As I understand it, the frequency is only one part of the equation, as there are other variables that are not fixed. eg. size or depth of gold, mineralization, coil size & type, moisture, phase of the moon (just kidding), etc. Lower frequency is generally better on conductive metals like silver & the longer wavelength gets better depth. Higher frequency is somewhat better on low conductivity metals (like gold and iron), better on small targets but more sensitive to ground mineralization. A detector in the middle is a compromise. In the field, what works best in one small spot can change just a few feet away, let alone across the country. I also understand that multi-frequency gold nugget detectors don't necessarily solve this problem either.
