Coil Field Dynamics, & Three Factors That Determine Unmasking Ability (More Than One Way To Skin That Cat)

I wrote this series of posts that sort of relates to the excellent "Beneath The Mask" article by Thomas Dankowski and further explains why something even as small as that staple (like he said) can block a detection field. It also goes into other aspects of masking and unmasking ability that govern how well detectors and coils do in those respects. This is also why I have serious doubts about the new Minelab's ability to "see" two targets in the field at the same time, and my money (maybe I'm wrong...need to see more) is on this being just a prior target history. Everything I've ever read on the technical aspects of detection fields and the natural unchangeable physical laws that govern them tells me that seeing two targets at once (which is impossible from everything I've ever read, unless they are at the same depth and so close they are overlapping) and IDing them separately is impossible. For that reason I'll have to see some pretty hard proof that says these seemingly static laws of nature can be even bent, let alone broken. The detection field stops with the shallowest/first metal object it sees, and has no ability to reach further and see something else at the same time. Ask yourself this...If this machine does indeed have some new outstanding breakthrough in separation or unmasking abilities then why the need for a 6" coil? And why did Minelab word it so vaguely that it could mean several different things, rather than boldly and clearly proclaiming just what these new abilities are? I'm still considering this machine but with great claims comes the requirement of great proof. If it can out-do another Minelab using a good aftermarket coil in terms of depth and separation then MAYBE it'll be worth that kind of money to me, but if there isn't a clear and bold advantage in depth or separation compared to say a GT, Explorer, or Etrac using a good deeper/better separating coil such as the 12x10 then I'm not biting.

Three Factors That Determine Unmasking Ability (After Tests)

[www.detectingequipment.com]



Edited 4 time(s). Last edit at 05/31/2012 04:21PM by critterhunter.

These have been my exact (quietly reserved) thoughts about the 3030.

Also........... extremely enhanced 'adjacent' target separation.............. is NEVER to be confused with 'unmasking'.

I could write hours worth of data on this exact topic........... but would waste time...due to speculation. Why speculate........ when scientific testing will prove otherwise......... thus....... any writings would THEN be expended fruitfully on real 'hard evidence' data.

Yep.

I also read Tom’s article, and had to give it a try with the E-trac. Couldn’t find a staple, so I used a medium sized paperclip, (one that’s strongly attracted to a magnet) cut and shaped it like a staple. Using a rectangular search pattern, the coin was detected at 2 locations around the paperclip, but was masked when the coil was directly over the paperclip. The conclusion was that the iron did override the coin’s signal at that depth, but when the coil was directly over the iron.
With previous finds, when iron was a few inches above (directly above or at an angle above) a detected coin, the coin was almost always pinpointed at an angle away from the iron. The E-trac can detect targets below iron, but usually at an angle opposite to the iron.

The 2 most impressive targets near iron finds I’ve made so far was a 10+ inch deep quarter lying directly on top of a 5” long rusted nail/spike lying parallel to the coil, in the wet sand of a saltw@ter beach. After something like that, you’d be impressed. The 2nd find was a nickel size piece of lead inside of a ½ inch shell of rusted iron (all the iron had rusted away). Although the ferrous value on the E-trac was 35, it picked up the 09 conductive value of the lead disk. Confirming that in heavily iron rusted saltw@ter areas, the ferrous value jumps up to the 30s on non ferrous targets at depth, while the conductivity value increases only slightly, if at all.
Unfortunately, the E-trac is the only detector that I have used for more that a few weeks, and can’t compare it to other detectors, and can only cite from personal experiences.

I believe that seeing 2 different targets while sweeping back and forth is possible. If you’ve ever detected one target while sweeping left to right, and then detected another while sweeping right to left, and recovered 2 targets very close together, you can begin to understand one possibility of how target trace keeps track of 2 targets under the coil. Also the E-trac responds to the strongest signal only, while target trace records multiple targets under the coil. I believe that sweeping back and forth over multiple targets allows this capability.

Remembering back when the SEF coils were hitting the scene , the 10 x 12 and the 12 x 15 were used a lot .....One attribute that the SEF coils were known for was that they were GREAT coils for finding coins that were on end as their ability to read targets horizontally was quite good !!..... I don't know enough about the newer coils that are on the 3030 to make any judgement call , but I , like Critter , would really like to see how the screen looks when 2 targets are being read, and even more , I would like to hear what it sounds like when the two targets are close together ...... Will they average the numbers out like a Soveriegn , or will they read 2 different numbers ? .....Will they show 2 different colors if the targets are Ferrous and Non Ferrous ? ....... As I said in an earlier thread , if the 3030 does not do a marketably better job with masking than the E Trac does , it's really of no use to me ...... Jim