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| Joined: | Sep 22nd, 2008 |
| Location: | Doylestown, Pennsylvania USA |
| Posts: | 130 |
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The circuit you have posted needs a resistor from the diode to the base of the coil for the current to flow from the top of the coil through the diode and back to the coil .
The input jack of the recorder may not have a return to ground and the resister is necessary. The crystal earphone shown also needs the resistor because the nature of a crystal earphone is capacitive and will not present a proper load to the diode.
The tuning capacitor shown will tune radio stations that can block evp in the static noise. Leave it out or tune to quiet space between stations.
joecioppi