The Challenge: Make a radio from a saucepan
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How to Set Up and Use the Radio
After checking that all the connections are as clean as possible, touch the fine
coiled wire on the face of the crystal and listen in using the earpiece.
You should hear a click every time this wire is connected or disconnected.
If you hear nothing, try changing the contact position on the crystal. You'll
need to be patient. You'll also need to listen very carefully!
Next, slowly turn the saucepan handle and listen for a signal. If after a while
you hear nothing, try using half the number of turns on the coil. To do
this, undo the connection between the end of the coil and connector A, and
remake a connection between the center of the coil and connector A. If that
doesn't work, halve the number of coil turns again. When you do find
a station, mark the position of the handle on the board.
The capacitor is probably the most variable component. The gap between the plate
and the saucepan needs to be very small, but not so small that they touch.
The plate and saucepan need to be large enough to get a decent overlap (capacitance),
but not so large that there's little variability in capacitance, and
so won't tune very well.
Reception varies throughout the day. Short-wave signals tend to fade in and out, sometimes
so quickly that it sounds as if something has suddenly become disconnected.
If you wait awhile, any signal will usually return.