So, the good match is likely mostly due to loss. Of course, since you have
two transformers in the measurement, the loss through one is half the S21
values. Still, most of the good match is due to losses. A 2:1 SWR is 10
dB return loss. Most of your earlier plots and SWR indicated at or less
than 1.5:1. This is certainly in line with the loss measurement. 1.5:1
SWR is return loss of 13.98.
Dave - W?LEV
Dave - W?LEV
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On Tue, Mar 17, 2020 at 10:47 PM Kerr Smith <kerrsmithusa@...> wrote:
So, the match is good over HF. Thinking after I hit send: Why not
connect
the secondaries together as you did for the S11 measurement and do an S21
measurement to assess loss? That way, both ports are in a 50-ohm system.
I have just removed the 50 ohm resistor off the second transformer and
attached CH1 of the NanoVNA instead. The attached image is the S21 plot of
the sweep from 1 to 30MHz. At 7.15MHz the gain shows as -22dB.
--
*Dave - W?LEV*
*Just Let Darwin Work*
*Just Think*
