Please measure S21 instead of S11 using the NANOVNA! All S11 tells us is
the match (which is pretty bad!).
Dave - W?LEV
On Thu, Mar 13, 2025 at 12:14?AM Mitch NK3H via groups.io <mitch=
[email protected]> wrote:
Thank you Alan. I've attached an image of the whole setup including the
filter, the test rig and the VNA. Please note that I'm just using hookup
wire to connect the filter to the testing rig--no SMA or BNC connectors. It
made no visible difference when testing on the scope using the wires or
direct to a leg of the input and output capacitors. The other image is with
a wire connecting the input to the output of the test right. The result is
0db flat across the range for S21. The signal generator has 50 ohm output
impedance, and the scope has a very high impedance input. Not sure about
the VNA. I tried the setup with a 50 ohm resistor to ground on the filter
output and found no difference in the VNA behavior. Thanks for your help.
73, Mitch NK3H
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*Dave - W?LEV*
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Dave - W?LEV
