If your Electroscope® is not properly tuned you could miss a desired target. Here is a method I use to tune the Model 20 in a particular area.

Put a sample silver or gold target in front of you. Sweep the area that contains your specimens. If the scope attaches on one side or the other of your sample, adjust the tuning dial. Continue sweeping and adjusting until the target is dead center to the middle antenna, when the lock is achieved. Note the setting now. It could be any number and still the Model 20 will be perfectly tuned. As long as you stay in the general vicinity your scope is properly adjusted.

If you end up on #1 you will be running on low discrimination the whole time you are in the area, but don't despair. When you pick up a target in perfect tune you should box it in. Then turn your discrimination up to #10. Sweep over the target while on #10 to see how strong it is. If the target is no good, the lock will probably disappear.

If the target is still there, you can see how big it is before you dig. Start backing up. The further you back up the weaker the signal should get. As a general rule of thumb I use 1000 feet. If you can back up 1000 feet, maintaining the same intensity of the signal, then you have a major cache: GO FOR IT! If it is a coin you will lose it by about the time you get out 75-100 feet. Silver dollars will probably extend to 125 feet.