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TELEPHONE_BUG

2014-11-19 08:46  
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TELEPHONE_BUG
Q1 is an oscillator tuned to a quiet spot in the FM broadcast band. Dc from the line powers the bug. Diodes D1 through D4 ensure proper polarity. R1 maintains a suitable voltage drop for the bug. Audio on the line causes incidental FM, which can be heard on an FM receiver tuned to the frequency of the oscillator.Warning: Use of this device for certain purposes could violate federal and/or state laws and subject the violator to prosecution.