Quote:
Originally Posted by Fred
Hi Qiaozhi,
I agree that is very likely, but you cannot completely rule out that if there is some (let´s call it) halo effect, holding a metallic coil or whatever above ground at a particular and regular height on edge of detection may detect it...
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Hi,
yes, we talk about that, I remember the "halo" issue well.
Though I think the so called "halo" really exist and not only for ferrous items, long time buried... cause had experiences that cannot be easy explained not considering that kind of effects.... I must say that the idea of PD detecting a supposed "halo" of e.g. a coin from meters far is pretty unrealistic.
That's cause we found no connections happens at long range, the device seems work (as a normal MD) in the short range only, unless a very (BUT VERY) big object is in front of it... in which case is not impossible reading a detection also at 4-5meters away... that's the case of very large (several square meters) conductive objects, usually big iron doors, when disc work not properly.
It's halo ? No. The square meters of a large door can be detected also by other kind of sensitive MDs... expecially PIs, I must say that the fact an old off-resonance MD design can do that doesn't surprised me much at that time.
My last idea of PD is that is a bit of black magic + some old style electronics.
Why black magic ? Easy: it's the unexplained there... the broadband receiver is there just cause the general idea is, like in the goldgun stuff, detecting the presence or absence of some radio signal, with undefined frequency or subject to frequency shifts.
If you ask about if the PD works or not... you'll better ask yourself if the goldgun could ever work.
For me it's clear that will not work... but others seems still think that the goldgun "principle" as the right way to the promised land of working LRLs.
Kind regards,
Max