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Posted: Mar 28th, 2009 08:13 PM |
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joecioppi![]()
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RHGHAngel wrote: Hey Hey!! Hi Angel, I'm a disabled electrical engineer who has been studying the paranormal for the last few years. The "Raudive" detector is an untuned crystal diode detector that folks have been connecting to recorders lately to pick up EVP voices. The use of the germanium diode has been popular because it has a low conduction voltage threshold which allows it to detect low level radio noise. The radio noise or atmospheric static is rectified by the diode and coupled to the recorder input. Since the noise currents have to pass through the diode to detect EVP sounds to record, the diode has to be connected to other components that provide a path for the signals to follow. A radio choke coil, diode, and resistor form a circular path for signal currents picked up by a small antenna. The diode detects sounds included in the noise and the sound signal appears across the resistor. The resistor is connected between the center wire of your mic cable and the shield braid return around the outside. That signal is then recorded by the recorder. I've attached a mspaint drawing of the connection diagram. I've built this into a mic plug with miniature components for other experimenters like yourself. Joe Attached Image (viewed 7576 times):
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