On a totally unrelated note, I cascaded two preamps to get 40 dB of gain
about 30 years ago. They were identical circuits, both using MGF-1202 GaAs
FETs.
The input was a Zener diode noise generator. The second preamp fed a 3dB
splitter which fed two inputs of a low-loss passive nulling circuit I
designed. The output of that fed a 2m to 10m RX converter, which fed 10
meter receivers.
That nulling circuit nulled all of that noise, much to our delight. But
it's not practical on 160m. :-)
And the preamps' piston trimmers could be adjusted either for maximum gain
or for lowest NF, but NOT at the same setting.
73, Mike
www.w0btu.com
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