Done that, back when I was about six. Big coil, cap, long wire
antenna.

A few have forgotten I think, no batteries. But an antenna can
actually pick up power. You may tune the desired frequency for
reception and feed it to headphones, but now I am thinking that the
extra power coulod be used to run a local oscillator and then you have
a hetrodyne reciever. Much better and easire to tune.

Intersting.

JURB