Search Coils for Metal Detectors, page 10

Search Coil Swinging Discipline in Details:
Searchcoil Detection Pattern Effectiveness - Overlap Sweeps At Least 50% with Concentric Search Coils

(...CONTINUED from previous page)

Now let us take a closer look at more realistic stuff in relation to the electromagnetic detection field pattern of the concentric search coil. This cone-shaped pattern contains regions of decreasing effectiveness with respect to target size and depth as shown on illustration below.

Concentric Coil's Electromagnetic Field Detection Pattern

Concentric Coil's Electromagnetic Field Detection Pattern

Detection pattern effectiveness is directly proportional to the surface area of the target. In other words, you might be able to metal detect an iron bucket buried at two feet, but you will not detect a coin at the same depth.

If a dime is buried 7-8 inches deep, it would fit into the effective detection area of the concentric 8" coil, which would be approximately the size of a half-dollar as shown on illustration below (the dime is not up to scale and should be half the size in the picture).

Concentric Coil's Effective Detection Area for Coin-Sized Targets

Concentric Coil's Effective Detection Area for Coin-Sized Targets

With 50% overlap, the possibility exists that you can miss the coin during the next sweep. 75% overlapping of the previous sweep will greatly increase your chances that the most effective detection pattern area will not miss the dime.



Number of pages: < Previous | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | Next >


Source: "Detectorist" by Robert Sickler.