Experiment 31: One Radio, No Solder, No Power
264 Chapter 5
earphone. A normal modern earphone or headphone will not work in this circuit.
The return wire from the headphone is connected to a jumper wire, the other
end of which can be clipped to any of the taps in your coil.
One last modification, and you’ll be ready to tune in. You have to ground the
jumper wire. By this I mean connect it to something that literally goes into
the ground. A cold-water pipe is the most commonly mentioned option, but
(duh!) this will work only if the pipe is made of metal. Because a lot of plumb-
ing these days is plastic, check under the sink to see if you have copper pipes
before you try using a faucet for your ground.
Another option is to attach the wire to the screw in the cover plate of an elec-
trical outlet, as the electrical system in your house is ultimately grounded. But
the sure-fire way to get a good ground connection is to go outside and ham-
mer a 4-foot copper-clad grounding stake into reasonably moist earth. Any
wholesale electrical supply house should be able to sell you a stake. They’re
commonly used to ground welding equipment.Figure 5-65. The simple pleasure of picking up a radio signal with ultra-simple components
and no additional power.