Electronics Projects: How to Add an Antenna to a Crystal Radio Circuit
A good, long antenna is an electronic component vital to the successful operation of a crystal radio. In general, the longer the antenna, the better. If possible, try make your antenna at least 50′. Longer is better.
You can make your antenna from just about any type of wire, insulated or not. RadioShack sells a 60′ roll of 18-gauge, solid hook-up wire that’s perfect.
The best configuration for a crystal radio antenna is to run the wire horizontally between two supports as high off the ground as you can get them.
For your antenna, you probably won’t find actual poles. However if you look around, you should be able to find two suitable points to which you can connect the ends of your antenna. Fence posts, trees, basketball hoops, flag poles, swing sets, or almost any other tall structure will do the trick.
Notice that one end of the antenna wire must run to the ground to a convenient place where you can connect it to your crystal radio. You’ll need to run this wire to the location at which you intend to operate your radio.
Wood isn’t a great insulator, and most metals, of course, are excellent conductors. It’s vital that your antenna is well insulated from the ground. Thus, you must be careful about how you support the ends of the antenna wire to make sure you don’t inadvertently ground the antenna.
If you use insulated wire for the antenna, you can secure the ends to wood by using @@bf1/2″ eye screws available from any hardware store. Screw the eye screw into the wood, and then simply tie the end of the antenna wire to it.
If the wire is uninsulated, you’ll need to support it with something that doesn’t conduct electricity. A PVC pipe fitting makes a good insulator and can be found in the sprinkler parts department of a local hardware store. You can screw this fitting into wood or use duct tape or zip ties to secure it to metal, then loop your antenna wire through the fitting and tie it off.
A crystal radio is a relatively safe electronics project, but there are a few dangers associated with the antenna. Here are some things to be careful of:
Don’t string up your antenna in a thunderstorm! Lightning loves wires, and you don’t want to tempt Mother Nature by providing her with a convenient path to discharge her fury through.
Likewise, don’t operate your crystal radio in a thunderstorm!
Do not under any circumstances run your antenna wire anywhere near a power cable or other utility line. That’s a sure way to become a statistic.
Be very careful if you must climb a ladder to string your antenna.