AM battery less reciever!

serch in google "crystal radio" you fine many link

Several decades ago when germanium transistors were common (they would work on under 1 V) you could put out a long wire antenna with a diode to rectify signals from local MW broadcast stations to power a crystal receiver with audio amplifier for the MW broadcast band.

Crystal receivers without audio amplifiers work best with crystal ear phones (they are more sensitive than magnetic types) which are hard to find these days.

Take a look at:
http://www.arrl.org/tis/info/pdf/129756.pdf
or
http://www.clarion.org.au/crystalset/mystery.html

Regards,
IanP