Hi Arie, read your article with great interest. I understand my nanoVNA, I think, and I understand complex algebra and Z = R + jX. But I get VERY confused by standard radio or ham talk. I made a crystal radio over the past 2 years, and never understood why or how it would be 50 ohms. I always wanted to measure my Z, but I think the main thing the antenna signal is ¡°looking at¡± is my diode, since my tank circuit has near-infinite resistance and thus is almost an open circuit. Are you suggesting I can simply plug my nanoVNA in where my antenna usually goes and get a receiver input impedance? Also, you spent a bunch of time on an attenuator, but later (I think) you concluded you didn¡¯t need it. Why would I want one? Any other suggestions for a naive beginner? I am thinking about matching Z from antenna to receiver, but I can¡¯t measure either, and when I guess at values and then design a little LC circuit to match impedances, I find it will resonate at darn near my target f, sending my desired signal to ground!
Andy
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On Feb 10, 2022, at 5:43 AM, Arie Kleingeld PA3A <pa3a@...> wrote:
Coming back on the title, how to measure...
I wrote an article about that a couple of months ago, measuring the input impedance of a Elecraft K3 receiver.
It was published in the SARC Communicator sept- Oct 2021. This is the link:
See page 43
73,
Arie PA3A
