Are Air Tests of Any Value? Please Comment

[Michigan Badger]

I think the first thing we all like to do with a new machine is see how far from the coil we can "detect" a coin through the air.

Question:

Do air tests tell us anything at all about a detectors potential ability out in the field?

 

[U.K. Brian]

Its a pity you said potential. Good topic and I would say yes they are of value but not really a true indicator of in ground performance.
I'm a great believer in manufacturers returning to the old practise of saying coin X should be able to be detected at Y distance in air in all metal or at the Pre-Set control positions.
You can then get your new machine out the box and know something is up when you can only get half the quoted distance. There's machines going out either not well set up in the factory or with a large number of componants only just making spec. and some rather iffy coils. If your in a club you have the chance to try a coil swap or see if your doing something totally stupid. If your on your own at present you could spend months thinking your at fault and often sell the machine on and say on the net that on your ground a particular machine is rubbish.
If you do air tests and combine them with in ground you get the best of both worlds. Air tests alone are of little use as its easy for a manufacturer to go for maximum in air and ignore the effect of ground conditions or application of discrimination. We all know that there's machines on the market that don't air test with the bestl but lose little or no in ground depth.

 

[neilo]

Zeb it depends on how you do it.If the coil is put on the ground and the target is moved over the coil,the machine is having to compensate for the soil conditions as well.This is a far more acurate way of guaging the capacity of the machine.To just swing the coil over a target at variying heights in mid air is virtually useless. The ground conditions generally dictate the depth capabilities ?of the machine,some machines might give impressive air testing away from the ground but when ground conditions come into play they fail dismally.
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? seeya Neilo

 

[stoney56]

IMO, air tests are just good for showing max depth in the air while in all metal mode. Since all soil has various amounts of mineralizaion (some of which, you couldn't detect a silver dollar lying on top--well almost), it's only use is to get an educated guess as to where the break point is for various items are such as small gold rings break the disc. at about 3/3.5 on mine. There's a lot more to a machine than depth.

 

[bobm31]

I performed both air tests and in ground tests on my ACE250 with coins and got virtually the same results.

 

[stoney56]

I performed both air tests and in ground tests on my ACE250 with coins and got virtually the same results.

It may be due to that Garrtt is out of Texas as well and has used Texas soil for a baseline sensitivity test. Maybe?

 

[jeff of pa]

It Depends on the Detector.

In some Cases Like the Sovereign, The Detector

Supposedly Measures the content of the Ground, Versus the Object or Objects,

Then Decides IF it should Tell you it's there,

and in the case of Multiple Targets, and a degree of Discrimination,

Which one it should Report back to you on.
I THINK this is the reason you must work slower with the sovereign, to give it time to do all this.

I KNOW the Depth is definately better under ground then in air tests,

And in the case of Older targets there longer, even better.

 

[Michigan Badger]

I performed both air tests and in ground tests on my ACE250 with coins and got virtually the same results.

Years ago I tested the old TR's and found the same thing. Actually, I've never really checked any of my VLF machines.

At any rate, I hope you're right. I just took my Tesoro outdoors and laid several objects on the ground and did the air test thing. I backed sensitivity off just slightly and could easily detect a dug Indian cent at 10 inches. At this depth it doesn't read on the meter though. That meter stops at 9 inches. At 9 inches it reads on the bar graph "zinc" with numbers in the high 60's to low 70's. This is the same reading I get on dug wheat cents. New or clean pennies read 95 and zinc.

Once again, I hope it does go this deep in the soil! If so I'm looking forward to a very good spring.?