FrancoItaly here is new frontend preamplifier for your LRLs.
I am thinking about direct J-FET demodulation using well known interdependency between Is (source current) and Vgs (gate voltage) with very low Id (drain current). You already know that linearity of demodulated sugnals is much better when using ordinary diode like 1n4148. And input voltage at the input could be smaller than 100mV, so we get better sensitivity and in same time better linearity.
Maybe we need additional sitmulus for example "bomb" the gold with short impulse bursts for example 100KHz like it had realised in Heatkit GD348 ?
Tell me what do you think about upper things ?
What should be done next in your opinion ?
Regards
Dragan