Is it Ever a Good Target When...?

[beepsilver]

I'm accustomed to switching freqs to eliminate bottlecaps. If I'm using 4K and the TDI goes lower when I switch to 8K or 12K, then I know I'm most likely dealing with a bottlecap or iron or ?. My question is, is there ever a keeper (coin) under the coil when the TDI behaves like this, or is it always something for the relic pile?

 

[Ism]

There is the occasion when a nearby target can raise or lower the TID of the target you are actually over.

I have had nearby iron cause the serious increase in TID of coins as well as causing them to show a lower TID than the coin should.
Iron just won't behave in a reliable manner. However a lower conductor non-ferrous target near a coin will lower the TID of the targets to an average of the two.

Of course this phenomenon depends on reactivity, frequency, and target placement. Lower reactivity sees a higher incident of target blending.
Coin spills are a good example of target blending. I do a lot of jewelry hunting so my example is referenced at that TID level.

A zinc penny (85 TID) near a copper penny (91 TID) will generally blend and give a TID of 88-89.
A quarter (95 TID) and a dime (91 TID) will blend to around 93 TID.

I have had nearby iron raise the TID of dimes to 98 and lower them into the high 70's. It's not real common but I have observed the effect often enough to ignore TID on occasion and dig because of the audio.
Sometimes it's a bottle cap or other trash, but I've been pleasantly surprised by a coin in the hole.

So it depends on just how serious the area you are in and whether its just easier to retrieve the target and move on, or to spend time analyzing it and wonder if you were right to walk away.
Most shallow crown caps are easy, but I have had deep silver and copper where I was sure I was going to dig a crown. Something told me to dig.
After that experience, I just do it on those iffy crown caps. Once in a long while it's a coin.

 

[beepsilver]

Ism, thanks for the reply! Everything you said makes perfect sense and I've experienced target blending many times...and as you said, lower reactivity does seem to make it more common. I'm learning to listen for the good tones in those "off" TID numbers to help me make the dig, no-dig decision. Thanks again!

 

[Big Boys Hobbies]

The best discrimination is your shovel. Only way to learn and be positive 100%.

 

[samandnoah]

I wrote some about this recently and the lessons I learned. If the target is shallow (and I mean in the top couple of inches, maybe to 3"), I have never had the frequency switch test fail me. And I have been digging these recently to reestablish a baseline for how I want to hunt my trashy parks. So I still find this to be true for me.

However, once you start getting deeper, I have found the "surety" of this test becomes less valid. As you get deeper, the VDI can and will be off, particularly with other targets in the vicinity and under the coil. I have dug non-ferrous targets that have violated the expected relative readings. That's when audio is your friend. And your shovel, as Bart pointed out.

I'm not claiming any absolutes. I am sharing my experiences, and how I will use the information in my hunting.

Good luck and happy hunting!
Rich