear that any frequency specs of a MOSFET pertain to how fast it can be turned on and off, not how high

Miro: As far as your "academic" question goes, it's clear that any frequency specs of a MOSFET pertain to how fast it can be turned on and off, not how high frequency current they can pass. In fact,

This feature is already in NanoVNA Saver. Wind a few turns on the ferrite. Select the graph shown below and look for the "crossover" frequency. Then compare that with manufacturer specs for complex

I'd suggest that as a start, this be a feature to one of the PC applications that controls a NanoVNA. Or a standalone application. It's hard to fit things into the firmware, and at some point there

Thank you!

Antenna experimenting has caused me to wish for another feature addition to the NanoVNA firmware library. The new "resonance" search is very handy. Now I'd like to see a more complicated-to-design

In fact, that may actually help.. If the gate circuit is slow, that's great. The bane of switches is when the RF signal causes the switch state to change (a classic problem with diode switches, which

Because the FET is not really switching things at the RF rate, the gate being DC biased; the channel is just being opened or closed by the gate and looks like a bias-dependent resistor (plus all of

It's not a circuit model, just an arbitrary number to allow comparing switches. The linked articles talk more about the theory.

Yep, that's the next on my list :) This is interesting value, will need to read a bit more, appears to represent N channel as RC comprised of Coff and Ron

I've used a lot of MMIC FET switches over the years, but not actually designed them, so I can't speak to "bandwidth of the part" vs "bandwidth of the switch". I'm going to guess, based

Let's say that my use case is the one where "cross channel leakage" and "off isolation" are not overly critical (HF antenna switching). The biasing - to be honest, in my "thought experiment" I

Fair point - my use case is more forgiving - I'm "exploring" options to replace relay based HF antenna switch, where "OFF isolation" is marginally critical. But back to "academical" side of the

Brent, see this topic. It shows the jig I used to measure the ferrite beads: /g/nanovna-users/topic/79953788#20089 But I calibrated it with a 50? SMD resistor, rather than the

Thank you Roger Here's why it seemed to connect at low level and then it didn't work anymore. So that solves my notice problem :( -- F1AMM (Fran?ois)

NanoVNA-F is not compatible with NanoVNA App because the -F does not use a binary transfer protocol. Roger

That will be the challenge - off isolation. (and the usual issues with biasing, just like using diodes as switches) You might look at T/R switch literature - It's a similar problem - slow switching,