HOW DO I GET MORE DEPTH IN MINERALIZIED SOIL

[JOHNL]

I WOULD LIKE SOME IDEAS ON HOW TO GET MORE DEPTH WITH MY METAL DETECTOR OR ANOTHER EVEN DOWN LEVEL DETECTOR..
I HAVE BEEN METAL DETECTING FOR COINS ON & OFF SINCE 1974
BEEN USING A MINELAB XS FOR ABOUT 5 YEARS NOW. OVERALL A GOOD MACHINE BUT IN SOME SOILS I CANNOT GET SUFFICIENT DEPTH. I KNOW THAT IN SOME OLD PARKS THERE ARE A FAIR AMOUNT OF BARBER & SEATED DIMES. TROUBLE IS IN SOME MINERALIZIED (?) SOILS I HAVE TO OPERATE THE SENSITIVITY AT 10 OR LESS IN ORDER TO MAINTAIN A TONE. 10 OR LESS LIMITS ME TO ABOUT 4-5 INCH DIMES. SO THE MINELAB IS NOT THE ANSWER.
I'M FURTHER PERPLEXED BECAUSE I HUNTED THIS SAME FAIRGROUNDS IN THE 1970'S WITH A TR MACHINE OPERATING AT 50-100 KH & GOT GOOD DEPTH ( 10 INCHES FOR BARBER QUARTERS). SO, I THOUGHT THIS FAIRGROUNDS TO BE FAIRLY MINERALIZATION FREE.
TODAY IN THAT SAME FAIRGROUNDS, THE MINELAB XS CAN ONLY OPERATE AT A SENSITIVITY OF 10 & HAS LESS DEPTH CAPABILITY THAN THE 1974 WHITE'S COINMASTER TR ??
ALSO , THE MINELAB XS SENSITIVITY HAS TO BE REDUCED A GREAT DEAL THE CLOSER I GET TO A HOUSE WHEN I AM HOUSE HUNTING ?
I FEEL THERE ARE A LOT OF OLD COINS IN SOME PARKS,ETC. BUT WHAT MACHINE WILL DO THE JOB?
JOHN

 

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[X-Terra70_TreasureHunter]

John Get a Double D coil they work better than the stock
coils in mineralized ground

 

[George (MN)]

Possibly part of the problem is more electrical noise in most areas? Mineralized ground for sure will reduce depth & throw off target ID. I must have some of the worst ground there is, highly variable. I've never got a coin below 7" & most areas can't get a consistent correct ID beyond 4", ifthat deep.

Some of the new detectors have more sensitivity, but this may cause more false signals. One thing that is very important on some newer detectors is to have the coil wire wrapped tight around the lower rod & nake sure the coil connector is pushed in all the way.

For my soil with the highly variable mineralization, what works best is what I stupidly got rid of: a detector that has ground track & lock & a 12.5" concentric coil. But the DD may be better in consistently high mineralization. Some numbers displayed on detectors about ground characteristics are not really intensity of ground minerals, but they read type of ground minerals.

Someone who probably knows more than me said to measure intensity of ground minerals, start with the detector at waist height & set for a threshold tone. Then lower the coil, & the sooner the tone gets stronger or weaker, the more intense your ground minerals are.

Maybe your ground is like mine & the answer is still in the future. HH, George (MN)

 

[Reg]

Getting a DD coil may help, but the answer lies in what is happening. As a general rule, the ground signal adds to the target signal resulting in a new signal that doesn't act like the original target response. In many areas, this shift or offset has a tendency to cause the target signal to increase on a TID detector. In other words, a deeper dime may read as a quarter or even as high as a dollar.

Now, what happens is this shift continues the deeper the target, so at some point, it shifts past the dollar up into limbo.

Many years ago, I showed this to a guy using a Whites TID unit that could program in or out a wide range of targets. We buried a dime and at about 6" the dime shifted out of range and was no longer detected as a good signal in the disc mode. It was still there and could be heard in the VLF all metal mode, but it was ignored in the disc mode.

Now, I had the guy turn on the hotrock reject signals, the highest positive numbers and the -96 and a couple more if I remember. This all occurred around 1990 so my memory is a little fuzzy. Anyway, with a few more numbers programmed in, the dime came through as a good signal again. The result was there was a gain in depth of close to an inch.

The guy kept arguing with me that I was detecting the dime as a hotrock. I tried to explain what was happening but to no avail because he had "read it somewhere that the higher number and lowest negative numbers were hotrocks even though he saw the results with his own eyes.

Yes, there was a chance that some rocks would now generate a response, but that response generally would be easy to determine. Besides, only metal targets would give a positive response in the all metal mode and then in the added disc area. So, using a little common sense, one could gain some depth using this method.

A few years back, George Payne utilized this concept in modifying a chip for his Discovery units that would take advantage of this technique. The result was an additional depth capability. For those of you interested in some of the technical aspects, here is a link to some information posted by George Payne a few years back.

http://jb-ms.com/Baron/

You may have to wait a little before all of the info is available since it seems to take a while to fully download some of the time. The article on ground balance and coils as well as Id meters are excellent articles. Actually, most everything George writes is excellent.

For those of you unfamiliar with George Payne, is the guy who designed the first VLF (while working for Whites), VLF discriminator (the Red Baron while at Bounty Hunter), first TID (while at Teknetics), first audio ID, first with surface blanking, first with notch (again, while at Teknetics) and actually designed the first auto ground balance backin the 80's. A modified version ended up as a push button ground balance on early models.

Reg