Here’s how to make a fantastic (and simple) AM radio, Grendel – “I just finished making quite possibly the world’s most simple radio. I had read a few HOWTOs for constructing a crystal radio. Some links offered the basic formulas for figuring the specs needed for the coil if you wanted to tune various frequencies. I purchased 3 spools of “Enamel-Coated Magnet Wire” from Radio Shack for ~$5, and picked up a crystal ear piece while at EPO in Houston.” [via] – Link.
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Other radio related projects – Link.
This is a classic “Foxhole radio” a good example is at http://hometown.aol.com/djadamson7/articles/foxhole.html