Just how useful are air tests with the X-70?

[Ancient Dave]

I have a X-70 which I got just before the snows come so I only have 9 hrs. swing time on it. I've had some good success so far, an 1888 5 cents, thanks to this forum and the FAQFAQ section. It's simply the best X-70 resource anywhere.....period.
I've been doing some air tests on coins and various objects and was surprised on some of the results. A flat coin ID'd as expected but I also air tested all the coins on edge to see what I would get.
Surprisingly many of the coins on edge ID'd as -6.

I do plan to repeat the tests with all items buried 4" once the snow is gone but still I was surprised. These coins were Canadian.

So does air testing have any value?

Thanks,
Dave

 

[khouse]

Where did you have your GB on the air tests? Where was the sensitivity set? How fast were you waving your targets across the coil? I manually set the GB at #45 for any air test. Also you must be away from your wireless anything. Also stay away from fluorescent lights.

 

[nero_design]

I think any target is capable of giving different ID readings based on the angle you approach it.
From memory, the manual for the X-Terra 70 recommends approaching any target twice during scanning
... the second scan being at a 90 degree angle to the last pass. Air tests are to me, form a kind of "Ideal Probability" scale for the user.

This was one of the first things taught to me by a detectorist when I was first looking into the hobby
and he said that any target should be approached from a different angle to ensure a good signal was received.

I think air tests can show the capability of a coil/detector by showing the size of object one can detect with
the coil in question. It can also show a fairly consistent ability to descriminate between objects based on their
metal content. Since so many objects are found on the top of the soil, air tests are useful in my opinion.

Reaching down with some degree of depth is going to depend on the abilities of the detector used.
As long as your coil can penetrate the soil, you should be able to at least get an ID.
Many Prospectors are advised to approach a target from different angles because even though the object
might be large (think of something like a wallet), the thin, narrow edge is going to give you a different value compared
to a wide, flat edge if the target is lying flat and exposing more surface area to the coil's signal.

Something I do when prospecting is dig my first Junk target for the day, remove it from the ground - and then place a smallish nugget into the hole attached to a thread (so I can find it quickly when I'm done). I pat down the soil and then do a re-scan with the detector. This tells me how the signal will likely sound if I come across a similar item of a similar size in that type of soil. I know, it's odd. But it works for me. I have to consider different depths, soil types and target sizes which all have different values to the detector.

When detecting coins, there's so many angles to consider that a coin might be buried in - coupled with so many coin variants, that the ID is really a "Likely Estimate".

So the air test is probably a good way to learn "Likely Target Values". Add a little leeway and I imaging that this is pretty handy. Most users hunting coins seem to be able to use the ID system with a consistent degree of success.

 

[Elton]

Like randy says dig it all..never miss anything

 

[Digger]

IMO, airtests with the X-Terra 70 are no better or worse than with any detector. But I believe they do have a value.

I don't use airtests to compare detectors of a different make or model. But, I will use airtests to analyze the operational characteristics of two identical detectors, using the same coil. Or compare two different coils on one detector.

I don't use airtests to determine depth of detection on specific targets. Too many "influences" in the dirt.

I did use airtests to determine a generalized coin TID chart, such as the one I have posted here in the past. But note that different coils may provide different numbers.

I use airtests to better understand separation characteristics. But I don't rely on those results to hold true "in the dirt".


Speaking of different TID numbers............... next time you find a ring whose band is broken (separated), sweep it under the coil and see what TID number you get. Now, press the two broken ends together and sweep it under the coil again.............. Hard to believe it is the same ring, isn't it?

HH Randy

 

[jackintexas]

Hey Elton: I neither have the time or the back to dig it all....Jack

 

[Elton]

n/t