Coffee-Can Radar

As I stand on the side of the road, a couple of joggers stop to ask about the two coffee cans sprouting coaxial cables. "I\´m testing a home-brew radar," I explain, adding as they jog off, "you\´re showing up just fine." It reminded me of an old "Star Trek" episode in which Mr. Spock is transported back in time and must construct a futuristic electronic gadget using only 1930s-era vacuum-tube technology. "What on earth is that?" asks his landlady. "I am endeavoring, ma\´am, to construct a mnemonic memory circuit using stone knives and bearskins," he answers.