Thanks for all this information and links!Yes - I am tempted to build my own crystal radio from scratch - just for the fun of it.
It's a pity they're not making the germanium crystal diodes any more... I guess they're just too expensive to produce, and there is not the demand.
Amazing that the POW's built crystal radios - I suppose it made perfect sense, then they could find out what was going on.
It's amazing that you can knock a radio together with just a few simple bits and pieces.