Air Test vs Field Test

I have a question. I have seen videos of folks conducting air tests on their MDs while it seems that field tests are most commonly conducted to advise on the efficiency of a MD. What is the difference in results between the two tests? I'm more inclined toward the field test just because it's the real thing, but not sure about the difference in results.

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		Quote:			Posted by Cyberborikua
	I have a question. I have seen videos of folks conducting air tests on their MDs while it seems that field tests are most commonly conducted to advise on the efficiency of a MD. What is the difference in results between the two tests? I'm more inclined toward the field test just because it's the real thing, but not sure about the difference in results.

You're going to love the answer GD gives you on this one  

 (Actually, if you do a search using the search function you'll find that you can use the air tests to help you determine the specific search pattern characteristics of your particular detector and coil---but it is a bit more involved than the standard air tests you see in the videos where a person waves a target across the coil and says "Ok, this detector will pick up a quarter at 12 inches in an air test" since it involves determing how far from the coil the target is picked up in various positions across the full face of the coil.....)

But when it comes to just the air test you've seen on most of the videos, there good for A) verifying the machine works and B) given you an idea as to the sound and general reading the machine will give you for a target as well as the theoretical maximum depth.  The field test will give you a more accurate real world depth -- but even that is going to be approximate since it will vary with soil conditions.

BA

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I feel so, er, um, inadequate.

The air test is an ideal circumstance test where there is nothing in the way to cause your field to be less than perfect. In ground, sand or water, other factors interfere with your field. Things like soil components, rotting wood, tree roots, water in the soil and long decomposed iron can cause your field to be attenuated giving you a diminished return. On rare occasions, like when a gentle rain moistens the soil, you might even get enhanced returns from a VLF/TR or PI machine. Most other types suffer from water in the ground.

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Ahhh, GD, no reason to feel inadequate.....you did good 


 (although I was expecting something more along the lines of what you wrote in

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     )......

and to be honest what I was really thinking about was a topic occupant started last year when he wrote:
"occupant  "Winter is getting old.  I'm ready for Spring and some nice weather.  But, since I'm still stuck inside, I wanted to try an experiment that may prove valuable when it is time to get outside and begin Treasure Hunting again.

Time and again we have been told that the shape of the detector's search field beneath the coil would look like a 'snow cone' if we could see it. Pointing down into the ground like a "V".  I do recall reading one article that described it more as half of a basketball, which always seemed  more accurate to me. But I still didn't know for sure.  So, how much should I overlap my swings in order not to miss anything? The following experiment gave me the answer and forever changed the way I will use my detector." "   see

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     That got into the whole shape and depth of the search field thing in a way that even a non-techie like myself can appreciate. )

BA

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Interesting experiment by Occupant with the BH. I agree that the air test may yield ideal results whatever those are, good or bad. The real test, however, is the ground test in the various conditions. Thus, although the air test yields interesting results that may surprise one, there is no match to the real experience of detecting on the field. That is, the air test yields hypothetical results, but the field test brings tacit knowledge to the operator. One can conclude then that a knowledgeable operator makes the difference between a good and a mediocre hunt. Bottom line is detect, detect, detect and pay attention to and learn the behaviors of your MD. Too many MDs, too many technologies, but in the end it's up to the operator to make of it a good hobby tool. I guess 

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