I ran across an old preamp in my junk box and I am trying to
find the source of the design, so I can modify it for AM BC DX.
It has an MPF102 JFET first stage and an MC1350 8-pin DIP
IF amp chip second stage. (Way too much gain.) The front has
a gain pot as well as a toggle switch to select between two
input toroidal coils with compression trimmers. One set for
160M and the other for 80M. The output has a toroidal core
transformer.
It is built on a circuit board and clearly assembled by ME since
the panel is in my handwriting. But I don't recall where the
design came from.
I have to think it was in some popular magazine or handbook,
and it must have been a serious enough project for someone
to make circuit boards available. I probably built this in the
mid/late 1980s or so.
Much of my library is still at the Colorado QTH so I have been
unable to do a complete search of my own data. Anyone have
any idea where this was published and can anyone steer me to
a copy or scan it for me?
Thanks -- John W0UN
It has been suggested that it might be the KD9SV design -- but that
is a single stage IGFET rather than this 2-stage JFET/IC design.
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