Let me begin by saying that I am a BIG fan of DD coils. I hunt a LOT of super trashy areas (ie. within the foundation walls of burned out houses, barns, etc.). I have found that the conical or mono coils have troubles here, even the smaller ones. Target masking occurs quite often. I first started using the White's DD coils and was doing okay. However, I heard about the Excellerator coils and tried them out. I did air-test depth and pattern comparisons w/ the White's 4x6 and 6x9 coils against the 5 and 8 inch Excel. respectively. In short, what I found was that the Excellerator coils gave 11/4 to 11/2 inch better depth and better coverage at depth (ie. on the 8" Excel. and 6x9 White's for example the "coverage" at max. depth was only 11/4-11/2 inches wide for the 6x9,while the 8" Excel. coil was almost 3" wide (and don't forget that this was about 11/2" deeper). Air tests are NOT the final answer w/ metal detectors. However, I've found this to holds true in the field w/ undug targets. These are the best coils that I have found for depth, target ID, target separation, etc.....Hopes this helps. Phil.
