I followed the steps explain in the link below to measure the noise level of an amplifier I built.
The outcome was 5.2dbm/Hz. When I switch the LNA and amplifier DUT to measure the noise level of the LNA, I got the same result (the LNA is a cheap one? with no noise figure specs!) Then I modified the biasing the DUT amplifier following the recommendation for lowest noise level from the manufacturer (current 2mA instead of 18mA), and redone the measurement, I got the same 5.2 dbm/Hz.
Having the same result every time made me suspicious about the steps I did being wrong or missing.
I documented the steps I followed in the attached PDF. Did I miss anything?
