Hello, All...
I recently had a need to measure an unknown matching transformer. As it was
in a sealed enclosure with noth but the wire terminal and coax connector
exposed, and I didn't want to damage the enclosure, I pulled out my trusty
NanoVNA.
All I knew about the "black box" was that it was used with a
10-12-15-17-20m EFHW wire antenna. That made me assume it would be
somewhere in the range of a 49:1 ratio.
I pulled out my decade resistance box and dialed in 2450 ohms (50 ohms x
49) and put that between the output wire terminal and ground. I then
connected the NanoVNA to the coax input.
I then played with the decade box until I got a flat response from the
NanoVNA and the needed resistance to get there was 2501 ohms. Technically,
that makes the matching network about 50:1 ratio.
All of this told me what I wanted to know, but I'm wondering if there would
be an easier, more direct way of getting there with the NanoVNA.
I'm good with the idea that I may have just stumbled onto the right answer
in my madness.
Take Care & 73
--
de KC6UFM
Charles
