From the Blog

Metal Detector Discrimination Revisited


Having come into the hobby of metal detecting in the pre discriminator era, I learned quickly to appreciate a basic discriminating metal detector. However, not knowing the nuances of discrimination, I am confident that I used too much (too frequently) and many goals that others who were patient enough in learning to distinguishing targets by sound differences, found what I missed. A major treasure hunting experience dramatically changed my use of discrimination.

In 1978, I had a monumental opportunity to hunt a large city block area that housed a high school from 1917 to 1964. The property was sold after the school facility was destroyed in 1964 and this built-up city block was a play area for many children of lower income level families that lived in that community. September of 1978, the owner of the property bought in heavy equipment and began lowering the entire block down to the street level of all the rest of the neighborhood. Tons of dirt were removed every day and every day opened up new treasure possibilities. I obtained permission to come in every day after the workers left and metal detect that entire property. I had been researching about discrimination systems on detectors of that time, and decided to back off to minimal small-foil levels. I did dig a lot of trash, but over the next three months I dug over 1000 keeper coins from the former school yard and 283 predated 1940, including 40 V Nickels and 73 partial and full date Buffalo nickels that many other hobbyist missed by using too much discrimination. This area produced my oldest authenticated coin find, a bronze half shekel of 69 AD and my only 1950 D nickel find. I learned a big lesson about discrimination during that three month period. Having technology that can perform wonders is great but learning when and how to properly use it makes the user a wiser coin hunter and pays great dividends. The three month coin finds there are worth more than $ 5000.00 dollars, and less discrimination played a great part in this very profitable venture. Less than a month ago I applied this knowledge to a new entry-level metal detector, the Fisher F2.

I wanted to do a review of this latest addition to the Fisher line. For $ 199.00 Fisher was offering a very high tech instrument with a bonus 4 "coil. Of the many technical features of the unit I was impressed that a four-tone target ID system was included. and yes, lowering the discrimination, I wanted to see how well this ID system worked. curve but the technology of the F2 came to my aid as the notch system erased the iffy problems. I took the F2 to a foundry in Tarpon Springs. and this one was no exception. Machine parts were both shallow and deep and only a few inches apart. Using the 4 "coil I located four old nickels, three silver dimes, two wheat cents and a 1898 Barber Half dollar. The two hour hunt was worthwhile and the F2 was an incredible starter machine. Many of the good finds were 5-7 inches deep and the small coil cave clear signals on all of them. I was able to correctly ID by sound all four nickels and two of the three dimes. The third dime was standing on edge and read as junk to me and as a zinc cent on the F2 screen display.

In summary, use less discrimination and you will go deeper and find many targets that you have missed. Some old sites can be revised and be like new places to detect. Here's to "diggin it"! Larry

Source by Larry E. Smith