Metal Detecting - Understanding the Technology is Important

Metal Detecting for fun or profit can be one of the most exciting and rewarding of hobbies. A metal detector can cost very little, as low as $50 or higher that $400 for a top of the line model. This is one hobby where you really do get what you pay for, because the more expensive top of the line detectors use the most advanced technology and they have the best features available.

Metal Detectors use one of three types of technology:

BFO (Beat Frequency Oscillation) - Metal Detectors using BFO technology have two coils of wire, one large coil is located in the search coil of the detector, the other small coil of wire is located within the System Control Pack. Each coil of wire is connected to an oscillator that produces pulses of current. These pulses of current pass through the coils generating radio waves. A receiver housed within the System Control Pack receives the radio waves and makes a series of tones based upon the frequencies of the radio waves. When the detector search coil passes over a coin or other metal item a magnetic field is created around the coin or metal item, this magnetic field causes interference with the frequency of the radio waves generated by the search coil. And changes the tone produced by the reciever.
Metal Detectors using BFO technology are the ones your likely to get when paying under $100 for, that's right, the cheapies. The BFO technology is the easiest and cheapest to make, thus the prices of the detectors are cheap. The only problem is, BFO technology is very limited when compared to PI and BFO detectors, and the ability to distinguish between junk metals and silver or other coins is very poor.