Easy targets?

Here's the scenerio. While rehunting sites I pick up coins on occasion that only read good from one direction of approach. This is usually in the springtime but can occur regardless if there was a deep frost the previous winter or not.

Now when checking the dirt pile/dirt clod in all metal which I always do because of the amount of iron co-located targets at these type sites, on the coins in question there is no manmade iron object present. So what causes the coin to be detectable from only one direction? I have noted this where the coins impression in the dirt indicated it was laying flat in the ground and also when only on a slight angle to the coil. Could there have been some very small bit of iron adjacent to the coin that would not signal on the detector? The coins are typically at depths that should be no problem in my ground (5-7" deep). I have seen it happen with Fishers and also with Minelab detectors.

Any thoughts?

Tom

Moisture Activated "Directional" Silent-Masking.


Painfully common occurence. Doesn't even require a man-made iron/steel (or non-Ferrous) object in close proximity to achieve. A small clump of decay'd natural Fe just barely off to one side of desired non-Fe target will cause this. If ground is bone-dry..... you may detect coin from both/all directions. If ground has higher moisture content....the Fe will become more electromagnetically 'sensitive'.....activated enough to "Silently Mask" good target from one (or more) sweep directions. ...... I demonstrated 'Silent Masking' on DVD. What I really wanted was to demonstrate 'moisture activated directional silent-masking'..... but could not find a way to discretely control percentage of ground moisture for a regulated test/demonstration.

Signed,

Mumbo-Jumbo

Come on up here within the next couple weeks with your camera and I'll put you over a couple of those targets. LOL I forgot to mention these are usually copper pennys/IH's and have a thick moist green patina that comes off very nicely leaving good looking coins underneath (usually).

Thanks for the reply MJ. That makes sense since the ground is evenly damp from the winter thaw and after the natural decaying effect winter has on ground minerals. Good for the plants and grasses but not so good for detecting!

Tom



Edited 1 time(s). Last edit at 03/25/2007 11:01AM by Jackpine.