Free Energy From Radio Waves. (Video)
Crystal radio being used to light up 10 LEDs. I would estimate my antenna to be over 200 feet long. I used a kite to hang it over a tall pint tree.
A "crystal set" is a radio receiver that requires no batteries, or household electric current to operate. It has no apparent power supply. I will tell you at the end of this article how this radio gets it's power.
The crystal set was the first radio for broadcast reception. Back then, these radios used a galena crystal (a piece of rock that acted as a semiconductor to recover the audio from radio frequency waves). Since then, the semiconductor diode has replaced the galena in most designs as it is one less thing that the user has to fiddle around with.
Since the crystal set is self powered, headphones are required for listening. This ain't your son's ghetto blaster. The sound is quite faint but still easy to hear.
Here's a How To Build one yourself.
How did wireless come about? At the turn of the 20th century, an American scientist, Greenleaf Whittier Pickard, found that a number of naturally occurring crystalline minerals could be used to detect radio signals. The detection occurs at the contact point between the crystal and the tip of a piece of wire. Radios employing this kind of detector became known as crystal radios. In the typical early radio-wave crystal detector, the crystal rock was fixed into a brass cup and the radio operator found the loudest signal by touching the wire, called a cat’s whisker, to various points on the surface of the crystal.