Will this AM radio receiver work?

Question

What I'm essentially trying to do is to add an amplifier to a simple passive radio receiver:

^{simulate this circuit – Schematic created using CircuitLab}

XFMR2 consists of two inductors 0.4 uH and 730 uH. C3 varies between 35 and 235 pF (or something like this). Numbers and the whole left part is taken from here.

The idea is to demodulate negative part of a signal via D1, R1, C5 and pass it to an inverting amplifier based on OA1.

If this circuit is going to work: I'm interested in receiving medium frequencies. It is said they're quite tough to receive in a city due to industrial and home EM noise, especially during days. Am I going to need something more sophisticated instead of this circuit? (not going into antenna discussion here)

Also, why germanium diode OA47? Can I replace it with a Schottky diode?

Answer 1

It wont work .C4 stops the detector diode from working .Remove C4 by shorting it .R2 is way way to low and will load the tuned circuit meaning no selectivity.Use a high impedence buffer like say a MPF102 or an opamp to keep some selectivity.Your audio output stage looks iffy so recheck the biasing .The Ge diode is slightly better than the Schotty here.