Building a radio in 10 minutes.

http://sci-toys.com/scitoys/scitoys/radio/ten_minute_radio.html 

For our 10 minute radio, we will need these parts:

• A ferrite loop antenna coil

  In our other crystal radios we wound the coil by hand. In this project we use a much smaller coil with a ferrite rod inside, from our catalog. The ferrite rod allows the coil to be smaller, and it can be moved in and out of the coil for coarse tuning.

• A variable capacitor (30 to 160 picofarads)

  We carry this in our catalog. You can also find them in old broken or discarded radios.

• A Germanium diode (1N34A)

  We carry this in our catalog.

• A piezoelectric earphone

  Also in our catalog.

• Two alligator jumper wires

  We use alligator jumper wires here for convenience. They are used to connect the ground and antenna wires to a good ground and a long wire antenna. We carry these in our catalog.

• About 50 to 100 feet of stranded insulated wire for an antenna.

  This is actually optional, since you can use a TV antenna or FM radio antenna by connecting our radio to one of the lead-in wires. But it's fun to throw your own wire up over a tree or on top of a house, and it makes the radio a little more portable.

• A block of wood or something similar for a base