Science Buddies: "Ask an Expert"

Is it possible to have a crystal radio circuit without a ground? Or are there any alternatives to a ground?

JonathanBD - Unfortunately, a ground of some sort is required to receive any meaningful AM broadcast. Unless you were extremely close to the transmitting antenna, no meaningful signal strength could be demodulated into the audio component. The ground does not have to be an earthen connection, and often a water pipe or grounded appliance might suffice to get acceptable signal strength that could be heard in the earphones. A very sensitive, high impedence earphone will also improve reception. Because there is no RF or AF amplification in a simple crystal set, the kind of signals we are talking about are mere millivolts. Hope this helps.

Rick Marz