Re: Just what is the purpose of a "probe"?
well it is used to probe the ground for a solid object. It is esp. useful when digging in parks and school yards, or shall I say on lawns of any type. It lets you know that your pinpointing is not way off and that the object is either on surface or at say 5" deep.
I always use a probe and the main reason now is to exactly mark the hot spot on my DD coil before I pull the coil away. this way i won't start the hole 3-5" off the mark and risk damaging a great coin OR just flat out digging in wrong place.
If you probe the ground and get no solid hits - you know you're way off, or probably have a big chunk of iron off to the side of PP area.
It also helps when you have a coin spill of multiple coins in same area. You can find coins that are close together under a your standard sized coil. Realize that 4-5 coins in a 8" diameter are not easy to pinpoint. And if you leave the ground looking like the Caddyshack gopher was there - you'll soon find that spot off limits to MD'ing of any kind.
I would never hunt any lawn without a coin probe. When you get done with a dig on grass - no one should know you were ever there. That's how you'd want your lawn to look... Remember the golden rule!