a volume "booster" of the signal that comes off a positively detected target that the Explorer has managed to locate.
These signals also get boosted when it has come off a target that is a hot rock or ones that can also be composed of concentrations of dense iron oxide or targets that are made up of other types of metal oxide concentrations.
It also amplifies a lot of other unwanted, spurious signals from other background sources.
Such "false"signals don't repeat when you pass the coil over what is or might seem, a possible target composed of "whole" metal or tangible oxide concentrations.
Other than naturally occurring metallic mineral concentrations, some targets can also be the completely oxidised remnants of man made objects that can prevent the Explorer from detecting through them or give the Explorer the impression it is a viable solid metal target.
This is especially so when such signals do not repeat at all even when a target may have been located and a detecting approach is done from any angel.
I think it's a good idea to dig a deep signal that repeats. It's most likely going to be a piece of non oxidized metal and there is the odd occasion that it is a piece oxidized metal(possibly a concentrated oxide).
I have actually been digging the smaller less broad signals that null the background threshold(variable volume of this as well ) with some interesting results.
In the past, I have simply walked over these target and never considered them as a possible viable target to dig.
Now I have to go back over all the places I've been to over the last 7 years and re hunt them by using this method of detecting.
GAIN is a control that gives a repeatable detected target an audible dynamic depth of field.
If you you correlate that with your depth meter it will also help determine the targets size, to a degree.
Set GAIN at it's highest level then you'll have less audible dynamic, as the signal of a detected target within a certain depth, will sound out loud as possible and just as loud as shallow target.
The volume control will reduce ALL or amplify ALL other sound controls of the Explorer, including the GAIN.
Hard Nosed Dave