I read an article by "George Payne", the engineer that initially engineered the ground canceling, target id & discriminating circuitry. He stated that the best frequency to use for U.S. nickels & gold jewelry is 16.5 khz. If what he stated is fact, wouldn't it be logical to acquire a detector on or near 16.5 khz? One would believe that it would have an advantage. I am aware that there are many people that have found gold jewelry at frequencies much lower than the above. Just a thought to throw out into the forum.