How does your circuit differ from the simple circuit
used by AAVSO (i.e. "CAP's design")?
The original AAVSO circuit has about the same range as ours
because the diodes drop and limit the
upper and lower parts of the signal.
We made our own minor improvements and put
the detector portion (D1 & D2) of the circuit and the signal-level
capacitor (C2) in a
shielded box along with the opamp instead of the way
done in the original AAVSO design.
In the original, the
long unshielded 4-conductor cable caused oscillations back to the antenna.
When we redid this minor arrangement of the components
to only send back DC levels across the wires, we realized considerable