Higher frequency vlf metal detectors operate at sometimes 10 times the power of lower frequency metal detectors, hence the greater the field of radiation (AKA radiated field), the greater the ability to find smaller items. This is why higher frequencies find smaller nuggets than lower frequency ones, because they are running at higher gain (power). It has absolutely nothing to do with the actual operating frequency of the unit. This is why the new GB3 for example, at 19 Khz, will find tiny nuggets just as easily as a 52 or 70Khz freq.
Just as George Payne and Jack Gifford say in their engineers notes this one is going to tell you the same; That the air depth of ANY vlf is the best indicator of the ground depth potential of said detector. Here is how it works:
The metal detector produces a field of magnetic lines of force and strength (AKA waveforms, or "waves"). Along with this field when weak in intensity the detector is incapable of reading the signal because the tiny nugget cannot carry the signal. When the field is higher in radiation intensity (meaning the distance it radiates because it is running more powerfully) it is also making the tiny nuggets, etc easier to read and recognize, due to their increased ability to carry inducted electrical and magnetic fields. When a radiated field is produced that is weak the nuggets will not be recognized easily or at all - due to their inability to carry the transmitted electrical and magnetic fields.
The air depth of a metal detector is thereby directly (not inversely or disproportionately) indicative of a metal detector's transmitting power and air/depth potential - and the resulting field intensity can (ALWAYS) be recognized by by air depth readings. Hence, the better the air depth readings the better the ground depth readings will likely be. This is why many metal detectors running freqs of between 1 and 30 Khz most often all have nearly identical air depths along with nearly identical ground depths when they are all running with identical power (gain). It's simply because they all have the same power and depth of field, nothing more.
So to make it simpler to understand, the air depth readings are only showing the actual power (gain) of a detector's output. The air depth of a detector is directly proportionate to it's ground depth potential, although both air and ground uses are ALWAYS decreased by field disturbances and interferences such as any mineral that it encounters i.e. iron, copper, aluminum, etc. They are also degraded (reduced in power) by other interferences such as 60 cycle electricity, radar, other EMF's, x-rays, radar, etc.
There are stories about some detectors going deeper in the ground than in air but those stories are merely fabrications, nothing more. It is in all practical sense - impossible for this to happen unless a target has somehow spread itself into a wider pattern somehow, and I'm not talking about halos either. Halos are merely ions and molecules that have bled off on mostly iron and to a much lesser degree some semi-precious metals.
The most popular/most used nugget hunter in Arizona, Washington, Nevada, and Oregon is the Fisher GoldBug2. Even the detector sales place here uses it instead of their White's, Tesoros, Minelabs, and nearly nobody uses a Garrett here, the soil is too mineralized for them. Whites main plant is right down the street.
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