How to Build a Makeshift Radio Receiver
Building a crystal radio has long been a popular selection for science projects .One of the things that makes crystal radios so interesting is the fact that you don't need to worry about hooking them up to an external power source such as batteries or an electrical outlet. They run on the power provided by the radio waves that the antenna captures. The fact that they contain very little in the way of movable parts makes them even easier to build.
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Things You'll Need
- Plastic bottle or oatmeal container
- Nail or other sharp object
- #24 or #22 insulated wire
- Electrical or masking tape
- Pen or pencil
- Wire cutters
- Germanium diode
- Phone receiver
- Battery (AA, C, or D)
- Soldering gun
- Alligator clip leads
- 50-100 feet of stranded insulated wire
Instructions
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1
Using a nail or other sharp object, poke two small holes in the top of the plastic bottle or oatmeal container about 1/2 an inch from the top and about 1/2 an inch apart from each other. Repeat this step at the bottom of the container.
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2
Slide the wire through the two holes at the top and pull about 8 to 12 inches of wire through to the other side. Place a piece of tape over the wire where it goes through the holes to keep it in place.
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3
Wrap the long side of the wire around the top of the container five times.
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4
Wrap a small loop of wire around the pen or pencil.
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5
Wrap the wire around the container five more times, then wrap another loop around the pen or pencil. Keep doing this until the whole container is wrapped in wire and you've reached the two holes you punched in the bottom of the container.
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6
Measure off 8 to 12 inches of wire (the same amount you used at the top) and cut the wire.
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Thread the extra length of wire through the two holes at the bottom of the container the same way you did at the top.
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8
Remove the insulation from the last inch of the ends of the wires, as well as the loops sticking out on the side of the container.
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Hook the Germanium diode up to the wire at the bottom of the container (you can solder them together or wrap the wires and cover them with tape).
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10
Get the phone receiver, and cut off the plastic adapter that plugs into the phone jack.
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11
Check the wires inside the insulated phone cord. If there are yellow and black wires, these are the ones that you want to use. If they're all the same color, take the insulation off the wires, and test them by touching them on a AA , C or D battery (put one wire on the + end and one on the - end). When you hear a clicking sound in the phone receiver, those are the wires that you want.
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12
Attach one of the wires from the phone receiver to the wire of the Germanium diode that's not hooked up to the wire from the container (it's better to solder this wire than twist-and-tape).
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13
Attach the other wire from the phone receiver to the wire at the top of the container (soldering it if possible).
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14
Go outside and set up the antenna by taking the stranded insulated wire and hooking it up to a TV antenna or throwing it up in a tree or over a roof. Do not under any circumstances use a live power line as an antenna.
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15
Go back inside, and hook an alligator clip lead to the antenna, and the other end to one of the loops sticking out on the side of the container.
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Hook another alligator clip lead to the wire at the top of the container, and the other end to a cold water pipe or another metal object that leads into the ground. Do not under any circumstances use a live power line as a ground wire.
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17
Listen to the phone receiver, and you should be able to hear a radio station in the earpiece. If you move the alligator clip to different loops on the side of the container, you'll be able to get different stations.
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Tips & Warnings
If you make the antenna higher or longer, you should be able to get better reception.
If you want, mount the radio to a wooden board to improve its appearance.
Do not tap the radio into a live electric line. You could cause serious harm to yourself, or even die.
You should unhook the radio from the antenna (or better yet bring the antenna inside) during a storm.
