things you'll need:
1 16 oz. sturdy plastic bottle, 5 to 7 inches long
50 ft. 22-18 gauge enamel-coated magnet wire
1 germanium diode
A telephone handset
1 Set of alligator jumpers
50 to 100 ft. stranded insulated wire (antenna, optional)
Instructions
1
Use an icepick and make two holes 1/2 inch apart near the top of the bottle. Make two holes the same way near the bottom of the bottle. Try to make the holes only slightly larger than the wire.
2
Insert the wire and thread it through the bottom holes. Pull about 8 inches of wire out. Use the long end of the wire and wrap it around the bottle five times keeping each round close to the previous one. Stop and wrap the wire around a pencil to make a loop. Leave the pencil in place temporarily.
3
Wind the wire another five times and make another loop. Keep wrapping the bottle five turns at a time making a loop around the pencil every five turns until the bottle is completely wrapped in wire down to the second set of holes at the bottom. Trim the end of the wire to 8 inches and thread it through the two bottom holes.
4
Remove the pencil once the bottle is completely wrapped in wire. Use sandpaper to strip the insulation from the tips of the enameled wire and from the small loops or "taps" made around the pencil. Use a sharp knife to remove the insulation from vinyl-coated wire.
5
Solder the germanium diode to the bottom wire. Twist the wires and tape them, or use alligator jumpers instead of soldering, though soldering is best.
6
Cut the end off the telephone handset cord. Remove one of the modular connectors and find four wires inside. Solder either the yellow or black wire to the Germanium diode. Use the remaining wire (yellow or black) and solder it to the wire at the top of the bottle.
7
Clip an alligator jumper to one of the taps on the coil and clip the other end of the antenna. Join a second alligator clip to the wire at the top of the bottle (the ground wire.) Listen to different radio stations on the telephone handset by clipping the alligator to the other taps on the coil.
things you'll need:
Long wire for antenna
Small cardboard tube
Magnet wire
Alligator clip
Copper penny
Long wire for grounding
Earpiece
Square piece of Styrofoam or cardboard
Tacks or glue
Wire cutter or knife
Short wire
Main Parts
1
Wrap the magnet wire around the length of the cardboard tube about 100 to 150 times. Leave enough room on at least one end to secure the tube to the Styrofoam.
2
Attach one end of the magnet wire that comes off the tube to the antenna wire by wrapping the ends of the wires together.
3
Attach the other end of the magnet wire that comes of the tube to the ground wire by wrapping the ends of the wires together. This wire will run from your radio to metal that eventually contacts the earth (hence, the term ground wire). Attaching the ground wire reduces static electricity in the radio circuit that can cause interference.
4
Glue or tack the cardboard tube in place on the Styrofoam.
Additional Wires and Parts
1
Cut the connector end off the earpiece and trim back insulation from the wire a bit. Wrap the exposed earpiece wire to the joint of the magnet and ground wires.
2
Attach the alligator clip to the joint of the earpiece, magnet and ground wires.
3
Wrap the tip of the short wire to the joint between the magnet wire and antenna wire. The short wire will connect the magnet and antenna wires to the transistor of the radio (the copper penny).
4
Heat the copper penny in a flame until it turns black with carbon. Connect the second end of the alligator clip to the penny and glue the penny in place on the Styrofoam.
5
Secure the ground wire to any metal that goes into the ground.
6
Put the earpiece in your ear and touch the short wire that runs off the magnet wire joint to the carbonized penny. You should be able to pick up at least a local radio station.
Any type of wire will do for the antenna, ground and short wire. Get wires that are not too thin and that are made of a metal that conducts well.
You will need very high heat to get carbon on the penny. Take the necessary precautions to avoid being burned