Newbie question from New Zealand.

[Kiwijohn]

I'm new to detecting and new to the forum. Just got my ACE 250 from the US and had a couple of outings to get the hang of things... Would you believe my first real signal was a coin! NZ 5 cents.(Colour me hooked)
My question if this. Will I get a reliable signal with an object waved 'ABOVE' the coil?
That may sound dumb, but I'm thinking, on the beach I don't want to lay the ACE down on wet sand, just rest the coil there with the stem upright, then wave my handfull, or plastic scoop full of goodies over the top to confirm I have the riches in there. Any advice would be appreciated. Thanks.

 

[LuckyLarry]

Kiwi, your Ace, as with ALL IB machines - produces nearly the same field pattern on top of the detector as it does the bottom, the sides, the edge, etc. It does not look like a cone at all, nor does it look like two cones stacked on on top of the other back-to-back either. In fact with it's normal operation it is usually distorted and appears like a big 5 ft diameter potato with cancerous sores all over it, making it look like it is about ready to have internal convulsions or a Big Mack Attack. .

In fact it produces somewhat of a distorted type of configuration resembling a fat, 4-6' ft diameter elongated globe, of sorts, with the flattish coil in the middle of the thing and the radiation spewing away from the housing. Not all detectors have this near same configuration of radiation pattern of course, but for simplicity this is the closest example of what you get with most detectors. In most cases you will have a positive pattern under the coil and a negative configuration over the top. This is not just a magnetically charged radiation though, it is also an electrical field at work too, and it too contributes to what will be, or is, affected by the changes in (disturbance of) it's EMF and/or it's altered inductance into the soil, etc.

So to answer your question best, you could reasonably say that it would give you about an 80% close mirror of what you would find by just checking under the bottom of the coil instead. Neither of course are reliable ways to give someone better than a 70%-80% accurate reading on a target. Remember that (normally) if the field has not been substantially affected or disturbed somehow, there is negative voltage and magnetism on the top, and a positive voltage and magnetic field on the bottom. And yes, the negative side is normally a tad bit weaker than the positive end, just as it is with a bar magnet, or the earth itself, for example. Additionally, positive and negative voltage are both the same - with magnetism too both flowing freely unless they are "disturbed". Yours is a reasonably good way to check your targets, unless you are working in some certain types of ores, for example.

Hope this helps.

Larry

 

[Sandman]

Larry knows his stuff. What he says is true about the way the coils work.

Good Luck,
Sandman

 

[seas1to2]

I got a nickle from NZ about a year ago at the beach here in FL (usa).Read were they are no longer used,dime is the smallest coin used...yes what the others say about the coil,you can detect above the coil.

 

[Kiwijohn]

Thanks for your replies. And Larry thanks for an excellent description of the field shape. Swinging a giant
mutated potato on the end of stick brings a whole new meaning to detecting.

 

[greydigger]

so is a mxt a "IB" machine? and what does that mean?
and I have a weird potatoe search field on the end of my stick.

Means the "cone" theory is bogus.

...waiting for new input.

Grey

 

[LuckyLarry]

Good questions there Grey.


Yes, the "cone theory" is nothing but an idealist's rendition of blithering idiocy and lunacy put forth by an outhouse artist/dreamer....of sorts. The MXT, etc and about 99% of all metal detectors currently being sold and marketed are Induction Balance - otherwise known as "Ground Exclusion Balance" detectors. It's just a comfy way to say that the circuitry balances the positive/negative signal to the prevailing iron or other substance that would (might) interrupt it's otherwise ideal, perfect, or test-tube, clinical operand. If they are not balanced this way the field would have heck to pay staying operating as efficiently as would normally otherwise be possible.

In the case of Tesoro detectors and some cheaper White's, older Compasses, older Fishers with auto GB where there is no "manual" GB the super-quick circuitry takes over and retunes so fast that when we use a manual one we could not EVER keep up with it and them, not in 4 light years of effort and speed training - while using liquid meth as a backer. This is why some detectors that are a whole lot cheaper actually handle bad ground better than do some very expensive ones, and they often go deeper too.

And yes, an MXT is an IB machine, but so called GEB by it's maker, just for giggles and an explanation of it being able to balance the ground to coil signal, thereby omitting the iron signals (interruptions of it's field) from the iron, etc in the ground. This is why the field becomes all lumpy and distorted, because there is no such thing as idealism, save for in the minds of the artists, dreamers, and wishers. And yes, you do "have a wierd search field at the end of" your stick, even if you use the thing in a total vacuum or somewhere out in space away from any possible interference, although that is almost as imposssible, to say the least.

Larry