it looks like oscillation. Connect the output of the amplifier to the VNA
through a 6 or 10 dB attenuator and have another look at s11.
Dave - W?LEV
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On Thu, Jan 9, 2020 at 12:01 AM Leif M <sala.nimi@...> wrote:
This is probably not NanoVNA specific.
I made a quick and simple amplifier of leaded BF199 and some passive
components. Collector is via a coil I happened to have. There is no
matching. Input is calibrated with a 20dB attenuator.
Gain is 23dB but S11 looks strange in a Smith chart. Is this oscillation
or just feedback from output.
--
*Dave - W?LEV*
*Just Let Darwin Work*
*Just Think*
