which is better in parks,sport fields and beachs,for finding coins and jewellery,yes i have read randy's site.the medium frequency concentric or the hf dd coil.i'm currently using the hf dd coil.i have never found any gold jewellery with it,maybe there wasn't any to find but it does get me to wondering am i using the right coil or frequency.i know that americans seem to favour the small 3khz coil to search for lost silver but here in australia nobody i know goes looking for predecimal currency with it,i could be wrong.our predecimal currency had silver in it and one still finds the odd one here and there,but nothing to rave about unless it's a holey dollar,he,he,he!emubob