I've been trying to learn the DFX. I finally found my first silver quarter!!!! I've been changing programs when it happened. Now, my question is....I was using the standard 950 coil....I was getting silver dimes down at about 5-6"...do I have to change the program if I change coils? I put on a 12 1/2" excel2 coil on and I seem to be having trouble finding anything...I get the signals but when I go to dig them...nothing is there. I didn't change any settings,I just changed the coil????Any advise would be appreciated, Chuck.