DIY Electronics Projects: Easy Radio Receiver
There are plenty of radio project kits on the market, but it's much more satisfying to build one from scratch. Radio receivers are easy to build if you're able to follow directions and pay close attention. This model is dead simple and that makes it a good starting point for electronics hobbyists: it's cheap, it can be built on a budget, and it's a good idea if you're at a loss for what to build first. The parts and tools, if bought from an electronics retailer, will total no more than twenty dollars. If you happen to have some of these pa laying around the house - and most people do - you might not spend more than ten. To build it, you will need:
- One 15ft length of copper wire. The cheapest you're likely to find
- Pair of headphones
- Wire stripper
- Germanium diode
- Soldering iron and solder, or electrical tape
- Metal stake approx. 5 inches long
Take one 15ft length of wire and wrap it around the stake. Don't overlap or go back and forth: just make sure you get dense coils. Leave a foot or so unwrapped. Solder or tape the coil to the stake at either end. Look at the package the germanium diode came in: germanium diodes conduct current in only one direction. Connect the diode so that it connects current from the stake and out the end of the diode. Strip one inch of insulation from the end of the 15ft insulated wire. Connect this to the free end of the diode with solder or tape.
Finally, cut off the 'jack' end of the headphone cord (the part that you would ordinarily plug into an MP3 player or computer). This will expose two wires. Strip the headphone insulation to lay the two wires bare. Connect each headphone lead to each end of the diode. If the diode ends are too covered in tape to make contact with the headphone leads, connect the headphone leads to the exposed copper wire on either side instead. The 15ft insulated copper wire is your antenna: try stringing it between fence posts or chairs in order to maximize your reception.
Note that this radio may not work unless you live near an AM broadcasting station. If you cannot hear anything, try adjusting the antennae wire. If this doesn't work, then try connecting the wire to a large metal object. Be careful! Don't connect the wire to any electrical structures.
(picture courtesy of public-domain-image.com)