Ever conducted any air-tests....lb

[larrybass]

Here's one for you folks...Ever air-tested your detector?

Seriously, have you ever sat down for say, at least an hour or two, so that you could get to really know your detector? There are many versions of how you should possibly go about that process. I've practised a few myself over the years. That includes testing my 3 machines alone and with three other MD'ing buds with their combined 5 or 6 other MD's which were altogether sampled for these types of tests.

So, anyway, how many of you in here, do or have done, air-testing, to some degree or other? Any comments? Do you perhaps, think that you already know your equipement well enough? Why waste time with air-tests? Well then, don't be shy my friends, post your thoughts and comments in here if you have them. This TNet forum just thrives, to a large degree on a really massive exchange of ideas and feelings and things that we all like to discuss, so keep 'em coming fellow wand swingers, and I repeat, don't be shy about posting or following a thread or starting a kool side-thread of your own too, even, anywhere on the boards 8)

Let's hear what you've got, on this air-testin' stuff then...


LarryB

 

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[U.K. Brian]

I've air tested over 250 machines. Then followed up with an in ground test-bed.
Air tests are not a true test as some machines drop inches in performance when you get out in the field while another that does not test as well will hardly loose any depth.
The big plus is in being able to note down a few easily repeated test results which can be repeated every few months to see if your machine is failing or coil going off tune.

Brian

 

[larrybass]

Hi Brian, thanx for your input. I'm having a slight problem with this part though...

Air tests are not a true test
Brian

First, a true test of what? Second, if it's depth that YOU are talkin' about, then that was not even mentioned in my post, no mention of depth, at all? Even comparing the two (air test vs ground test) is way off topic here. But thanx for tellin' me it's not, anyway. I did after all, ask for input in here, and I'll take whatever folks are willing to toss up on the boards.

I was trying fairly hard there, to get people to focus on getting to know (to some better degree) their own equipement, through some form of air-testing. only! Which, by the way on a side note, makes me wonder why you don't have your detector listed on the side of the page like most members in here do? Most folks that participate on this forum, that I have seen anyway, are quite proud of their make or model and very happy to get a chance to show it off a bit, there. I know I sure get a kick out of pointing out my little ol' Dinosoro! 8)

Anyway, thanx again for posting.

lb

 

[99thpercentile]

I've spent hundreds of thousands of dollars air testing metal detectors used for landmine and UXO detection. The purpose has been twofold, first to determine the repeatability of the sensors as a function of age, amount of use, ambient temperature, ambient humidity, and decreasing battery voltage. The second reason is to collect very high resolution data over known targets such as unexploded ordnance and landmines to use in forward and inverse models. At work we have three test stands for air tests that are all made of pultruded fiberglass. Two of the stands are ten feet tall with eight foot by eight foot platforms and instrumented to control and monitor all of the parameters I mentioned above. The other stand is ten feet tall with a 15 by 18 foot platform. It can control the location of a sensor anywhere above the platform surface while recording its position with millimeter accuracy. Underneath the platform is an elevator system for mounting targets which allow the user to remotely change the height, pitch and yaw of the target. This is a great way to understand the response of your equipment, although out of reach for the hobbyist.

 

[U.K. Brian]

Not a true test of anything except the performance in air on a certain item ,done in a certain way.

Most machines air test deeper if the coin/ring is first swept near the coil so there is an audio response, then gradually moved away. (Rather than miles out then moved nearer).
Also you can't say with a 1900 copper penny or X date silver coin as as little a difference as a nice patina on an older coin affects depth.
With rings you could say X carat, gents ring weighing X amount but then is the gold alloyed with aluminium which would improve the results or perhaps iron (thats used to enrich the colour) where if any discrimination was used depth would be reduced.

Reason I don't say what detector I use is that I detect full time using two main wet beach beach machines, one underwater, one large beach dry/sand. Two top of beach. One main pasture and two plough soil. Most have two coils, some three.
Whats used is according to ground conditions.
Average finds are 12,000-15,000 coins per year, 100 rings, cannonballs, spear/arrow heads, Roman coins, hammered silver etc. Which anyone in Europe can do if there prepared to put the hours in with the right equipment.
When I posted pictures on the 'Friendly Forum', which included in the last six months an extremely rare Greek gold coin plus 89 other gold coins and my share of silver bars (I got ten) I then found many people switched detectors to what I was using though they were not really what was best for their ground/use. I now get several e-mails each week asking what they are doing wrong.

To return to air tests you can't even really decide what sweep speed should be used. Ground effect makes such a huge difference. They will show you have a lemon if you can borrow the same type of detector to compare and most important warn that something is going wrong, most likely a coil going off tune. Your right that people should experiment more but air test results do have to be tempered with what actually happens when several inches of soil is added to the mix.

Brian

 

[larrybass]

Thanks for the post 99thpercentile, a great way to know a machine but, a little out there for our average hobbiests as you mentioned. My tests are WAY easier and anyone with ANY detector, can try some of them out, just for fun, and end up learning much about their machines which they did not know before the air-tests. If I can get a few folks in here to try what I've been talking about so far, then I can go on and offer a few variations to add to the ways the machine is being tested now. It can, I repeat, be lots of FUN. Just to keep it simple though to start, forget anything at first, about the depth factor in your first tests. It's metal I.D we are interested in here! What does your machine think a certain object is? Etc Etc.

Brian, thank you for clarifying a few points. This whole topic, posted anywhere MD's are talked about, could easily turn into a fairly complicated subject, but for me that takes the fun out of it. My original reason to post here was to try and encourage others who had not done any air-testing yet, to do so. My way of getting them, more into their machines. A fun way to learn about really getting into something. The cheapest detector ever sold, could entertain a little group of poeple anywhere using only air-tests, provided it was being operated and demonstrated by a man who knew it inside out and backwards. 8) The same machine in the next 10 peoples hands just becomes a bad joke that some how doesn't seem to work at all.

It's been said many times before but it's worthwhile saying here again, because it totally applies in the little scenerio outlined above. Knowledge is the key to success!

Exanimo!

Lb