Question about ace250..and metal detectors in general

[Copperhead]

I was doing an air test with my recently purchased ace. First I scanned the floor in the coin mode. Then I put a penny down and scanned it. I got no hit on it until I was within about an inch of it, and only then when a certain part of the coil was over the target. I turned about 90 degrees to the penny and got a strong tone over 5 inches and with the coil over any part of it. Perplexed, I went to the basement and realized there was a large flexible air duct with a foil covering BELOW where I placed the penny. When I was sweeping parallel to the duct I got the poor signal, when I turned perpendicular I got the good signal. Is this due to the fact of the machine having a fixed ground balancing, something else, or something I am doing wrong ? I believe this would be a problem in the field if there was lot of trash in the area....i.e. ..my yard. Thanks.

 

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[Ricardo_NY1]

Re: Question about ace250..

I don't exactly know the technical reasons for the detectors behavior, but this is one more reason for me to cover areas from different directions.

 

[Hoosier Kingfisher]

Re: Question about ace250..

An airtest should be done with the coil in the air!! Lay it on the kitchen table and let the coil overhang a foot or so. Remove all jewelry from your hands.

 

[Sandman]

Re: Question about ace250..

You can not test the detector in the house with a target on the floor, to much metal nearby.

 

[Copperhead]

Re: Question about ace250..

Thanks for the replies...While I now understand that I shouldn't be air testing the machine on the floor...my question is really is about the performance of the machine given a large metal object under the target, is this normal? Will a coin be masked out by a metal object beneath it, and is that just related to my particular machine?

 

[khouse]

Re: Question about ace250..

You bet it will mask it. Not to mention all the iron, ie.- nails, screws and staples in the floor. Do your air test just like the DVD shows you. The 250 is a great detector. Learn it in the coin mode. Then move up to jewelry and relic mode.

 

[Copperhead]

Re: Question about ace250..

Thanks khouse. I appreciate you all for taking the time to respond to my post. I think I went about asking my question the wrong way. I'll try again. Let's forget about the air test and the floor. (I understand this was wrong). Say a coin is buried in the ground, with no other type of metal objects around it. Now say a coin buried in the ground has a piece of foil(or some other metal) UNDER it. Will there be a difference in my machine being able to detect it? If so WHY? I confess that I don't understand the principals of how metal detectors work, and maybe that's my problem. Is there somewhere that explains technically about how metal detectors work and what changes are taking place in their operation when discrimination and ground balancing are set? Thanks again.

 

[khouse]

The "clean" coin is not what you will be fighting in the field. When you get a hit on a coin with no other influences you will know in your gut that it's a good target. The problem is a lot of the time your good target is next to a bad one. This is where you need to know your detector. Your 250 has a feature some would pay $500 for alone. That's tone ID. If you get a trash beep in the foil range but every 3rd beep is a belltone. You need to see what that is. Depending on how long you have to hunt or your tolerance for digging trash. Just yesterday I hit a target that Id's all over the place but I could get a belltone sometimes 3 times in a row. I dug it up and the first thing I recovered was a 2 inch piece of steel wire. Next down about 3 inches was a 22 casing half rotten. I rechecked the hole and then I got a strong dime reading. Down 2 more inches and out popped a copper cent. Will you have results like this on all iffy beeps - no. But if you have the time and have already cherry picked the site then iffy beeps may get you another goodie or two.
PS: Listen for your coin beeps that try to come through the trash beeps.

 

[Sandman]

For more info on how metal detectors work, the book section of Western & Eastern Treasures advertises many that explain it so even I can understand.

What you want to visualize is a ball of energy going down from your coil and up too. Any object in the field is read by the receive section of the coil and reported or not depending on your discrimination. If two targets are there as Khouse states, both will be found as ONE object with the detector giving two or more different tones. Some times coming at it at a different angle or faster or slower speed changes the tone too due to the orientation of the objects.

That's in in a nut shell. The authors of the various books explain it better than I. But good luck and never stop reading or learning. I've been told by some that they don't buy the magazines because they take away from their profit..................

HH,
Sandman

 

[Ricardo_NY1]

Regarding the masking..........a good target (coin) will almost certainly be masked if it is laying above the target. When the trash is under the coin, your best bet will always be to be at a sensitivity where the trash under the good target is not getting picked up. Think about it like this, if your sens is set at high, it will pick up a can at 5 inches along with your coin at 2 inches.......and the signal will more than likely be mixed. The same situation with a lower sens will result in only the coin getting picked up and a clean signal. One of the most important lessons I have learned since I started is going over the same area using different sens settings and approaching from different directions. The ACE does a good job of telling you if there is a deeper object causing interference. You might note that sometimes you get a half or dollar signal at 6-8 inches along with a quick jump to a dime signal at 4. At this point the machine is telling you to lower your sens to avoid detecting that probably false half or dollar signal so it can pick up the dime at 4 inches cleanly.

 

[Copperhead]

Thank you for all your info, tips and explanations. I said it before, but I'll say it again..I really appreciate all of you for taking the time to respond to questions from inexperienced users. I've got lots to learn, but hopefully some day I'll gain enough knowledge to help someone else.

 

[khouse]

Copperhead,
One way to make it a little more fun is to guess in your head and visualize your target. Then dig it up and see how close you were. I do it everytime I dig. This will really hone your skills.