Project XTAL Radio – Parts Acquisition
Rules:
1. No money can be spent on this project.
2. All parts must be recycled.
Parts:
1. insulated wire – 30’ to 90’ – enamel or plastic coated wire
2. coil form – can be from paper towels, toilet paper, or PVC; 1” to 4” in diameter
3. two aluminum cans
4. aluminum foil
5. tape – clear mailing tape is best
6. detector - germanium diode – the “crystal” for the crystal (xtal) radio
7. board – 8” X 8” is a good size – thick enough so screw/tacks do not penetrate to the opposite side
8. paper clips – ten
9. wood screws – 15
10. earphone or ear piece
All of the above parts must be acquired from something that would normally be thrown away. Go on a
scavenger hunt for the parts.
The wire for the coil must be insulated; using wire without insulation will render the crystal radio inoperable.
30’ to 90’ feet of wire is required to make the coil. Old electric motors, generators, alternators and transformers
are great sources for enamel-coated wire. Discarded speaker wire, lightweight power cords, and even the wires
striped from a computer keyboard cable are other sources of wire. If one complete length of wire is not
obtainable, it is ok to connect wires together, even if the size is slightly different. When connecting different
wires together for the required length it should be of the same type, all enamel coated or all plastic covered.
Pictured below is a transformer on the left and a computer power supply on the right. The yellow arrows
indicate parts that contain usable wire.
The form for the coil is dependent on the wire type and size. Enamel coated wire 28 to 18 gauge requires a form
of 1 to 3 inches in diameter and plastic coated wire needs a form of 3 to 5 inches in diameter. The classic toilet
paper roll tube, used mailing tubes, and scrap PVC all do nicely for coil forms.
