| Metal Detecting for fun or profit can be one | | | | transmits electricity rapidly many times per |
| of the most exciting and rewarding of | | | | second, first in one direction around the |
| hobbies. A metal detector can cost very | | | | coil, then in the other direction. The other |
| little, as low as $50 or higher that $400 for | | | | coil called the 'Receiver Coil' acts just |
| a top of the line model. This is one hobby | | | | like the name implies it receives frequencies |
| where you really do get what you pay for, | | | | or data that come or 'bounce' back from the |
| because the more expensive top of the line | | | | objects the transmitter coil detects in the |
| detectors use the most advanced technology | | | | search area. This type of Metal Detector is |
| and they have the best features available. | | | | great for it's ability for being able to |
| | | | distinguish between different types of |
| Metal Detectors use one of three types of | | | | metals. |
| technology: | | | | |
| | | | The first metal detector my wife and I bought |
| BFO (Beat Frequency Oscillation) - Metal | | | | together cost about $69.00 it was one of them |
| Detectors using BFO technology have two coils | | | | cheap ones that used the 'BFO' technology. |
| of wire, one large coil is located in the | | | | This was one of them metal detectors you see |
| search coil of the detector, the other small | | | | in the magazines that sell other household |
| coil of wire is located within the System | | | | items, etc. You can buy cheap metal detectors |
| Control Pack. Each coil of wire is connected | | | | like these at most Radio Shack stores, and |
| to an oscillator that produces pulses of | | | | some K Marts and Wal Marts. The first day we |
| current. These pulses of current pass through | | | | took the metal detector outside we started |
| the coils generating radio waves. A receiver | | | | finding some neet things and my wife and I |
| housed within the System Control Pack | | | | were hooked. We did find our share of junk |
| receives the radio waves and makes a series | | | | items in the yard, like aluminum foil, nails |
| of tones based upon the frequencies of the | | | | and the usual pull tabs and junk metal. But |
| radio waves. When the detector search coil | | | | we also found 7 old diecast cars in great |
| passes over a coin or other metal item a | | | | condition. They were all different and were |
| magnetic field is created around the coin or | | | | 'TOOTSIE' diecast vehicles. I looked on eBay |
| metal item, this magnetic field causes | | | | and the bunch was worth around $15 or more. |
| interference with the frequency of the radio | | | | We also found a 1961 silver Roosevelt dime in |
| waves generated by the search coil. And | | | | fine condition, in our yard, plus the usual |
| changes the tone produced by the reciever. | | | | pennies. |
| | | | |
| Metal Detectors using BFO technology are the | | | | After reading about how the 3 different types |
| ones your likely to get when paying under | | | | of Metal Detector technologies work and |
| $100 for, that's right, the cheapies. The BFO | | | | differ from each other, you must decide how |
| technology is the easiest and cheapest to | | | | or what you will be mostly using your metal |
| make, thus the prices of the detectors are | | | | detector for. Will you be hunting for small |
| cheap. The only problem is, BFO technology is | | | | objects like coins, jewelry and gold nuggets, |
| very limited when compared to PI and BFO | | | | or searching for a large cache or object. The |
| detectors, and the ability to distinguish | | | | things you may want to use your detector for, |
| between junk metals and silver or other coins | | | | play one of the most important factors |
| is very poor. | | | | besides pricing in deciding what type of |
| | | | detector to buy. Most folks want a detector |
| PI (Pulse Induction) - Metal Detectors using | | | | that is great at finding coins, gold nuggets, |
| PI technology sometimes use a single coil or | | | | and jewelry on the land and in small creeks |
| a series of coils working together as a | | | | and streams, this would be a detector using |
| transmitter and receiver. Short bursts of | | | | 'VLF' technology. Almost all of the modern |
| electrical current are send through a coil of | | | | detectors have a waterproof search coil which |
| wire, causing a magnetic field. When the | | | | make searching in shallow creeks and streams |
| burst of electrical current ends the magnetic | | | | possible. |
| field reverses polarity. A sharp electrical | | | | |
| spike is created, then more pulses are | | | | There is Computer Software that is made just |
| created, the whole process repeats and works | | | | for the hobby of Metal Detecting. The |
| like a series of echoes, giving a different | | | | software is called: Metal Detector - Treasure |
| report or echo depending upon the metal it | | | | Hunter Professional, and may be seen at this |
| encounters. This type of metal detector is | | | | website address: |
| not very good for discrimination between | | | | |
| different types of metals or coins, but it is | | | | By Robert W. Benjamin |
| good to use where some other types of metal | | | | |
| detectors have trouble working, such as in | | | | Copyright © 2005 |
| salt-water, and metals can be detected much | | | | |
| deeper with this technology than the others. | | | | You may publish this article in your ezine, |
| | | | newsletter on your web site as long as it is |
| VLF (Very Low Frequency) - Metal Detectors | | | | reprinted in its entirety and without |
| using this technology have two search coils. | | | | modification except for formatting needs or |
| One coil called the 'transmitter coil' | | | | grammar corrections. |