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"BFO (beat frequency oscillator) metal detectors use two oscillators, each of which produces a radio frequency. One of these oscillators uses a coil of wire that we call the search loop. The second oscillator uses a much smaller coil of wire, and is usually inside the control box and is called the reference oscillator. By adjusting the oscillators so their frequencies are very nearly the same, the difference between them is made audible as a beat note, this beat note changes slightly when the search loop is moved over or near to a piece of metal." Link.
Build your own metal detector...
"BFO (beat frequency oscillator) metal detectors use two oscillators, each of which produces a radio frequency. One of these oscillators uses a coil of wire that we call the search loop. The second oscillator uses a much smaller coil of wire, and is usually inside the control box and is called the reference oscillator. By adjusting the oscillators so their frequencies are very nearly the same, the difference between them is made audible as a beat note, this beat note changes slightly when the search loop is moved over or near to a piece of metal." Link.
Posted by Phillip Torrone |
Jan 10, 2006 05:50 AM
DIY Projects, Electronics, Science |
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This is a pretty schematic for building a BFO type metal detector, we also have some schematics and other resources on our site DetectorX Metal Detecting drop by and check some of the information out.
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Make magazine is one of the greatest magazines ever published. My only wish.. that it came out more than 4 issues a year. With that said, I'm a detector nut, and this looks like a great project!!!
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