Some more stuff about Crystal Sets. Either this will further pique your interest or cause a severe case of nausea, vomiting, loss of sex drive and maybe even make you go bald.
Crystal sets are like the Roaring 20's. Their entry onto the scene during the 1920's was exciting, vibrant and downright leading-edge technology. But in 1929 that all came to an abrupt end. For those in their 50's (born in 1970) likely the Roaring 20's and Crystal Sets mean nothing.
Thus, always a good idea to get some "skinny" (a term from my Navy days) about Crystal Sets and as usual Jeff Bezos is your friend. Buy this book through the Solder Smoke Daily News Blog.
There is a Xtal Set Society which promotes the use and advancement of Crystal Sets, and the above book (cheapest one I could find) has projects from that organization.
I have seen some pretty exotic crystal set circuits including lifting a diode bridge rectifier from a power supply and fitting it on to a pine board. Selectivity was an issue with simple tank circuits and some designs included a band pass filter.
This schematic above shows the BPF and two diodes. Driving a loudspeaker directly is a question mark.
Or how about a two coil Crystal Set? Caution La and Ld should not be two widely spaced coils. For this to work they must be closely spaced likely on the same form with a small gap between the windings. Also, of import -- phasing of the windings would be a concern. I do not know the why of the design other than selectivity.
I have reached my gag level and long ago probably yours. But keep in mind simple circuits with few components yet capable of receiving radio signals.
73's
Pete N6QW