Soil depth exceeding air depths on identical targets

Hi Tom,

I've recently read a claim that some types of detectors are capable of responding more deeply on a target in the ground (without reference to ground phase/magnetite BTW) than on the same target in the air. Such targets would include iron as well.

At such times I wish I had an electronics engineering background in order to better evaluate such statements. What do you say? Thanks,

Jim.

Gosh, I'm short on time..... but this is something critical to report upon. A few years ago..... with one of the final proto F75's, I reported this phenomenon to Dave Johnson & John Gardiner, regarding this exact matter. I had detected a 1898 Indian Head penny at a measured 13" depth. In a controlled air-test, the F75 would only detect this exact same coin to 12.1". How/Why did this (is this) phenomenon possible? In laymans terms;

--There were a couple of very tiny (nearly disintegrated) 'pieces'/slivers of a nail just above the IH penny.... maybe approx 3" above the penny. With the F75 pushed to max limits/capabilities.... and in a very critical control panel set-up config...... the F75 reported 'something non-ferrous'. What is happening is the F75's 'squelch' (silent search) is broke.... and the audio circuitry is now open-and-reporting ..... reporting the nail slivers, BUT...... in this same audio carrier..... and riding this audio carrier... is just enough of a non-ferrous detection of the penny (naw that the audio circuitry is gated open)...... so as to report ..... in a 'blurred' audio fashion.... a smeared audio non-ferrous report of the penny. Is the ID correct on the penny with the F75? No,,,, BUT.... at least it can 'see' and report "something non-ferrous". What would other detectors report? Nothing! They would be silently masked. At best... a few of the other detectors might report 'iron'. In head-to-head testing, I have verified/validated/proven this phenomenon, , , time-and-time again. Yes, the F75 is not impervious to being masked & silent masked most of the time ...... but, under certain conditions it'll expose this unique performance. A exacting control panel set-up config is required/mandatory.
In summation, I have never witnessed this type of performance response in my life.... with any detector.

Tom

Thankyou Tom.

Tom, I read over a 105 page report from an independent consortium that claimed greater soil depths over air depths. This allegation did not look right to me. After reading through it, I discovered some key, invalid methodologies as to how the tests were conducted.

I reported my views last night, but I am ever so grateful for your input. We are indeed fortunate to have your experience so readily available to us. When all else fails, by golly it's good to have the common sense that prevails on your forum.

I owe you a debt of gratitude sir.

Jim.

Accuracy/validity is paramount. The methodology in which something is tested can have too many induced variables..... some not quite so obvious. Unbiased honesty is also contingent. I know that I'm not infallible; yet, I like to police my own tests/conclusions. Conclusive analysis is more difficult to ascertain than most would think.

It is the collective concerted efforts of the folks on this very forum that have retained/maintained the highest order-of-magnatude accuracy reporting system. In recognition, Jim, you are 'key' to your own debts-of-gratitude! In highest regard, we thank YOU!

Tom

I found something odd the other day in my test garden.

I have a dime buried at various depths, one at 11" 8" and 6"

The 11" dime is toning in a broken signal, but is telling me it's there.

The odd part is that it will not pin-point. Strange because AM should go deeper than DM?

Try lifting the coil..... invoke the pinpoint...... then bring the coil into the 11" deep dime.