Big Boys Hobbies

Air test comparisons?

D

dutchroots

Full Member
Joined
Jan 16, 2007
Messages
215
Location
West Michigan
Has anyone done air test or bench test comparisons between different models of detectors? I haven't come across too many videos like that on youtube.

Since winter has settled in (in a big way) I thought I might do some comparisons with my 3 machines.

Garrett Ace 250 with stock coil and sniper coil
Whites XLT with stock coil and 12" hotshot coil
Whites MXT with stock coil and Super 12" coil

Anybody interested in the results? Have any suggestions on how to do the tests and what items to use?

Chris
 
Yup... I did an air test comparison between by ACE and X-Terra 30. Items I tested were all modern clad (I had no older coins), pull tab, foil, .925 silver ring, and a 14k gold chain.
 
I would be really interested in an air test between these machines. I have a spectrum XLT and was always wondering how it performed compared to a MXT. Will you be testing the Spectrum XLT or E-series XLT?
 
tony48 said:
Will you be testing the Spectrum XLT or E-series XLT?
Click to expand...

I have a Spectrum XLT, but was always told there wasn't much difference between it and the E-series.

I'm supposed to start construction on a new house on Monday but if I chicken out and stay home because of the nasty weather I'll try to do some testing and get it on video.
 
sectshun8 said:
Yup... I did an air test comparison between by ACE and X-Terra 30. Items I tested were all modern clad (I had no older coins), pull tab, foil, .925 silver ring, and a 14k gold chain.
Click to expand...

Are those results posted on the board here somewhere? If so, I'll search them out.

I've got modern clad, might throw in a few Canadian coins and the new American dollar coin. Somewhere I've got a Mercury dime and an Indian head penny - unfortunately these were purchased and not found in the ground. Also add some trash like pull tabs, foil and hair pins. And then there are some finds I made in England, like a hammered silver coin, old coppers, buttons, etc. Yikes, this testing could take a while! :D
 
dutchroots said:
I have a Spectrum XLT, but was always told there wasn't much difference between it and the E-series.

I'm supposed to start construction on a new house on Monday but if I chicken out and stay home because of the nasty weather I'll try to do some testing and get it on video.
Click to expand...

I always thought that too until someone at a local Metal detecting hunt came up to me and said that the Spectrums are better because they have a Texas Instruments chip in them and the e-series don't. Not quite sure about that though:?:
 
No, the results of the air test are not posted, but I mean... things rang up as expected. On the ACE, the coins came up in the respective areas on the dispaly. And on the X-Terra, the coins rang up as the VDI numbers I had from a chart. So as far as air testing, both were accurate on coins. Gold and silver rang up as expected also.
 
There's air test figures all over the internet for most machines but air doesn't relate to ground performance.

The E-Series XLT had a new decal and a price increase over the original XLT.
Not one fraction of depth or discrimination improvement though you can scan through the menu's a little faster as the display chip was changed. Last production runs of the original XLT also had the faster chip.

Best Spectrum version remains the "Slimline" long box Spectrum but the drawback with this model is less programme slots and the battery system made it a bit heavier. (Get the last production runs of this machine and the handle was mounted further along the shaft giving a better balance).
 
tony48 said:
I always thought that too until someone at a local Metal detecting hunt came up to me and said that the Spectrums are better because they have a Texas Instruments chip in them and the e-series don't. Not quite sure about that though:?:
Click to expand...
Like you, I wouldn't put much faith in that (Voodoo?) thought.
 
You may do air tests, but most of us know they arent worth beans except maybe to adjust settings. With all the influences of EMI, minerals, trash, settings, and style of hunting those air tests just wont be the same as putting the coil to the ground. Id feel more confortable hearing from some test garden results. These results allow the detector to process, ground balance, and disc properly giving a more realistic result. If you plan on buying a detector based on air tests you are going to get the biggest disappointment.
 
dewcon said:
You may do air tests, but most of us know they arent worth beans except maybe to adjust settings. With all the influences of EMI, minerals, trash, settings, and style of hunting those air tests just wont be the same as putting the coil to the ground. Id feel more confortable hearing from some test garden results. These results allow the detector to process, ground balance, and disc properly giving a more realistic result. If you plan on buying a detector based on air tests you are going to get the biggest disappointment.
Click to expand...
I agree. If you don't believe it, try air-testing a PI machine sometime. My PI will hardly find a dime in the air if you tape it to the coil, but it'll send me to China after a tiny silver ear ring in the sand.
 
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I've never owned a PI detector so I can't comment on how they air test, but you can learn from the air tests of the VLF's.

No an air test won't tell you how well your detector will preform in the field, but it will give you a rough idea of whats possible.
 
Lowjiber said:
Like you, I wouldn't put much faith in that (Voodoo?) thought.
Click to expand...

With that being said, does anyone know what the achievable depths are on a dime/penny in the ground with an XLT? I have never burried a coin just to see this and when I go detecting, I am not sure if there are not alot of deep coins or if I am missing them?:?:
 
I feel the same way. My M6 should be able to go deeper than 4 inches but thats as deep as I can find coins with it. I know air tests are not a real world test, but heres an air test I just did with the M6, MXT and, Prizm IV, using U.S. coins.
 
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The air test of around two hundred different machines that was conducted, "Testy" something, placed the XLT which had just come out, as best performing detector of all at that time.
Points were awarded for each item's air result then the whole lot added up. The XLT did best but was noted as having one of the higher loses of depth "in ground".

The huge Belgium test of last year proved that air tests are fit for only one purpose....to test a new machine then keep the test data and re check every few months to see if the detector is failing/coil going off tune etc.

Many of the detectors had excellent air performance but in ground had no pickup on certain targets what so ever. There's no check on the effects of minerals, iron see through, target masking etc.
 
Hmm, well I knew air tests weren't conclusive when compared to in the ground conditions but I thought there would be at least some relationship in the comparisons. In other words, if one machine could detect a penny in the air at 10" and another would pick it up at only 4", then it would seem logical that the 10" machine would also be better in ground conditions.

If that is not the case then air tests aren't good for much except possibly impressing newbies who are looking to buy a detector.

Bajanik, thanks for the chart! I was going to try something similar.
 
Again I say air tests do have value. Use just a bit of common sense to understand why.

For example. If you use tone ID then air tests will tell you what targets have what tones. Same tones in the air or ground.

Target ID: My DFX gives me the same target ID on a target in the air or in the ground, up to a certain depth of course. A nickle is a 21 in both cases, unless deeper than conditions allow. As such, air tests can also be used to see where different targets read, AND allows you to experiment with discrimination settings with a good idea of how they will read AND be discriminated in the ground.

A little common sense goes a long ways.

In fact I'd be more apt to believe the only thing you can't learn from an air test is how deep it will go in the ground.
 
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dutchroots said:
Hmm, well I knew air tests weren't conclusive when compared to in the ground conditions but I thought there would be at least some relationship in the comparisons. In other words, if one machine could detect a penny in the air at 10" and another would pick it up at only 4", then it would seem logical that the 10" machine would also be better in ground conditions.
Click to expand...

Think about using your high-beam headlights in the fog. What happens? The real question is how well do these detectors deal with mineralization and salt? The air test represents a zero mineralization scenario. To much sensitivity can also distort discrimination response from the detector. There are a lot of factors that go into finding a deep coin. Air testing can be a great learning tools as long as you keep in mind that it does not for the most part represent a real world target scenario. Garden testing is much more accurate but does not account for the time factor and the soil matrix. As you find targets in the field is the ideal test situation. Mark a good target and come back with the rest of your equipment and test away. Dig the target and measure the depth. These are the results I like to see.

Keep Swing'in
Jack
 
Those who go to the bother of establishing a standard test bed test bed will know that ground and air are very different whether tone or meter is used.

Then make a second test bed with a row of the same coins (copper or silver) and find how the effect of mineralisation changes the readings. This saves you looking at the albums a few years on and wondering why you have few good or old finds compared to others.

The DFX results were compared on this forum soon after it started and proved discrimination can't be trusted.

Only in the last week or two Nickel I.D. numbers for the MXT were compared.
Results were
Nickel 14 (above is trash.
12 in many areas (average depth)
V's 14
Buffalo's 18
Deep 4-20
Deep 12
On edge different again, depending on degree of tilt, depth and mineralisation.

Then relate the rubbish items that run all over the above target numbers and add that the same variation applies to all target types and that the U.S. coinage supply was so poor during most of the nineteenth century with coins like the gold and silver eagles not being issued for nearly forty years so that foreign coins were used to fill the need (Spanish American being legal tender until 1857) then both private and State small mints were allowed to produce their own coins.

Finally try to take into consideration the effect of damage to the coins surface and that a good patination, that means the coin is going to be more collectable, can also reduce the depth and target reading.
 
While I agree conditions, such as ground and target, can give varying tones and ID's, my point is if a buffalo reads 18 in the ground it most like will read 18 in the air test. If a V reads 14 in the ground it will most likely read 14 in an air test.

Now I'm strictly speaking about my results. It could be that our Kansas soil doesn't have the profound difference in air and ground due to low minerals? In either case, it looks as if I need to do a video showing that my DFX will get the same tones AND VDI in an air test and ground test. I dig coins all the time, especially nickles and rings, that read a dead on 18 to 21 in the ground, and a dead on 18 to 21 in an air test once out of the ground.

A silver dime in the ground WILL read a solid 81-82 in both the air and once out of the ground. Of course I am talking about more shallow targets. Once you get over 5-6" the air test is far more accurate. And I'm not talking about 100% of the time. There will always be that odd target that completely defies the norm. I've dug a few gold rings that read high penny until they were out of the ground, then read in the nickle range. Most were pretty deep in the black muck of a dried up swimming hole.
 
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